If you’ve always felt a little vertically challenged, perhaps a bit disadvantaged due to your inability to see the stage in large crowds, or envied your taller counterparts who don’t have to carry a footstool in order to reach your higher cabinets, you have one more reason to feel slighted. People with shorter armspans and leg lengths have a higher risk of dementia and Alzheimer’s disease.
According to the article “Fact or Fiction?: It’s No Tall Tale, Height Matters”, in Scientific American online, people who are taller tend to be more successful and earn higher saleries. Height is associated with intelligence and educational attainment, and now, according to a paper titled “Knee height and arm span: A reflection of early life environment and risk of dementia” published in Neurology, people with shorter limbs are also at greater risk for dementia and Alzheimer’s disease and other chronic diseases as well.
OK. Full disclosure. The author of the study in Neurology was me. I learned from an anthropologist I met at a conference that limb length is primarily determined in the first few years of life. Given that the brain is also developing at that time (especially the regions involved in Alzheimer’s disease), we decided to use limb length as marker for early life nutrition to examine risk of dementia. Limb length had already been associated with hypertension and other chronic diseases, like cardiovascular disease and diabetes, and had been shown to be associated with dementia in a Korean population. Ours was the first to show the effect in a Western population.
So now, dear reader, you are probably thinking, “isn’t height genetic?” and either “but I am/my friend is/my brother is… vertically challenged, and we weren’t starving”. “Yes” I say to both questions. Height is 80% genetic and 20% environmental in Western developed countries, but the proportion of variation due to genetic factors is lower in developing countries where there are more people who can’t afford a well balanced diet. The population we were looking at was born between 1888-1924. Given that so little was known about nutrition back then, its likely that that proportion of variation due to environmental factors (mostly nutritional) was much higher than 20%. Much research has been done on the causes of stunting, and consensus by those in the field is that stunting is not determined by the total number of calories, but the quality of nutrition (the variation of nutrients and amount of protein) in the diet. Furthermore, there is still much to learn about the effects of minerals, nutrients and phytochemicals on our health. So while there are recommendations for new mothers on how to adequately feed their newborns, recommendation are continuing to evolve with more research.
I was advised that this research was not worth pursuing as “there is nothing you can do about height”. But is there something we can do about the height of future generations? “Yes we can!”. Readers can help educate young parents, contact your legislators to help fund programs that help feed young children, or donate to organizations that do. And is there something that we can do to lower our risk of developing dementia and Alzheimer’s? “Yes we can!”. For those who are vertically challenged, or have a genetic susceptibility to any disease, it’s important to keep in mind what you can change. You can make sure that you eat a balanced diet, eat plenty of fruits and vegetables, get enough fatty fish (or alternative sources of omega-3′s). You can keep abreast of current research on nutrition, exercise and health. You can consult a nutritionist to make sure that your diet contains all the essential nutrients you need to stay healthy. We need to exercise, keep their mind active, and maintain social connections.
And if you are not completely soothed by what knowing what you can do to lower your risk, keep this in mind: Being vertically challenged does not prevent you from publishing in Neurology, or from Scientific American from picking up your story!