Epidemiology of osteoarthritis overall and by body mass index category in the United States: A retrospective analysis of the National Health and Nutrition Examination Survey.

BACKGROUND

Obesity is a known risk factor for both the incidence and progression of osteoarthritis (OA). This retrospective analysis describes the prevalence of OA and demographic, clinical, and prescription characteristics by body mass index (BMI) category.

METHODS

This was a retrospective, cross-sectional, observational, descriptive epidemiologic study based on the secondary analysis of the 2015-2016 and 2017-2018 National Health and Nutrition Examination Survey (NHANES) databases. Adults ≥ 20 years with self-reported OA were evaluated. Measures were reported overall and by BMI category (i.e., underweight, normal weight, overweight, class I, II, and III obesity) and included OA prevalence, demographics, comorbidities, weight-related self-reports, time since arthritis onset, and prescription arthritis medications used in the prior 30 days. Analyses were descriptive and weighted to be representative of the United States (US) population.

RESULTS

In total, 31,936,699 adults (aged ≥ 20 years) in the US had OA, with a prevalence (per 1000 persons) of 135.0 (95% confidence interval, 122.9-147.0). Prevalence was highest in adults aged ≥ 65 years (315.7) and increased by BMI category from 72.4 in underweight individuals to 191.4 in class III obesity. Approximately 30.2% of people with OA had overweight, and 51.8% had obesity (i.e., 25.1%, 14.9%, and 11.8% in obesity classes I, II, and III, respectively). At the survey date, people had been living with OA for a mean (standard error) of 13.5 (0.7) years. Common self-reported comorbidities included hypertension (58.4%), cancer/malignancies (25.4%), and thyroid problems (24.5%). Among people with OA, 57.8% reported that a doctor told them they had overweight, and 39.2% reported they were currently controlling or losing weight. The most commonly prescribed OA-related medications were nonsteroidal anti-inflammatory drugs and opioids (used in 16.2% and 13.9% of the population, respectively.

CONCLUSION

The prevalence of OA in people with obesity class III was more than twice the prevalence in people with normal weight.