CHECK: Obesity Doubles Odds of Patellofemoral OA Within 8 Years
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TORONTO — Obesity at baseline was associated with development of patellofemoral osteoarthritis within 8 years, according to an analysis of the CHECK cohort presented here.
“Cross-sectional and longitudinal studies have consistently shown that obesity is a risk factor for incidence of tibiofemoral osteoarthritis,” Harvi F. Hart, PhD, of the University of Western Ontario, in Canada, said. “A systematic review has shown that people with patellofemoral osteoarthritis have a higher body mass index, when compared to people without osteoarthritis.”
However, she noted that there are currently no longitudinal data showing the relationship between obesity and patellofemoral osteoarthritis. “Based on that, the primary aim of this study was to determine the relationship between baseline BMI to incidence of patellofemoral or tibiofemoral osteoarthritis over 8 years,” she said.
The researchers also aimed to look at how change in BMI over 8 years could impact tibiofemoral or patellofemoral OA risk. The hypothesis was that those who were overweight at baseline or increased in BMI over 8 years would have increased risk of these two outcomes.
Data for individuals aged 45-65 years from the CHECK cohort were used for this analysis. Eligible participants had no evidence of radiographic knee OA at baseline.
The researchers used the OARSI Atlas to determine patellofemoral OA, while KL score of 2 or greater was used to define tibiofemoral OA. Normal BMI was defined as 25 or lower, while 25-30 was overweight and 30 or above was obese. Regarding change in BMI, the threshold was a gain or loss of 5%. The analysis was adjusted for age and sex.
The study included 656 participants with a BMI of 26 4. Normal BMI was reported in 41% of the group.
According to study results, at 8 years, 35% of the cohort had radiographic OA. Breakdown showed that 14% had tibiofemoral OA, 10% had patellofemoral OA, and 11% had both.
Looking at the relationship between baseline BMI and patellofemoral OA, Hart reported that the adjusted odds of incident patellofemoral OA was 17% for those with normal baseline BMI, 23% for those who were overweight at baseline, and 29% for those who were obese at baseline.
Similarly, the risk of tibiofemoral OA was 22% for those with normal baseline BMI, 25% for those who were overweight, and 33% for those who were obese.
“Those who were in the obese category had approximately two times the odds of patellofemoral OA at 8 years,” Hart said. “And once again, those who were in the obese category had approximately two times the odds of tibiofemoral osteoarthritis at 8 years.”
However, Hart reported that change in BMI failed to yield a similar result. The risk for patellofemoral OA was 20% for participants who had no change, 26% for those who lost weight, and 27% for those who gained. For tibiofemoral OA, the risk was 28% for those who had no change, 24% for those who lost, and 30% for those who gained. “We saw no significant association between these categories and incidence of patellofemoral or tibiofemoral osteoarthritis,” Hart said.
Obese individuals at baseline had greater odds of developing patellofemoral or tibiofemoral OA at 8 years, Hart concluded. “Obesity is related to development of tibiofemoral OA, in agreement with previous research,” she noted. “Our study showed obesity also significantly increases the risk of incidence of patellofemoral OA 8 years later. Obese individuals should be counselled to lose weight.” —by Rob Volansky
Reference:
Hart HF, et al. Abstract #74. Presented at: OARSI 2019 World Congress on Osteoarthritis; May 2-5; Toronto, Canada.
Disclosure: Hart reports no relevant financial disclosures.