People who are underweight in middle-age, or even on the low side of normal weight, face an increased risk of dementia as they get older—contrary to current thinking about obesity and dementia, according to new research from The Lancet.
In fact, increased weight may have a protective effect, according to the researchers, from the London School of Hygiene and Tropical Medicine. Very obese people, with a BMI over 40, were 29% less likely to get dementia 15 years later than those in the normal weight category.
However, the study’s message is not that it is okay be overweight or obese in middle-age. “Even if there were to be a protective effect in dementia, you may not live long enough to benefit because you are at higher risk from other conditions,” said lead author Dr. Nawab Qizilbash from Oxon Epidemiology.