Khaberni - A recent study published by the American journal "Science" reveals that the impact of genes on lifespan is not constant, but changes according to living conditions and the surrounding environment, where health and environmental advancements allow for a new reading of the differences between individuals in expected lifespan.
According to the study, it was previously believed that genes played a secondary role in lifespan, while environmental factors and daily habits dominated the outcomes. However, analysis of twin datasets from Scandinavian countries showed that the inheritability of lifespan can be as high as about 55% when excluding deaths caused by external factors such as infections, accidents, and famines, compared to previous estimates of 20–25%. This reflects an improvement in health conditions and the reduction of external risks, making the impact of genes more evident.
The study further explained that the impact of genes increases in societies where external risks are reduced, a phenomenon similar to what is seen in other traits such as height, where heredity becomes more influential with proper nutrition and stable living conditions.
It also pointed out that age-related diseases, such as dementia and cardiovascular diseases, are significantly linked to genetic factors, and with an increase in average lifespan, these diseases become the main cause of death, thereby enhancing the role of genes compared to the past.
However, the study affirmed that genes do not negate the impact of lifestyle; individuals who lead a healthy, balanced life can reduce genetic risks, while harmful habits may undermine the advantages of genes, making lifespan a product of ongoing balance between genetic and environmental factors.
The study concludes that the relationship between genes and the environment is complementary, not competitive, and understanding this dynamic can guide future research in aging and enhance public health policies to improve quality of life.
