Association between physical activity and mortality in patients with osteoporosis: a cohort study of NHANES

We utilized data from the NHANES to investigate the impact of physical activity on mortality in osteoporotic patients. Our study suggests that osteoporotic patients may require higher volumes of physical activity to reduce mortality risk compared to the general population. In osteoporotic patients, the dose-response relationships between physical activity volumes and both all-cause and cardiovascular mortality were linear. In contrast, these relationships were non-linear in participants without osteoporosis. Purpose: To determine the impact of physical activity on mortality in osteoporotic patients. Methods: A total of 5606 participants were included in this study, including 716 osteoporosis patients. Physical activity was assessed using standardized questionnaire. Participants were categorized into four groups: inactive (no physical activity), low active (physical activity volumes < 150 min/week), moderate active (>= 150 min/week but < 300 min/week), and high active (>= 300 min/week). Multivariable Cox regression models, using the inactive group as the reference and adjusted for potential confounders, were performed to estimate the hazard ratio (HR) and 95% confidence interval (CI). Results: Osteoporotic patients demonstrated higher mortality rates attributed to various causes compared to non-osteoporosis participants. Physical activity was associated with lower mortality regardless of osteoporosis status. However, Multivariable Cox regression analysis indicated that among osteoporosis patients, only those engaging in >= 300 min/week physical activity experienced a significant decrease in mortality (all-cause mortality, HR (95% CI) 0.453 (0.268, 0.767) and cardiovascular mortality, HR (95% CI) 0.521 (0.259, 1.049)), surpassing the threshold of 150 min observed in non-osteoporosis patients. In sensitivity analysis, or when the proportion of vigorous physical activity was included as a confounder in the multivariate Cox regression analysis, only the high active group still showed a significant reduction in mortality. No significant interactions were observed when the analysis was stratified according to age, sex, and body mass index (P for interaction > 0.05). Restricted cubic spline analysis revealed a linear relationship between physical activity volume and all-cause mortality (P < 0.01 [overall] and P = 0.470 [non-linearity]) and cardiovascular-specific mortality (P = 0.003 [overall] and P = 0.610 [non-linearity]) in patients with osteoporosis. In contrast, these relationships were non-linear in participants without osteoporosis. Conclusion: Patients with osteoporosis need to engage in >= 300 min/week physical activity to significantly reduce their mortality risk. And the higher the volume of physical activity, the lower the risk of death.