Life expectancy at birth is an estimate of the number of years of life that a person can be expected to live, given the place and the population into which they were born. Of note, life expectancy differs significantly between men and women, with women living an average of eight years longer. So far, the only known place where this figure has not been confirmed is in the Blue Zone of Sardinia. In some villages in this remote area in the middle of the Mediterranean, the number of centenarians of the two genders is equivalent. Seulo, a small village in the southern Barbagia region, is so far the only case in the world where the number of male centenarians has been proven by official data to exceed that of their female counterparts.
The island of Sardinia as a whole is actually not even a Blue Zone. In fact, the proportion of centenarians in the population on the island is comparable to that of the rest of Italy. However, the situation changes dramatically when analyzing the demographic data of a group of thirteen villages located in the historic regions of Barbagia and Ogliastra, which comprise the Sardinian Blue Zone. In this area, there are six times as many centenarians as in the rest of Italy, and thirty times as many as in the U.S. Until 2017, in Seulo, there were 7 centenarians living simultaneously. As Seulo is home to only around 900 people, this is equivalent to a rate of nearly 1 in 100. Considering the fact that, in the rest of the world, the proportion of centenarians is more like 1 in 10,000 people, this figure is nothing short of surprising.
It has already been established by numerous scientific studies that longevity is influenced by a myriad of factors, which are interconnected in various ways. Among the important factors are genetics, diet and lifestyle, the environment, and the social fabric and community relationships.
The complex historical events that have taken place over the centuries in Sardinia have certainly affected the communities of the entire island, particularly those of the more isolated areas. In Sardinia, the mountain ranges, even more than the sea, are responsible for the deep isolation of the Sardinian people. Since the Bronze Age, the era in which the Nuraghic civilization rose, these small urban centers have turned inward, abandoning the coastal territories that were frequently targeted for conquest by other Mediterranean peoples. This aspect, along with the spread of malaria that occurred with the first deforestation by the Carthaginians, determined not only the formation of a society that is wary and little open to the outside, but also a social structure marked by strong internal social cohesion. This is an evident defense strategy, the only means of survival.
These days, one of the most serious problems putting public health at risk is social isolation. One must consider that more than a third of the world’s population claims to have only two people on whom they could rely in case of urgent need.
In contrast to this, the villages of the Sardinian Blue Zone are entirely based around the concept of family and strong social cohesion. Families themselves, and the communities in which they are situated, constitute a complete social network, based on the principles of reciprocity and mutual support. In this context, the elderly function as the hub of society. Elders are considered wise bearers of knowledge, who are not considered a burden and left alone, but rather are seen as maintaining continuity with the past of a thousand-year-old tradition. Because of this, these villages have become independent but genetically convenient satellites, where people in the community can easily find partners and give cultural continuity. It is important to note that isolation is always considered a disadvantage from a genetic point of view, because it reduces genetic variation and therefore the potential for adaptation, but not if it promotes the maintenance of traits within the population’s gene pool that potentially promote the extension of life expectancy.
Researcher Juliane Lustand of Brigham Young University conducted a series of studies on thousands of middle-aged people in the U.S. The research considered a number of social, behavioral, and environmental factors, including lifestyle, diet, daily physical exercise, participation in sports, access to medical care, smoking and alcohol consumption, social status, etc. After several years, a correlation was established between aging and health, by analyzing how many people had failed to survive. To answer the question, “Which aspect most reduces the possibility of premature death?” a list of the most powerful predictors was generated. It is interesting to note that apparently basic aspects of the place where one lives, such as air quality and pollution, the proportion of people who are obese, and the amount of daily exercise and physical activity have only a small influence on the life span. Even just undergoing seasonal vaccination for at-risk categories has been shown to be more effective than regular physical activity. The interesting fact was that the strongest predictors of lifespan were two factors related to social interaction and integration. The second strongest predictor was the close social relationships: the close relationships with close friends and family. Surprisingly, however, an even stronger predictor was the social integration of the second degree. These are the casual daily social interactions; for example, the connection with the local fruit vendor.
These kinds of interactions and relationships, which take place within a strongly interdependent community, this multiplies the opportunities for meeting and exchange, which seems to have an effect on our mood and health. Face to face interactions promote the release of a multitude of neurotransmitters that undoubtedly play a role in affecting our mood. For example, the production of dopamine and oxytocin increases confidence and acts as a true natural anti-stress factor (by decreasing the production of the stress hormone cortisol).
Walking through the alleys of these villages perched on the steep slopes of the island, one can often observe that all of the doors have keys outside. This allows neighbors to access the house in case of need, as though the boundaries of the household extended to the entire village community. Many of the fundamental activities of daily living, such as breadmaking, are carried out at the community level. This has practical benefits, such as reducing the costs for wood by lighting the oven less often, and accomplishing the task more efficiently with the help of a group. Perhaps more importantly, it strengthens and re-establishes rapport, and keeps alive the ties and relationships between community members.