A prospective cohort study on the independent and combined effects of body mass status and grip strength on premature...

Obesity and handgrip strength are independently associated with mortality risk; however, research evidence regarding their effects on premature mortality risk, either individually or in combination, remains limited. Concurrently, the European Association for the Study of Obesity (EASO) has introduced a novel obesity classification framework offering more refined criteria for weight status categorisation. Research re-evaluating the relationship between obesity and mortality risk based on this new framework is urgently required.

To investigate the association between weight status (WS), handgrip strength (HGS), their combined effect, and premature mortality risk.

This study utilised data from the UK Biobank (2006-2010) to construct a dynamic cohort of older adults (aged ≥60.0 years). Multivariable Cox proportional hazards models were employed to analyse the independent associations of body weight status and HGS, as well as their combined effects, with the risk of premature mortality. Heterogeneity was explored by stratifying for age, sex, and age at death.

The study ultimately included 200,405 older adults. During a median follow-up of 5311.0 days, 28,094 all-cause mortality and 5172 premature mortality (2.6%) occurred. Obesity prevalence was significantly higher (62.5%) when defined by the new EASO framework compared to BMI-based obesity (24.9%). After adjusting for confounding factors, both weight category and muscular function were independently associated with premature mortality under the new classification. Compared to individuals with normal weight, underweight individuals (HR = 2.40, 95% CI: 1.79-3.23) and obese individuals (HR = 1.07, 95% CI: 1.00-1.14) exhibited significantly elevated premature mortality risks. Conversely, overweight individuals demonstrated a significantly reduced risk of premature mortality (HR = 0.78, 95% CI: 0.69-0.89). Compared with normal grip strength, abnormal grip strength increased premature mortality risk (HR = 1.46, 95% CI: 1.35-1.57). In the combined analysis of weight categories and grip strength, the underweight with abnormal grip strength (UW/A-HGS) group exhibited the most pronounced increase in premature mortality risk relative to the normal weight with normal grip strength group (HR = 4.96, 95% CI: 3.07-8.01). Conversely, a significantly decreased risk was observed in the overweight with normal grip strength group (HR = 0.79, 95% CI: 0.69-0.91). Stratified analysis revealed notable gender- and age-specific differences in outcomes.

This study demonstrates that: 1) The new obesity criteria significantly enhance obesity detection rates and improve mortality risk prediction sensitivity; 2) Both weight status and grip strength independently and synergistically influence premature mortality risk; 3) Combined assessment of WS and HGS significantly optimises premature mortality risk stratification in older adults, with effects exhibiting gender and age heterogeneity. Integrating the EASO obesity criteria with grip strength into geriatric health assessment systems enables more precise identification of high-risk populations, providing critical scientific evidence for early intervention and personalised health management.