Preconception, gestation, and childhood exposure to air pollution and risk of polycystic ovary syndrome (PCOS) in a US girls cohort study

Abstract

Background: Exposure to ambient air pollution (AP) during sensitive developmental periods could dysregulate the reproductive system, resulting in later in life menstrual disorders, including polycystic ovary syndrome (PCOS). Minimal research exists examining the relationship between AP exposure and PCOS.

Objectives: To determine if residential ambient particulate matter (PM) and nitrogen dioxide (NO₂) exposure during preconception, gestation, and childhood increases the risk of PCOS.

Methods: We used data from 3,321 female participants with gestational data available born between 1989 and 1994 in the Growing Up Today Study 2 (GUTS2), an ongoing United States (US) cohort initiated in 2004. Exposure to ambient PM (≤2.5, 2.5-10, and ≤ 10 μm) and NO₂ were estimated using nationwide spatiotemporal models based on biennially updated maternal residential addresses. Conception month was estimated based on reported gestational age and participant date of birth. Preconception was defined as the three months before the estimated conception month. Gestation was defined as conception month to date of birth. The gestational period was further stratified by first, second, and third trimester, calculated from conception month and date of birth. Childhood exposure was defined as the averaged monthly exposure from birth to age at menarche. Participants self-reported PCOS via questionnaires. Hazard ratios (HR) were estimated for PCOS per interquartile range increase using Cox proportional hazard models with combined inverse probability weights.

Results: In total, 7.1 % of participants self-reported a PCOS diagnosis. Exposure to PM_2.5 in the first trimester showed an higher risk of PCOS (aHR 1.38 [95 % CI 1.03, 1.85] per 5.4 μg/m³). Exposure to PM_2.5-10, PM₁₀, and NO₂ during preconception, gestation, and childhood showed little association of PCOS risk, with the exception of PM₁₀ exposure during the first trimester which showed a suggestive association of higher PCOS risk (aHR 1.29 [95 % CI 0.97, 1.72] per 9.6 μg/m³).

Discussion: Higher exposure to PM_2.5 in the first trimester was associated with an increased risk of PCOS.

Keywords: Air pollution; Environmental exposure; Nitrogen dioxide; Particulate matter; Polycystic ovary syndrome; Reproductive health; Traffic-related air pollution.