Rate of cognitive decline in elderly tied to age, abdominal obesity

Age and abdominal obesity appear to affect the rate of cognitive decline in elderly adults, a recent population-based study has found.

The study included 478 elderly adults (mean age, 81.9±6.3 years; 66.7 percent female) in whom fasting blood samples were collected and assayed for indicators of glycaemia, insulin resistance, obesity and inflammation. The main outcome of interest was the slope of decline in global cognition. Almost a fifth carried the apolipoprotein E-4 (APOE-4) allele.

Waist-to-hip ratio (WHR) was used as a measure of central obesity, with median values of 0.97 and 0.86 for males and females, respectively. Regression analyses found that predictors of cognitive decline changed according to WHR status.

For instance, in those with WHR below the median, age (coefficient, –0.23; p<0.001) and being a carrier of the APOE-4 allele (coefficient, –0.49; p=0.002) were all significant predictors of cognitive decline; other covariates and metabolic factors, however, were not.

In contrast, aside from age (coefficient, –0.18; p=0.002), glycated haemoglobin (HbA1c) also emerged as a significant predictor of cognitive decline in those whose WHR fell above the median value (coefficient, –0.15; p=0.006).

Classification and regression tree analysis further found that among participants with high WHR, HbA1c 6.2 percent predicted faster cognitive decline in those aged <88 years. Among those with low WHR, on the other hand, high adiponectin indicated a more rapid decline in participants aged <87 years.