The correlation of chest radiograph and pulmonary function tests in asbestos miners and millers.

An environmental-cum-medical survey was carried out in asbestos mines and milling units at Pullivendalla, Cuddaph (A.P.) India. This was done in two mines and six milling units with 95% of the total work force being surveyed. Out of a total of 633 registered workers, 329 (52%, all males) were employed in mines while 135 (21.4%) workers of whom 114 (84%, all females) were employed in the milling units. All subjects underwent limited medical examination, spirometry and chest radiographs. The levels of asbestos fiber concentration was much below threshold limit value (TLV) in underground mines but several times higher than TLV in milling units. The percentage of workers with abnormal pulmonary function tests (PFT) and chest radiographs increased with duration of exposure in smokers as well as non-smokers. Restrictive pattern of lung functions (159 workers-16.27%) was more common than obstructive (33 workers-5.21%) and combined type (22 workers-3.4%). Similarly, the parenchymal changes (156 workers-24.6%) were more common than pleural (27 workers-4.3%). As most of the males were employed in mines, where the fiber levels were much below TLV, the number of male workers with normal PFT and chest radiographs were ten times (61.3%) more than male workers with both the parameters abnormal (6.3%). As most of the females (114 our of 120--95%) were employed in milling units, where the levels of fibers were several times higher than TLV, the number of females having both the parameters normal 29 (24.1%) or abnormal 35 (29.2%) were similar.

Dustiness, silicosis & tuberculosis in small scale pottery workers.

Studies were carried out in eight small scale potteries to find out the airborne dust concentrations and the prevalence of dust related diseases like silicosis and tuberculosis in 292 workers. Chest radiography revealed that 44 (15.1%) pottery workers were suffering from silicosis and an equal number showed radiological evidence of tuberculosis. The environmental study showed that the concentrations of airborne dust, containing free silica, in the work environment of all departments (except packing department) of potteries were higher than threshold limit values (TLVs). The prevalence of silicosis and tuberculosis correlated with the levels of airborne dust. The prevalence of tuberculosis increased with radiological severity of silicosis. Dust control measures combined with pre-employment and periodical medical examinations are recommended for the control of silicosis and tuberculosis in the pottery industry.

Humoral immunological profile of workers exposed to asbestos in asbestos mines.

Humoral immunological profile including immunoglobulins IgG, IgA, IgM, C-reactive protein, rheumatoid factor, antinuclear antibodies and circulating immune complexes were studied in a representative sample of 36 workers suffering from asbestosis (group A), 35 workers who are exposed to asbestos but not having evidence of asbestosis (group B) and 28 control workers (group C). Mean IgG and IgA levels were found to be significantly higher in the two exposed groups than in the controls. Circulating immune complexes of IgG, IgA and IgM class were detected in a significant percentage of cases in exposed groups than in controls. In groups A and B, the percentage of positive ANF cases was much higher than in the controls. The results suggest that immunological changes are associated with exposure to asbestos and these may play an important role in the pathogenesis of the disease process.

Pulmonary function tests--a comparison between urban industrial and rural agricultural workers of Andhra Pradesh.

Physical parameters and pulmonary function tests (VC, FEV1, FEV1% and FEF25-75%) were collected in 112 urban industrial workers and 104 rural agricultural workers. These average values, values according to age and smoking habits were compared between urban and rural workers. Inspite of no differences in age, rural workers average height, weight, BSA is significantly lower than urban workers. A significant increase in VC value to the extent of 0.22 lit (7.1%), significantly lower FEV 1% value by 4.7% and reduce FEF25-75% value (4.7%) is demonstrated in rural than urban workers. Smoking is shown to produce airway obstruction in both urban and rural workers. A wide variation of PFT values between the present workers and other reported values in India is observed. This study indicates rural workers have better pulmonary capacity and less flow rates than their urban counterpart.

Pulmonary function status of shopkeepers of Ahmedabad exposed to autoexhaust pollutants.

The study deals with evaluation of pulmonary function status (VC, FEV1% and FEF25-75%) in Ahmedabad shopkeepers stationed near different traffic junctions and relating them with the levels of oxides of nitrogen (NOx) near these junctions categorised as Heavy, Medium and Low polluted area junctions. The pulmonary function test (PFT) values of heavy polluted and medium polluted area shopkeepers is compared with low polluted area shopkeepers. The influence of smoking habits and duration of exposure over PFT values was seen. The prevalence of airway obstruction in shopkeepers was compared with USA population. The results indicated significant impairment in FEV1% and FEF25-75% value in high polluted area shopkeepers where NOx level is much higher than TLV value. In medium polluted area, where NOx level is slightly higher than TLV value, shopkeepers demonstrated significant impairment in FEF25-75%. Smoking is found to have an additive effect. A linear increase in the prevalence of pulmonary impairment with increasing duration of exposure was evidenced. Shopkeepers exhibited higher prevalence of impairment in both smokers and non-smokers than USA population attributing it to the effect of autoexhaust pollutants. This study also denoted that FEF25-75% is an early indicator of obstruction in smaller airways which is the primary site of deposition of inhaled pollutants.

Pulmonary function studies in 15 to 18 years age workers exposed to dust in industry.

Pulmonary function tests (VC, FEV1% and FEF25-75%) were evaluated in 15 to 18 years age workers employed in slate pencil industry exposed to silica dust, in wool carpet industry exposed to wool dust and in diamond cutting and polishing exposed to carbon dust. These values were compared with the values obtained in clinically healthy non-smokers of the same age group. The results revealed significant impairment of VC in diamond workers, and FEF25-75% in slate pencil workers. When the values were observed according to smoking habits in diamond workers, VC, FEV1 and FEF25-75% were all significantly reduced in smokers whereas in non-smokers only VC was lowered significantly. Among slate pencil workers FEF25-75% was significantly reduced in both smokers and non-smokers. Wool dust exposed workers showed reduced values than normal subjects. The detailed results including the prevalence of various pulmonary impairments were presented.

Pulmonary function studies in Gujarati subjects.

In this study a multiple regression equation for prediction of ventilatory pulmonary function tests (FVC, FEV1%, FEF25-75% and PEFR) is developed in average healthy non-smoker male and female Gujarati subjects. The average adult female values showed a reduction varying from 21.0 to 29.0% compared to adult male subjects. There is a deviation of the present study values from other studies in Indian subjects and values from European studies are higher than the present values. This study demonstrated that the present regression equation is the most ideal and appropriate for prediction of pulmonary function values in Gujarati subjects either for assessing physical fitness in normal subjects or for determining the pattern of ventilatory impairment in respiratory disease patients. The pulmonary function values assessed by substituting the average age, height and weight of females in male regression equation revealed lower values in females ranging from 14.0 to 19.0% attributable only due to difference in sex.

Acute effects of heat on neuropsychological changes and physiological responses under noise condition.

To examine the effects of heat and noise individually and jointly on certain physiological responses and cognitive and neuromotor based functions, 12 male participants were tested under 6 experimental conditions which resulted by combining 3 levels of heat (25 degrees, 30 degrees and 35 degrees C) and 2 levels of white noise (70 and 100 dB). The experiment was carried out in a controlled climatic chamber following two 6 x 6 latin square designs. The results indicated elevations in heart rate, oxygen uptake and body temperature due to the independent effect of heat or the combined effects of heat and noise. The independent action of noise was found to be depressive on the first two responses. On the neuropsychological effects, the heat adversely affected the speed in card sorting (by design configuration) and digit symbol tests, and also the accuracy and error rate in the reasoning ability test. The noise caused performance improvements in critical flicker frequency (simultaneous) and in error rates in card sorting (by design configuration). The combined effects of heat and noise indicated higher error rates in card sorting (by face value), decreased accuracy in reasoning ability and improvements in performance in accuracy scores and error rates in digit symbol test.