Cholinesterase levels and morbidity in pesticide sprayers in North India

Background Pesticide sprayers in North India use different application methods for different crops. Aims To compare cholinesterase activity and symptoms in knapsack and tractor-mounted pesticide sprayers. Methods Blood cholinesterase activity and symptoms were recorded for 42 knapsack and 66 tractor-mounted sprayers attending a health camp in North India in 2009 and for 30 controls. Results One hundred and eight of 197 (55%) eligible sprayers consented to participate. Mean acetylcholinesterase (AChE) and butyrylcholinesterase activity was 33 and 60% lower, respectively, in knapsack sprayers than in controls (P < 0.001) and 56 and 62% lower, respectively, in tractor-mounted sprayers than in controls (P < 0.001). AChE depletion was greater in tractor-mounted sprayers than in knapsack sprayers (P < 0.001). In knapsack sprayers compared to controls, odds ratios (OR) were significantly raised for musculoskeletal symptoms (OR 3.9, 95% CI 1.03-18) but not for other symptoms. In tractor-mounted sprayers compared to controls, ORs were significantly raised for neurological (OR 7, 95% CI 2-23), ocular (OR 8.7, 95% CI 2.7-32), respiratory (OR 5.14, 95% CI 1-29), cardiovascular (OR 7.5, 95% CI 2-42), gastrointestinal (OR 5.43, 95% CI 2-18) and musculoskeletal (OR 6.12, 95% CI 2-26) symptoms but not for dermal symptoms (OR 1.93, 95% CI 0.3-20). Conclusions The risk of cholinesterase inhibition and symptoms is greater in tractor-mounted than in knapsack pesticide sprayers and in both groups compared to controls. Occupational exposure in pesticide sprayers in North India needs better control, perhaps through redesign of spraying equipment.