The relationship of physical activity and sedentary behavior patterns with osteoporosis in older women: a...

Osteoporosis frequently affects older women and is strongly linked to their daily routines, which include both sedentary behavior (SEB) and physical activities (PA) of different intensities. This study investigates the dose-response relationship of different SEB and PA patterns among community-dwelling older women and assesses the potential impact of time reallocation on osteoporosis risk through an isotemporal substitution analysis.

In this study, 1,106 older women aged between 60 and 70 years in Tianjin participated. Their moderate to vigorous physical activity (MVPA), light physical activity (LPA), and SEB were objectively assessed using an accelerometer. The connection between MVPA, LPA, SEB, and osteoporosis was assessed using binary logistic regression models and isotemporal substitution models.

The osteoporosis group and non-osteoporosis group comprised 461 and 645 subjects respectively, accounting for 41.68 and 58.32% of the total cohort. The osteoporosis group had significantly higher daily SEB compared to the non-osteoporosis group (p < 0.01), whereas LPA (p < 0.05) and MVPA (p < 0.01) were notably lower. Dose-response analysis adjusted for variables revealed: increases of 60 min/d in total SEB, as well as 10-min, 30-min, and 60-min SEB bouts, were positively correlated with the risk of osteoporosis. While increases of 30 min/d in total, sporadic, and bouted LPA were negatively associated with osteoporosis risk. More notably, adding 10 min/d to total, sporadic, and bouted MVPA significantly decreased the risk of osteoporosis (p < 0.01). Isotemporal substitution model analysis demonstrated: replacing 30 min of SEB with equivalent durations of LPA and MVPA increased osteoporosis risk by 9 and 56%, respectively. Substituting 30 min of SEB with equivalent durations of LPA and MVPA reduced osteoporosis risk by 8 and 47%, respectively. Switching 30 min of LPA with the same duration of MVPA reduced osteoporosis risk by 28%, while exchanging 30 min of MVPA with the same duration of LPA showed no significant difference.

PA and SEB in older women exhibit a significant dose-response relationship with osteoporosis. Avoiding prolonged sitting and increasing PA duration both offer protective effects against osteoporosis in older women, with achieving a certain level of MVPA being the most effective protective measure.