http://www.zerohedge.com/medical/longevity-isnt-really-about-our-genes-study-reveals
a new study has shown that how long we live has more to do with our behavior than with our genes, implying that our choices may have a much more profound impact on our longevity than we may have thought.
The Study
The authors of the study, published in the Human Kinetics Journal, sought to analyze the relationship between physical activity and sedentary behavior, and their associations with mortality based on a score that evaluated genetic risk factors. The study involved 5,446 post-menopausal women 63 years of age or older. The women were put into three groups based on their genetic risk factors. These risk factors were measured by a “small selection of single-nucleotide polymorphisms” that are well-known to affect longevity.
Single-nucleotide polymorphisms (SNPs) are variations in a genetic sequence that affects one of the sequence’s basic building blocks—adenine, thymine, cytosine, or guanine. SNPs help predict an individual’s response to certain drugs, his or her susceptibility to environmental factors such as toxins, pesticides, or industrial waste, and his or her risk of developing certain diseases.
The study authors conclusively found that, regardless of their genetic risk factors, participants who had a higher rate of physical activity showed a lower risk of mortality, and those who had a higher level of sedentary behavior increased their chances of dying during an average follow-up period of more than six years.
Ultimately, the findings support the importance of more physical activity and less sedentary behavior for reducing mortality risk in older women, regardless of their genetic predisposition for longevity.
Genes and Longevity
An article titled “Human Longevity: Genetics or Lifestyle? It Takes Two to Tango,” published in Immunity and Aging in 2016, found that a combination of genetic and non-genetic factors determines healthy aging and longevity in humans. It says that family studies found that about 25 percent of the variation in human longevity is due to genetic factors. Interestingly, the article also states that studies have indicated that caloric restriction, as well as epigenetic factors, genetics, and lifestyle, play a role in healthy aging.
Epigenetics is the study of how our behaviors and environment can change the way our genes function. Unlike genetic changes, these epigenetic changes are reversible because they don’t affect our DNA.
In contrast, a study published in 2018 in the journal Genetics analyzed a staggering 54.43 million family trees by collecting birth and death records for 406 million people born from the 19th century to the mid-20th century from the databases of Ancestry.com. The study found that a mere 7 percent of people’s lifespan can be attributed to genetics or heritability.
Heritability measures how the differences in human genes account for the differences in individuals’ particular characteristics or traits. These include eye color, height, hair color, intelligence, and disorders such as schizophrenia and autism.
Lifestyle and Longevity
Longevity, or the biology of aging, is an exciting field of study that is making important discoveries about the factors that affect how long we live.
Until very recently, life expectancy for humans was between 19 and 35 years, but over the past 150 years, significant improvements in sanitation and living conditions, agricultural practices, access to clean food and water, and medical treatment have dramatically increased lifespans. The average lifespan now is about 76 years of age (it has declined significantly in the United States since 2020 due to COVID-19). If we look at it this way, managing how we age is a relatively new concern.
With aging comes a whole host of age-related diseases, such as heart disease, high blood pressure, kidney disease, diabetes, arthritis, cancer, dementia and Alzheimer’s disease, to name a few. And, as we get older, we are not only more likely to develop these conditions, but also to have several of them at the same time.
Scientists have been studying people who live to be over 100 years old (called centenarians) and those who live to be over 110 (called supercentenarians) in order to understand which factors contribute to their long lives. Scientists have discovered that these individuals have little in common with each other in regard to their education, profession, or income, but they tend to share similar lifestyles: They don’t smoke; they are not obese or overweight; and they cope well with stress. Also, most centenarians and supercentenarians are women.
In our elder years, eating a healthy diet, avoiding tobacco, limiting alcohol, and staying physically active can keep many of us healthy into old age. But in later life—at age 80 and beyond—genetics plays a prominent role in keeping people healthy and avoiding age-related diseases. Research suggests that many centenarians are able to live independently and avoid age-related diseases until the very last years of their lives.
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