Relative handgrip strength, lifestyles and cancer risk in older adults: a multi-country cohort study

BACKGROUND: The role of muscle strength in cancer prevention and the impact of modifiable factors on this association remain unclear. AIM: This study investigated the association between relative handgrip strength and cancer risk while also examining the role of lifestyle factors on this association in adults aged 50+. DESIGN: Prospective cohort study using data from 16 countries across three surveys. METHODS: Relative handgrip strength was the dominant-hand maximum grip divided by body mass index (BMI) and sex-standardized. Cancer cases were self-reported physician diagnoses. Cox proportional hazards models assessed the association between relative handgrip strength and cancer risk. Restricted cubic splines assessed potential nonlinear associations, with dose-response curves illustrating the relationship stratified by three lifestyle factors. RESULTS: Of 29,924 participants, 2614 developed cancer over 8.3 years of follow-up. Each 1-unit increase in relative handgrip strength was associated with a 7% lower cancer risk [HR (95% CI): 0.93 (0.89-0.97)]. Cancer risk declined progressively across strength quartiles, with Quartile 4 showing a 16% lower risk [HR (95% CI): 0.84 (0.74-0.95)] compared to Quartile 1, while Quartile 1 had a 20% higher risk [HR (95% CI): 1.20 (1.06-1.35)] than Quartile 4. Drinkers, smokers and physically inactive individuals consistently exhibited higher cancer risk than their healthier counterparts. A sex-specific tool was developed to estimate relative handgrip strength from BMI and absolute grip strength. CONCLUSION: Higher relative handgrip strength was linearly associated with a lower cancer risk, with a stronger protective effect in individuals with healthy lifestyles.