Association between the overnight urinary cortisol-to-creatinine ratio and self-reported osteoporosis in community-dwelling Taiwanese adults: a population-based cross-sectional study

Chronic psychosocial stress is increasingly recognized as an important determinant of healthy aging and may contribute to osteoporosis through activation of the hypothalamic–pituitary–adrenal (HPA) axis. However, the association between physiological variation in endogenous cortisol and osteoporosis remains uncertain. This population-based cross-sectional study included 847 community-dwelling adults aged ≥ 53 years from the 2006 Social Environment and Biomarkers of Aging Study (SEBAS) in Taiwan. Urinary cortisol was measured using 12-hour overnight urine specimens and expressed as a urinary cortisol-to-creatinine ratio. Participants were categorized into quartiles. Multivariable logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for self-reported osteoporosis. The mean age of participants was 65.6 ± 9.5 years, and 46.5% were women. Compared with participants in the lowest quartile, the adjusted ORs for self-reported osteoporosis were 1.04 (95% CI, 0.60–1.79), 1.07 (95% CI, 0.63–1.84), and 1.21 (95% CI, 0.70–2.08) for the second, third, and fourth quartiles, respectively. None of the associations reached statistical significance, and no significant linear trend was observed ( P for trend = 0.463). In exploratory subgroup analyses, an interaction by age group was observed ( P for interaction = 0.004); however, neither age group showed a consistent monotonic association across cortisol quartiles. The urinary cortisol-to-creatinine ratio was not significantly associated with self-reported osteoporosis in this population-based sample of middle-aged and older Taiwanese adults. The exploratory age interaction requires cautious interpretation and confirmation in larger prospective studies incorporating repeated cortisol measurements and objective assessments of bone health.