The Curious Case of Latino Longevity

 

As we get older, a certain amount of aches, pains and grumbles are to be expected, and we’re all generally resigned to the toll time will eventually take on our bodies. But some believe that, in the future, we won’t need to be…and there’s a growing body of research dedicated to investigating whether ageing is, in fact, preventable. But could it be that the genetics of one particular ethnic group could hold the key for understanding (and perhaps preventing) ageing?

Medical researchers have known about what’s called the “Hispanic Paradox” for years – the odd phenomenon that, although Hispanics seem to have the odds stacked against them in terms of mortality, working harder jobs for less money and less access to healthcare than whites, their mortality rate is actually better than whites, with Hispanics living, on average, for two years longer than their more privileged counterparts. [1].

This seems especially prevalent among first-generation Hispanic immigrants to the United States [2], and can’t be explained by lifestyle choices. Despite having lower mortality rates than whites, Hispanics have higher morbidity [3] – that is, they have a higher prevalence of disease and poor health, on average, than whites, even while they live longer. So it can’t just be a result of better eating habits or smoking less.

A recent study in Genome Biology [4] has tried to answer the question of why Latinos live longer, by looking at epigenetic clocks. Briefly, epigenetic clocks work by tracking parts of our DNA which correlate with life expectancy – so even when you adjust for other factors, like age, education, or body mass index, the correlation still holds.Importantly, epigenetic clocks need not correlate with everything we associate with ageing – such as how old you look superficially, for instance, or how many wrinkles you have. This is because, although it can tell you about mortality, it doesn’t necessarily tell you about morbidity (how diseased you are).

According to the finding of the study, different ethnicities age, in genetic terms, at varying rates – their epigenetic clocks runslightly slower or faster depending on ethnicity.In particular, the Tsimane Amerindians age slower genetically than whites, for example – even though they suffer more than whites from diseases like inflammation, which can cause them to look much older than theirgenetic age. So Tsimane can be expected to live longer, even though they have worse morbidity – and Hispanics and Tsimane share common ancestors, since Hispanics have Native American ancestry.

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This has led the authors of the study to suggest that it is because Hispanics have less intrinsic epigenetic age acceleration (IEAA) – which they’ve inherited from their Native American ancestors – that they have lower mortality than whites. Their epigenetic clocks are slower, so even though they’re less healthy, from their bodies’ point of view, they’re younger than whites who are chronologically the same age – which is why they seem to live longer.

So, how does this affect the non-Hispanics amongst us? Well, it throws up fascinating questions about everything we thought we knew about the importance of lifestyle factors in ageing – and could explain, for example, that 106-year-old chain-smoking grandma every smoker ever seems to use as an excuse not to quit. And scientists are now hoping that the study of epigenetic clocks and how they determine ageing may help us to turn back time on all of our ageing processes, potentially helping to unlock longevity for the wider population as well. Perhaps, at his age, Donald Trump should think twice before building that wall, eh?

  1. https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6417a5.htm?s_cid=mm6417a5_w
  2. https://www.princeton.edu/main/news/archive/S46/31/53A76/?section=topstories
  3. https://genomebiology.biomedcentral.com/articles/10.1186/s13059-016-1030-0
  4. https://genomebiology.biomedcentral.com/articles/10.1186/s13059-016-1030-0

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