Tanveer Husain

Respiratory Health Effect from Occupational Exposure to Wood Dust in Sawmills

Spirometric lung functions were recorded for 109 workers (mean age 26.4 +/- 8.2 yr) occupationally exposed (mean exposure 8.9 +/- 7.7 yr) to soft wood dust in local sawmills along with 88 unexposed controls (mean age 28.7 +/- 9.9 yr) belonging to the same socioeconomic status to assess the prevalence of respiratory impairment in the exposed population. The results of the study showed a significantly higher prevalence of overall respiratory impairment in the exposed group even after standardizing for smoking habits (p less than 0.001). The adjusted rate for respiratory impairment in the exposed group was 29.4% as compared to 2.2% observed in the unexposed controls. The pattern of respiratory abnormality observed in the sawmill workers was predominantly the restrictive type (28.4%), indicating lower levels of forced vital capacity (FVC) in the exposed group; while in the control group, there were none with lung restriction The prevalence of airflow limitation, however, was similar in the exposed workers (1.8%) and controls (2.2%), thereby, indicating that bronchial obstruction was independent of wood dust exposure. It is concluded that the dust exposure in sawmills is associated mainly with restrictive type of pulmonary impairment in the exposed workers.

Spirometric abnormalities among welders

A group of manual welders (N = 57) engaged in gas welding joint faces of moulded brasswares, age group 13-60 years (mean: 29.2 +/- 1.37 years), having a mean exposure period of 12.4 +/- 1.12 years (range: 1-35 years) were subjected to spirometry to evaluate the prevalence of spirometric abnormalities. The findings were compared with those obtained from a reference group (N = 131) (mean age: 31.2 +/- 1.35 years) engaged in nonwelding jobs such as packing, labelling, and transportation of the finished brassware articles. The welders showed a significantly higher prevalence of respiratory impairment (28.0%) than that observed among the unexposed controls (6.1%) (P less than 0.001), as a result of exposure to welding gases which comprised fine particles of lead, zinc, chromium, and manganese. This occurred despite the lower concentration of the pollutants at the work place. In the exposed group, the smoking welders showed a prevalence of respiratory impairment significantly higher than that observed in the nonsmoking welders (40.0 vs 18.7%) (P less than 0.10). A similar trend was observed in the control group indicating that smoking had a deteriorating effect on spirometric tests. The results of the pulmonary function tests showed a predominantly restrictive type of pulmonary impairment (12.3%) followed by a mixed ventilatory defect (8.7%) among the welders. The effect of age on pulmonary impairment was not discernible either in the exposed or unexposed group. The analysis of data in relation to duration of exposure showed significant correlation between the prevalence of respiratory abnormalities and length of exposure. Welders exposed for over 10 years showed a prevalence of respiratory abnormalities significantly higher than those exposed for less than 10 years (44.4 vs 13.3%) (P less than 0.01) thereby showing that occupational exposure to welding fumes resulted in increased prevalence of pulmonary impairment in the welders. Smoking also had a contributory role thereby suggesting an interaction between smoking and welding exposure on the prevalence of pulmonary impairment in the welders engaged in brassware industries.

A study of the prevalence of respiratory morbidity among agate workers.

SummaryA random sample of 342 workers engaged in chipping and grinding of agate stones were surveyed in a cross-sectional study to assess the prevalence of respiratory morbidity in the agate industry. The findings were compared with those obtained in controls. The study showed a significantly higher prevalence of lung diseases among agate workers than among controls (63.4% vs 35.5%, P < 0.001). The respiratory morbidity in agate workers and controls was maximal in the group aged 31+ years (83.3% and 42.2%, respectively). The prevalence of pneumoconiosis in agate workers (18.4%) was highly significant as compared with controls, in whom not a single case was found (P < 0.001). However, there was no significant difference between the prevalence of pneumoconiosis in men and women of the exposed group (17.9% vs 19.6%). Among the cases of pulmonary diseases in agate workers, pneumoconiosis formed the largest group (18.4%), whereas among controls it was tuberculosis (12.1%). The prevalence of pulmonary tuberculosis was very high in both agate workers and controls (15.5% and 12.1%, respectively), probably because of poor socio-economic and unhygienic living conditions. The prevalence of chronic bronchitis was found to be higher among the control population as compared with the exposed group (6.7% vs 2.6%). It therefore appeared that agate dust had no role in precipitating chronic bronchitis. However, bronchial asthma appeared to have been aggravated due to agate dust, as the risk among agate workers was 7-fold that found among the controls. The prevalence of pneumoconiosis showed a dose-response relationship in both male and female agate workers. Pulmonary tuberculosis and bronchial asthma did not show any significant trend in relation to the duration of exposure. Other lung diseases were also independent of exposure. As far as occupations are concerned, grinders were found to suffer more from pneumoconiosis (21.9%) than did chippers (7.3%, P < 0.05); this was because the respirable dust concentration at the workplace of grinders was 6-fold that at the workplace of chippers. Acute bronchitis was also more prevalent in grinders (P < 0.05). However, tuberculosis and asthma did not vary significantly between the two occupational groups.

Respiratory symptoms and ventilatory capacity in metal polishers

To evaluate the long-term effects of metal dusts on the bronchopulmonary system and the synergistic effect of cigarette smoke, a comparative study of spirometric measurements in 104 polishers and 90 unexposed controls was carried out in 25 brass and steelware polishing industries at Moradabad in northern India. The two groups were comparable in terms of age, height, smoking habit and socio-economic status. A total of 58.6% of the polishers had one or more respiratory symptoms, compared to only 25.5% of the controls (P<0.05). Chronic cough was present in 21 polishers (20.2%) as compared to 11.1% of the controls. However, this difference was insignificant. Chronic phlegm was nearly three times as frequent among the polishers as among the controls (17.5% vs 4.4%) (P<0.005). The prevalence of dyspnoea of varying grades was also significantly higher (16.3% as opposed to 4.4%) among the exposed groups. Chronic bronchitis (6.7%) and occupational asthma (4.8%) were found to be confined to polishers. The polishers also experienced acute respiratory symptoms during the work shift. The prevalence of acute respiratory symptoms was recorded for cough in 19 workers (44.1%) followed by dyspnoea in 14 workers (32.5%) and throat irritation in 11 workers (25.5%). Comparison of the mean values of pulmonary function parameters in the polishers and the controls showed significant differences in the smoking and non-smoking groups (P<0.001 ). The polishers exhibited significantly greater acute reductions in various lung functions over the work shift, particularly for forced expiratory flow over the 25-75% portion of the spirogram (FEF25_75%) FEF25% and FEF 50%, than did the controls. Among the exposed group, the acute changes in lung function were found to be significantly larger in the smoking than in the non-smoking polishers. The duration of exposure showed a direct correlation with the acute fall in lung function. Polishers who were exposed to dusts of various metals for more than 10 years showed a significantly greater acute reduction in all the pulmonary functions (P<0.001) thereby indicating that occupational exposure to multimetals in the work environment of the polishing industry had deleterious respiratory effects.

Thermal stress and physiological strain of children exposed to hot environments in a glass bangle factory.

SummaryA group of 19 male children (mean age 12.1 years SEM 1.6 years) occupationally exposed to an excessively hot environment for an average duration of 2.5 years SEM 1.7 years in the glass bangle factory in Firozabad, India, were studied to evaluate the physiological strain induced by the thermal radiation (mean radiant temperature 46.2° SEM 5.1° C) and high ambient temperature (38.2° SEM 3.4° C) prevailing in the factory. Over a work-shift the mean increase in oral temperature was 0.90° C in the exposed children, in comparison with the 0.40° C increase recorded in the control children (p<0.05). The maximum increase in oral temperature was recorded in ‘gulliwalas’ (0.90° C) and the minimum in ‘battiwalas’ (0.80° C). The mean peak value of oral temperature (37.5° C) was observed at 1600 hours. A significant increase in the pulse rate (25.9 beats·min−1) during the work-shift was observed in the exposed children in comparison with a mean increase of 9.4 beats·min−1 in the control group. Ventilatory studies showed pulmonary hyperventilation in the exposed workers. The increase in pulmonary ventilation was in the form of an increase in tidal volume and respiratory frequency induced by high environmental temperatures and thermal radiation. The cardio-respiratory responses showed physiological strain induced by the high ambient temperature and radiant heat prevailing in the glass bangle factory.

A study of the prevalence of ventilatory obstruction in textile workers exposed to cotton dust

A study was conducted in a cotton spinning mill to assess the prevalence of respiratory impairment in 189 asymptomatic workers and 133 byssinotics drawn from various sections of the plant exposed to airborne cotton dust in the work environment. Eight-four healthy controls belonging to the same socioeconomic status and ethnic group having never been exposed to cotton dust or any other pollutant was also studied for the purpose of comparison. Of the 189 asymptomatic workers, 13 (6.8%) suffered from bronchial obstruction whereas only 2 (2.3%) among the control showed obstructive pulmonary impairment. The byssinotics showed a significantly higher prevalence (15.7%) of bronchial obstruction than that (6.8%) observed among the asymptomatic cotton workers (P less than 0.005). Byssinotics (grade II) showed significantly higher prevalence (31.5%) of bronchial obstruction than that (9.4%) observed in acute byssinotics (grade I). The effect of smoking on the prevalence of bronchial obstruction in the asymptomatic and byssinotics was quite discernible as smokers showed significantly higher prevalence than that observed among the nonsmokers (P less than 0.05). The asymptomatic cotton workers and those with different grades of byssinosis having more than 10 years of exposure showed significantly higher prevalence of bronchial obstruction than that observed in the group with less than 10 years of exposure (P less than 0.005). The healthy cotton workers and byssinotics engaged in the preparatory section (card, blow, and waste plant rooms) showed an insignificant higher prevalence of bronchial obstruction (11.3 and 24.4%, respectively) than among those who worked in the spinning, reeling, and winding sections of the mill. The mechanism responsible for causing ventilatory obstruction in the textile workers is discussed.

Pulmonary function study in female grinders exposed to agate dust.

This paper reports a cross-sectional study of a non-smoking population of silica exposed female workers compared with a group of healthy non-exposed females. The exposed group is divided into cohorts according to the presence or absence of pneumoconiosis in either simple or complex form. The study revealed statistically significant difference in pulmonary function between each of the pneumoconiosis group and the controls and healthy exposed workers. Furthermore, there was statistically significant difference between the values of pulmonary function parameters of the healthy exposed group and the controls. The most important observation of the study is that almost equal decrement of pulmonary function values was observed in the diseased groups and in the healthy exposed group compared to the decrement seen between the latter group and the control group. VC and FVC showed a mean fall of 11.0 and 11.5% in the healthy exposed group as compared to those observed in the unexposed controls (p < 0.01 and p < 0.05) while in the pneumoconiosis group VC and FVC showed 16.9 and 18.2% decrease as compared with the values obtained in the healthy grinders (p < 0.01). Similarly FEV1 showed almost same decrease in the healthy (17.9%) and diseased (20.7%) exposed groups (p < 0.001). However, FEV0.75 and MVV parameters showed greater decrement (25.4 and 33.7%) in the pneumoconiosis group as compared to 15.7 and 18.5% observed in the healthy exposed workers. The important observation made in this study is that potential pulmonary debilitation may occur in pneumoconiosis before, or in the absence of, any radiologic findings.

Respiratory Symptoms and Ventilatory Capacity in Metal Polishers

To evaluate the long-term effects of metal dusts on the bronchopulmonary system and the synergistic effect of cigarette smoke, a comparative study of spirometric measurements in 104 polishers and 90 unexposed controls was carried out in 25 brass and steelware polishing industries at Moradabad in northern India. The two groups were comparable in terms of age, height, smoking habit and socio-economic status. A total of 58.6% of the polishers had one or more respiratory symptoms, compared to only 25.5% of the controls (P < 0.05). Chronic cough was present in 21 polishers (20.2%) as compared to 11.1% of the controls. However, this difference was insignificant. Chronic phlegm was nearly three times as frequent among the polishers as among the controls (17.5% vs 4.4%) (P < 0.005). The prevalence of dyspnoea of varying grades was also significantly higher (16.3% as opposed to 4.4%) among the exposed groups. Chronic bronchitis (6.7%) and occupational asthma (4.8%) were found to be confined to polishers. The polishers also experienced acute respiratory symptoms during the work shift. The prevalence of acute respiratory symptoms was recorded for cough in 19 workers (44.1%) followed by dyspnoea in 14 workers (32.5%) and throat irritation in 11 workers (25.5%). Comparison of the mean values of pulmonary function parameters in the polishers and the controls showed significant differences in the smoking and non-smoking groups (P < 0.001). The polishers exhibited significantly greater acute reductions in various lung functions over the work shift, particularly for forced expiratory flow over the 25-75% portion of the spirogram (FEF25-75%) FEF25% and FEF50%, than did the controls.(ABSTRACT TRUNCATED AT 250 WORDS)

A STUDY OF RESPIRATORY MORBIDITY AND PULMONARY FUNCTION AMONG SOLDERERS IN THE ELECTRONICS INDUSTRY

Pulmonary function assessment of 197 solderers engaged in soldering printed circuit boards and other electronic components using lead-tin alloy impregnated solder in five major electronics workplaces in India was compared with the findings observed in 143 unexposed controls. Spirometry showed a significant impairment in the values of vital capacity (VC) and forced expiratory volume/forced vital capacity (FEV1/FVC) percent ratio in 47.2% of the solderers in comparison to 1.3% in the reference group (p less than 0.001). In the exposed group, female solderers particularly showed significantly higher (55.0%) prevalence of overall respiratory impairment in comparison to the 32.3% observed in their male counterparts (p less than 0.001). Bronchial obstruction was recorded in 7.6% of the solderers compared with 1.3% of the unexposed controls (p less than 0.01). The prevalence of restrictive and mixed ventilatory impairment was found to be 28.9 and 10.6%, respectively, among the exposed workers, while there was none among the control group. The solderers showed a predominantly restrictive pattern of pulmonary impairment that was mild in nature. Smoking caused no significant effect on the pulmonary impairment among the exposed workers. The study also did not show any significant differences in the prevalence of respiratory impairment between solderers exposed either less or more than 10 yr, thereby suggesting that there was no link between the respiratory impairment and duration of exposure. The industrial hygiene study conducted in the assembly section where soldering was done showed the mean concentration of lead to be 0.40 micrograms/m3 (range 0.12-0.43 micrograms/m3).(ABSTRACT TRUNCATED AT 250 WORDS)