BMI May Sufficiently Capture Knee OA Risk Associated With Increased Localized Adiposity

Peripheral and central adiposity were associated with incident radiographic knee osteoarthritis (OA) to a similar extent as body mass index (BMI), implying that a simple measure of BMI is sufficient for capturing the increased risk for radiographic knee OA linked to higher amounts of localized adiposity, according to the results of an ancillary study from the Osteoarthritis Initiative (OAI) published in Osteoarthritis and Cartilage.

The investigators sought to determine whether central or peripheral adiposity measures are associated with radiographic knee OA independent of BMI or whether their relationship to radiographic knee OA was stronger than that of BMI. A total of 161 participants with incident radiographic knee OA from the OAI, 62% of whom were women, were matched with 186 control patients without incident radiographic knee OA, 58% of whom were women. Researchers measured baseline waist-height-ratio (WHtR), anatomic cross-sectional areas of thigh subcutaneous fat (SCF), and anatomic cross-sectional areas of intramuscular fat (IMF).

Results showed that BMI, WHtR, SCF, and IMF were all significantly associated with incident radiographic knee OA when analyzed separately, with similar effect sizes reported (odds ratio [OR] range, 1.30 to 1.53). After adjustment for BMI, ORs for central or peripheral adiposity measures were attenuated and no longer statistically significant. There was no measure of peripheral or central adiposity significantly more strongly associated with incident radiographic knee OA than BMI. Results were similar in both men and women.

The investigators concluded that specific measures of peripheral and central adiposity, along with BMI — a commonly used surrogate measure of adiposity — are comparably correlated with incident radiographic knee OA. They caution that these localized measures of adiposity may be linked to incident radiographic knee OA through mechanisms other than BMI, including distinct metabolic and biomechanical pathways.

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Reference

Culvenor AG, Felson DT, Wirth W, Dannhauer T, Eckstein F. Is local or central adiposity more strongly associated with incident knee osteoarthritis than the body mass index in men or women? [published online May 25, 2018]. Osteoarthritis Cartilage. doi:10.1016/j.joca.2018.05.006