Usually, longevity studies address individual longevity and aim at identifying specific traits or life trajectories of sporadic long-lived persons. Yet, some populations like in Sardinia have been identified where longevity is shared by a large portion of their members. In this case the term population longevity has been proposed as more appropriate.
When the spatial distribution of centenarians is non-random and the proportion of people surviving to oldest ages in a given population is greater than in neighbouring areas, it is referred as population longevity. When searching for the determinants of population longevity, the relevant characteristics or behaviors are those shared by a large part of the population. By considering these common characteristics, the chance to find more powerful explanatory variables is increased as most persons concerned are born and live in the same place and are more likely to share the same genetic makeup, early life conditions, as well as traditional behaviours and habits, including the same locally produced food.
Longevity Blue Zones 