Investigation of associations between exposures to pesticides and testosterone levels in Thai farmers

Abstract

We conducted a cross-sectional study to assess the relationship between pesticide exposures and testosterone levels in 133 male Thai farmers. Urine and serum samples were collected concurrently from participants. Urine was analyzed for levels of specific and nonspecific metabolites of organophosphates (OPs), pyrethroids, select herbicides, and fungicides. Serum was analyzed for total and free testosterone. Linear regression analyses revealed significant negative relationships between total testosterone and the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) after controlling for covariates (eg, age, BMI, smoking status). Positive significant associations were found between some OP pesticides and total testosterone. Due to the small sample size and the observational nature of the study, future investigation is needed to confirm our results and to elucidate the biological mechanisms.

Exposure to Organophosphate and Neonicotinoid Insecticides and Its Association with Steroid Hormones among Male Reproductive-Age Farmworkers in Northern Thailand

“…Most participants in the previous study were overweight or obese and a negative correlation between BMI and the testosterone level has been reported [ 40 , 41 ]. Furthermore, an epidemiological study reported that the mean testosterone levels in Thai male farmers and Venezuelan farmworkers were 7.4 and 6.7 ng/mL, respectively, which is similar to the level in our study [ 12 , 16 ]. In comparison with our study, a lower testosterone level (4.5 ng/mL) was reported in Mexican male floriculture workers during intense pesticide spraying, but a similar level (7.6 ng/mL) was reported during less intense pesticide spraying [ 9 ].…”

“…In comparison with our study, a lower testosterone level (4.5 ng/mL) was reported in Mexican male floriculture workers during intense pesticide spraying, but a similar level (7.6 ng/mL) was reported during less intense pesticide spraying [ 9 ]. This indicates that testosterone levels in our participants were within the normal range according to the World Health Organization guidelines and higher levels were found in males who had worked in agricultural fields for at least 1–20 years [ 9 , 16 , 42 ].…”

“…In each model, the urinary DAP and NEO/m concentration was the independent variable while the serum steroid hormone was the dependent variable. Each model was adjusted for age, body mass index (BMI), smoking status, alcohol consumption, ethnicity, education level, monthly income, total number of years spent as farmworker, status of farmworker, number of days per week and hours per day worked in the field, duration of last pesticide use prior to sample collection and hematological status based on current scientific knowledge [ 9 , 16 ].…”

“…Several investigations have reported a decline in sperm concentrations and sperm counts related to pesticides, leading to poor semen quality and reproductive hormones alterations in males [ 12 , 15 ]. A recent study of farmworkers in northern Thailand investigated the associations of pesticides with testosterone [ 16 ]. It found an association between OP metabolites and total testosterone; however, statistical significance association might be random due to the small sample size [ 16 ].…”

“…A recent study of farmworkers in northern Thailand investigated the associations of pesticides with testosterone [ 16 ]. It found an association between OP metabolites and total testosterone; however, statistical significance association might be random due to the small sample size [ 16 ].…”