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.