ABSTRACT
Objective: Composite Dietary Antioxidant Index (CDAI) values serve as a summary of an individual's combined dietary antioxidant intake. Although specific antioxidants are known to reduce thyroid damage from oxidative stress, the relationship between the CDAI and thyroid function remains uncertain. The purpose of this study was thus to investigate this relationship in greater detail while focusing on a representative American adult population. Methods: A total of 6,860 subjects from the 2007-2012 NHANES cohort were included in this study. Associations between CDAI values and thyroid function were evaluated with weighted linear regression models and smoothed curve fitting. Subgroup analyses were also performed. Results: The weighted mean (SD) values for variables analyzed in this study included a CDAI of 0.13 (0.06), serum free T4 (FT4) levels of 0.80 (0.01) ng/dL, and serum total T4 (TT4) levels of 7.80 (0.03) ug/dL. Lower CDAI values were found to be associated with higher levels of FT4 and TT4 using both unadjusted and adjusted models that accounted for relevant confounders (adjusted model, FT4 ß = -0.003, p = 0.005; TT4 ß = -0.035, p < 0.001). This negative correlation persisted when CDAI was categorized into quartiles (FT4, p for trend = 0.014; TT4, p for trend = 0.003). Conclusion: These findings suggest that a diet rich in antioxidants, as reflected by higher CDAI scores, is associated with significant decreases in levels of free and total T4. Further analyses will be necessary to better clarify the underlying mechanisms behind these observations.
ABSTRACT
Controlled Nutritional Status (CONUT) scores have been developed as quantitative tools that can be employed to gauge the nutritional status of individual patients. However, there has been very little research investigating the association between these CONUT scores and the function of the thyroid. As such, the present study was designed to address this research gap through the evaluation of a representative cohort of American adults. National Health and Nutrition Examination Survey (NHANES) data were herein used to separate subjects into those with normal nutritional status (CONUT score: 0-1) from those who were malnourished (CONUT scores > 1). Associations between these CONUT scores and the function of the thyroid were investigated through linear regression modeling, employing weighted analytical strategies and subgroup analyses. Overall, 8,082 individuals from the NHANES 2007-2012 cohort were enrolled in this analysis. These individuals exhibited a weighted mean CONUT score of 0.72 (0.02). 6661 (weighted proportion: 83.12%) in the normal nutritional status group and 1421 (16.88%) in the malnourished group. In adjusted analyses, subjects who were malnourished were found to present with an increase in FT4 levels (ß = 0.033; p < 0.001 together with reduced TT3 levels (ß = -3.526; p = 0.01). The present data offer evidence in support of higher CONUT scores, which correspond to malnutrition, being related to increases in FT4 levels together with reductions in TT3 levels. More studies will be crucial to further probe the mechanistic drivers of these results.