Relationships of sex hormone levels with leukocyte telomere length in Black, Hispanic, and Asian/Pacific Islander postmenopausal women.

BACKGROUND: Sex hormones may play important roles in sex-specific biological aging. In the study, we specifically examined associations between circulating sex hormone concentrations and leukocyte telomere length (TL). METHODS: A cross-sectional study was conducted among 1124 Black, 444 Hispanic, and 289 Asian/Pacific Islander women in the Women's Health Initiative Observational Cohort. Estradiol and testosterone concentrations were measured using electrochemiluminescence immunoassays; TL was measured using quantitative polymerase chain reaction. RESULTS: Women in the study were aged 50-79 years. Estradiol concentrations were not significantly associated with TL in this sample. The associations between total and free testosterone and TL differed by race/ethnicity (P(interaction)  = 0.03 and 0.05 for total and free testosterone, respectively). Total and free testosterone concentrations were not associated with TL in Black and Hispanic women, whereas in Asian/Pacific Islander women their concentrations were inversely associated with TL (P(trend)  = 0.003 for both). These associations appeared robust in multiple subgroup analyses and multivariable models adjusted for potential confounding factors. In Asian/Pacific Islander women, a doubling of serum free and total testosterone concentrations was associated with a 202-bp shorter TL (95% confidence interval [CI] 51-353 bp) and 203-bp shorter TL (95% CI 50-355 bp), respectively. CONCLUSIONS: Serum estradiol concentrations were not associated with leukocyte TL in this large sample of postmenopausal women. Total and free testosterone concentrations were inversely associated with TL in Asian/Pacific Islander women, but not in Black and Hispanic women, although future studies to replicate our observations are warranted particularly to address potential ethnicity-specific relationships.