Obesity during midlife linked to increased dementia risk in women
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Women who were obese during midlife had a 21% greater risk for dementia compared with women who were not, according to a study published in BMJ.
“We know from other studies that people who go on to develop dementia start to reduce their levels of physical activity and lose weight at least a decade before a diagnosis,” Sarah Floud, PhD, a senior epidemiologist in the Nuffield Department of Population Health at the University of Oxford, told Healio Primary Care.
She explained that while the findings suggest midlife obesity is a risk factor for dementia, “physical inactivity and poor diet in midlife may not be.”
Floud and colleagues evaluated data from 1,136,846 participants in the Million Women Study, a population-based prospective study of women in the United Kingdom. Those included in analyses had information available on weight, height, physical activity and caloric intake. Researchers used National Health Service records to identify hospital admissions that mentioned dementia during follow-up.
They found that 15 years from baseline, 18,695 women had hospital records that mentioned dementia at a mean age of 77 years. The risk for detecting dementia after 15 years was 21% greater (RR = 1.21; 95% CI, 1.16–1.26) in women with obesity at baseline compared with those with a desirable BMI.
According to the researchers, 2.1% of those who were obese at baseline were later diagnosed with dementia. In comparison, 1.6% of women who were considered to have a desirable BMI were diagnosed with dementia during follow-up.
Researchers found that low caloric intake and inactivity were linked to dementia risk for the first 10 years of follow up. However, both associations were almost null after 15 years. The study authors explained that this likely means that low caloric intake and inactivity do not cause dementia and are instead consequences of preclinical behaviors of the disease.
“This suggests that inconsistencies in the previous evidence were likely to be due to differing lengths of follow-up in the different studies,” Floud told Healio Primary Care.
“Taking the long-term associations to be most reliable, this study shows that obesity confers a 21% greater risk for dementia compared to women with a desirable BMI,” she said. – by Erin Michael
Disclosures: The authors report no relevant financial disclosures.