1 Life Expectancy, Aging, & Centenarian Research Carolyn R. Fallahi, Ph. D.

2 How has the life span changed? 20 th Century = 65 years old. 20 th Century = 65 years old. Definition of Life span = upper boundary of life, the maximum number of years an individual can live. Definition of Life span = upper boundary of life, the maximum number of years an individual can live. What is the maximum theoretically? What is the maximum theoretically?

3 Average Life Expectancy Males Males Females Females What influences when we will die? What influences when we will die? Sex differences associated with longevity. Sex differences associated with longevity.

4 What are the predictors of psychological longevity? Louis Terman 1921 – termite study Louis Terman 1921 – termite study Freidman et al (1995) – analysis of the “termites” Freidman et al (1995) – analysis of the “termites” Looked at: Looked at: –Effects of personality –Stressful life events –Health-related behaviors

5 Divided stress Parental divorce in childhood Parental divorce in childhood Marital instability in adulthood Marital instability in adulthood Both were found to be good predictors of the age of death. Both were found to be good predictors of the age of death. More explanation More explanation

6 Centenarians 1980 = 15, = 15, = 77, = 77, = 834, = 834,000 Why? Why? Segerber (1982) study looking at 1,200 centenarians Segerber (1982) study looking at 1,200 centenarians

7 Duke Longitudinal Study Palmore (1982) Palmore (1982) Longitudinal study over a 25 year period Longitudinal study over a 25 year period 270 volunteers 270 volunteers Physical, marital, social, laboratory tasks Physical, marital, social, laboratory tasks Best predictors of longetivity? Best predictors of longetivity?

8 The Nun Study David Snowdon David Snowdon 678 nuns from a convent in Minnesota 678 nuns from a convent in Minnesota Tests included cognitive & physical functioning & they will donate their brains upon death. Tests included cognitive & physical functioning & they will donate their brains upon death. What did they find? What did they find?

9 Theories of Aging Cellular Clock Theory: Leonard Hayflick (1977) theory. Cellular Clock Theory: Leonard Hayflick (1977) theory. –A microbiological theory of aging –Cells can divide a maximum number of times –Dividing ability decreases with age –Upper limit? –New research since Hayflick’s theory  Tips of the chromosomes - telomeres  Telomerase

10 Free Radical Theory Also a microbiological theory of aging Also a microbiological theory of aging Cells metabolize energy. Cells metabolize energy. Cells generate waste that includes unstable oxygen molecules = free radicals. Cells generate waste that includes unstable oxygen molecules = free radicals. Free radicals = damage within the cell structure. Free radicals = damage within the cell structure.

11 Mitochondrial Theory Mitochondria = tiny cellular bodies that supply energy for functioning, growth, and repair. Mitochondria = tiny cellular bodies that supply energy for functioning, growth, and repair. Why does mitochondria decay? Why does mitochondria decay? –Oxidative damage –Loss of micronutrients supplied by the cell –Free radicals –Evidence for this theory?

12 Hormonal Stress Theory Aging at the hormonal level = lower resistance & increased disease Aging at the hormonal level = lower resistance & increased disease Evidence: HPA or hypothalamic-pituitary – adrenal axis plays a role in aging. Evidence: HPA or hypothalamic-pituitary – adrenal axis plays a role in aging. What happens to the HPA as we age? What happens to the HPA as we age?

13 Which one is correct? We really don’t know. We really don’t know. Maybe all of them are involved. Maybe all of them are involved.