Instituto Nacional de Salud Pública, Av. Universidad 655, Col. Sta. María Ahuacatitlán, 62100, Cuernavaca, Morelos, CP, Mexico.
Physiology Department, Instituto Nacional de Cardiología Ignacio Chávez, Juan Badiano 1, 14080, Mexico City, C.P, Mexico.
Environ Health. 2019 Apr 11;18(1):33. doi: 10.1186/s12940-019-0470-x.
Adequate maternal thyroxine (T4) concentrations during the first half of pregnancy are fundamental to the embryo's or fetus' neural development. Organophosphate pesticides (OP) can act as thyroid disruptors and genetic polymorphisms for paraoxonase 1 (PON1), an enzyme that detoxifies OP, could be involved in individual's susceptibility to them. We assessed the association between para-occupational exposure to pesticides, including OP, during pregnancy and maternal hypothyroxinemia, as well as the potential genetic susceptibility conferred by PON1 polymorphisms.
We analyzed information from 381 healthy pregnant women (< 17 gestational weeks), who lived in a floricultural region of Mexico where pesticides, including OP, are routinely used. Women who were para-occupationally exposed to pesticides were those whose partner had an occupation involving contact with these products. Thyroid-Stimulating Hormone (TSH) and free T4 concentrations were determined using ELISA, and hypothyroxinemia was defined as free T4 concentrations <0.76 ng/dL. PON1192QR, PON155LM and PON1-108CT polymorphisms were determined through Polymerase Chain Reaction (PCR). The association between para-occupational exposure and genetic polymorphisms and hypothyroxinemia was estimated using logistic regression models.
One hundred and sixty two women (42.52%) were classified as para-occupationally exposed to pesticides. Hypothyroxinemia prevalence was 54%, and it was not significantly associated with pesticide para-occupational exposure (OR: 1.21 95% CI 0.75-1.94). Independently of para-occupational exposure, the likelihood of hypothyroxinemia was higher among women who were carriers of PON155MM than in those with PON155LL genotype (OR : 3.03; 95%CI 1.62, 5.70). PON1192 RR (OR : 1.72; 95%CI 0.93, 3.17) and PON1-108TT (OR : 1.60; 95%CI 0.90, 2.70) genotypes were marginally associated with hypothyroxinemia. No significant interaction was observed between pesticides para-occupational exposure and PON1 polymorphisms.
These results suggest that PON1 polymorphisms could affect thyroid function during pregnancy in women living in areas where pesticides, including OP, are routinely used. Low exposure variability in this population, could be a possible explanation for the lack of association between para-occupational exposure and thyroid function.
妊娠前半期母体甲状腺素（T4）浓度充足对胚胎或胎儿的神经发育至关重要。有机磷农药（OP）可作为甲状腺干扰物，而对氧磷酶 1（PON1）的基因多态性，一种可解毒 OP 的酶，可能与个体对它们的易感性有关。我们评估了妊娠期间职业性接触农药（包括 OP）与母体甲状腺功能减退症以及 PON1 多态性赋予的潜在遗传易感性之间的关联。
我们分析了 381 名健康孕妇（<17 周妊娠）的信息，她们居住在墨西哥一个花卉种植区，那里常规使用农药，包括 OP。职业性接触农药的孕妇是指其伴侣从事接触这些产品的职业。采用 ELISA 法测定甲状腺刺激激素（TSH）和游离 T4 浓度，游离 T4 浓度<0.76ng/dL 定义为甲状腺功能减退症。通过聚合酶链反应（PCR）确定 PON1192QR、PON155LM 和 PON1-108CT 多态性。采用 logistic 回归模型估计职业性接触和遗传多态性与甲状腺功能减退症之间的关联。
162 名女性（42.52%）被归类为职业性接触农药。甲状腺功能减退症的患病率为 54%，与农药职业性接触无显著相关性（OR：1.21，95%CI 0.75-1.94）。独立于职业性接触，PON155MM 携带者发生甲状腺功能减退症的可能性高于 PON155LL 基因型携带者（OR：3.03；95%CI 1.62,5.70）。PON1192RR（OR：1.72；95%CI 0.93,3.17）和 PON1-108TT（OR：1.60；95%CI 0.90,2.70）基因型与甲状腺功能减退症呈边缘相关。未观察到农药职业性接触与 PON1 多态性之间存在显著交互作用。
这些结果表明，PON1 多态性可能会影响在常规使用包括 OP 在内的农药地区生活的孕妇的妊娠期间甲状腺功能。该人群的暴露变异度较低，可能是职业性接触与甲状腺功能之间缺乏关联的一个可能解释。
