Abstract
BACKGROUND: Grip strength is increasingly recognized as a modifiable and easily measurable protective factor against chronic diseases. Lower grip strength may compromise joint stability, predisposing periarticular tissues to local inflammation, which has been implicated in hand osteoarthritis (HOA), a condition affecting approximately 189 million people globally and imposing substantial health and socio-economic burden. Whether lower grip strength is a risk factor for clinically relevant symptomatic HOA remains unclear. We aimed to examine the association between grip strength and incident symptomatic HOA to inform targeted preventive strategies.
METHODS: We conducted prospective cohort studies and Mendelian randomization analyses using data from the Xiangya Osteoarthritis (XO) Study and UK Biobank. Individuals without baseline symptomatic or hospital-diagnosed HOA were included. Genetic instruments for grip strength were derived from genome-wide association studies. Symptomatic HOA in the XO Study was defined as the presence of radiographic HOA with symptoms, whereas hospital-diagnosed HOA in the UK Biobank was ascertained through hospital inpatient records.
RESULTS: Among 2869 XO Study participants (5461 hands; 55.9% women; mean age of 63.2 years), 166 (3.0%) hands developed incident symptomatic HOA during a mean follow-up of 3.7 years. Compared with the lowest grip strength quartile, odds ratios (ORs) and their corresponding 95% confidence intervals (95% CIs) of symptomatic HOA in the second, third and highest quartiles were 0.51 (95% CI, 0.31-0.84), 0.62 (95% CI, 0.39-0.99) and 0.46 (95% CI, 0.28-0.75), respectively (p for trend = 0.003). Similar associations were observed among 481 582 UK Biobank individuals (54.2% women; mean age of 56.4 years). Mendelian randomization analyses showed ORs of genetically determined grip strength of 0.56 (95% CI, 0.40-0.78, p < 0.001) for incident symptomatic HOA in the XO Study and 0.37 (95% CI, 0.25-0.56, p < 0.001) for incident hospital-diagnosed HOA in the UK Biobank.
CONCLUSIONS: Higher grip strength was associated with a lower risk of incident symptomatic HOA. These findings offer empirical evidence that interventions aimed at enhancing grip strength may help prevent symptomatic HOA and reduce its individual and societal burden.