Agricultural Pesticide Exposure, Endocrine Disruption, and Reproductive Health Outcomes Among Rural Male Farmers in North West Nigeria: A Prospective Cohort Study

Endocrine-disrupting pesticides pose increasingly recognized reproductive toxicity risks for male agricultural workers, yet prospective evidence from Nigerian farming communities linking occupational pesticide exposure to endocrine disruption and reproductive outcomes is entirely absent from the literature. This doctoral prospective cohort study investigated associations between organochlorine and organophosphate pesticide exposure, hormonal endocrine disruption, and male reproductive health outcomes among farmers in Kano, Jigawa, and Sokoto States, North West Nigeria. Eight hundred male farmers were enrolled at agricultural season onset and followed for two growing seasons. Pesticide exposure was assessed through dermal patch monitoring, urinary biomarker measurement, and pesticide use diaries. Serum reproductive hormones (testosterone, FSH, LH, and inhibin B), semen analysis parameters, and sperm DNA fragmentation index were measured at baseline, mid-season, and off-season time points. Serum testosterone declined significantly during peak pesticide application periods (mean change: -18.3%), with dose-response relationships confirmed for dialkyl phosphate urinary metabolite concentrations. Sperm concentration, motility, and morphology were significantly impaired during high-exposure periods compared to baseline. Sperm DNA fragmentation index exceeded 25 percent in 38.6 percent of high-exposure farmers at peak season. Hormonal parameters demonstrated partial recovery in off-season assessment, suggesting reversibility at current exposure levels. This study provides the first prospective evidence of pesticide-induced male reproductive endocrine disruption in Nigerian agriculture and recommends integrated pest management adoption, reproductive health surveillance, and revised pesticide regulatory standards. Keywords: pesticide exposure, endocrine disruption, male reproductive health, prospective cohort, North West Nigeria.