Visceral fat area linked to mobility disability in obese older adults

Visceral fat area is the strongest indicator of mobility disability among obese, community-dwelling, older adults, according to a recent Singapore study.

“Our study compared the performance of four measures of obesity—namely body mass index (BMI), waist circumference, percent body fat, and visceral fat area—in discriminating between community-dwelling oldest-old Chinese adults with and without mobility disability,” the researchers said.

“Our findings provided evidence implicating the role of visceral fat in mobility disability among the oldest-old in the population,” they added.

The study included 589 participants (aged ≥85 years, 60.4 percent women) drawn from a population-based cohort in Singapore. All were community-dwelling and of Chinese ethnicity. Percent body fat and visceral fat area, along with appendicular skeletal mass, were all measured using bioelectrical impedance analysis (BIA). The Loco-Check questionnaire was used to assess mobility disability.

Pearson’s correlation analysis showed that all four measures of obesity were highly associated with each other, with pairwise coefficients ranging from 0.59 to 0.94. Almost half (48.2 percent; n=284) of the participants had mobility disability. [BMC Geriatr 2021;21:282]

Receiver operating characteristic (ROC) curve analysis revealed that of all obesity markers, visceral fat area was the best indicator of mobility disability, with an in-sample area under the curve (AUC) of 0.71 (95 percent confidence interval [CI], 0.67–0.75). BMI, on the other hand, was the worst indicator (AUC, 0.68, 95 percent CI, 0.64–0.72). The difference was statistically significant (p=0.002).

Waist circumference (AUC, 0.70, 95 percent CI, 0.65–0.74; p=0.12) and percent body fat (AUC, 0.70, 95 percent CI, 0.66–0.74; p=0.075) were only marginally better than BMI at predicting mobility disability.

In men, the researchers obtained an optimal cutoff point for visceral fat area of ≥104 cm², which yielded a sensitivity of 60 percent and a specificity of 65 percent. In women, the optimal threshold was ≥137 cm², with corresponding performance values of 60.8 percent and 59.9 percent.

Using these cutoff values, the researchers found that 48.6 percent (n=286) of the participants were viscerally obese. In this subgroup, the likelihood of developing mobility disability was more than two times higher (odds ratio [OR], 2.36, 95 percent CI, 1.61–3.47), according to logistic regression analysis, adjusted for demographic factors and comorbidities.

Notably, additionally adjusting for the other measures of obesity, visceral fat area remained significantly associated with mobility disability (OR, 2.04, 95 percent CI, 1.10–3.77).

None of the other obesity measures were correlated with mobility disability.

“Our findings are aligned with studies which implicate the putative role of visceral fat with risk of chronic diseases among older adults, and they provide support for measuring visceral fat using BIA in the screening of at-risk oldest-old individuals in the community,” the researchers said.

“Clinical interventions targeting the reduction of visceral fat may also decrease the likelihood of mobility disability in the oldest-old population,” they added.