A longevity mystery has been puzzling scientists for some time, according to a new study published online from Genome Biology. Latinos in America have a life expectancy of 82 years, three more years than the nearest ethnic group, Caucasians. Latino women also age slower than Latino men and live more than 2 years longer than women from all the other groups.
Measuring Age with the Epigenetic Clock
The in-depth study profiled the biology of Hispanics, Tsimane (native of Bolivia), Caucasians, East Asian, African Americans, and African farmers/hunter-gatherers. Biological samples from 6000 individuals were taken. These tissue samples included saliva, blood, brain tissue and lymphoblastoid cells. These were used to determine the “epigenetic age” of the cells. Scientists use a biomarker called the “epigenetic clock” which is the most accurate way to measure aging in human tissue. The study proved that Hispanics had a slower epigenetic clock (or aging rate). The Tsimane did as well, but due to their vulnerability to infectious diseases, their lifespan is short.
Immune System CD4 Cells and T cells – The Lower the better?
The Study included comparisons of so-called fighter cells (CD4 / T cells) from all groups of people. Hispanics and Tsimane have low levels of the cells as compared to Caucasians and other ethnic groups. These cells are vital to the immune system, because they help fight infectious diseases. Latinos still live longer, but Tsimane people only live to 54 on average.
Inflammation, Chronic Disease, and Infections
Latino life expectancy is higher despite the predisposition to illnesses such as hypertension, cardiovascular disease, and diabetes. Since Latinos age at a slower rate, inflammation and diseases progress at a slower pace.
The Tsimane people have a very short lifespan of just 54 years. This is among the lowest of any group anywhere in the world. The main cause is elevated inflammation, which makes them to be more prone to infection. On the other hand, their populations have very low levels of chronic diseases like diabetes, and heart disease. The study concluded that Tsimane people age slowly, but succumb to infectious diseases due to stressed immune systems.
The Hispanic and Tsimane Paradoxes
The two most surprising results from these studies were the lifespans of Hispanics and the Tsimane people. Hispanics in the U.S. live longer, but have higher rates of chronic disease. Tsimane people do not suffer from chronic diseases and don’t live as long. Scientists are referring to these puzzles as paradoxes. The main paradox seems to come from the fact that both Hispanics and Tsimanes have lower CD4 cells and T cells, which are part of the immune system that helps to fight infections. This would explain why the lifespan of Tsimanes is about 54 years, but not why Hispanics live to 82 on average.
Although not a definitive study of biological aging in humans, the findings warrant further research to resolve some of the surprising paradoxes, such as the relationships between long life, inflammation and disease, and the low count of immune system cells. Scientists want to learn the biological secret that gives Latinos an advantage in longevity in hopes of improving life expectancy for everyone.