Effects of diabetes and obesity on cognitive impairment and mortality in older mexicans

Diabetes is a risk factor for dementia and mortality, while obesity later in life is associated with a reduced risk. Their co-occurrence, diabesity, is common, but its association with dementia and mortality is unclear.

Using data from the Mexican Health and Aging Study, we used multinomial logistic regression to examine the associations of diabetes and body mass index (BMI), and diabesity, in 2012, with cognitive impairment and mortality in 2018, among participants aged ≥60 years with normal cognition at baseline (n = 7,885).

Diabetes was associated with cognitive impairment, compared to not having diabetes (RRR=1.83, 95% CI=1.48-2.26). BMI was not associated with cognitive impairment. Regarding mortality, diabetes was associated with an increased risk (RRR=2.28, 95% CI=1.98-2.63) and being overweight or having obesity was associated with a reduced risk (RRR=0.74, 95% CI=0.65-0.86; RRR=0.79, 95% CI= 0.66-0.95). When BMI and diabetes were combined, having diabetes only (RRR=2.01, 95% CI=1.40-2.87), being overweight with diabetes (RRR=1.42, 95% CI=1.02-1.97) or having diabesity (RRR=1.50, 95% CI=1.08-2.06) were associated with cognitive impairment, compared to having a normal BMI without diabetes. Diabetes, regardless of BMI, was associated with an increased risk of mortality, while being overweight or having obesity was associated with a reduced risk of mortality.

With the increase in the prevalence of obesity and diabetes among Mexicans, it is important to understand how these conditions and their co-occurrence impact cognitive impairment and mortality. Among older Mexicans, diabesity is associated with 6-year mortality and cognitive impairment onset, likely driven by the effect of diabetes.