Name of Department

Division of Clinical Epidemiology

Objective/Function of the Department

  • To carry out epidemiological studies related to hazardous working environment and find out prevalence of morbidity and mortality.
  • To correlate morbidity and mortality with levels of harmful environmental factors and suggest measures to reduce them.
  • To suggest the recommendations for prevention of occupational diseases to the government i.e. enforcing agencies.
  • To train the medical officers/safety officers/hygienists on the subject of occupational health.
  • To create awareness on occupational hazards among the workers and organizations involved in welfare programmes of workers.

Details of Scientific & Technical staff




Dr. H. G. Sadhu
Scientist 'F'
Dr. Ranjana Choudhari
Scientist 'D'
Dr. A. Viramgami
Scientist 'B'
Dr Avinash R Pagdhune Scientist 'B' dravinashpd{AT}gmail{DOT}com
Shri M .H. Vakharia
Shri A.R. Shah
Smt. S.V. Upadhyay
Smt. S.Y. Vaghasiya
Technician 'B'
Shri P M Solanki
Shri Sunil Kr Meena

Laboratory Facilities & Instruments

Respiratory Physiology Division

  • In this department, Lung Function Test measurement and assessment is carried out in epidemiological studies in subjects exposed to vegetable dust (Cotton, Tobacco, wool etc.) mineral dust (silica, asbestos, coal, manganese etc.) and air pollutants (ambient, vehicular indoor and chemical); in patients referred by ESI, Civil Hospitals; in compensation awards of byssinosis, silicosis, asbestosis diseases and in determining normal values. The determination of prevalence rates of different types of functional abnormalities, their association with sex, age, smoking habits, duration of exposure and in relation to respiratory symptoms and pneumoconiosis are evaluated. A dose-response relationship between dust/pollutants exposure with lung function are determined and early detection of functional impairment is carried out. Regular demonstration programmes to the students of medical colleges and in exhibitions are conducted.


  1. Spirometer used in determination of lung function values and flow-volume curves.
  2. Wright Peak Flow Meter For measuring Peak Expiratory Flow rate.
  3. Morgan TLC equipment - For measuring RV, FRC, TLC and spirometry.
  4. Morgan Transfer Test Model - For measurement of transfer factor diffusion capacity of the lung.
  5. Morgan Body Plethysmograph -For determination of Air Way Resistance, Thoracic Gas Volume, Lung Volumes, Flow Volume Curve
  6. Morgan Exercise Test along with Bicycle ergometer -For measuring VO2 max, tidal volume, Respiratory frequency, Heart rate, ECG in Submaximal and Maximal Exercise Test
  7. IL 1312 Blood Gas Manager and Co-oximeter -For determining PO2, PCO2, PH, haemoglobin, oxyhaemoglobin, Carboxyhaemoglobin


On going Proejcts

  1. Child Labour
  2. Silicosis
  3. Firefighters

1. Child Labour, Occupational Health Problems, Evaluation and Control

The project is sponsored by the Ministry of Health and Family Welfare, Govt. of India. In the constitution of India, a poly is declared which preserves the fundamental right and protection of children, ‘Children against exploitation and employment in the hazardous occupations’. As per official statistics 1983, seventeen million children below the age of 15 years are in the country. A large number of them are employed in different occupations, some of them are hazardous from health view point e.g. slate pencil industries, glass industries, carpet industries, match industries, gem polishing industries etc. The national policy on child labour is identified. Some industries where health problems can arise e.g. (a) Match industries, Sivakasi, Tamil Nadu (b) Precious stone polishing industries, Jaipur, Rajasthan (c) Hand made carpet industries, Mirzapur, Bhadoi (Uttar Pradesh) (d) Slate industries, Markapur (Andhra Pradesh).

The main objective of the study is to find out the health status of children engaged in above occupations and also assess the working environment responsible for the health effects. The study has been completed in match industries and the study in the other occupation will be taken up soon.

2. Health Risk Assessment and Development of Intervention Programme in Cottage Industries with High Risk of Silicosis

Pneumoconiosis resulting from exposure to free silica is the commonest, best known and most extensively studied of all occupational diseases of lung. The studies carried out in National Institute of Occupational Health in 1980s showed that in state pencil cutting industry about 55% workers were suffering from silicosis and about 115 workers were suffering from tuberculosis in stone cutting industry 17% workers were suffering from silicosis and 355 were suffering from tuberculosis and in ceramic industry 15% workers were suffering from silicosis and tuberculosis.

Stone quartz grinders are one such groups of unorganized workers exposed to silica dust during the process of crushing the large stones into small pieces and also during loading of the stone quartz into transport vehicles. Most of such stone crushing industries are located at Godhra. Thus as a part of silicosis elimination programme the study of stone quartz grinders was carried out.


  • To study the prevalence of silicosis and other dust related morbidity.
  • To assess the workplace environment for physical and chemical hazards.
  • To study the environment and the health status of the community living in the area surrounding to these industries.
  • To introduce the intervention strategies and preventive technology (like engineering control, and personal protective equipment) to reduce exposure risks to the workers.
  • Creation of awareness in the workers and surrounding community.
  • Manpower development for the compliance of law.

Under this programme, 226 ex-workers of quartz grinding units were studied to determine the prevalence of silicosis and silico-tuberculosis.  The study revealed silicosis in 40 (17.7%), tuberculosis in 12 (5.3%) and silico-tuberculosis in 52 (23.0%) workers according to ILO classification of Pneumoconiosis.  In the month of June 2001, a follow up study of these ex-workers was carried out with the objective to study the progression of lesions and development of new lesions.

In the follow-up study, out of 226 stone quartz grinders only 136 participated.  All these subjects were again subjected to chest radiography and Pulmonary Function Tests.  24 (16.8%) cases of silicosis, 33 (24.3%) cases of silico-tuberculosis and 17 (12.5%) cases of tuberculosis were detected.  63 (46.0%) subjects were free from any respiratory morbidity even in the follow up study.

In the second phase of the study 184 percent workers of quartz stone cruching units were studied.  All these subjects were subjected to complete clinical examination, Pulmonary function testing and chest radiography.  Biochemical analysis for serum Angiotensin Convertase Enzyme (ACE) levels was carried out in 147 subjects and serum copper levels was estimated in 136 subjects.  Chest radiography revealed tuberculosis in 10 (5.5%) subjects, silicosis grade 1/1 in one subject while remaining 172 (93.9%) subjects were normal.  Pulmonary function testing revealed combined type of functional impairment in one subject, restrictive type of impairment in 13 subjects and obstructive type of functional impairment in 17 subjects.  Pulmonary function tests were normal in rest of the subjects.  Mean serum ACE levels in 146 subjects was found to be 67.29 + 14.45 IU/L and the mean serum copper level in 135 subjects was found to be 87.08 + 21.20 μg/dl.

Engineering control system (Local powerful exhaust system) was set up in 12 locations of quartz crushing unit to minimize dust exposure.  Four units had set up such control system in their plants at Godhra.  The dust efficacy testing will be carried in due course.  DMRC, Jodhpur also attempted such type of control system in one of the stone quarries.  The dust efficacy will also be tested in these units.

Other sectors exposed to free silica dust such as ceramic and pottery workers and slate pencil workers will also be covered under this programme.

Future Programmes

  • The epidemiological studies will be carried out about hazardous occupations for which no information is available in Indian working population. This will include industrial as well as agricultural sectors.


Project Completed

  1. Silicosis
  2. Asbestosis
  3. Byssinosis
  4. Tobacco
  5. Agate
  6. Salt Workers

1. Silicosis: Silicosis was studied among following industries

  • Slate pencil industries
  • Agate industries
  • Quartz grinding industries
  • Stone quarries.

The prevalence of silicosis was studied in each industry. The prevalence was very high and cases of simple silicosis and progressive massive fibrosis were found. The mortality was also very high. The intervention measures to reduce the dust level and thereby prevention were recommended for each industries.

2. Asbestosis

Asbestosis was studied in:

  • Asbestos cement industries
  • Asbestos textile industries
  • Asbestos mining and milling industries

The prevalence of asbestosis was higher in asbestos textile and asbestos mining industries.

3. Byssinosis

Byssinosis was studied in cotton textile mills of Ahmedabad. The prevalence of byssinosis was especially high in blow room, card room of spinning dept. of textile mills. To reduce the incidence of byssinosis recommendation were given and the report was submitted to the chief inspector of factories.

Intervention studies were carried out in ginning industries to suggest use of bractless cotton for prevention of byssinosis.

4. Occupational Health of Tobacco Harvesters and their Prevention

The Ministry of Health and Family Welfare, Govt. of India sponsors this project. There are many studies on acute health effects due to green tobacco handling in agricultural workers but no information is available on long term health effects of green tobacco handling. Therefore, the main objective of the study is to find out chronic health effect of exposure to green tobacco during the cultivation of tobacco. The second objective of the study is to evaluate effectiveness of various types of gloves and suggest suitable hand gloves for prevention of absorption of nicotine, which is a toxic chemical in tobacco plants.

The study has been undertaken in Kaira district of Gujarat state where maximum tobacco is grown. 685 exposed workers from three villages and 655 non-exposed workers from two villages were examined in the study. To find out the chronic health effect, prevalence of hypertension, ECG abnormalities, reproductive abnormalities and visual activity were examined in tobacco workers.

The result of the study regarding hypertension, ECG and reproductive abnormalities were compared in exposed and control groups. The data were comparable in both the groups and did not show statistical significance.

To prevent the absorption of nicotine through skin, different types of hand gloves like cotton, cotton PVC polka dots, cotton polyester, only polyester and nylone have been tested for their efficacy and suitability. Before and after the use of gloves sample have been collected, nicotine and its metabolite, cotinine from urine samples have been measured by HPLC method. This work is under progress and results will be reported within a short time.

5. Prevention, Treatment and Control of Silicosis and Silico-tuberculosis among the Agate workers of Khmabhat

This study is sponsored by the Ministry of Health and Family Welfare, Government of India, Agate Industry, a cottage type of industry, which is located in and around Khambhat (Cambay), in Gujarat. Among other processes agate grinding in which agate stones are grinded against a rotating emery wheel, generates lots of silica dust that is most hazardous. An epidemiological study carried out by NIOH in 1987 showed 38.2% prevalence of silicosis among the agate grinders.It was also observed that the dust generated by agate grinding machine also pervaded the indoor air thereby, resulting in dust exposure to the family members and community subjects residing in and neighboring houses although, they are not engaged in this occupation.

The study was undertaken in Khambhat and surrounding villages. A total of 1927 subjects which included 397 present grinders, 341 past grinders, 127 family members, 748 community persons and 314 subjects working in processes other than grinding such as polishing, drilling, chipping etc. In addition 841 subjects who never worked in agate industry were selected as control from two villages situated about 20 km from Khambhat.

Detailed medical examination and chest x-ray were carried out in all the subjects. Pulmonary Function Test (PFT) were carried out in 1575 subjects and serum Angiotensin Convertase Enzyme (ACE) and copper estimation in 342 subjects were carried out.

The prevalence of tuberculosis (TB) in control subjects was 3.7% which is comparable with the national prevalence. As compared to this, the prevalence of tuberculosis (TB) in other categories was significantly higher (18.8-53.7%). The odds ratio of 6.1-6.6% in the categories of community subjects, other workers and family members was significantly higher than the controls, whereas, that in present grinders had odds ratio of 9.6% and in past grinders it was 30.3%.

The prevalence of silicosis was compared in all the groups (6.8-38.1) as compared to controls (zero prevalence). Similarly, the prevalence of silico-tuberculosis was also higher in all the other groups (2.8-27.3) as compared to controls (zero prevalence). The prevalence of silicosis also showed significantly increasing trend with the duration of grinding.

The prevalence of all the three diseases was significantly higher in the subjects having suffered from pulmonary tuberculosis in the past as compared to those who never suffered. Among the subjects with past history of tuberculosis, the odds were at least 9.3 times higher for tuberculosis, 5 times higher for silicosis and 6.2 times for silico-tuberculosis then those without. The levels of serum Angiotensin Convertase Enzyme (ACE) and copper showed significant increase with the increasing grade of profusion in silicosis and silico-tuberculosis.

The multiple regression analysis with adjusted R2 showed 30% variation in profusion grade is explained by serum Angiotensin Convertase Enzyme (ACE), copper, age and tuberculosis status. However, the contribution of serum Angiotensin Convertase Enzyme (ACE) is highest as suggested by the regression co-efficient. Hence, serum Angiotensin Convertase Enzyme (ACE) can be used as a good indicator of progression or profusion of small opacities in workers exposed to the silica dust.


6. Prevention and Control of Occupational Health Hazards Among Salt Workers Working in Remote Desert Areas of Gujarat and Western Rajasthan

Prevention and Control of Occupational Health Hazards Among Salt Workers Working in Remote Desert Areas of Gujarat and Western Rajasthan

The subsoil brine in the desert areas of the Little Rann of Kutch in Gujarat and Western Rajasthan contains very high salinity (15-20%) as compared to that of seawater (3.4%). The workers engaged in the salt production under the unorganized sector have to stay and work in isolation at the remote sites in the adverse weather of the desert during the work season (from October to June). The workers, most of the time barefoot, enter the brine for 6-8 hours during the process of crystal reshuffling. The hazardous effects of intense reflection of sunlight from the salt and a direct effect of sodium chloride dust on mucosa of the eye are responsible for various eye morbidities, whereas the direct contact of feet and hands with highly concentrated salt solution causes different types of skin problems among these workers and are widely reported in the literature.

The National Institute of Occupational Health (NIOH), Ahmedabad, carried out a study in 143 workers (103 men and 40 women) from a salt manufacturing site in the Little Rann of Kutch and a control group of 128 subjects (76 men and 52 women) from a nearby village. The skin abnormalities were observed in 51.74% salt workers as compared to 11.71% controls, whereas the eye abnormalities were noted in 45.45% of workers and 33.59% of control subjects. In addition to this, high prevalence of hypertension was observed in both – the control and exposed groups. The controls had a prevalence of 13.15% in men and 19.23% in women, whereas in the salt workers it was still higher – 40.77% and 30.0% for respective sexes. The exposed group also showed an overall high prevalence of hypertensive retinopathy (22.3% in men and 17.5% in women) as compared to controls.

The causative factor(s) responsible for development of hypertension and hypertensive retinopathy remain to be identified. The repeated injuries by the sharp edges of salt crystals cause lesions such as ulcers, fissures, cracks and warts in the skin. The resultant breech in the integrity of the skin may help enhanced absorption of salt into the body of the workers as their hands and feet remain in prolonged and direct contact with highly concentrated brine during work hours. The drinking water used by the exposed and the control population has a high salt content, which may partly be responsible for the higher prevalence of hypertension. However, this hypothesis needs to be confirmed. To investigate these occupational hazards in depth and for their prevention, an intervention study sponsored by the Ministry of Health and Family Welfare, Government of India, involving 1500 salt workers and 1200 control subjects is planned.

So far, 1332 salt workers and 115 control subjects have been included in the study. Detailed occupational and medical history with skin and ophthalmic examinations along with blood pressure measurement as per the WHO protocol is carried out in these subjects. Investigations like serum urea, cholesterol, creatinine, electrolytes and Angiotensine Convertase Enzyme (ACE), blood haemoglobin, urinalysis and electrocardiography are also carried out. Study of the remaining subjects and data analysis are under progress.


International Programme 

Biological Markers of Manganese Exposure and Effects in Manganese Miners (An INDO-US Collaborative Project). Rural areas of India have manganese that are high enough to be of commercial importance. Mining activity has ongoing for a number of decades. Clinical cases of neurological manganism have been identified among manganese miners. Although the clinical features of the overt diseases have been reasonably well characterized, the appearance and pattern of onset of subtle signs and symptoms of sub-clinical manganism are vague and poorly evaluate. Thus the present study was undertaken with following objectives:

  1. Environmental epidemiological study to evaluate exposure and health effects in miners exposed to manganese.
  2. To characterize neuropathological changes due to exposure to manganese.
  3. To evaluate fine motor coordination and tremor by the use of electronic sensor portable device.
  4. To correlate certain biochemical parameter such as blood/urine manganese, chloride, blood soluble sialic acid levels and blood total nucleotides with the clinical observation.
  5. To find out whether or not there is a link between chronic low level environmental/occupational exposure and development of neurodegenerative changes.

In the first phase of study a total of 465 manganese miners selected randomly were included. Using interview technique as a tool for data collection, the demographic and occupational characteristics were recorded by occupational health physician on a pre-designed and pre-tested proforma. This was followed by detailed clinical examination, pulmonary function testing and chest radiography of each subject. Blood manganese levels were analyzed. Atomic Absorption Spectrophotometer. 47.5% of the subjects belonged to the 35-45 years age group while 43.4% had total exposure duration of less than 15 years were working in mining and filling departments. Tremor (3.4%), tingling and numbness (23.4%), joint pain (32.3%), backache (44.0%) and chest pain (13.1%) were the common symptoms observed. The subjects with three or more neurological symptoms were found to be associated with high levels of manganese in blood suggesting that higher manganese levels may result in neurological disorders. Pulmonary Function Tests revealed that 77 (26.3%) were having respiratory abnormality with 44 (9.0%) restrictive, 26 (15.6%) obstructive and 7 (1.5%) combined type of respiratory abnormality. The morbid conditions were analysed in relation to the factors such as age, smoking habit, obesity status, duration of exposure, department of working and blood manganese levels.

In the second phase a follow-up of these manganese miners was carried out after a period of two years. Out of 465 manganese miners included in first phase only 349 could be included in the follow up study. The data analysis and biochemical analysis is in progress.

Publications and Research Reports

Miscellaneous Information