Fruit and vegetable intake and their pesticide residues in relation to semen quality among men from a fertility clinic

Abstract

Study question: Is consumption of fruits and vegetables with high levels of pesticide residues associated with lower semen quality?

Summary answer: Consumption of fruits and vegetables with high levels of pesticide residues was associated with a lower total sperm count and a lower percentage of morphologically normal sperm among men presenting to a fertility clinic.

What is known already: Occupational and environmental exposure to pesticides is associated with lower semen quality. Whether the same is true for exposure through diet is unknown.

Study design, size, duration: Men enrolled in the Environment and Reproductive Health (EARTH) Study, an ongoing prospective cohort at an academic medical fertility center. Male partners (n = 155) in subfertile couples provided 338 semen samples during 2007-2012.

Participants/materials, setting, methods: Semen samples were collected over an 18-month period following diet assessment. Sperm concentration and motility were evaluated by computer-aided semen analysis (CASA). Fruits and vegetables were categorized as containing high or low-to-moderate pesticide residues based on data from the annual United States Department of Agriculture Pesticide Data Program. Linear mixed models were used to analyze the association of fruit and vegetable intake with sperm parameters accounting for within-person correlations across repeat samples while adjusting for potential confounders.

Main results and the role of chance: Total fruit and vegetable intake was unrelated to semen quality parameters. High pesticide residue fruit and vegetable intake, however, was associated with poorer semen quality. On average, men in highest quartile of high pesticide residue fruit and vegetable intake (≥1.5 servings/day) had 49% (95% confidence interval (CI): 31%, 63%) lower total sperm count and 32% (95% CI: 7%, 58%) lower percentage of morphologically normal sperm than men in the lowest quartile of intake (<0.5 servings/day) (P, trend = 0.003 and 0.02, respectively). Low-to-moderate pesticide residue fruit and vegetable intake was associated with a higher percentage of morphologically normal sperm (P, trend = 0.04).

Limitations, reasons for caution: Surveillance data, rather than individual pesticide assessment, was used to assess the pesticide residue status of fruits and vegetables. CASA is a useful method for clinical evaluation but may be considered less favorable for accurate semen analysis in the research setting. Owing to the observational nature of the study, confirmation is required by interventional studies as well.

Wider implications of the findings: To our knowledge, this is the first report on the consumption of fruits and vegetables with high levels of pesticide residue in relation to semen quality. Further confirmation of these findings is warranted.

Study funding/competing interests: Supported by National Institutes of Health grants ES009718, ES022955, ES000002, P30 DK046200 and Ruth L. Kirschstein National Research Service Award T32 DK007703-16. None of the authors has any conflicts of interest to declare.

Keywords: fruits and vegetables; pesticide; semen quality.

Figure 1

Adjusted total normal sperm count and total motile sperm count according to quartile intake of high or low-to-moderate pesticide fruits and vegetables (n = 155 men, 338 semen samples). Values are adjusted normal count (95% CI) across (A) quartiles intake of high pesticide residue fruits and vegetables (P-trend = 0.003) and (B) intake of low-to-moderate pesticide residue fruits and vegetables (P-trend = 0.15); adjusted motile count (95% CI) across (C) quartiles intake of high pesticide residue fruits and vegetables (P-trend = 0.003) and (D) intake of low-to-moderate pesticide residue fruits and vegetables (P-trend = 0.17); the results are adjusted for total energy intake, abstinence time, age, BMI, physical activity, race, prudent and western dietary patterns, smoking status and history of varicocele. (A) and (C) were additionally adjusted for low-to-moderate pesticide fruit and vegetable intake. (B) and (D) were additionally adjusted for high pesticide fruit and vegetable intake. Tests for trend were conducted across quartiles using the median value of a variable in each quartile. Asterisks represented significant differences between groups, *P < 0.05. Error bar indicated 95% CI. L-M, low-to-moderate.

Figure 2

Adjusted prevalence of excellent sperm quality according to quartile intake of high or low-to-moderate pesticide fruits and vegetables (n = 155 men, 338 semen samples). Excellent sperm quality is defined as semen sample that met the following criteria: total sperm count ≥39 million, sperm concentration ≥15 million/ml, total motility ≥40%, normal morphology ≥4% and ejaculate volume ≥1.5 ml. Values are adjusted prevalence of excellent sperm quality (95% CI) across (A) quartiles intake of high pesticide residue fruits and vegetables (P-trend = 0.05) and (B) intake of low-to-moderate pesticide residue fruits and vegetables (P-trend = 0.79); results are adjusted for total energy intake, abstinence time, age, BMI, physical activity, race, and western dietary patterns, smoking status and history of varicocele. (A) was additionally adjusted for low-to-moderate pesticide fruit and vegetable intake. (B) was additionally adjusted for high pesticide fruit and vegetable intake. Tests for trend were conducted across quartiles using the median value of a variable in each quartile. Asterisks represented significant differences between two groups, *P < 0.05. Error bar indicated 95% CI.