Integrating Leg-Press Strength and Nutritional Status Improves 16-Year Mortality Risk Stratification in General Older Adults.

backgroundMalnutrition and muscle weakness are critical prognostic factors for mortality in older adults. While indices like the Geriatric Nutritional Risk Index (GNRI) are well-established, the long-term prognostic value of integrating nutrition with muscle strength (MS) remains insufficiently established in community-dwelling populations. Currently, very few studies have evaluated the effects on mortality of directly measured leg-press strength, which includes most of the major leg muscles in both lower extremities and involves a substantially larger muscle volume than handgrip or quadriceps muscle strength. This study aimed to clarify whether directly measured leg-press strength predicts mortality and whether integration with GNRI (MS-GNRI) enhances mortality risk stratification.

methodsWe analysed data from 1065 Japanese community-dwelling individuals aged ≥ 70 years from the Tsurugaya Project, followed for 16 years. Participants were categorized into two groups based on optimal cutoff values for directly measured leg-press strength adjusted for body size (high and low) or by GNRI (poor and good), respectively. Finally, these baseline classifications were integrated to stratify participants into the following four MS-GNRI groups: (1) high-strength/good-GNRI, (2) high-strength/poor-GNRI, (3) low-strength/good-GNRI and (4) low-strength/poor-GNRI. Hazard ratios (HRs) for all-cause mortality were calculated using Cox proportional hazards models.

resultsDuring the follow-up, 415 deaths occurred. Low leg-press strength and poor GNRI were independently associated with higher mortality than high strength and good GNRI, respectively; adjusted HRs were 1.81 (95% CI: 1.45-2.25) and 1.59 (1.30-1.95), respectively (both p < 0.01). The MS-GNRI revealed a survival gradient: Using the high-strength/good-GNRI group as the reference, adjusted HRs (95% CI) were 1.55 (1.18-2.03) for the high-strength/poor-GNRI group, 1.69 (1.29-2.23) for the low-strength/good-GNRI group and 2.47 (1.78-3.13) for the low-strength/poor-GNRI group (p for trend < 0.001). Notably, the high-strength/poor-GNRI group and the low-strength/good-GNRI group showed comparable survival probabilities. MS-GNRI significantly improved predictive accuracy and risk reclassification over either indicator alone (Net Reclassification Improvement: 0.62 over strength; 0.41 over GNRI).

conclusionsDirectly measured leg-press strength is a potent predictor of all-cause mortality. Integrating muscle strength with nutrition via MS-GNRI enhanced mortality risk stratification, suggesting that preserved muscle strength may substantially contribute to longevity alongside nutritional maintenance.