Greater Height Correlates with a Lesser Risk of Dementia
Being taller is associated with a shorter life span, for reasons that are far from fully explored. The role of growth hormone in longevity is no doubt close to the roots of this correlation, but there are plenty of questions remaining, such as why lung disease plays a sizable role in greater mortality for taller people in later life. As illustrated by the research here, there is a bright side to being taller, which is that epidemiological studies show taller people to have a lesser incidence of dementia. Again, why exactly this is the case is far from fully explored. These and other natural variations between people are interesting, but we should expect them to vanish with the introduction of the first rejuvenation therapies in the near future, swamped by the benefits that might be achieved by directly addressing the causes of aging.
This study examined the relationship between body height and dementia and explored the impact of intelligence level, educational attainment, early life environment, and familial factors. A total of 666,333 men, 70,608 brothers, and 7388 twin brothers born 1939-1959 and examined at the conscript board were followed in Danish nationwide registers (1969-2016). Cox regression models were applied to analyze the association between body height and dementia. The findings of this current study provide substantial support to previous evidence of a link between body height and dementia. All previous studies had accounted for educational level and other socioeconomic indicators, yet none of these studies had adjusted for intelligence level earlier in life. Intelligence level has been suggested to be a stronger marker of brain and cognitive reserve than educational level. Intelligence level is furthermore correlated with body height and by itself associated with dementia.
In contrast to previous studies, we also investigated the impact of other potential early-life familial factors including genetics and socioeconomic resources in the family that may influence both body height and later risk of dementia. Body height has been shown to have a strong genetic component with around 80% of the variation in populations being explained by genetic differences between individuals. The genetic component of height has furthermore been found to be consistent across countries independent of living standards. The genetic and environmental variation influencing body height, but not risk of dementia, is smaller within brothers than between men in general, which may weaken the association between body height and dementia in the latter compared to the former group. Through this mechanism, the finding of a stronger association within brothers may be explained by less dilution of the effects of different harmful exposures early in life influencing both body growth and risk of dementia. These findings furthermore suggests that genetics has a minor role in the association of body height and dementia.
In conclusion, taller body height at the entry to adulthood, supposed to be a marker of early-life environment, is associated with lower risk of dementia diagnosis later in life. The association persisted when adjusted for educational level and intelligence test scores in young adulthood, suggesting that height is not just acting as an indicator of cognitive reserve.
That one is easy, if your are well nourished in your youth you get taller, riddle solved, where should I pick up my nobel prize.
@Tom: But you would expect that good nutrition in youth would also build the body in ways that would extend your life, but it doesn't on average.
I commented today to thank Reason for constant optimism. "...in the near future". To tell you the truth, I was expecting a breakthrough or several last year, and there wasn't any. My optimism at the start of 2019 was sobered by the increasing number of studies showing how complex the longevity problem is. In fact, I ended the year feeling like the solutions are further away then the were perceived to be at the beginning of the year. I'm glad Reason's enthusiasm wasn't curbed.
I know the answer. 1/6 have mosaicism with T21. A bit Down syndrome. Those with T21 get AD earlier.
I forgot to add. Those 1/6 are lower. And if you have a higher % of T21 in your mosaicism you are lower.
Because bigger taller people are more likely to die sooner than shorter smaller people. If you are for instance 85 years old you might get/have dementia; "big chuck" the full back on said 85 years old's Highschool football team would be lucky to make it to 65. If the big tall person has a massive coronary at 58 he isn't going to get dementia at 88. Probably why women get dementia more than men do; simply because they on average outlive men.
I will add my 2 cents to the nutrition hypothesis. Better and more abundant nutrition enhances height. Less abundant nutrition is a form of a weak calorie restriction. So, if we take height as a proxy for abundant nutrition that could explain some of the shorter lifespan. And the individuals that made it to drop old age were inherently in better shape this less dementia.
As I read by a comment in previous post. Genes on chromosome 21 make b amyloid. If you have mosaicism with T21 as 1/6 of population you will age faster.