A lifestyle pattern combining active leisure-time behavior with office-based occupation was associated with higher lumbar spine BMD, while an occupationally physical-labor lifestyle was associated with lower hip BMD relative to both other clusters.
Key Findings
Results
Office/mental-labor workers with an active leisure-time lifestyle (OA cluster) showed significantly higher lumbar spine BMD compared to office/mental-labor workers with low leisure-time activity (OL cluster).
Adjusted difference = 0.024 g/cm2 (95% CI 0.012–0.036, P < 0.001)
Analysis used multivariable-adjusted models with age modeled via restricted cubic spline, sex, BMI, and hospital fixed effects
Lumbar spine BMD data were available for 4,028 participants
Associations were broadly consistent across sex, age, and BMI strata, though attenuated among participants aged ≥70 years and those with obesity
Results
Physical-labor workers (PL cluster) showed lower hip BMD than both the OL cluster and the OA cluster, despite the occupational physical activity inherent to manual labor.
PL vs. OL adjusted difference = -0.041 g/cm2 (95% CI -0.056 to -0.027, P < 0.001)
PL vs. OA adjusted difference = 0.028 g/cm2 (95% CI 0.011–0.044, P = 0.002), indicating OA was higher than PL
Hip BMD data were available for 4,654 participants
This finding held despite occupational physical activity inherent to manual labor, suggesting occupation type and leisure activity patterns have distinct effects on BMD
Methods
Three distinct lifestyle clusters were identified through k-means clustering of eight lifestyle variables residualized on age and sex.
Clusters were: office/mental-labor workers with low leisure-time activity (OL), physical-labor workers (PL), and office/mental-labor workers with an active leisure-time lifestyle (OA)
Total sample of 5,324 adults from Beijing collected 2016–2020 in a cross-sectional, multi-center design
Eight lifestyle variables were included in clustering; variables were residualized on age and sex before k-means clustering (k = 3)
Complete lifestyle questionnaire data were required for inclusion
Results
Exercise and sun exposure showed non-linear associations with BMD at both lumbar spine and hip sites in dose-response analyses.
Non-linear associations were identified for both exercise and sun exposure across the full cohort
Analyses were conducted as dose-response and cluster × exposure interaction analyses
These associations did not vary by cluster in the interaction analyses
Results were site-specific (lumbar spine and hip) in their patterns
Results
Calcium supplementation frequency showed a consistent negative linear association with BMD that did not vary by cluster.
The negative linear association was observed at both BMD sites
The association did not differ significantly across the three lifestyle clusters in interaction analyses
This finding was described as not varying by cluster, suggesting it is independent of overall lifestyle pattern
The direction of association (negative) was noted as consistent across the full cohort
Results
Associations between lifestyle clusters and BMD were attenuated among participants aged ≥70 years and those with obesity.
Stratified analyses were conducted by sex, age group, and BMI group
Attenuation was observed specifically in the ≥70 years age group and the obesity BMI group
Overall, associations were described as 'broadly consistent across sex, age, and BMI strata'
These findings suggest effect modification by age and obesity status
Results
The BMD associations exhibited site-specific patterns, with the OA lifestyle advantage most evident at the lumbar spine and the PL disadvantage most evident at the hip.
Lumbar spine BMD was higher in OA vs. OL but hip BMD differences between OA and OL were not the primary reported finding
Hip BMD was lower in PL relative to both OL and OA clusters
The authors describe these as 'site-specific patterns' in their conclusions
This site-specificity suggests that different types of physical activity may load different skeletal sites differently
What This Means
This research suggests that the type of physical activity people engage in — whether through their job or during leisure time — matters for bone health in different ways depending on which bones are measured. Among over 5,000 Chinese adults studied in Beijing, people who worked desk jobs but were physically active in their free time had higher bone density in their lower spine compared to desk workers who were relatively inactive. Surprisingly, people whose jobs involved heavy physical labor had lower hip bone density than both groups of desk workers, even though manual labor involves a lot of movement. This challenges the assumption that any kind of physical activity uniformly benefits bones.
The study also found that exercise and sun exposure (which helps the body produce vitamin D) had non-linear relationships with bone density — meaning there may be an optimal amount rather than a simple 'more is better' effect. Interestingly, taking calcium supplements more frequently was associated with lower bone density across all groups, though the researchers caution this could reflect reverse causation (people with lower bone density may be more likely to supplement). These associations were generally consistent across men and women and different age groups, but were weaker among people over 70 and those with obesity.
This research suggests that leisure-time physical activity may be particularly important for bone health at the spine, and that occupational physical labor — which may involve repetitive, high-impact, or awkward movements rather than the structured exercise seen in leisure activity — does not confer the same skeletal benefits and may even be harmful to hip bone density. Because this was a cross-sectional study (a snapshot in time rather than following people over time), the findings show associations but cannot prove cause and effect. Prospective studies tracking people over time are needed to clarify these relationships and their clinical significance for preventing osteoporosis.
Check Your Own Numbers
Upload your bloodwork. We'll cross-reference your results against this study and 4,700 others.
Lei S, Wang M, Lei X, Lei Z. (2026). Lifestyle clusters and bone mineral density in Chinese adults: a cross-sectional study with cluster analysis.. Frontiers in endocrinology. https://doi.org/10.3389/fendo.2026.1904158