Demographic, Comparative, and Differential Aging

Some definitions of aging:

Sum of all changes occurring in an organisms over time phase of normal life cycle
or: Sum of all changes occurring with time and leading to functional impairment and death
or: Changes with time in membranes, cytoplasm and/or nucleus

Outline of first lecture:
Demography of aging:
Differential aging

DEMOGRAPHY:
the statistical study of human populations especially with reference to: size and density distribution, vital statistics (births, deaths, also diseases: epidemiology)

Major points:
* Increasing in average lifespan from middle of 18th cantury to end of 20th century.
* Increased lifespan in all countries (Developed and Underdeveloped)
* Longer lifespan in women than men
* Fastest growing proportion of the population +80 years
* Increased maximal lifespan
* Compression of morbitity (pg. 26 PBAG)

Mortality Transition
Country/Time Period Life expectancy (at birth) Infant mortality (per 1000)
Prehistoric 25 250
Sweden 1750 37 210
India 1880 25 230
US 1900 48 133
France 1950 66 52
Japan 1996 80 4

Life expectancy in the U.S. in 1900: Men 45 and Women 48
Life expectancy in the U.S. in 1990: Men 73 and Women 78

Increase in Average Life Expectancy in Some Countries, 1950-1995, Total(Male + Females)

Developed Countries
Country Years
Japan 14.8
Sweden 6.1
Italy 11.2
France 10.4
United Kingdom 7.0
USA 6.9
USSR(previous) 6.3
Developing Countries
Country Years
Argentina 8.8
China 30.1
Turkey 23.7
Brazil 15.2
Egypt 19.2
India 21.7
Kenya 18.0

Average Life Expectancy at Birth for Females, 1990-1995
Female (F) to Male (M) comparison with advantage in years for females

Developed Countries
Country F-M
Japan 81.6 5.7
Sweden 80.8 5.6
Italy 80.3 6.4
France 80.8 7.8
United Kingdom 78.7 5.0
USA 79.3 6.7
USSR(previous) 74.7 9.0
Developing Countries
Country F-M
Argentina 74.8 6.7
China 72.6 3.4
Turkey 70.0 5.2
Brazil 69.1 5.6
Egypt 62.8 2.4
India 60.7 0.6
Kenya 60.8 3.7

Probable Causes of "Gender Gap" in Longevity in Favor of Women

Genetic (XX vs. XY phenotype)
or
Environmental (geography, country, income)

Some causes include:
1. Lesser life stress in females, hence lower incidence of cardiovascular diseases
2. Less smoking (although the numver of women smokers is on the increase in several countries)
3. Protective action of estrogens (e.g. on cardiovascular system)
4. Higher gene recombination frequency
5. Lesser accumulation of mDNA deletions.mutations with better proection against oxidative damage

DIFFERENTIAL AGING(read chapters 2 & 3 PBAG)

* decreased physiological competance with aging?

* increased pathology and mortality with aging (Gompertz Law pg. 24)
"The older we get, the faster we get old"

* however, great heterogeneity of the aging process has led to three trajectories:

  1. disease and disability
  2. usual aging, absence of overt pathology but presence of some functional decline
  3. successful aging, little or no functional loss and no pathology

* mechanism of successful aging include:

  1. maintaining high cognitive and physical function
  2. engagement with life, (better education)
  3. avoiding disease

Epidemiologic Transistion

* Previously, most people died from acute infectious diseases, often in childhood.
* Currently, most people die from chronic degenerative diseases, usually at older ages.