Objective: The impact of long term exposure to cholinesterase (ChE)-inhibiting organophosphate (OP) and carbamate (C) pesticides on the respiratory health of agricultural workers in India was investigated.
Methods: Three hundred and seventy-six nonsmoking agricultural workers (median age 41 yr) from eastern India who sprayed OP and C pesticides in the field and 348 age- and sex-matched control subjects with non-agricultural occupations from the same locality were enrolled. Prevalence of respiratory symptoms was obtained by questionnaire survey, and pulmonary function tests were carried out by spirometry. Chronic obstructive pulmonary disease (COPD) was diagnosed by the Global Obstructive Lung Disease (GOLD) criteria, and erythrocyte acetylcholinesterase (AChE) was measured by the Ellman method.
Results: Agricultural workers had greater prevalences of upper and lower respiratory symptoms, and appreciable reduction in spirometric measurements. Overall, lung function reduction was noted in 48.9% of agricultural workers compared with 22.7% of control, and a restrictive type of deficit was predominant. COPD was diagnosed in 10.9% of agricultural workers compared with 3.4% of controls (p<0.05 in chi(2) test), and the severity of the disease was greater in agricultural workers. Red blood cell (RBC) AChE was lowered by 34.2% in agricultural workers, and the fall in AChE level was positively associated with respiratory symptoms, lung function decrement and COPD after controlling for education and income as potential confounders.
Conclusions: Long-term exposure to cholinesterase-inhibiting agricultural pesticides currently in use in India is associated with a reduction in lung function, COPD and a rise in respiratory symptoms.