Rationale In the last decade, due to expansion of commercial horticultural green houses and irrigated farms the use of pesticides in Ethiopia has increased dramatically (more than 10-fold) leading to potential health risks.

Objective To investigate if occupational exposure to pesticides is associated with respiratory symptoms and lung function impairments.

Methods and measurements We performed two independent but sequential (2 years apart) cross-sectional surveys. In the first survey we studied respiratory symptoms among 1,104 subjects of which 601 were occupationally exposed to pesticides (applicators and re-entry workers) selected from three commercial farming systems (large scale open farms, large scale greenhouses and small scale irrigated farms) in Ethiopia. In the second survey we performed additionally lung function measurement in 387 subjects of which 206 were occupationally exposed to pesticides (applicator from all the farming systems but only green house re-entry workers). Daily and cumulative lifetime exposure was estimated using detailed exposure algorithms.

Main results Significant (p < 0.05) exposure response associations of respiratory symptoms(chronic cough and shortness of breath) and cumulative and daily pesticide exposure estimates were observed in both surveys. We observed a significant increase in risk for chronic cough OR = 3.15 (95% CI: 1.56–6.36) and shortness of breath OR = 6.67 (95% CI: 2.60–17.58) with exposure status (yes/no) in the first survey. In the second survey symptoms were objectified by significant reductions in FEV1 (140 ml) (95% CI: 30–250 ml), FEF 25–75 (550 ml) (95% CI: 310–800 ml) and risk of FEV1/FVC ratio < 0.8(OR = 4.31) (95% CI: 2.11–8.81) with occupational pesticide exposure.

Conclusions These findings indicate an increased risk of adverse respiratory health. As workers were young (27 years) with effects occurring within a relative short duration of exposure (4 years) implementation of stringent occupational health measures are warranted.