Relationship between Body Mass Index and Thyrotropin in Euthyroid Women: Differences by Smoking, Race and Menopausal Status

摘要

Objective: To evaluate potential effect modifications on the association between BMI and thyrotropin (TSH) by smoking, race, and menopausal status among euthyroid women. Methods: A cross-sectional population-based study was carried out in the city of Rio de Janeiro, Brazil, in 2004–2005. Households (1,500) were selected using three-stage probability sampling. A sample of 1,084 women aged 35 years or older and with TSH values within the reference range (0.3–4.0 mIU/l) was investigated. Weight and height were measured at household and blood collected for serum TSH and anti-thyroperoxidase (anti-TPO) antibody analysis. Results: Overall, BMI was positively and significantly associated with serum TSH (β = 0.87; p = 0.001). This association was modified by smoking, race, and menopausal status (p Conclusion: BMI was positively associated with serum TSH specifically in its normal range, but only for those women who tested negative for anti-TPO. Smoking and race are negatively associated with anti-TPO, possibly explaining the effect modification observed.