Dose-Response Gradient Found Between Increasing BMI and Hip, Knee OA

HealthDay News – Obesity increased risk of osteoarthritis (OA) at the hip, knee, and hand in a dose-response gradient according to body mass index (BMI). A maximum incidence rate of 19.5 per 1 000 person-years in subjects with grade II obesity (BMI ≥35 kg/m2) was found by researchers compared to 3.7 per 1,000 person-years in subjects with normal BMI. These findings were recently published in Arthritis & Rheumatology.

Carlen Reyes, MD, PhD, from Universitat Autònoma de Barcelona in Spain, and colleagues conducted a population-based cohort study using primary care records for subjects aged ≥40 years who were without a diagnosis of OA on January 1, 2006, and had body mass index (BMI) data available. A total of 1 764 061 subjects were observed for a median follow-up of 4.45 years.

The researchers found that the incidence rates of knee, hip, and hand OA were 3.7, 1.7, and 2.6 per 1,000 person-years, respectively, for subjects in the normal-weight category, and 19.5, 3.8, and 4.0, respectively, for those with grade II obesity. 

Being overweight or obese versus normal weight increased the risk of OA at all three joint sites, especially at the knee. The risk of knee OA increased two-, 3.1-, and 4.7-fold with a status of overweight, grade I obesity, and grade II obesity, respectively.

“Being overweight or obese increases the risk of hand, hip, and knee OA, with the greatest risk in the knee, and this occurs on a dose-response gradient of increasing BMI,” the authors write.

Summary and Clinical Applicability

“Obesity is a modifiable risk factor, and correctly identifying a population of subjects who may be at higher risk of developing OA, such as the one identified by our study, could help shape prevention strategies aimed at reducing the symptoms or even the future progression of OA,” the authors concluded. 

Several authors disclosed financial ties to the pharmaceutical industry.

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Reyes C, Leyland KM, Peat G, Cooper C, Arden NK, Prieto-alhambra D. Association between overweight and obesity and risk of clinically diagnosed knee, hip, and hand osteoarthritis: A population-based cohort study. Arthritis Rheumatol. 2016;68(8):1869-75.