Serum parathyroid hormone levels predict falls in older adults with diabetes mellitus

OBJECTIVES: To examine the association between serum parathyroid hormone (PTH) levels and incident falls in older adults with diabetes mellitus. DESIGN: Longitudinal analysis of incident falls over 1 year in a substudy of participants with diabetes mellitus in the Health, Aging and Body Composition Study. SETTING: Pittsburgh, Pennsylvania, and Memphis, Tennessee. PARTICIPANTS: Well-functioning, community-dwelling black and white adults aged 70 to 79 with diabetes mellitus (N=472). MEASUREMENTS: Measured baseline serum PTH. Self-report of falls over the subsequent 12 months. Baseline physical performance and self-reported demographic, behavioral, and health status measures including kidney function, chronic conditions, and medication use. RESULTS: One-third (30.3%) of participants reported falling over 1 year of follow-up. Mean baseline serum PTH was 53.5±30.0 pg/mL in nonfallers and 62.6±46.2 pg/mL in fallers (P=.01). For every 1 standard deviation (36 pg/mL) increment in baseline serum PTH, there was approximately a 30% greater likelihood of reporting a fall in the subsequent year, after adjusting for age, sex, race, field center, alcohol consumption, body mass index, physical activity, and winter or spring season (adjusted odds ratio (aOR)=1.30, 95% confidence interval (CI)=1.06-1.59). Further adjustment for kidney function, chronic conditions, medication and supplement use, and physical performance attenuated the association slightly (aOR=1.26, 95% CI=1.01-1.58). A trend remained after additional adjustment for reported falls in the previous year. CONCLUSION: Higher serum PTH was associated with incident falls in older, well-functioning men and women with diabetes mellitus. Further investigation aimed at understanding the underlying mechanism for the association between serum PTH and falls is needed.