Accelerometer-measured weekly and diurnal moderate-to-vigorous physical activity patterns and incident osteoporosis

This study investigated accelerometer-derived MVPA patterns and osteoporosis risk. Weekend warrior pattern demonstrated comparable osteoporosis risk reduction to regular activity. Performing MVPA maximally reduces osteoporosis risk in elderly and high-genetic-risk individuals, and evening/mid-morning timing offers optimal protection. Findings guide personalized exercise timing to mitigate osteoporosis, especially for vulnerable groups.

This study investigated the association between accelerometer-measured "weekend warrior (WW)" pattern and the risk of osteoporosis and also explored the differential impacts of diurnal moderate-to-vigorous physical activity (MVPA) patterns on osteoporosis risk.

We included 69,310 UK Biobank participants with valid wrist-worn accelerometer data. Based on World Health Organization (WHO) guidelines (≥ 150.0 min/week), we categorized participants as inactive (MVPA < 150.0 min/week), active regular (MVPA ≥ 150.0 min/week and ≥ 50% of total MVPA occurred within > 2 days), and active WW (MVPA ≥ 150.0 min/week and ≥ 50% of total MVPA occurred within 1-2 days). For guideline-adherent individuals, diurnal MVPA patterns were classified via K-means clustering based on hourly activity distribution. The study outcome was incident osteoporosis. Osteoporosis cases were identified using International Classification of Diseases 10th Revision (ICD-10) codes M80, M81, and M82 within the "first occurrence" field.

During a median follow-up of 7.7 years, 1544 participants developed osteoporosis (OP). In multivariable-adjusted models, both active WW (HR: 0.78, 95% CI: 0.69-0.89) and active regular (HR: 0.77, 95% CI: 0.67-0.87) participants demonstrated comparable and statistically significant risk reductions compared with inactive individuals. For diurnal MVPA patterns, we used the early-afternoon group as the reference; the evening and mid-morning groups exhibited equivalent risk reductions, and they were (HR: 0.67, 95% CI: 0.52-0.87) and (HR: 0.69, 95% CI: 0.54-0.87), respectively. The early-morning group was associated with modest risk reduction (HR: 0.77, 95% CI: 0.64-0.92).

Accumulating MVPA predominantly within 1-2 days confers osteoprotective benefits comparable to evenly distributed weekly activity. Furthermore, the optimal time for osteoporosis risk reduction occurs during evening and mid-morning, followed by early-morning.