Scholarly article on topic 'Effects on respiratory system due to exposure to wheat flour'

Effects on respiratory system due to exposure to wheat flour Academic research paper on "Clinical medicine"

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Abstract of research paper on Clinical medicine, author of scientific article — Adel Mohammed Said, Eman Badawy AbdelFattah, Abd-Almonem Mohsen Almawardi

Abstract Background There is growing consensus on the deleterious effects of organic dust on respiratory symptoms and function of industrial workers. Flour dust is widely incriminated to cause impairment of lung function. Exposure to flour dust occurs across a range of food industries including grain mills, flour mills and bakeries. Aim of work To assess the effects of exposure to flour dust on respiratory symptoms and lung function of bakery workers at a number of bakeries in Cairo. Subjects and methods The study was conducted on 30 bakery workers working at bakeries in Cairo state, the cases matched for age, sex, and height. All bakery workers participated in this study were subjected to following: Full medical history taking, Thorough clinical examination, Routine laboratory investigation, BMI was calculated, Chest X-ray, Spirometric lung function test, Diffusion capacity for carbon monoxide (DLCO), Further proper radiological assessment using CT scan for cases that show abnormalities in their chest X-ray or DLCOSB. Results All workers included in the study were males. The age of the flour milling workers ranged between 14 and 56years. They worked at least for 10h per day for 6days per week for total working years ranged between 2 and 30years. This study reported that there was an increase in respiratory symptoms among bakery workers due to exposure to wheat flour. Also, 16.6% of the studied population had abnormal spirometry compared to the reference value, 30% had abnormal diffusion capacity of lung to carbon mono-oxide compared to reference value. Nine participants underwent HRCT chest as their DLCOSB has shown diffusion defect, 5 (55.6%) of them have normal HRCT chest and 4 (44.4%) of them have interstitial changes. Conclusions Exposure to wheat flour increases the risk of developing respiratory symptoms; it also causes reduction in the pulmonary function parameters, as regards spirometry and DLCOSB. Exposure to wheat flour causes interstitial lung disease as detected by HRCT chest. Smoking augments the wheat flour induced lung disease.

Academic research paper on topic "Effects on respiratory system due to exposure to wheat flour"

Egyptian Journal of Chest Diseases and Tuberculosis xxx (2017) xxx-xxx

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Egyptian Journal of Chest Diseases and Tuberculosis

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Effects on respiratory system due to exposure to wheat flour

Adel Mohammed Saida, Eman Badawy AbdelFattah a'*, Abd-Almonem Mohsen Almawardi

a Faculty of Medicine, Ain Shams University, Cairo, Egypt bAbbassia Chest Hospital, Cairo, Egypt

ARTICLE INFO

ABSTRACT

Article history: Received 9 August 2016 Accepted 20 November 2016 Available online xxxx

Keywords:

Wheat flour

Mills workers

Pulmonary functions

Computed tomography of the chest

Background: There is growing consensus on the deleterious effects of organic dust on respiratory symptoms and function of industrial workers. Flour dust is widely incriminated to cause impairment of lung function. Exposure to flour dust occurs across a range of food industries including grain mills, flour mills and bakeries.

Aim of work: To assess the effects of exposure to flour dust on respiratory symptoms and lung function of bakery workers at a number of bakeries in Cairo.

Subjects and methods: The study was conducted on 30 bakery workers working at bakeries in Cairo state, the cases matched for age, sex, and height. All bakery workers participated in this study were subjected to following: Full medical history taking, Thorough clinical examination, Routine laboratory investigation, BMI was calculated, Chest X-ray, Spirometric lung function test, Diffusion capacity for carbon monoxide (DLCO), Further proper radiological assessment using CT scan for cases that show abnormalities in their chest X-ray or DLCOSB.

Results: All workers included in the study were males. The age of the flour milling workers ranged between 14 and 56 years. They worked at least for 10 h per day for 6 days per week for total working years ranged between 2 and 30 years. This study reported that there was an increase in respiratory symptoms among bakery workers due to exposure to wheat flour. Also, 16.6% of the studied population had abnormal spirometry compared to the reference value, 30% had abnormal diffusion capacity of lung to carbon mono-oxide compared to reference value. Nine participants underwent HRCT chest as their DLCOSB has shown diffusion defect, 5 (55.6%) of them have normal HRCT chest and 4 (44.4%) of them have interstitial changes.

Conclusions: Exposure to wheat flour increases the risk of developing respiratory symptoms; it also causes reduction in the pulmonary function parameters, as regards spirometry and DLCOSB. Exposure to wheat flour causes interstitial lung disease as detected by HRCT chest. Smoking augments the wheat flour induced lung disease.

© 2017 Production and hosting by Elsevier B.V. on behalf of The Egyptian Society of Chest Diseases and Tuberculosis. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/

licenses/by-nc-nd/4.0/).

Introduction

Occupational lung diseases are a group of illnesses that are caused by either repeated, extended exposure or a single, severe

Abbreviations: BMI, body mass index; HRCT, high resolution computed tomography; COPD, chronic obstructive pulmonary disease; DLCO, diffusion capacity of the lung to carbon monoxide.

Peer review under responsibility of The Egyptian Society of Chest Diseases and Tuberculosis.

* Corresponding author. E-mail addresses: adelsaid60@hotmail.com (A.M. Said), emanbadawy2006@ yahoo.com (E.B. AbdelFattah), dr_abdo97@hotmail.com (A.-A.M Almawardi).

exposure to irritating or toxic substances that leads to acute or chronic respiratory ailments [1].

Occupational diseases are caused by a pathologic response of the patients to their working environment [2]. There is growing consensus on the deleterious effects of organic dust on respiratory symptoms and functions of industrial workers [3]

Many studies have shown that flour dust exposure causes respiratory symptoms and is associated with impairment of lung function [4]. A threshold limit value of 0.5 mg/m3 of flour dust were proposed in 2009 by the American Conference of Governmental Industrial Hygienists (ACGIH) as the occupational exposure level (OEL) in breathing zones for workers in flour mills [5].

http://dx.doi.org/10.1016/j.ejcdt.2016.11.006

0422-7638/® 2017 Production and hosting by Elsevier B.V. on behalf of The Egyptian Society of Chest Diseases and Tuberculosis. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Flour dust is widely incriminated to cause such effects. Exposure to flour dust occurs across a range of food industries including grain mills, flour mills and bakeries. Wheat flour is a complex organic dust with a large diversity of antigenic or allergenic components. The antigens involved can be wheat flour proteins, flour parasites or technical additives [3].

Wheat flour consists of water-soluble albumins, salt-soluble globulins, gliadins and glutens. Albumins and globulins appear to be the most important proteins contributing to immediate hyper-sensitivity reactions to wheat proteins [6].

Flour dust is an asthmagen and is known to cause sensitization, allergic rhinitis and occupational asthma amongst bakers and millers [7].

Flour dust can also act as an irritant and may give rise to short-term respiratory, nasal and eye symptoms, or it may provoke an asthma attack in individuals with pre-existing disease. In the UK, for example, flour and grain dust are the second most commonly cited agents associated with occupational asthma [8].

The respiratory effects of exposure to flour dust are influenced by the dose and duration of exposure [9]. And these differ from one work environment to another. Therefore, it may not be correct to extrapolate the results of studies conducted in a different environment to our bakeries [10].

Unhygienic conditions are observed in the workplace environment of flour mills as fine organic flour dust gets airborne in the indoor environment of the flour mills. The results of previous study show that flour mill workers are receiving a heavy dose (average exposure concentration, 624 ig/m3) of flour dust, to determine the impact of flour dust on the lung function of the workers spirometric analysis was conducted. Significant declines in forced vital capacity (FVC), peak expiratory flow rate (PEFR) and forced expiratory volume in one second (FEV1) were observed. The analysis of questionnaires reveals that most of the workers were suffering from asthma and respiratory problems. This previous study recommends the compulsory use of personal protective equipment (nose mask) by flour mill workers during working hours. This would help to protect the workers' health from the flour dust prevalent in the workplace environment. A regular periodic examination is necessary to measure the impact of particulate matter on the health of the flour mill workers. The flour dust particles easily enter the respiratory tract of an exposed person. These particles attach to the inner wall of the respiratory tract and disturb the process of inhalation and exhalation of air. The inner cell wall of the respiratory tract does not accept the foreign particles (flour dust), causing a slight irritation in the respiratory tract which is the primary symptom of respiratory disorder [11].

Patients and methods

Study population

The study was conducted on 30 bakery workers working at bakeries in Cairo, the cases matched for age, sex, and height, these bakeries workers worked for at least 8-10 h a day for 6 days per week, without using any self-protective measures.

Exclusion criteria

1. Bakery workers with skeletal abnormalities, neuromuscular

diseases.

2. Known cases of bronchiectasis or asthma.

3. Subjects with morbid obesity.

4. Subjects with abnormalities of RBCs.

Study tools

All bakery workers participated in this study were subjected to following:

• Full medical history taking:

Asking all participate about age, marital status, residence and if smoker or not, Smoking index was calculated for every subjects.

The participants were asked about history of any chronic disease including chest disease and tuberculosis, drug allergy and surgical intervention. Work related history obtained as regards numbers of working hours per day, numbers of working days, and total period of working in bakeries, also if there was another work before and if there is another work beside.

Amount of exposure to wheat flour differ according to nature of working in bakeries, so we divide our participants into to 2 groups:

Before dough making: for example, Flour room staff, sweeper, and bagging; as heavy exposure participants.

After dough making: for example, oven worker, dough making; as light exposure participants [12].

They were asked about upper respiratory symptoms including sneezing, rhinorrhea and change of voice, and asked about lower respiratory symptoms including cough, expectoration, shortness of breath, coughing blood, wheezy chest and chest pain and if there is any relation to working hours.

• Thorough clinical examination:

General and local examination of all body systems on emphasize of the respiratory system were carried out for all participants.

• Routine laboratory investigation:

Complete blood picture, serum urea, serum creatinine, liver enzymes and random blood sugar was investigated.

• Body mass index:

Weight and height was measured and BMI was calculated for all participants.

• Chest X-ray:

PA Chest X-ray was done for all participants

• Spirometric lung functions test:

The maneuver was explained to each subject, Spirometry was performed for all participants, the measured parameters were: forced vital capacity (FVC), forced expiratory volume in one second (FEV1), forced expiratory ratio (FEV1/FVC%) and forced expiratory flow (FEF) at 25%, 50% and 75%, of FVC (FEF25%, FEF50%, and FEF75%, respectively).

The test was performed with the subject in sitting position using a nose clip. The test was repeated three times after adequate rest and results were obtained in the spirometry. The results of spirometry were ex-pressed as percentages of the predicted values according to current guidelines.

• Diffusion lung capacity for carbon monoxide (DLCO):

The maneuver was explained to each subject, the single-breath diffusing capacity test was performed for all participants.

The test is performed by having the subject blow out all of the air that he can, leaving only the residual lung volume of gas. The

person then inhales a test gas mixture rapidly and completely, reaching the total lung capacity as nearly as possible. This test gas mixture contains a small amount of carbon monoxide (usually 0.3%) and a tracer gas that is freely distributed throughout the alveolar space but which doesn't cross the alveolar-capillary membrane. The test gas is held in the lung for about 10 s during which time the CO (but not the tracer gas) continuously moves from the alveoli into the blood, then the subject exhales.

Further proper radiological assessment for cases that shows abnormalities in their chest X-ray or DLCO.

• High resolution computed tomography for chest was performed for only participant that shows any abnormalities in their chest X-ray or DLCO.

Results

Table 2

Work history distribution of the study population.

History of working Statistics

No. of working hours/day Range (Mean ± SD) 12(12±0)

No. of working days/week Range (Mean ± SD) 6 (6 ± 0)

No. of total working years

Range (Mean ± SD) 2-30 (12.97 ± 7.65)

Other work before

Yes 2 (6.7%)

No 28 (93.3%)

After or before dough making Before 8 (26.7%)

After 22 (73.3%)

N.B After dough making: light exposure to wheat flour

Before dough making: heavy exposure to wheat flour

A total of 30 workers were included in this study, exposed to flour dust in the work place without any protective equipment. All workers included in the study were males. The age of the flour milling workers ranged between 14 and 56 years with a mean of (29.5 ± 9.98) years. They work at least for 10 h per day for 6 days per week for total working years ranged between 2 and 30 years with a mean of (12.97 ± 7.65).

Table 1 shows that the age of the bakery workers ranged between 14 and 56 years with a mean of (29.5 ± 9.98) years, half of them were smoker, seven of them were single, and five of them had history of surgical operation.

Table 2 shows that participants in current study worked at least 10 h per day for 6 days per week for total working years ranged between 2 and 30 years with a mean of (12.97 ± 7.65), two of them had a different work before working in bakeries, first one worked as flowers vendor and the second as cars repair worker.

Table 3 shows that only 3 subjects suffered from upper respiratory symptoms while 19 had Lower respiratory symptoms and only 7 subjects suffered from work related symptoms.

Upper respiratory symptoms in the form of sneezing, rhinor-rhea, change of voice, Lower respiratory symptoms in the form of cough, expectoration, chest wheeze, dyspnea and Work related symptoms means symptoms that developed during working hours and improved by leaving the work.

Table 4 shows that body mass index ranged from 19 to 40 with a mean of (25.4 ± 5.6), all of them have normal blood pressure, normal respiratory rate, normal heart rate, normal temperature, normal complex, and not diabetic.

Table 1

Demographic data distribution of the study population.

Table 3

Symptoms distribution among the study population.

Demographic Data Statistics

Age (years)

<40 years 24 (80%)

>40 years 6(20%)

Range (Mean ± SD) 14-56 (29.5 ± 9.98)

Smoking

Smoker 15 (50%)

Non-smoker 15 (50%)

Smoking index 20-700 (339.33 ±219.17)

Marital status

Single 7 (23.3%)

Married 23 (76.7%)

History of surgery

Yes 5 (16.7%)

No 25 (83.3%)

Data are expressed as mean ± SD for parametric data. Data are expressed as frequency and percentage data.

Symptoms

Upper respiratory symptoms

Lower respiratory symptoms

Yes 19

Yes 20

Expectoration

Yes 19

Chest wheeze

Dyspnea

Work related symptoms

90.0 10.0

36.7 63.3

33.3 66.7

36.7 63.3

96.7 3.3

86.7 13.3

76.7 23.3

Table 5 shows that as regard local examination two subjects revealed harsh vesicular breathing, two revealed rhonchi, and three revealed crepitations.

Table 6 shows that none of participants in the current study had abnormality as regard renal function, hemoglobin, Random blood sugar, Total leucocytic count, Platelets. Only one had abnormal liver enzymes.

Table 7 shows that 16.6% of study population have abnormal pulmonary function as regard spirometry compared to the reference value, one subject showed restrictive pattern, three of subjects showed obstructive pattern, one subject showed mixed pattern, and four subjects showed small airway affection.

Table 8 shows that nine subjects (30% of study population) had abnormal pulmonary function as regard diffusion capacity of lung to carbon mono-oxide compared to reference value.

Only one participant had abnormal chest X-ray while the nine participants with diffusion defect underwent HRCT chest, 5 (55.6%) of them have normal HRCT chest and 4 (44.4%) of them have interstitial changes (Table 9).

Table 10 shows statistically significant increase between <40 years workers group and >40 years workers group as regard

Table 4

General examination distribution among the study population.

Table 6

Laboratory data distribution among the study population.

General examination Statistics

Body mass index Range (Mean ± SD) 19-40 (25.4 ± 5.6)

BMI [kg/(ht)2] Normal weight Overweight Obesity 15 (50%) 9(30%) 6(20%)

Systolic blood pressure Range (Mean ± SD) 90-140 (115.7 ±12)

Diastolic blood pressure Range (Mean ± SD) Normal blood pressure 60-90 (75.7 ± 30 (100%) 7.7)

Respiratory rate Range (Mean ± SD) Normal Respiratory rate 14-18 (16.2 ± 30 (100%) 1.3)

Heart rate Range (Mean ± SD) Normal Heart rate 70-100(82.8: 30 (100%) ±7.7)

Temperature Range (Mean ± SD) Normal Temperature 36.8-37.2 (37 30 (100%) ±0.1)

Complex - No. (%) No 30 (100%)

*(BMI) Body mass index.

Table 5 Local examination distribution among the study population.

Local examination No. (%)

Limited movement No 30 (100%)

Skin abnormality No 30 (100%)

Position of trachea Central 30 (100%)

Tenderness No 30 (100%)

Type of breathing Normal HVB 28 (93.3%) 2 (6.7%)

Ronchi No Yes 28 (93.3%) 2 (6.7%)

Crepitations No Yes 27 (90%) 3 (10%)

Clinical signs No Yes 26 (86.7%) 4 (13.3%)

lower respiratory symptoms, the rest have insignificant statistical difference, using Chi-square test with p-value <0.05 S.

Table 11 shows statistically significant difference between <40 years workers group and >40 years workers group as regard mean FVC (B/P) being higher in the <40 years workers group, the rest have insignificant statistical difference.

Table 12 shows statistically significant difference between smoker and non-smoker as regard lower respiratory symptoms, the rest have insignificant statistical difference.

Table 13 shows statistically significant difference between smoker and non-smoker as regard FEV1 (B/P) and FEV1/FVC, and the presence of interstitial changes in HRCT chest, the rest have insignificant statistical difference.

Laboratory data Statistics Range (Mean ± SD)

Serum urea Normal 15-40 (27.5 ± 7.9) 30 (100%)

Serum creatinine Normal 0.4-1.2 (0.8 ±0.2) 30 (100%)

SGPT Normal Abnormal 15-126 (31.4 ±20.7) 29 (96.7%) 1 (3.3%)

SGOT Normal Abnormal 10-70 (33.6 ±13.2) 29 (96.7%) 1 (3.3%)

Random blood sugar Normal 80-160 (104.9 ± 19.6) 30 (100%)

Hemoglobin Normal 11.4-15 (13.3 ±1.1) 30 (100%)

Total leucocytic count Normal 4-11.2 (7.6 ±2.2) 30 (100%)

Platelets Normal 155-470 (306.8 ± 89.6) 30 (100%)

*SGPT (serum glutamic-pyruvic transaminase). *SGOT (Serum glutamic oxaloacetic transaminase).

Table 7 Spirometric data distribution among the study population.

Spirometry Statistics

FVC (B/P) Range (Mean ± SD) 73.4-123.1 (98 ±13)

FEVI (B/P) Range (Mean ± SD) 59-134.3 (96.3 ± 16.1)

FEVI/FVC Range (Mean ± SD) 57.2-99.1 (83.5 ± 10.4)

MMEF (B/P) Range (Mean ± SD) 35.9-195 (87.7 ±33)

Interpretation of spirometry Normal Obstructive Restrictive Mixed Associated small airway affection 25 (83.3%) 3(10%) 1 (3.3%) 1 (3.3%) 4(13.3%)

*FVC (forced vital capacity). "FEV1 (forced expiratory volume in one second). *FEV1/FVC (forced expiratory ratio). *MMEF (maximum midexpiratory flow).

Table 8 DLCOSB parameter among the study population.

DLCOSB Statistics

DLCOSB Range (Mean ± SD) 59.8-116.2 (89.64 ±13.02)

Interpretation of DLCO(B/P) Normal Mild Moderate 21 (70%) 8 (26.7%) 1 (3.3%)

DLCO (Diffusion lung capacity for carbon monoxide). *DLCOSB (Diffusion lung capacity for carbon monoxide single breath).

Table 9

Chest imaging distribution of the patients.

Chest imaging No. %

Chest X-ray

Normal 29 96.7

Abnormal 1 3.3

HRCT chest

Normal 5 55.6

Interstitial changes 4 44.4

*HRCT (High resolution computed tomography).

Table 14 shows that there is significant statistical difference between working before and after dough making as regard DLCOSB in a group of smoker being lowered in the group working before dough making.

Table 15 shows no statistically significant difference between <10 years working and p 10 years working as regard upper and

lower respiratory symptoms, clinical signs, and work related symptoms.

Table 16 shows statistically significant difference between <10 years working and p 10 years working as regard FEV1 (B/P) and FEV1/FVC being lower in p 10 years working group, the rest have insignificant statistical difference.

Table 17 shows that there is statistical significant difference between <10 years working and p 10 years working as regard FEV1/FVC in a group of non-smoker.

Table 18 shows that there is statistically significant difference between <10 years working and p 10 years working as regard DLCO in a group of before dough making (heavy exposure to wheat flour).

Table 19 shows statistically significant difference between before and after dough making as regard prevalence of upper respiratory symptoms and work related symptoms, the rest have insignificant statistical difference.

Table 10

Comparison between 24 workers <40 years and 6 workers >40 years as regard upper and lower respiratory symptoms, clinical signs, and work related symptoms.

Symptoms

<40 years

>40 years

Chi-square test

p-value

Upper respiratory symptoms

Lower respiratory symptoms

87.5 12.5

45.8 54.2

100.0 0.0

0.0 100.0

Clinical signs

Work related symptoms

91.7 8.3

75.0 25.0

66.7 33.3

83.3 16.7

Table 11

Comparison between <40 years workers group and >40 years workers group as regard spirometry and DLCOSB, HRCT chest.

Spirometry <40 years Mean ±SD >40 years Mean ±SD t/x2* p-value

FVC (B/P) 100.31 12.31 88.80 12.23 2.051 0.049

FEV1 (B/P) 98.46 12.84 87.75 25.19 1.487 0.148

FEV1/FVC 84.46 10.28 79.51 10.59 1.049 0.303

MMEF (B/P) 88.88 25.41 83.03 57.72 0.382 0.705

Interpretation of spirometry

Normal 21 87.5% 4 66.7% 4.833* 0.184

Obstructive 2 8.3% 1 16.7%

Restrictive 1 4.2% 0 0.0%

Mixed 0 0.0% 1 16.7%

DLCOSB 89.73 11.87 89.28 18.27 0.073 0.942

Interpretation of DLCO (B/P)

Normal 18 75.0% 3 50.0% 2.210* 0.331

Mild 5 20.8% 35 50.0%

Moderate 1 4.2% 0 0.0%

HRCT chest

Normal 4 66.7 1 33.3 0.900 0.343

Interstitial changes 2 33.3 2 66.7

*X2 - Chi-square test; t - Independent sample t-test.

*FVC (forced vital capacity).

*FEV1 (forced expiratory volume in one second).

*FEV1/FVC (forced expiratory ratio).

*MMEF (maximum midexpiratory flow).

*DLCO (Diffusion lung capacity for carbon monoxide).

Table 12

Comparison between smoker and non-smoker as regard upper and lower respiratory symptoms, clinical signs, and work related symptoms.

Symptoms Smoker Non smoker Chi-square test

No. % No. % x2 p-value

Upper respiratory symptoms

No 13 86.7 14 93.3 0.370 0.543

Yes 2 13.3 1 6.7

Lower respiratory symptoms

No 0 0.0 11 73.3 17.368 <0.001

Yes 15 100.0 4 26.7

Clinical signs

No 12 80.0 14 93.3 1.154 0.283

Yes 3 20.0 1 6.7

Work related symptoms

No 11 73.3 12 80.0 1.681 0.571

Yes 4 26.7 3 20.0

Table 13

Comparison between smoker and non-smoker as regard spirometry and DLCOSB, HRCT chest.

Spirometry Smoker Non smoker t/x2" p-value

Mean ±SD Mean ±SD

FVC (B/P) 96.46 16.06 99.55 9.20 -0.65 0.523

FEV1 (B/P) 90.64 18.75 101.99 10.79 -2.03 0.047

FEV1/FVC 79.17 11.75 87.77 6.66 -2.47 0.020

MMEF (B/P) 78.27 38.29 97.15 24.60 -1.61 0.119

Interpretation of spirometry

Normal 10 66.7% 15 100.0% 6.000" 0.112

Obstructive 3 20.0% 0 0.0%

Restrictive 1 6.7% 0 0.0%

Mixed 1 6.7% 0 0.0%

DLCOSB 90.69 14.58 88.58 11.66 0.44 0.664

Interpretation ofDLCO (B/P)

Normal 11 73.3% 10 66.7% 1.548" 0.461

Mild 3 20.0% 5 33.3%

Moderate 1 6.7% 0 0.0%

HRCT chest

Normal 1 25.0 4 80.0 2.723 0.049

Interstitial changes 3 75.0 1 20.0

*X2 - Chi-square test; t- Independent sample t-test. *FVC (forced vital capacity). "FEV1 (forced expiratory volume in one second). *FEV1/FVC (forced expiratory ratio). *MMEF (maximum midexpiratory flow). *DLCO (Diffusion lung capacity for carbon monoxide). HRCT (High resolution computed tomography)

Table 14

Comparison between working before and after dough making in each group of smoker and non-smoker as regard DLCOSB.

Dough Smoker Non smoker

Mean ±SD Mean ±SD

DLCOSB Before 77.27 16.67 85.82 7.64

After 94.05 12.60 89.96 13.38

t-test T -1.954 -0.634

p-value 0.050 0.537

*DLCOSB (Diffusion lung capacity for carbon monoxide single breath).

Table 20 shows statistically significant difference between before and after dough making as regard DLCOSB, the rest have insignificant statistical difference.

Discussion

Flour dust refers to dust coming from finely milled or otherwise processed cereal. Hypersensitivity reactions as well as irritant

symptoms caused by flour dust constitute a well-recognized occupational problem world-wide [13].

The flour dust in the bakery industry may contain several other non-cereal components, so called dough-improvers, such as a variety of enzymes (e.g. a-amylase of various origin, malt enzymes, cellulase, hemi-cellulase, xylanase), chemical ingredients (e.g. preservatives, bleaching agents, antioxidants), flavourings, spices, and other additives (e.g. baker's yeast, egg powder, sugar) as

Table 15

Comparison between <10 years working and P10 years working as regard upper and lower respiratory symptoms, clinical signs Work related symptoms.

Symptoms <10 years working P 10 years working Chi-square test

No. % No. % x2 p-value

Upper respiratory symptoms

No 10 90.9 17 89.5 0.016 0.900

Yes 1 9.1 2 10.5

Lower respiratory symptoms

No 5 45.5 6 31.6 0.578 0.447

Yes 6 54.5 13 68.4

Clinical signs

No 10 90.9 16 84.2 0.271 0.603

Yes 1 9.1 3 15.8

Work related symptoms

Yes 7 63.6 16 84.2 1.684 0.199

No 4 36.4 3 15.8

Table 16

Comparison between <10 years working and P10 years working as regard spirometry and DLCOSB, HRCT chest.

Spirometry <10 years working P10 years working t/x2* p-value

Mean ±SD Mean ±SD

FVC (B/P) 99.39 11.59 97.21 13.92 0.439 0.664

FEV1 (B/P) 103.14 11.59 92.37 17.27 1.836 0.047

FEV1/FVC 89.87 5.83 79.76 10.69 2.883 0.007

MMEF (B/P) 100.11 25.68 80.53 35.28 1.606 0.120

Interpretation of spirometry

Normal 10 90.9% 15 78.9% 4.163* 0.244

Obstructive 0 0.0% 3 15.8%

Restrictive 1 9.1% 0 0.0%

Mixed 0 0.0% 1 5.3%

DLCOSB 88.15 6.00 90.50 15.84 -0.471 0.641

Interpretation of DLCO (B/P)

Normal 9 81.8% 12 63.2% 1.394* 0.498

Mild 2 18.2% 6 31.6%

Moderate 0 0.0% 1 5.3%

HRCT chest

Normal 1 50.0 4 57.1 0.032 0.858

Interstitial changes 1 50.0 3 42.9

*FVC (forced vital capacity).

"FEV1 (forced expiratory volume in one second).

*FEV1/FVC (forced expiratory ratio).

*MMEF (maximum midexpiratory flow).

"DLCOSB (Diffusion lung capacity for carbon monoxide single breath). "HRCT (High resolution computed tomography).

Table 17

comparison between <10 years working and P10 years working in each group of smoker and non-smoker as regard FEV1/FVC.

Working years Smoker Non smoker

Mean ±SD Mean ±SD

FEV1/FVC <10 years 82.12 5.85 92.01 4.97

P 10 years 76.64 12.51 84.07 5.81

t-Test t 1.434 2.823

p-value 0.175 0.014

*FEV1/FVC (forced expiratory ratio).

well as contaminants such as storage-related mites and microbes [14].

A total of 30 workers were included in this study, exposed to flour dust in the work place without any protective equipments. All workers included in the study were males. Two female bakery workers participated in our study but both were excluded because one of them failed to perform DLCO examination, the other one excluded for fear of statistical bias.

The age of the bakery workers ranged between 14 and 56 years with a mean of (29.5 ± 9.98) years. They work at least for 10 h per day for 6 days per week for total working years ranged between 2 and 30 years with a mean of (12.97 ±7.65).

Two of participants had a different work before working in bakeries, first one worked as flowers vendor and the second as cars repair worker.

Table 18

comparison between <10years working and p10 years working in each group of after and before dough making as regard DLCO.

Working years Before After

Mean ±SD Mean ±SD

DLCOSB <10 years P10 years 86.93 69.65 7.54 13.93 89.60 92.95 3.76 14.47

t-Test T p-value 2.370 0.045 -0.505 0.619

*DLCOSB (Diffusion lung capacity for carbon monoxide single breath).

Table 19 Comparison between before and after dough making as regard upper and lower respiratory, clinical signs Work related symptoms.

Symptoms Dough making Chi-square test

Before After x2 p-value

No. % No. %

Upper respiratory symptoms No Yes 6 2 75.0 25.0 21 1 95.5 4.5 2.727 0.049

Lower respiratory symptoms No Yes 3 5 37.5 62.5 8 14 36.4 63.6 0.003 0.954

Clinical signs No Yes 7 1 87.5 12.5 19 3 86.4 13.6 0.007 0.935

Work related symptoms No Yes 3 5 37.5 62.5 20 2 90.9 9.1 9.355 0.002

Table 20

Comparison between before and after dough making as regard spirometry, DLCOSB, and HRCT chest.

Spirometry Dough making t/x2* p-value

Before After

Mean ±SD Mean ±SD

FVC (B/P) 100.51 8.25 97.10 14.35 0.632 0.532

FEV1 (B/P) 101.78 8.37 94.33 17.87 1.125 0.270

FEV1/FVC 87.90 7.35 81.86 10.95 1.440 0.161

MMEF (B/P) 94.61 20.75 85.20 36.60 0.684 0.500

Interpretation of spirometry

Normal 8 100.0% 17 77.3% 2.182* 0.536

Obstructive 0 0.0% 3 13.6%

Restrictive 0 0.0% 1 4.5%

Mixed 0 0.0% 1 4.5%

DLCOSB 82.61 11.50 92.19 12.81 -1.856 0.044

Interpretation of DLCO (B/P)

Normal 4 50.0% 17 77.3% 3.853* 0.146

Mild 3 37.5% 5 22.7%

Moderate 1 12.5% 0 0.0%

Specific finding in HRCT

Normal 2 50.0 3 60.0 0.090 0.764

Interstitial changes 2 50.0 2 40.0

*FVC (forced vital capacity).

"FEV1 (forced expiratory volume in one second).

*FEV1/FVC (forced expiratory ratio).

*MMEF (maximum midexpiratory flow).

"DLCOSB (Diffusion lung capacity for carbon monoxide single breath). HRCT (High resolution computed tomography).

Eight of participants (26.7%) worked before stage of dough making, twenty-two of participants (73.3%) worked after stage of dough making.

Body mass index was calculated for all participants, fifteen (50%) of them were within normal weight range, nine (30%) of them were overweight, six (20%) of them were obese. This classification was done according to WHO classification of obesity by BMI as follow:

Underweight: 18.5 Normal weight: 18.5-25.0 Overweight: 25.0-30.0 Obesity: 30-635 Severe obesity: p35-40kg/m2. Morbid obesity: P40-44.9 kg/m2. Super obesity: P45-50 kg/m2.

On general examination, all participants were not hypertensive, not diabetic, within normal respiratory rate, normal heart rate, and normal temperature. By local chest examination, auscultation of two of participants revealed harsh vesicular breathing, two revealed rhonchi and three revealed crepitations.

According to laboratory investigation, all participants had no abnormality as regards renal functions, hemoglobin, random blood sugar, total leucocytic count, and platelets. Only one had elevated liver enzymes without history or current symptoms of chronic liver disease.

Descriptive analytical data showed that three (10%) of participant had upper respiratory symptoms included sneezing, rhinor-rhea, change of voice, nineteen (63.3%) had lower respiratory symptoms included cough, expectoration, chest wheeze, dyspnea and seven (23.3%) had work related symptoms which included any symptoms that developed during hours of working and improved by leaving the work.

Five (16.6%) of participants had abnormal pulmonary functions as regards spirometry, three subjects (10%) showed obstructive pattern, one (3.3%) subject showed restrictive pattern, which might be due to increase body mass index of this particular subject without affection on DLCO [15], four subjects (13.3%) showed small airway affection. Only one (3.3%) subject showed mixed pattern.

Nine subjects (30%) had abnormal pulmonary functions as regards diffusion capacity of lung to carbon monoxide in single breath.

Only one (3.3%) participant had abnormal chest X-ray that showed right- sided fibrotic bands.

Four (44%) out of those nine subjects (who had abnormal DLCOSB) had picture of interstitial lung disease in their HRCT chest.

The most common respiratory symptoms among bakery workers at the current study were cough and expectoration, this is in agreement with many studies carried out on flour mill workers and bakers, there was a study conducted by Mohammadien et al. [16] in the flour mills located in Sohag Governorate, Southern Egypt between March 2009 and November 2011 on two hundred flour mill workers, found that respiratory symptoms were significantly higher in flour mill workers than in controls, these data obtained by the questionnaire that included: questions on work history, respiratory symptoms, and smoking status of the study subjects. A significantly higher prevalence of respiratory symptoms in flour mill workers was related to the shortness of breath, wheezes, productive cough.

Also Gimenez et al. [17] have observed that flour dust exposure causes cough, phlegm production among flour mill workers compared to their matched controls. Similarly, Bohadana et al. [18], showed that regardless of exposure to relatively low concentration levels of inspirable flour dust, subjects working in the baking industry are at risk of developing respiratory symptoms.

Also Neghab et al. [19] conducted a study in Iran showed that prevalence of regular cough, productive cough, wheezing, phlegm and dyspnea was significantly higher in exposed subjects to wheat flour than in non-exposed employees.

At the current study and previous studies, all subjects were not using any protective equipment.

Exposure to occupational dusts and chemicals plays a major role in the development of COPD for many individuals. Occupational exposure to organic and inorganic dusts, such as dust from coal, cotton and grain, can cause COPD [20].

One in ten of all adults who suffer from asthma, work was the cause. There are at least 1500 cases each year. Bakers are one of the most vulnerable groups, as flour and grain is the second biggest cause of occupational asthma. Some 65,000 baking industry workers are potentially at risk from flour dust [20].

The current study showed that five subjects(16.6%) of study population group had abnormal pulmonary function as regard spirometry compared to the reference values, There was study conducted in Sudan by Ahmed et al. [21] has shown that exposure to flour dust in bakeries in Khartoum State is associated with impairment of lung function if exposure continues for three years or more, in the previous study, Pulmonary function tests were carried out using a portable electronic spirometry for 36 bakery workers in Sudan.

Mohammadien et al. [16] found that Flour mill workers had lower FVC%, FEV1%, FEV1/FVC%, FEF25%, FEF50% and FEF75% compared to the controls with highly statistically significant difference. At the previous study by Mohammadien et al., Spirometry was performed for 400 workers, 200 flour milling workers (exposed to flour dust in the work place) and 200 workers (unexposed to such hazard, control group).

Similarly Corzo and Naveda [22] observed that spirometric changes due to high concentrations of wheat dust at a wheat processing plant in anthropometrically matched subjects. They reported a decrease in the Peak Flow Rate (PFR), Forced Expiratory Volume (FEV%), Forced Expiratory Flow at 25% (FEF25%), and Forced Expiratory Flow at 75% (FEF75%). In addition, Von Essen [23] demonstrated that grain dust exposure (flour, feed and seed mills) is a common cause of that workers developed obstructive changes on pulmonary function testing.

Macrophages and the mucociliary system are responsible for the clearance of flour particles from the lungs. However, heavy exposure may lower the ability of macrophages to eliminate particles, which may result in penetration of the dust particles into the interstitium [14].

The particles deposited on the airways, are generally cleared by the mucociliary mechanism, though such clearance may be prolonged if the airways are damaged by cigarette smoke or fume inhalation [24].

Hypersensitivity pneumonitis, which was originally recognized by Bernardino Ramazzini in wheat reapers in 1713, is an interstitial lung disease caused by an immune response to an inhaled antigen

Hypersensitivity pneumonitis (HP), also known as extrinsic allergic alveolitis, is a complex condition of varying intensity, clinical presentation, and natural history. It is the result of an immuno-logically induced inflammation of the lung parenchyma in response to inhalation exposure to a large variety of antigens

[26]. These are primarily organic antigens to which patients have been previously sensitized and are hyper-responsive [27]. Miller's lung is a type of hypersensitivity pneumonitis which caused by Sitophilus granarius (i.e., wheat weevil) in Dust-contaminated grain and affecting pulmonary function and reduces DLCO [28].

The current study found that 30% of study population group have abnormal pulmonary function as regard diffusion capacity of lung to carbon mono-oxide compared to reference value. Kapoor et al. [29] reported that DLCO was decreased significantly and rest of the parameters was decreased insignificantly in flour mill workers as compared to control subjects.

In population-based studies, Lynch et al. [30] found that the sensitivity of chest radiography for detection of occupational lung disease is relatively low. Many patients may indeed have normal radiographs [31]. Similarly the result of current study which found that only one (3.3%) participant had abnormal chest X-ray showed right side fibrotic bands.

HRCT is far more likely to show abnormalities and is considered standard for evaluating parenchymal changes in hypersensitivity pneumonitis and other pneumoconiosis [32].

As regard HRCT of the chest, the current study reported that DLCOSB test of nine participants (30%) had shown diffusion defect,

all of these nine participants examined by HRCT chest, five (55.6%) of them have normal HRCT chest and four (44.4%) of them have interstitial changes. This result agrees with Flors et al. [33] who found that HRCT plays an increasing role in the evaluation of occupational lung diseases. The diseases studied in previous studies were uncommon occupational lung disease as siderosis, talcosis, berylliosis, calcicosis, hypersensitivity pneumonitis (due to wheat flour and isocyanates), and Ardystil syndrome. The characteristic HRCT findings together with clinical features and related occupational history improve the diagnostic accuracy of these diseases.

The results of the current study showed statistically significant difference between <40 years workers group and >40 years workers group as regard lower respiratory symptoms being more prevalent in age group more than 40 years, however There is no significant difference between <40 years workers group and >40 years workers group as regard upper respiratory symptoms. and this agree with study conducted by in India by Singh et al. [34] who found that age had no influence on the incidence of rhinitis in bakery workers, however, age significantly influenced the incidence of breathlessness.

Mohammadien et al. [16] found that there was a statistically significant association between work-related respiratory disorders and age unlike the current study that reported that there is no statistically significant difference between <40 years workers group and >40 years workers group as regard work related symptoms, this result may be due amount of exposure in each study as Mohammadien et al. conducted their study in flour mills not in bakeries as the current study.

Also the current study showed statistically significant difference between <40 years workers group and >40 years workers group as regard FVC (B/P) but There is no significant difference between <40 years workers group and >40 years workers group as regard mean FEV1/FVC, and DLCO.

This comes in agreement with the finding in earlier study by Pruthi and Multani [35] who reported that the difference in the mean values of FVC amongst different age groups is statistically significant whereas the difference in mean value of FEV1/FVC is not statistically significant.

And this is of value that participants at the current study who had defect in spirometric parameter especially obstructive pattern and DLCO not affected by age.

Also Study conducted in Nigeria by Ige and Awoyemi [36] matched our results and reported that there was no statistical difference between different age groups as regard pulmonary function but there was statistical difference between cases who exposed to wheat flour and control group in each age groups.

The current study reported that there is statistically significant difference between smoker and non-smoker groups as regard lower respiratory symptoms, Singh et al. [34] found that smoking habit influenced significantly the incidence of cough but had no direct effect on breathlessness and rhinitis. According to Moham-madien et al. [16] a highly statistically significant association was detected between the presence of respiratory symptoms, and tobacco smoking and also there was statistical significance between the presence of work related symptoms and tobacco smoking. Unlike the previous study, the current study reported that there is no statistically significant difference between smoker and non-smoker group as regard work related symptoms. Again this may be explained different smoking habits or the work place related factors between the current study and the other studies.

The current study demonstrated that there is statistically significant difference between smoker and non-smoker groups as regard mean FEV1 ratio and mean FEV1/FVC. Mohammadien et al. [16] reported that there were highly statistically significant differences in lung function parameters between smokers and non-smokers.

The current study reported that there is statistically significant difference between smoker and non-smoker as regard interstitial changes in their HRCT of the chest. As 75% of participants their HRCT chest showed interstitial changes were smoker. Unlike Sel-man et al. [37] who reported that organic dust induced lung disease is less frequent in smokers than in non-smokers under the same risk of exposure to the organic dust. But other studies as Dangman et al. [38] observed that cigarette smoking can potentially obscure the diagnosis, and may contribute to the apparent "protective" effect of smoking on the development of organic dust induced lung disease.

This may be explained by the finding of Furuiye et al. [39], who found that in short-term exposure (4 weeks), cigarette smoke decreased inflammation and lymphocyte proliferation, whereas long-term exposure to cigarette smoke (17 weeks) enhances lung inflammation with fibrosis.

Case report was done by Sundaram et al. [40], included two cases of mixed dust fibrosis which occurred in the setting of poorly ventilated flour mills where various kinds of grain, chiefly wheat, were ground using stones whose silica content was analyzed to be more than 80 percent. While one patient was a non-smoker and the other was an ex-smoker, both cooked on kerosene stoves in the same room. They proposed the term 'Flour mill lung' for this form of pneumoconiosis which diagnosed by restrictive pattern in spirometry and interstitial changes in HRCT chest.

In addition the current study show that there is statistical significant difference between before dough making group (heavy exposure) and after dough making group (light exposure) as regard DLCOSB in a group of smoker group, and no statistical difference between two groups as regard DLCOSB in non-smoker group. Also Kapoor et al. [29] reported that there is statistically significant reduction was seen in smoker workers only in TLCO. As compared to non-smoker control subjects suggestive that smoker more liable for interstitial lung disease when exposed to wheat flour dust. In addition, Barker et al. [41] found that cigarette smoking and intense exposure predispose workers to sensitization to some substances.

Previous studies have estimated the latency period for the development of respiratory symptoms by asking asthmatic bakers for the time since first exposure and the onset of first symptoms, The mean latency period for each study population varied from 4 to 13 years, and on individual levels this varied even more (months to >30 years) [42-47].

In the current study we determined duration of exposure to wheat flour by number of working years in bakeries for each subject and considered working more than 10 years as a long duration of exposure due to two reason, first one, just two subjects at the current study working less than 5 years in bakeries so less than 10 years may cause statistical bias, the second reason to compare our results with the study conducted in Egypt by Mohammadien et al. [16], as we supposed that it was the same circumstances of work environment as regard type of wheat flour, amount of exposure, absence of protective measures and to some extent similar study group. Accordingly the participants at the current study were divided into two groups:

Working less than 10 years in bakeries and working for 10 years or more in bakeries.

Nevertheless, the current study showed no statistically significant difference between <10 years working and p 10 years working groups as regard upper and lower respiratory, clinical signs, work related symptoms unlike Mohammadien et al. [16] that reported that duration of employment was found to be an important factor that influenced the prevalence of respiratory symptoms. Workers with a longer duration of employment reported a significantly higher prevalence of symptoms (96.2%) than those with shorter duration (83.3%). In addition Ajeel and Al-Yassen [48] in

2007 and Karjalainen et al. [49] in 2003 who found that the longer the duration of employment the higher the prevalence of allergic symptoms.

This can be explained by wide range of latency period between population in different studies, for examples study conducted by Ahmed et al. [50] in Sudan has shown that exposure to flour dust in bakeries in Khartoum State is associated with increased respiratory symptoms if exposure continues for three years or more.

Mohammadien et al. [16] found that there is significant decline in lung function parameters in bakery workers with increasing duration of exposure, a significant decline in FVC, FEV1%, FEV1/ FVC%, was found in bakery workers with more than 10 years of exposure when compared with workers with less than 10 years of exposure .

Awad et al. [51] also observed a significant decline in the lung function parameters, FVC and FEV1, in workers exposed to flour dust compared to the control group.

In addition, Meo in 2004 [52] and Dhillon and Kaur in 2011 [53] studied the relationship between duration of exposure on the lung function in flour mill workers and observed that FVC, FEV1 and PEF were decreased in flour mill workers compared to their matched controls. Our results confirm the results observed by previous studies as regard FEV1and FEV1/FVC%.

The current study reported that there is statistical difference between <10 years working and p 10 years working groups as regard FEV1/FVC in a group of non-smoker .This agree with Shams-sain [9], who observed ventilatory function in non-smoking flour processing male bakery workers and reported that the exposed group had significantly lower forced expiratory indices than the control group. In addition Ahmed et al. [50] reported that bakery workers for three years or more scored significantly lower mean FEV1 and FVC, percent predicted when compared with controls, all workers in previous study were non-smoker. And this confirms the effect of exposure to wheat flour on pulmonary function as regard FEV1/FVC when effect of smoking was excluded.

As regard DLCOSB, no statistically significant difference between <10 years working group and p 10 years working group was detected, and this can be explained by statistical difference found in current study between <10 years working and p10 years working as regard DLCO in a group of before dough making (heavy exposure to wheat flour). This mean that when bakery workers exposed to high concentration of wheat flour dust, duration of exposure considered as an important factor affecting DLCO.

According to the Dutch Expert Committee on Occupational Standards (DECOS) [54] calculations, a person who starts working in the bakery industry for the first time would have an additional risk of 10% to ever becoming sensitized to flour dust, if occupation-ally exposed to an average of 1.2 mg/m3 inhalable dust. The type of occupation was considered as the most important determinant of dust exposure and the best way to categorize bakery workers into exposure groups for studying dose-response relationships [55,56].

Morren et al. [12] performed a cross-sectional survey of 279 bakery workers in a modern British bakery. Employment was categorized by perceived dustiness and ranked from 0 (no exposure) to 10 (highest exposure). In general, the ranking correlated well with the concentrations of inhalable dust obtained from personal air measurements.

At the current study there was no available equipment to measure amount of exposure at work places, so according the previous study we divide participants by nature of working in bakeries into:

Before dough making: for example, Flour room staff, sweeper and bagging; as heavy exposure participants.

After dough making: for example, oven worker and dough making; as light exposure participants.

The current study showed statistically significant difference between before and after dough making groups as regard upper

respiratory symptoms and work related symptoms. this confirm the results of Mohammadien et al. [16], who reported a highly statistically significant association detected between the presence of respiratory symptoms, site of work (which determines the level of exposure to flour dust), The study showed that 96.8% of those with a high level of exposure to flour dust in the workplace (packing unit) had respiratory symptoms compared to 66.7% in those with a low level of exposure.

Also Massin et al. [57] demonstrated the relation between dust exposure levels and the respiratory health status of workers in grain and flour mills and observed a dose-response relationship between dust exposure levels and chronic respiratory symptoms, suggesting that exposure to grain and flour dust may lead to chronic bronchitis.

The current study has shown no statistically significant difference between before and after dough making groups as regard spirometric parameters. This result is in agreement with Meo [52] in 2004 andDhillon andKaur[53] in2011studied the relationship between dose responses and duration of exposure on the lung function in flour mill workers and observed that FVC, FEV1and PEF were decreased in flour mill workers compared to their matched controls and this impairment was significantly associated with the increased duration of exposure to flour dust in the flour mills not to the amount of exposure.

It could be explained by that all participants underwent pulmonary function test in pulmonary function unit in the hospital at the holiday (away from work place).

Another cause for this results that several studies demonstrating that sensitization causes workers to leave the exposed work environment [58-60]. Especially asthma has been shown to cause workers to leave [61]. It is also possible that a migration of symptomatic and/or sensitized individuals towards tasks associated with lower exposure has taken place.

Unlike Corzo and Naveda [22] observed spirometric changes due to high concentrations of wheat dust at a wheat processing plant, they and [62] divided the flour mill workers into heavy-exposure group and light-exposure group and observed that FEV1, FVC, MEF and PEF were significantly decreased in the heavy-exposed group than lightly exposed group.

The current study showed statistically significant difference between before and after dough making groups as regard DLCOSB, Similarly Kapoor et al. [29], reported that TLCO was decreased significantly and rest of the parameters were decreased insignificantly in flour mill workers as compared to control subjects. 30% of participants have abnormal pulmonary function as regard diffusion capacity of lung to carbon mono-oxide, and 44% of participants who have abnormal DLCOSB have picture of interstitial lung disease in their HRCT chest.

Mohammadien et al. [16], found that IPF was diagnosed in 5% of flour mill workers and none of controls with significant difference.

Conflict of interest

There is no conflict of interests. References

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