[Association between physical activity and sarcopenia among older adults aged 65 and above in longevity areas of China].

The prevalence of sarcopenia among older adults aged 65 and above in 18 longevity areas of China was 50.36%.

• Total sample size was 5,224 adults aged 65 years and above from the Healthy Ageing and Biomarkers Cohort Study (HABCS) conducted in 2021.
• Mean age of participants was (85.42±11.56) years.
• Sarcopenia was evaluated using the SARC-CalF scale.
• Total physical activity, leisure-time activity, and household activity scores [M (Q1, Q3)] were: 52.20 (8.60, 106.00), 8.60 (0.00, 21.40), and 35.00 (0.00, 81.00), respectively.

Every increase of one interquartile range (IQR) in total physical activity score was associated with a 58% reduction in the risk of sarcopenia.

• OR=0.42, 95%CI: 0.37–0.49, after adjusting for confounders.
• Multivariate logistic regression was used for analysis.
• Physical activity was assessed using the Physical Activity Scale for the Elderly (PASE).
• Participants were categorized into four groups: no physical activity, and low, moderate, and high levels defined by tertiles of the activity score among those with activity.

Compared with inactive individuals, low, moderate, and high total physical activity groups showed progressively greater reductions in sarcopenia risk, with a significant exposure-response relationship.

• Low physical activity group: OR=0.60, 95%CI: 0.48–0.75 (40% reduction).
• Moderate physical activity group: OR=0.41, 95%CI: 0.33–0.52 (59% reduction).
• High physical activity group: OR=0.27, 95%CI: 0.21–0.34 (73% reduction).
• Significant exposure-response trend: P for trend <0.001.

Restricted cubic spline (RCS) analysis showed a linear negative relationship between total physical activity score and sarcopenia risk.

• P overall <0.001.
• P nonlinear = 0.290, indicating the relationship was linear rather than nonlinear.
• RCS analysis was used to examine the exposure-response relationship between physical activity score and sarcopenia.

Among individuals who engaged only in leisure physical activity, each IQR increase in leisure activity score was associated with a 15% reduction in sarcopenia risk.

• OR=0.85, 95%CI: 0.79–0.92.
• This subgroup comprised 1,733 participants.
• Low, moderate, and high leisure activity groups showed 41%, 62%, and 61% reductions in sarcopenia risk compared with the inactive group, respectively.
• Significant exposure-response trend: P for trend <0.001.
• RCS analysis revealed a non-linear negative association between leisure activity score and sarcopenia risk (P overall <0.001, P nonlinear=0.001).

Among individuals who engaged only in household physical activity, each IQR increase in household activity score was associated with a 31% reduction in sarcopenia risk.

• OR=0.69, 95%CI: 0.60–0.80.
• This subgroup comprised 2,093 participants.
• Low, moderate, and high household activity groups showed 26%, 42%, and 58% reductions in sarcopenia risk compared with the inactive group, respectively.
• Significant exposure-response trend: P for trend <0.001.
• RCS analysis demonstrated a linear negative association between household activity score and sarcopenia risk (P overall <0.001, P nonlinear=0.579).

The association between leisure-time activity and sarcopenia risk followed a non-linear pattern, whereas total physical activity and household activity showed linear associations with sarcopenia risk.

• Total physical activity vs. sarcopenia: P nonlinear=0.290 (linear).
• Leisure activity vs. sarcopenia: P nonlinear=0.001 (non-linear).
• Household activity vs. sarcopenia: P nonlinear=0.579 (linear).
• All overall associations were significant at P overall <0.001.