The relationship between obesity/abdominal obesity and osteoarthritis in American adults: Evidence from NHANES 2005 to 2018

Osteoarthritis (OA) is a prevalent musculoskeletal disorder worldwide, and its onset is closely associated with obesity. The prevalence of obesity among American adults continues to rise; however, the impact of different types of obesity (general obesity vs abdominal obesity) on OA remains to be thoroughly investigated. This study utilized data from the National Health and Nutrition Examination Survey in the United States between 2005 and 2018, incorporating 21,709 participants aged 20 years and above. The association between OA and both body mass index (BMI) and waist circumference (WC) was analyzed using multivariate logistic regression. The models were adjusted for demographic characteristics, lifestyle factors, and metabolic factors, and restricted cubic spline analysis was employed to examine the dose-response relationship. The fully adjusted multivariable analysis demonstrated significant positive associations of both BMI (odds ratio [OR] = 1.06, 95% confidence interval [CI]: 1.05-1.07) and WC (OR = 1.02, 95% CI: 1.02-1.03) with OA prevalence. Participants with obesity (BMI ≥ 30 kg/m²) exhibited an adjusted OR of 2.72 (95% CI: 1.67-4.43) for OA versus the underweight group (BMI < 18.5 kg/m²), and 2.29 versus the normal-weight group (BMI 18.5-24.9 kg/m²). Those with abdominal obesity showed an adjusted OR of 1.57 (95% CI: 1.35-1.82) compared to the normal WC group. Subgroup analyses revealed significant interaction effects for race (interaction P = .002) and smoking status (interaction P < .001), with no significant interactions observed for other demographic or metabolic indicators (all P > .05). Both general obesity and abdominal obesity are independently positively associated with the prevalence of OA, and the strength of these associations increases with higher levels of BMI and WC. Public health interventions should focus particularly on obesity control, especially the management of visceral fat accumulation, to reduce the burden of OA.