Exceptional longevity in Okinawa: Demographic trends since 1975.

Demographers have studied the Japanese mortality pattern since Japan became the most longevous population worldwide, half a century ago. Nutrition and lifestyle were considered by epidemiologists, gerontologists and other scientists as the most important reasons explaining the Japanese superiority. In Okinawa, the mortality pattern is even more exceptional, but few demographers have pointed out this exception. Other scientists proposed different explanations - for example some genetic characteristics, less salt and more animal protein in the food, a mild climate, a higher level of activity, a better consideration of the oldest in the population and, globally speaking, a more traditional lifestyle. At the end of the 1980s, lower improvements of mortality among young adults were identified in Okinawa. In 2002, Okinawa fell from the 4th to the 26th place in the ranking of the 47 Japanese prefectures by male life expectancy. This has been considered by the population of Okinawa as a 'shock'. Our in-depth analysis of available life tables and associated mortality rates proves that the population of Okinawa is divided into two groups of generations: those born before World War II and those born after. The older generations clearly experience a highly favourable mortality pattern, whereas the younger generations show mortality levels that are definitively higher compared to mainland Japan. This contribution considers which factors may explain such a situation, including the plausible invalidation of the age of some oldest in the population. We plea for in-depth demographic age validation that will enhance all scientific findings so far and boost the exceptional longevity in Okinawa.

Specific features of the oldest old from the Longevity Blue Zones in Ikaria and Sardinia.

Human longevity may be found in single individuals as well as in the population as a whole ("population longevity"). Longevity Blue Zones (LBZs), which are areas with an unusually high number of oldest old, have been identified in Sardinia and the Greek island of Ikaria. We compared the lifestyle, health status and some genetic markers of the LBZ populations with those of reference populations from Italy and Greece; the data were extracted from the GEHA database. In the LBZs, the proportion of individuals who never married or were married and still living with their spouse was significantly greater. Nonagenarians males and females with a high self‒perception of optimism and/or a high score for self-rated health were also found in larger proportions in LBZs. Among the variables with lower frequency were the proportion of the widowed, the percentage of subjects who had suffered a stroke and the frequency of Apoε4 and Apoε2 and the TT genotype of FOXO3A gene. Compared to behavioral and health indicators, the impact of genetic factors might be relatively less important in the LBZs. Nevertheless, further research is needed to identify potential epigenetic traits that might play a predominant role due to the interaction between genetics and the human and physical environments.

Fertility History, Children's Gender, and Post-Reproductive Survival in a Longevous Population.

The question of whether mothers' fertility history influences their post-reproductive survival has been addressed frequently in the scientific literature. Using data from Villagrande Strisaili, Sardinia, where longevity is higher than anywhere else in Europe, we analyzed the relationship between the fertility pattern of mothers who survived past age 50 (n = 539) and their post-reproductive lifespan. We find that, after adjustment for potential confounders (mothers' birth cohort, survival of spouse), the mothers who on average delivered their children later displayed a reduced mortality risk (‒2.9 percent for each additional year), supporting previously reported findings. We also find that a male-skewed offspring ratio was associated with decreased mortality risk of mothers, with longer survival of mothers who delivered their sons above age 35 (p = 0.005), a result not found for daughters. So far, no biological explanation has been suggested for the positive effect of delivering sons later in life. We conjecture that in our dataset stronger nonbiological factors such as gender-specific sociocultural and economic factors may have masked the negative effect reported in other populations, for which a biological explanation was proposed.

Centenarians' Marital History and Living Arrangements: Pathways to Extreme Longevity.

OBJECTIVES: Mortality risk for older persons is associated with marital status and living arrangements, for example, living alone, with a spouse, with others but without a spouse, or in a collective household. This study analyzed the marital history and living arrangements of centenarians with the aim of identifying which trajectories are associated with reaching an advanced age. METHOD: Original longitudinal register-based data for 3,000 Belgian centenarians born between the years 1893 and 1903 were used to reconstruct their marital history and living arrangements during their later life (from age 60 to 100). RESULTS: The marital history and living arrangements for male and female centenarians were strikingly different after they reached the age of 60. From age 60 to 100, male centenarians lived twice as long with their wife as female centenarians did with their husband. Female centenarians lived alone for more than half of their lives. Male centenarians had younger wives and female centenarians had older husbands than non-centenarians. More than half of the widowers remarried and did so with a woman who was generally more than 10 years younger. Most centenarians ended their life in a nursing home but entered it very late in life. DISCUSSION: In very old age, living with a spouse is beneficial for men but not for women, for whom living alone is more advantageous than living with a spouse. This study compares the marital history and living arrangement trajectory of centenarians with people who did not live as long to determine associated mortality risks confirming that men are often not able to live by themselves, whereas women seem to have few problems to manage on their own.