Objectives Although some studies have shown a negative relationship between grip strength and hand osteoarthritis (OA), little is known about how grip strength is related to specific radiographic features of hand OA, such as osteophytes, joint space narrowing, and erosion. In addition, no reported study has examined whether grip strength, as a measure of muscle activity, is related to knee OA, which may also show a one-way effect of reduced muscle strength on OA. In this large, population-based cohort study, we took advantage of the availability of subjects without hand pain to evaluate the effect of grip strength on OA using a novel, semi-quantitative grading system. We also examined whether grip strength was related to detailed radiographic features of OA.
Methods Data from 2,251 subjects enrolled in the Dong-gu study, who had no hand joint pain, were analyzed to investigate the relationship between grip strength and OA. Hand grip strength was measured using a hand-held dynamometer, and radiographs of the hand and knee were scored according to a semi-quantitative grading system. Multiple linear regressions were used to explore associations between grip strength and radiographic features of OA.
Results Grip strength in men and women was negatively related to hand (both p<0.001) and knee (men, p<0.001; women, p=0.010) OA after adjusting for confounders. Hand (men, p <0.001; women, p=0.001) and knee (both p<0.001) joint space narrowing showed the strongest associations with low grip strength, regardless of sex. Moreover, the severity of hand osteophytes in women (p=0.001), knee osteophytes in men (p=0.006), hand malalignment (men, p=0.008; women, p=0.041), and subchondral cysts (men, p<0.001; women, p =0.007) was correlated with low grip strength in both sexes.
Conclusions Among subjects without hand joint pain, low grip strength was associated significantly with hand and knee radiographic OA, regardless of sex. Among all types of OA radiographic damage, low grip strength showed the strongest association with joint space narrowing.
Disclosure of Interest None declared