Exposure to insecticides and impact on steroid hormones in farmworkers in Chiang Mai Province

Abstract

Chiang Mai province. The present study evaluated the exposure to organophosphates (OPs) and neonicotinoids (NEOs) among reproductive-age farmworkers and estimated the association between organophosphate metabolites, dialkylphosphates (DAPs), and neonicotinoids and their metabolites (NEO/m) and steroid hormones. In addition, this study was to investigate the association between DAP and NEO/m and haematological parameters among male farmworkers in Fang district, an intensive agricultural area of Chiang Mai province. This study was a cross-sectional study in reproductive-age farmworker couples. Urinary concentrations of DAP, including dimethylalkylphosphates (DMPs) and diethylalkylphosphates (DEPs), were analysed in 288 urine samples collected from 144 farmworker couples using gas chromatography coupled with flame photometric detection (GC-FPD). The results showed that concentrations of DEPs were highly than DMPs. Diethylphosphate, diethylthiophosphate, diethyldithiophosphate were detected for 100, 99 and 79% of analysed samples and their concentrations were 20.7, 23.9 and 9.3 ng/mL, respectively. Urinary concentrations of NEO/m were also measured in 288 samples using liquid chromatography tandem mass spectrometry (LC-MS/MS). NEO/m including N-desmethyl-acetamiprid (N-dm-ACE), imidacloprid (IMI), clothianidin (CLO), thiamethoxam (THX) and IMI-olefin (Of-IMI) were most frequently detected for 99, 99, 96, 95 and 56% of analysed samples and their concentrations were 25.4, 11.3, 17.5, 32.7 and 4.4 ng/mL, respectively. The haematological parameters were measured in 143 male farmworkers using automated haematology analyser. The average haematological parameters of all samples were normal. The mean of haemoglobin was 15.1 g/dL, haematocrit was 46.2%, mean corpuscular volume was 87.4 fL, mean corpuscular haemoglobin was 28.6 pg, mean corpuscular haemoglobin concentration was 32.7 g/dL, red cell distribution width was 12%, red blood cell count was 5.3 x 106/uL, white blood cell count was 6300 cells/uL, neutrophil was 60.4%, lymphocyte was 37.2%, eosinophil was 1.0%, monocyte was 1.1%, and platelet was 229,000 cells/uL. The overall mixed exposure to OP and NEO/m was significantly associated with mean corpuscular haemoglobin concentration (MCHC). CLO showed obviously decreasing association with MCHC among male farmworkers. The steroid hormones were analysed in serum samples of 143 male farmworkers by using LC-MS/MS. The results showed that androstenedione, cortisol, cortisone, dehydrocorticosterone (DHC), dehydroepiandrosterone (DHEA), deoxycorticosterone (DOC) and testosterone ranged from 0.8-140 ng/mL. A significant association between NEO/m and steroid hormones among male farmworkers were found. IMI level was positively associated with testosterone (B = 0.24; 95% CI =0.04,0.43), DHC (B = 0.23; 95% CI = 0.04, 0.42) and DHEA (B = 0.29, 95% CI = 0.12, 0.45) levels. Of-IMI and DHEA (B = 0.22; 95% CI = 0.05, 0.39) levels were positively associated. THX were negatively associated with DHC (B = -0.18; 95% CI = -0.35, -0.003) and DOC (B = -0.15; 95% CI =-0.29,-0.002) levels. CLO (B = 0.26; 95% CI = 0.08,0.45), THX (B = 0.19; 95% CI = 0.01, 0.38) and N-dm-ACE (B = 0.37; 95% CI = 0.20, 0.54) levels were positively associated with the androstenedione level. CLO (B = -0.22; 95% CI = -0.31, - 0.05) and THX (B = -0.19; 95% CI = -0.32, -0.06) levels were negatively associated with the cortisone level.