Sarcopenic obesity may increase risk of knee osteoarthritis, finds research

A new study published in the PLOS ONE journal showed that in middle-aged and older Chinese people, obesity, sarcopenic obesity, and low muscular strength were linked to an increased risk of occurrence of symptomatic knee osteoarthritis (OA) seven years later.

The growing number of people at risk for osteoarthritis and other health issues is a result of the changing aging demographics and the rising incidence of obesity. About 80% of all cases of OA worldwide are caused by knee OA, which is a common ailment. Sarcopenia is a physiological phenomenon that naturally happens with aging and is characterized by a loss of muscle mass and strength that can be increased by co-morbid illness states.

Also, obesity raises the risk of sarcopenia due to ectopically accumulated lipids and chronic inflammation in skeletal muscle. This study examined whether reduced muscular strength may mediate the effects of obesity on the start of knee OA in middle-aged and older Chinese populations, as well as the possible impacts of muscle strength and sarcopenic obesity on the incidence of knee OA.

The China Health and Retirement Longitudinal Study yielded a total of 12,043 participants. Using Poisson regression models, the effects of sarcopenic obesity on the development of knee OA were computed. The mediating proportion of muscular strength on the relationship between obesity and incidence of knee OA was estimated using mediation analysis.

A total of 12,043 people were included in the trial, and 2,008 of them developed knee OA. Poisson analysis showed a causal relationship between the start of knee OA and both abdominal and overall obesity. The participants who had the greatest degree of normalized grip strength were 0.33 times less likely to experience incident knee OA than those in the control group, and chair-rising time was linked to a 0.65-fold higher risk of incident knee OA.

Similar findings were found via sensitivity analysis. When compared to the reference group, the participants with sarcopenic obesity had an approximately twofold increased incidence of acute knee OA. The relationship between obesity and the incidence of knee OA was mediated by normalized grip strength and chair-rising time. Overall, the study found that incidence-symptomatic knee OA is influenced by sarcopenic obesity and low muscular strength in middle-aged and older Chinese individuals. 

Source:

Yan, L., Ge, H., Wang, Z., Shen, A., Xu, Q., Jiang, D., & Cao, Y. (2024). Roles of low muscle strength and sarcopenic obesity on incident symptomatic knee osteoarthritis: A longitudinal cohort study. In S. Agostini (Ed.), PLOS ONE (Vol. 19, Issue 10, p. e0311423). Public Library of Science (PLoS). https://doi.org/10.1371/journal.pone.0311423