Association between thyroid dysfunction and total cholesterol level in an older biracial population: the health, aging and body composition study.

BACKGROUND Thyroid dysfunction increases with age. Less is known about the prevalence of thyroid disease in older black adults and whether an association between thyroid function and serum cholesterol level exists, as in older white adults. METHODS A cross-sectional study of 2799 well functioning white and black participants, aged 70 to 79 years, were recruited for a population-based study. Participants underwent thyrotropin, free thyroxine, and total cholesterol testing; a medical history; and physical measurements. RESULTS Among the entire cohort, 94% were euthyroid based on biochemical testing results. Approximately 10% were taking thyroid hormones. Subclinical hypothyroidism was the most prevalent disorder (3.1% of all participants not taking thyroid hormones), but black men and women had lower rates of this condition than white men and women. After excluding those taking thyroid or lipid medication and adjusting for potential confounders, an elevated thyrotropin level (>5.5 mIU/mL) was associated with a 9 mg/dL (0.23 mmol/L) higher cholesterol level, and a suppressed thyrotropin level (<0.35 mIU/mL) was associated with a 19 mg/dL (0.49 mmol/L) lower cholesterol level. CONCLUSION Healthy community-dwelling older black adults have a lower prevalence of thyroid dysfunction compared with older white adults, but the association between increased thyrotropin and increased cholesterol levels is similar in both races.