title: Couples' urinary concentrations of benzophenone-type ultraviolet filters and the secondary sex ratio.
abstract: The secondary sex ratio (SSR), defined as the ratio of males to females at birth, has been investigated in relation to endocrine disruptors to search for environmental toxicants perturbing human sex selection. Benzophenone (BP)-type ultraviolet (UV) filters, which are used in sunscreens and personal care products, have been reported to exert estrogenic and anti-androgenic activities. This study aimed to evaluate the association between maternal, paternal, and couple urinary concentrations of BP-type UV filters and the SSR, given the absence of previous investigation. The study cohort comprised 220 couples who were enrolled in the Longitudinal Investigation of Fertility and the Environment (LIFE) Study between 2005 and 2009 prior to conception and who had a singleton birth during the follow-up period. Couples' urinary concentrations of five BP-type UV filters (ng/mL) were measured using triple-quadrupole tandem mass spectrometry: 2,4-dihydroxybenzophenone (BP-1), 2,2',4,4'-tetrahydroxybenzophenone (BP-2), 2-hydroxy-4-methoxybenzophenone (BP-3), 2,2'-dihydroxy-4-methoxybenzophenone (BP-8), and 4-hydroxybenzophenone (4-OH-BP). Modified Poisson regression models were used to estimate the relative risks (RRs) of a male birth for each BP-type UV filter, after adjusting for potential confounders. When maternal and paternal urinary BP-type UV filter concentrations were modeled jointly, both maternal BP-2 (2nd vs 1st tertile, RR, 0.62, 95% confidence interval [CI], 0.43-0.91) and paternal BP-2 (3rd vs 1st tertile, RR, 0.67, 95% CI, 0.45-0.99; p-trend, 0.04) were significantly associated with an excess of female births. Contrarily, maternal 4-OH-BP was significantly associated with an excess of male births (2nd vs 1st tertile, RR, 1.87, 95% CI, 1.27-2.74; 3rd vs 1st tertile, RR, 1.80, 95% CI, 1.13-2.87; p-trend, 0.02). Our findings provide the first evidence suggesting that BP-type UV filters may affect the SSR. However, future corroboration is needed, given the exploratory design of this study.
authors.affiliation: Department of Preventive Medicine, Catholic University of Daegu School of Medicine, 33 Duryugongwon-ro 17-gil, Nam-gu, Daegu 42472, Republic of Korea; Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, 6100 Executive Boulevard, Rockville, MD 20852, USA. Electronic address: jialove@cu.ac.kr.
authors.forename: Jisuk
authors.initials: J
authors.lastname: Bae
authors.affiliation: Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, 6100 Executive Boulevard, Rockville, MD 20852, USA. Electronic address: kims2@mail.nih.gov.
authors.forename: Sungduk
authors.initials: S
authors.lastname: Kim
authors.affiliation: Wadsworth Center, New York State Department of Health, Empire State Plaza, P.O. Box 509, Albany, NY 12201-0509, USA; Department of Environmental Health Sciences, School of Public Health, State University of New York at Albany, Empire State Plaza, P.O. Box 509, Albany, NY 12201-0509, USA. Electronic address: kurunthachalam.kannan@health.ny.gov.
authors.forename: Kurunthachalam
authors.initials: K
authors.lastname: Kannan
authors.affiliation: Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, 6100 Executive Boulevard, Rockville, MD 20852, USA. Electronic address: louisg@mail.nih.gov.
authors.forename: Germaine M
authors.initials: GM
authors.lastname: Buck Louis
mesh_terms: D001577:Benzophenones / Q000652:urine*; D004781:Environmental Exposure / Q000706:statistics & numerical data*; D004785:Environmental Pollutants; D005260:Female; D006801:Humans; D008297:Male; D012744:Sex Ratio; D013473:Sunscreening Agents / Q000378:metabolism*
chemical_list: D001577:Benzophenones; D004785:Environmental Pollutants; D013473:Sunscreening Agents
keywords: Benzophenones; Endocrine disruptors; Fertility; Sex ratio; Sunscreen agents