A higher body-mass index (BMI, a measure of body weight that takes height into account) is linked to a lower risk for dementia in both men and women, according to a new study published in the Journal of Alzheimer’s Disease.
Dementia, or advanced cognitive impairment, is more common in older age in both men and women — especially in people with diabetes. Studies have shown that having poorly controlled diabetes, in particular, is linked to a higher risk for cognitive impairment and dementia in people with diabetes, while those who maintained normal blood glucose levels were not at higher risk. Aside from blood glucose control, there are many lifestyle measures that may reduce your risk for dementia — including getting enough physical activity, avoiding inflammatory foods, consuming enough fiber, eating foods rich in antioxidants, and even drinking coffee or tea.
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For the latest study, researchers looked at the relationship between BMI and dementia risk in both men and women based on medical records in 832 general doctor’s practices in Germany. A total of 296,767 participants were included, with an average age of 70. Based on their BMI, 0.9% of participants were classified as underweight, while 25.5% had a normal weight, 41.5% were overweight, and 32.1% had obesity. In looking at how BMI was related to the risk of developing dementia over 10 years, the researchers adjusted for participants’ age, sex, and other health conditions.
Dementia risk linked to BMI
The researchers found that in both men and women, the risk for dementia was highest in participants who were underweight and got lower in each increasing BMI category. For women, the 10-year risk for dementia ranged from 11.5% in those who were underweight to 9.5% in those with obesity, while for men, it ranged from 12.0% to 8.2%. From one BMI category to a neighboring category, though, these differences tended to be small — so small, in fact, that almost every difference in dementia risk between BMI categories was not statistically significant (meaning it could be due to chance). The only differences in dementia risk that were statistically significant were a 7% lower risk for dementia in overweight women compared with those with a normal body weight, and a 58% higher dementia risk for dementia in underweight men compared with those with a normal body weight.
The researchers noted that since not many studies have looked at the relationship between body weight and dementia in later life, more research is needed to confirm these findings. But based on these results alone, it looks like there are only small differences in dementia risk between neighboring BMI categories — with the notable exception that underweight men appear to be at especially high risk for dementia.
Want to learn more about maintaining cognitive health with diabetes? Read “Nine Tips to Keep Your Memory With Diabetes,” “Keeping Your Brain Strong With Diabetes” and “Memory Fitness: How to Get It, How to Keep It.”