DataSheet1_Association between thyroid hormones and cognitive functioning in euthyroid elderly adults: a cross-sectional preliminary study from the NHANES 2011–2012 survey.pdf

ObjectiveChanges in serum thyroid hormone levels may affect cognitive functioning in euthyroid individuals. This study used representative data from the National Health and Nutrition Examination Survey (NHANES) to comprehensively examine the association of thyroid hormones with different tests of cognitive functioning among US elderly people aged ≥60 years.
MethodsThis study was a cross-sectional preliminary study with a total of 734 participants from the NHANES 2011-2012 survey. Thyroid function was measured using competitive binding immune-enzymatic assays, while cognitive functioning was measured using a series of assessments, including the Consortium to Establish a Registry for Alzheimer’s Disease-Word Learning (CERAD W-L), Animal Fluency Test, and Digit Symbol Substitution Test (DSST). Weighted multiple linear regression models and binary logistic regression analyses were used to examine the association between thyroid hormone levels and cognitive functioning. All statistical analyses were performed using SPSS version 20.0, and R software.
ResultsWeighted multivariable linear regression showed that FT3 was negatively associated with the Animal Fluency Test and DSST (β=-0.113, 95% CI: -3.279, -0.803, P=0.001; β=-0.062, 95% CI: -6.565, -0.470, P=0.024, respectively) after adjustment for potential covariates. subgroup analysis stratified by sex revealed a negative association between FT3 levels and the Animal Fluency Test in men (β=-0.163, 95% CI: -4.643, -1.153, P=0.001). For female participants, FT3 was negatively associated with not only the Animal Fluency Test but also DSST (β=-0.099, 95% CI: -3.543, -0.093, P=0.039; β=-0.093, 95% CI: -10.288, -1.326, P=0.011). Binary logistic regression showed that the significantly increased adjusted odds ratios (aORs) (95% CI) between the risk of impaired cognitive functioning and FT3 across Q3 and Q4 compared with Q1 were 2.025 (1.092, 3.753) and 2.365 (1.261, 4.433), respectively, for DSST in overall participants. Furthermore, there were significant differences between participants with and without impaired cognitive functioning for serum FT3 levels in overall participants based on DSST score (P=0.020).
ConclusionsThere was a significant inverse relationship between FT3 levels within the normal range and cognitive functioning after adjusting for potential covariates. Future longitudinal cohort studies should be conducted to determine the causal relationship between thyroid hormone levels and cognitive functioning.

研究目的：血清甲状腺激素水平的变化可能影响甲状腺功能正常个体的认知功能。本研究利用美国国家健康与营养调查（National Health and Nutrition Examination Survey, NHANES）的代表性数据，全面考察了美国60岁及以上老年人群中甲状腺激素与不同认知功能测试指标之间的关联。
研究方法：本研究为横断面预实验，共纳入2011-2012年NHANES队列的734名参与者。甲状腺功能采用竞争性结合免疫酶分析法进行检测，认知功能则通过一系列评估手段进行量化，包括阿尔茨海默病登记联盟词汇学习测试（Consortium to Establish a Registry for Alzheimer’s Disease-Word Learning, CERAD W-L）、动物流畅性测试以及数字符号替换测试（Digit Symbol Substitution Test, DSST）。本研究采用加权多重线性回归模型与二元logistic回归分析，探究甲状腺激素水平与认知功能之间的关联。所有统计学分析均通过SPSS 20.0版本与R软件完成。
研究结果：加权多变量线性回归分析结果显示，在校正潜在混杂变量后，游离三碘甲状腺原氨酸（FT3）水平与动物流畅性测试及数字符号替换测试得分呈负相关（β=-0.113，95%置信区间：-3.279~-0.803，P=0.001；β=-0.062，95%置信区间：-6.565~-0.470，P=0.024）。按性别分层的亚组分析显示，男性群体中FT3水平与动物流畅性测试得分呈负相关（β=-0.163，95%置信区间：-4.643~-1.153，P=0.001）；而女性群体中，FT3水平不仅与动物流畅性测试得分负相关，同时也与数字符号替换测试得分呈负相关（β=-0.099，95%置信区间：-3.543~-0.093，P=0.039；β=-0.093，95%置信区间：-10.288~-1.326，P=0.011）。二元logistic回归分析结果显示，在总体参与者中，以Q1组为参照，Q3与Q4组FT3水平升高与数字符号替换测试认知损伤风险的校正优势比（adjusted odds ratios, aORs）（95%置信区间）分别为2.025（1.092, 3.753）与2.365（1.261, 4.433）。此外，基于数字符号替换测试得分划分的总体参与者中，认知功能损伤组与非损伤组的血清FT3水平存在显著差异（P=0.020）。
研究结论：在校正潜在混杂变量后，正常范围内的血清FT3水平与认知功能呈显著负相关。未来需开展纵向队列研究，以明确甲状腺激素水平与认知功能之间的因果关联。