The general population is continuously exposed to phthalates via various consumer products. Epidemiological research relating phthalate exposure to thyroid function during non-developmental periods is limited. This study aimed to investigate the associations between specific serum phthalate metabolites and indicators of thyroid function in adults. We measured 10 serum phthalate metabolites and thyroid hormones – total triiodothyronine (TT3), free thyroxine (FT4) and thyroid stimulating hormone (TSH) – in a subsample of 207 adults from the GraMo cohort. This subsample was made up of men and women (in equal proportions) of middle age (49 ± 17 years) and from Southern Spain (province of Granada). Data on age, sex, body mass index, residence area, tobacco use, alcohol consumption and attained education were obtained from a questionnaire. Phthalate metabolites were log-transformed and categorized into tertiles. Cross-sectional associations of each metabolite with thyroid hormones were analyzed using multivariable-adjusted linear regression models. The mixture effect of metabolite phthalates was assessed using weighted quantile sum regression. After multivariable-adjustment, the following phthalate metabolites were significantly associated with TT3 in a dose-response manner: MMP (β = : 95% confidence interval 0.68,1.12), MEP (β = : 0.44, 0.90), MiBP (β = : 0.21, 0.77), MiDP (β = : 0.03, 0.52), MBzP (β = : 0.28, 0.73), MEHP (β = −: −0.82, −0.35) and MiNP (β = : −0.71, −0.14), when comparing highest vs. lowest exposed. The sum of all metabolites was also linked to FT4 levels. No significant associations were observed for TSH except for MiNP. Although phthalate metabolites with different molecular weight showed opposite associations, overall metabolite concentrations seem to associate with increased TT3 and FT4 serum levels. The cross-sectional nature of this analysis limits causal inference.

中文翻译：

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西班牙南部 GraMo 队列中血清邻苯二甲酸酯代谢物与甲状腺激素的关联

一般人群通过各种消费品持续接触邻苯二甲酸盐。有关邻苯二甲酸盐暴露与非发育期甲状腺功能的流行病学研究有限。本研究旨在探讨成人特定血清邻苯二甲酸酯代谢物与甲状腺功能指标之间的关联。我们在 GraMo 队列中 207 名成年人的子样本中测量了 10 种血清邻苯二甲酸酯代谢物和甲状腺激素——总三碘甲状腺原氨酸 (TT3)、游离甲状腺素 (FT4) 和促甲状腺激素 (TSH)。该子样本由来自西班牙南部（格拉纳达省）的中年（49 ± 17 岁）男性和女性（比例相同）组成。年龄、性别、体重指数、居住地区、吸烟、饮酒和受教育程度等数据均通过问卷获得。邻苯二甲酸酯代谢物进行对数转换并分类为三分位数。使用多变量调整线性回归模型分析每种代谢物与甲状腺激素的横截面关联。使用加权分位数和回归评估代谢物邻苯二甲酸盐的混合效应。多变量调整后，以下邻苯二甲酸酯代谢物以剂量反应方式与 TT3 显着相关：MMP (β = : 95% 置信区间 0.68,1.12)、MEP (β = : 0.44, 0.90)、MiBP (β = : 0.21, 0.77), MiDP (β = : 0.03, 0.52), MBzP (β = : 0.28, 0.73), MEHP (β = -: -0.82, -0.35) 和 MiNP (β = : -0.71, -0.14),比较最高暴露与最低暴露时。所有代谢物的总和也与 FT4 水平相关。除 MiNP 外，未观察到 TSH 显着相关性。尽管不同分子量的邻苯二甲酸酯代谢物表现出相反的关联，但总体代谢物浓度似乎与 TT3 和 FT4 血清水平升高相关。这种分析的横截面性质限制了因果推断。