Longevity Briefs: Shorter Of Height, Shorter Of Life?

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Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.

Why is this research important: Some studies report that people who are taller are healthier and live longer. However, human height is a complex trait that is influenced by many different factors, both genetic and environmental, and the effects of these factors are hard to disentangle. Taller people are thought to be at greater risk of cancer due to higher levels of growth hormone and simply having more cells that can mutate. Animal studies also suggest that growth hormone accelerates the ageing process. Yet shorter height correlates with lower levels of education, wealth and social status. Could the association between height and longevity be entirely down to the socioeconomic implications of being taller?

What did the researchers do: In this study, researchers collected data on nearly 850 000 adult deaths in Poland between 2004 and 2008. They obtained height information from their identity cards, and performed statistical analyses of the relationship between height and longevity for each sex individually.

Key takeaway(s) from this research:

Height was a poor predictor of longevity in general.
When socioeconomic factors are discounted, there may be an advantage to being shorter.
Many disadvantageous genetic traits also contribute to reduced height.

The researchers found that there was a statistically significant correlation between shorter stature and increased lifespan in those who lived until at least age 50, both in males and females. However, after eliminating the effects of changes in height over time, the correlation became extremely weak, though still statistically significant. In other words, height was not a good predictor of how long someone would live.

Relationship between longevity and height. Z scale is a measure of height relative to the average (mean). A Z score above zero means above average height.
*The association between body height and longevity: evidence from a national population sample*

Taller people did not have a longevity advantage, despite better nutrition and greater wealth being correlated with height, neither of which could be controlled for in this study. Because of this, the authors argue that taller people probably don’t have an inherent advantage when it comes to life expectancy. On the other hand, being genetically short is not necessarily a good thing, as the genetics of height aren’t a simple matter of ‘tall genes’ and ‘short genes’. Genes that negatively impact the immune system, sleep and metabolic function can all have knock-on effects on height (more childhood illness is associated with reduced adult height, for example).

This was a fairly straightforward study that didn’t attempt to control for any confounding factors. The main takeaway is that in most people, height probably plays a minor role at most in determining lifespan.