Obesity and the Development of Arthritis Among Adults in the United States Using NHANES Data.

Background: The alarming increase in the prevalence of obesity and arthritis in America in recent times is concerning both in terms of the deleterious health effects on the individuals and economic cost. The wear and tear on the musculoskeletal and the inflammatory effects of obesity may be the reasons for the rise in arthritis among individuals with obesity.

Objective: To investigate the association between obesity and the development of arthritis among adults in the United States.

Design: A total of 17 016 participants were included from the 2012 to 2018 National Health and Nutrition Examination Survey (NHANES). Most of the participants were aged 30 years and above (79.7%). The racial distribution included 64.0% Non-Hispanic whites, 15.3% Hispanics, 11.4% Non-Hispanics blacks, and 9.4% from all other races.

Methods: Obesity was defined as a body mass index (BMI) > 30 kg/m², and the outcome variable of interest, arthritis status, was self-reported. Survey weighted logistic regression was performed to calculate the odds ratio (OR) and 95% confidence interval controlling for potential confounding factors.

Result: Nearly 40% of all participants were individuals with obesity, and 27.5% reported having some form of arthritis. The risk of developing arthritis was higher in individuals with obesity (OR: 1.55, 95% CI: 1.35-1.80), women (OR: 1.94, 95%CI: 1.66-2.28), and individuals 30 years or older (OR: 10.81, 95% CI: 6.36-18.37) with non-Hispanic whites being the most affected race. The C-reactive protein (CRP) and white blood cell count (WBC) levels were higher in all individuals with obesity even though there was no statistical difference between individuals with obesity with and without arthritis.

Conclusions: Obesity substantially heightens the risk of developing arthritis due to the mechanical stress on weight-bearing joints and subsequent chronic-low level inflammation contributing to disease progression.