Getting risk factors under control helps stave off dementia in people with T2D

While people with type 2 diabetes (T2D) have an increased risk of developing dementia, this excess risk can be mitigated by maintaining a healthy lifestyle to keep several risk factors under control, according to a study presented at EASD 2021.

“Our findings support current risk factor treatment strategies and making lifestyle changes,” said presenting author April van Gennip, a doctoral candidate at Maastricht University Medical Centre, Maastricht, the Netherlands.

“These risk factors don’t just have an impact on the risk of developing dementia — they also have an impact on brain structure and current levels of cognitive function. Moreover, they are modifiable, making them important prevention targets,” she explained.

In the prospective UK Biobank study, 87,856 individuals (mean age 57 years, 49 percent women), of which 10,663 were cases with T2D who were matched to 77,193 controls, were categorized based on the number of risk factors (out of a total seven factors) that they were able to maintain within the guideline-recommended target range. The seven risk factors were: HbA1c, blood pressure, BMI, physical activity, diet, albuminuria, and smoking status. [EASD 2021, abstract 141]

After an average of 9 years of follow-up, patients with T2D were almost twice as likely to have incident dementia compared with controls (1.4 percent vs 0.5 percent; hazard ratio [HR], 1.88, 95 percent confidence interval [CI], 1.55–2.27) — which according to van Gennip, were consistent with prior studies.  

However, patients with T2D who were able to maintain five to seven risk factors within target range saw their risk of dementia nullified compared with controls (HR, 1.32, 95 percent CI, 0.89–1.95).

The risk of dementia gets progressively lower with more risk factors on target. The HR for incident dementia dropped from 2.42 in the category with the least number of risk factors on target (ie, only zero to two factors) to 1.70 in the category with four risk factors on target, and further down to 1.32 as mentioned above for the category with the most number of lifestyle-related factors under control.

“Maintaining the recommended levels of blood sugar, being a non-smoker, and the absence of albuminuria appeared to be the strongest risk reducers,” according to the researchers.

“Similarly, differences in processing speed, executive function, and brain volumes were progressively smaller for a higher number of risk factors within target range,” reported van Gennip.

For cognitive performance, decline in processing speed in T2D cases vs control were mitigated in a stepwise manner with more risk factors within target range. The difference in processing speed between the two groups became smaller from -0.18 in the least controlled group to -0.08 in the most well controlled group.     

In terms of structural brain abnormalities, white matter hyperintensity volume also decreased progressively from 0.35 in the category with the least number of risk factors on target to 0.04 in the category with the most number of risk factors on target. 

These findings on executive function and structural brain abnormalities were further validated in a separate cross-sectional cohort in the Maastricht Study, which involved 1,327 cases with T2D who were matched to 3,732 controls (mean age 59 years, 51 percent women).

As the study participants comprised mostly middle-aged Caucasian individuals, van Gennip acknowledged that the findings should not be generalized to other ethnic or age groups.