Individual longevity versus population longevity

The longevity questAreas of exceptional longevity around the world

Michel POULAIN

S.D.F.B. – Louvain-la-Neuve

3 Mai 2013

Individual longevity versus population longevity

• Gerontologists apply the term longevity to any individual who is beyond age 90 years and actively functional but the larger number of researches dealing with longevity considers only individual centenarians.

• In fact longevity is related to individuals (individual longevity) but also to populations as a whole (population longevity).

Individual longevity versus population longevity

By investigating population longevity, the chance to find more powerful explanatory variables is increased as most persons concerned

• are born and live in the same location• are more likely to share the same genetic make-up • had the same early life conditions• share the same traditional life style including the

same locally produced food.

Individual longevity versus population longevity

While the individual longevity is generally described by observing the age at death or the extreme survival of the oldest olds,

the population longevity can be characterised through various indexes that are mostly associated with life tables computed for that population as a whole.

Some longevity indicators

The centenarian prevalence, the ratio between the number of centenarians and the total population is largely used but could create misleading interpretations.

The probability to become centenarian may be extracted from cohort life tables.

The centenarian rate is obtained by comparing the number of persons aged 60 and those aged 100, 40 years later.

Comparing the probability to become centenarian

Longevity hot-spots

• In a 1973 National Geographic article, Leaf gave a detailed account of his journeys to countries of long-living people: the Hunzas from Pakistan, the Abkhazians from the former Soviet Union, and Ecuadorians from Vilcabamba. According to Leaf, there were ten times more centenarians in these countries than in most Western countries.

• However the same author acknowledged in 1982 that a

large number of the men and women he had met had exaggerated their age in order to improve their social status or to promote local tourism (Leaf 1982, 1990).

The crucial point : age validation

• Demographers have become increasingly concerned with the accuracy of longevity claims given the unprecedented growth in very old people in developed countries (Young et al. 2010).

• To identify a longevity island and to ensure its exceptional longevity, it is crucial to validate the exact age at death or the extreme survival of oldest olds.

Centenarians randomly distributed

Low prevalence High prevalence

Centenarians non-randomly distributed

No concentration High concentration

Proto-Sardinia, archaïc

zones and genetic

variations

Cavalli Sforza 1994

Summary of findings in the Sardinian BZVARIABLES BLUE ZONE

SENSU STRICTO

EXTENDED BLUE ZONE

NON BLUE ZONE

Population 2001 42,113 432,475 1,199,405Area (sq km)

1,559 13,053 11,038Extreme longevity index (ELI) 509 264 181Male centenarians 1880-1900 47 269 146Female centenarians 1880 - 1900 44 362 355Male longevity index 512 218 103Female longevity index 506 311 264Sex ratio for centenarians 1880 -1900 0.936 1.346 2.432

The concept of Blue Zones

The concept of Longevity Blue Zone has been defined as a rather limited and homogenous geographical area where the population share common life style and the same environment and their longevity has been proved to be exceptional.

Compared survival trajectories: males(source: Villagrande and Human Mortality Database)

A longevity BZ in the Nicoya Peninsula in Costa Rica

IKARIA

Three municipalities and 8,000 inhabitants

Comparing centenarian rates between BZ’s and countries

Lessons from the Blue Zones

• In the BZ’s, the population has been proved to live longer (especially for men) and in more healthy conditions (e.g. fewer dementia).

• Based on surveys carried out on the oldest olds in these BZ’s we were able to identify some characteristics associated with healthy ageing.

• What are the lessons from the BZ’s ? What can be done in our post-modern societies to optimize the lifestyle for a longer and healthier life ?

Physical activity : keeping engaged in regular physical activity, often part of a daily work routine

Physical activity : keeping engaged in regular physical activity, often part of a daily work routine

Nutrition : no specific food could explain longevity in the BZ’s

Most people in BZ’s have experienced in their life

caloric restriction and stop eating when their

stomachs are 80 percent full.

Avoiding meat and processed food.Favouring locally produced food.

Having a strong sense of purpose that serves as a buffer against stress.

Having a ‘plan de vida’ like Felipe in Nicoya and thinking positively.

No comment

Having strong family links and support

Ensuring a strong community support and considering the oldest olds as part of the treasure of the local community

Even for those who are in a nursing home

The need for future scientific research• Quantitative and qualitative surveys are under

development on a comparative way in Sardinia and Ikaria involving biomedical and cognitive aspects.

• Future plans involve investigations in two directions:

1. demography and anthropology

2. biomarkers, genetics and epigenetics

The need for future scientific research

• Individual life course approach is considered and an anthropological viewpoint is favoured in order to understand all transitions experienced in the local community.

• Longevity genes cannot be found, if any, because of the small size of the populations concerned.

• An innovative and promising approach would be the study of epigenetic marks, on the assumption that the long-lived phenotype is not solely a result of inherited genetic makeup, but it may be modulated by interaction with the environment.

The need for future scientific research

But, definitively, significant results can only result from a close cooperation between disciplines that are still too far from each other.

Developing research where biological and social sciences are interacting is crucial and integrating epigenetics and demo-anthropolical traits is our main expectation with BZ’s.

Policy implications for Healthy Aging

Expanding the Blue Zones

”Blue Zones, now limited to just a few populations in the world, can become commonplace”

Appel, L.J. Dietary Patterns and Longevity, Circulation 2008;118;214-215

Blue Zones Communities Creating Environments of Health

• The Blue Zones Project initiative to become a Blue Zones Community is a systems approach that allows citizens, schools, employers, restaurants, grocery stores and community leaders to work together on policies and programs that will make the most impact and move the community towards optimal health and well-being.

• Blue Zones Project Initiatives in Action in the US:1. Albert Lea, Minesota2. Three Beach Cities in California3. Ten Communities in Iowa

IKARIAan island where people take time for allIncluding to die…

Antonio TODDE(1889 – 2003),The oldest man on earth in Tiana (July 2002).

He experienced the secrets of longevity !

Three KEYWORDS

I N V E N T

Three KEYWORDS

I N V E N TDISCOVER

Three KEYWORDS

I N V E N TDISCOVERREMEMBER