Blue Zones, an Analysis of Existing Evidence through a Scoping Review

Abstract

"Blue Zones" refer to geographical regions with a high proportion of centenarians. This review aims to identify and synthesize scientific evidence regarding Blue Zones and their characteristics. A scoping review was conducted following PRISMA-ScR guidelines. Systematic bibliographic searches were performed across major scientific databases up to February 2025. Studies were included if they investigated regions which the authors identified as Blue Zones. Non-naturally occurring Blue Zones were excluded. A narrative synthesis of the evidence was carried out. Sixty-five records were included, identifying ten regions: Ogliastra (Sardinia, Italy), Ikaria (Greece), Cilento (Italy), one municipality in The Netherlands, Menorca (Spain), Okinawa (Japan), Rugao (China), Nicoya (Costa Rica), Martinique/Guadeloupe (French overseas regions in the Caribbean) and Loma Linda (California, United States). Longevity indicators revealed that Ogliastra, Okinawa and Nicoya exhibit higher longevity compared to national averages. Ikaria and Cilento show high life expectancy, the municipality in The Netherlands show a higher proportion of exceptional longevous population than other municipalities, whereas Guadeloupe/Martinique present a higher prevalence of supercentenarian deaths than metropolitan France. Data from Menorca remain inconclusive, and Rugao has fewer centenarians. No studies have been conducted in Loma Linda. Factors associated with longevity include diet, physical activity, climate, genetic factors and geographical isolation. The literature indicates that certain geographical areas demonstrated a higher percentage of centenarians than adjacent areas. While regions such as Okinawa, Ogliastra and Nicoya are well-characterized as Blue Zones, others remain under investigation, and some currently lack sufficient scientific evidence.