Recent declines in the secondary sex ratio (SSR), defined as the ratio of males to females at birth, in some industrialized countries may be attributed to exposure to environmental toxicants such as persistent organic pollutants (POPs). This study aimed to evaluate the association of couples’ preconception exposure to POPs with the SSR. The study cohort comprised 235 couples who were enrolled in the Longitudinal Investigation of Fertility and the Environment (LIFE) Study between 2005 and 2009 prior to conception and prospectively followed through delivery of a singleton birth. Upon enrollment, couples’ serum concentrations (ng/g) were measured for 9 organochlorine pesticides, 1 polybrominated biphenyl, 10 polybrominated diphenyl ethers, and 36 polychlorinated biphenyls (PCBs). Birth outcome data including infant sex were collected upon delivery. Modified Poisson regression models were used to estimate the relative risks (RRs) and 95% confidence intervals (CIs) of a male birth for each chemical. Of the 56 POPs examined, maternal PCB 128 and paternal hexachlorobenzene were significantly associated with a female excess (RRs, 0.75 [95% CI, 0.60–0.94] and 0.81 [95% CI, 0.68–0.97] per 1 SD increase in log-transformed serum chemical concentrations, respectively), whereas maternal mirex and paternal PCB 128 and p,p′-dichlorodiphenyldichloroethylene were significantly associated with a male excess (RR range, 1.10–1.22 per 1 SD increase in log-transformed serum chemical concentrations). After adjusting for multiple comparisons, only maternal mirex remained significantly associated with the SSR. This exploratory study on multiple classes of POPs demonstrated no conclusive evidence on the association between parental preconception exposure to POPs and the SSR.

在一些工业化国家中，次要性别比（SSR）的最近下降是指出生时男性与女性的比率，这可能归因于暴露于诸如持久性有机污染物（POPs）之类的环境毒物。这项研究旨在评估夫妻对POPs的先入之见与SSR的关联。该研究队列包括235对夫妇，他们在受孕之前进入2005年至2009年间参加生育力和环境纵向调查（LIFE）研究，并有意进行分娩。入组后，测量夫妇的血清浓度（ng / g），其中包括9种有机氯农药，1种多溴联苯，10种多溴联苯醚和36种多氯联苯（PCB）。分娩时收集包括婴儿性别在内的出生结局数据。修改后的Poisson回归模型用于估算每种化学品男性出生的相对风险（RRs）和95％置信区间（CIs）。在检验的56种POPs中，母体PCB 128和母体六氯苯与女性过量显着相关（logs-每增加1 SD，RRs 0.75 [95％CI，0.60-0.94]和0.81 [95％CI，0.68-0.97]”母体灭蚁灵和父本PCB 128以及p，p'-二氯二苯基二氯乙烯与男性过量显着相关（RR范围，对数转换后的血清化学浓度每增加1 SD，RR范围为1.10-1.22）。在调整了多个比较后，只有母体灭蚁灵仍与SSR显着相关。