Since today's Longevity Meme News was all about the ways in which excess fat tissue damages you over the years, I though I'd follow up with more of the same here. It's a correlation only, but like many of the others that tell us the same thing, it's sound science.
BACKGROUND: Although an increasing body of evidence links being overweight in midlife with an increased risk for dementia in late life, no studies have examined the association between being overweight in midlife and cognitive ability in late life. Our aim was to examine the association between being overweight in midlife as measured by body mass index (BMI) and cognitive ability assessed over time.
METHODS: Participants in the Swedish Adoption/Twin Study Aging were derived from a population-based sample. The participants completed baseline surveys in 1963 or 1973 (mean age 41.6 years, range 25-63 years). The surveys included questions about height, weight, diseases, and lifestyle factors. Beginning in 1986, the same individuals were assessed on neuropsychological tests every 3 years (except in 1995) until 2002. During the study period, 781 individuals who were 50 years and older (60% women) had at least one complete neuropsychological assessment. A composite score of general cognitive ability was derived from the cognitive test battery for each measurement occasion.
RESULTS: Latent growth curve models adjusted for twinness showed that persons with higher midlife BMI scores had significantly lower general cognitive ability and significantly steeper longitudinal decline than their thinner counterparts. The association did not change substantially when persons who developed dementia during the study period were excluded from the analysis.
CONCLUSIONS: Higher midlife BMI scores precede lower general cognitive ability and steeper cognitive decline in both men and women. The association does not seem to be mediated by an increased risk for dementia.
Getting fat generally implies more eating and less exercise. In recent years, researchers have proposed a range of plausible biochemical mechanisms linking overeating, excess fat, and reduced exercise to a faster rate of progressive deterioration in the brain. The present weight of scientific evidence tells us that if you're presently overweight and would like a better chance of living a longer, healthier life, then you should adopt a healthier lifestyle and diet that results in a lower stable weight and less visceral fat tissue.
In the long term, as we get older, our remaining health and life span will increasingly be determined by advances in medical science rather than our own efforts in lifestyle and diet. But we have no assurance that the date upon which science can rescue us from the effects of aging will come soon enough to help. We would therefore would be wise to take all reasonable measures to (a) maximize our own personal longevity within the limits of today's knowledge and available technology, and (b) help make the future era of longevity therapies come about more rapidly.