Visceral fat area (VFA) as a measure of obesity is associated with reduced cognitive function in older adults with type 2 diabetes (T2D), according to study results published in Clinical Obesity.

Obesity is not only associated with an increased risk for the development of T2D but has also been implicated as a risk factor for associated cognitive impairment. However, studies exploring the association between obesity and cognitive performance in older patients with T2D remain inconclusive. In addition, it is unknown whether the risk for cognitive deficits varies with regard to the degree of obesity. Researchers aimed to elucidate the relationship between obesity and cognition in older (aged ≥60 years) multiethnic Asian adults with T2D recruited to the Singapore Study of Macroangiopathy and Microvascular Reactivity in Type 2 Diabetes (SMART2D) study.

Neuropsychologic status was evaluated in 677 individuals (48.3% women; mean age, 67±5 years) using the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) standardized screening assessment. The test evaluates cognitive impairment based on 5 domains: immediate memory, delayed memory, attention, language, and visuospatial/constructional abilities.

Several measures of obesity, including body mass index (BMI), waist circumference, hip circumference, waist to height ratio, and VFA, were analyzed for their association with RBANS score. After adjusting for age, sex, ethnicity, T2D duration, and other factors, only VFA was significantly associated with total RBANS score (P =.005). VFA was also found to be associated with delayed memory, language, and immediate memory, but not attention or visuospatial/constructional ability.

The study population was divided into 4 groups based on BMI (normal or high) and VFA (normal or high), with high BMI defined as ≥23.0 kg/m2 and high VFA defined as ≥100 cm2. The majority (70.6%) of individuals were in the high BMI/high VFA group.

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Compared with the normal BMI/normal VFA group (reference), the presence of high VFA was associated with a lower overall RBANS score in individuals with both normal (effect size [β], -0.13; 95% CI, -0.22 to -0.05; P =.003) and high BMI (β, -0.14; 95% CI, -0.24 to -0.05; P =.004) in an unadjusted model. However, this association remained significant for the normal BMI/high VFA group after covariate adjustment (β, -0.09; 95% CI, -0.17 to -0.01; P =.025) but was attenuated in the high BMI/high VFA group, indicating that excess visceral fat was linked to reduced overall cognitive function scores only in normal-weight individuals.

In an analysis of domain-specific indices of cognitive impairment in individuals with high VFA, both high (β, -0.14; 95% CI, -0.24 to -0.04; P =.005) and normal BMI (β, -0.13; 95% CI, -0.21 to -0.04; P =.003) were associated with delayed memory. Normal BMI/high VFA was also associated with lower immediate memory (β, -0.09; 95% CI, -0.18 to -0.01; P =.031) and language (β, -0.09; 95% CI, -0.18 to -0.01; P =.033) scores. Normal VFA was not significantly associated with RBANS overall score or any domain-specific indices.

The researchers noted that the cross-sectional nature of the study prevents causal inference about the relationship between obesity and cognitive performance.

“[O]ur findings revealed that VFA outperformed other surrogate indices of central obesity as an independent associate of reduced cognitive performance in older multi-ethnic Asians with [T2D], thus highlighting the adverse effect of visceral obesity on cognition,” the study authors concluded. “Therefore, assessment of visceral adiposity and interventions that target visceral adiposity may help to prevent cognitive decline in older patients with diabetes, and reduce the global burden of dementia in ageing populations.”

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Reference

Moh MC, Low S, Ng TP, et al. Association of traditional and novel measures of central obesity with cognitive performance in older multi-ethnic Asians with type 2 diabetes. Clin Obes. 2020;e12352.