The advent of tools capable of accurately assessing the state of biological aging, such as measurement of changes in DNA methylation patterns, means that researchers can now produce additional and more robust data on quite small differences in longevity that exist when comparing various human populations. Measurement doesn't say much about why these differences exist: there we are back to discussing the degree to which it is genetics versus lifestyle and culture. Nonetheless, this particular study provides good evidence for the utility of DNA methylation as a biomarker of aging, given that the results match up fairly well with those obtained from statistical population data. Having a reasonably accurate measure of biological age is very important for the future development of rejuvenation therapies, as it will make it much faster and cheaper to determine what works and what doesn't work. The cost of research and development will be greatly reduced if researchers can immediately test the results of a potential rejuvenation therapy rather than having to wait and see what it does to health and life span.
"Latinos live longer than Caucasians, despite experiencing higher rates of diabetes and other diseases. Scientists refer to this as the 'Hispanic paradox.' Our study helps explain this by demonstrating that Latinos age more slowly at the molecular level." Latinos in the U.S. live an average of three years longer than Caucasians, with a life expectancy of 82 versus 79. At any age, healthy Latino adults face a 30% lower risk of death than other racial groups. Researchers used several biomarkers, including an "epigenetic clock", to track an epigenetic shift linked to aging in the genome. Epigenetics is the study of changes to the DNA molecule that influence which genes are active but don't alter the DNA sequence itself. The team analyzed 18 sets of data on DNA samples from nearly 6,000 people. The participants represented seven different ethnicities: two African groups, African-Americans, Caucasians, East Asians, Latinos and an indigenous people who are genetically related to Latinos. Called the Tsimane, the latter group lives in Bolivia.
When the scientists examined the DNA from blood - which reveals the health of a person's immune system - they were struck by differences linked to ethnicity. In particular, the scientists noticed that, after accounting for differences in cell composition, the blood of Latinos and the Tsimane aged more slowly than other groups. The research points to an epigenetic explanation for Latinos' longer life spans. For example, the biological clock measured Latino women's age as 2.4 years younger than non-Latino women of the same age after menopause. "We suspect that Latinos' slower aging rate helps neutralize their higher health risks, particularly those related to obesity and inflammation. Our findings strongly suggest that genetic or environmental factors linked to ethnicity may influence how quickly a person ages and how long they live."
The Tsimane aged even more slowly than Latinos. The biological clock calculated the age of their blood as two years younger than Latinos and four years younger than Caucasians. The finding reflects the group's minimal signs of heart disease, diabetes, hypertension, obesity or clogged arteries. "Despite frequent infections, the Tsimane people show very little evidence of the chronic diseases that commonly afflict modern society. Our findings provide an interesting molecular explanation for their robust health." In another finding, the researchers learned that men's blood and brain tissue ages faster than women's from the same ethnic groups. The discovery could explain why women have a higher life expectancy than men.