Comparative analysis of parameters of human senescence Natalia S. Gavrilova Leonid A. Gavrilov Center on Aging, NORC/University of Chicago, 1155 East 60th Street, Chicago, IL 60637

The idea of this study has been suggested by Fedor Severin in order to test whether aging is programmed or not.

The idea of this study is to compare variability for traits, which are known to be determined by the developmental program (such as ages at sexual maturity) with variability of traits related to aging (such as ages at menopause and death).

One of the arguments used by the opponents of programmed aging is a too high variation in individual lifespans compared to the observed variation of programmed events (such as the age of sexual maturation). The main goal of this study was to test the validity of this argument.

Measures of variability Absolute measure – standard deviation For distribution of lifespan, demographers often calculate standard deviation at age 10 – SD10 (Edwards & Tuljapurkar 2005). Relative measure – coefficient of variation. E quals the standard deviation divided by the mean

Historical Changes in Mortality Swedish Females Data source: Human Mortality Database

Age at onset of menarche is an example of characteristic determined by developmental program

Age at onset of menarche was declining in the XX century. Norway data. Source: "Age of Menarche in Norway [Chart]," in Children and Youth in History, Item #207, (accessed February 13, 2010). Annotated by Stephen Robertson

Similar results are obtained for Korean girls Source: Age at menarche in a Korean population: secular trends and influencing factors. Geum Joon Cho et al. EUROPEAN JOURNAL OF PEDIATRICS JAN 2010

Declining of the menarche age decelerated in developed countries now. Helm P, Grolund L (1998) A halt in the secular trend towards earlier menarche in Denmark. Acta Obstet Gynecol Scand 77:198–200 Similar results obtained for Finland and Iceland Mean age years, SD 1.15 years for Danish girls in 1996

What studies tell us about the variation of menarche age?

Mean age at menarche, its standard deviation and coefficient of variation for European women (The EPIC Study) CountryBirth yearsMean age at menarche (SD) Coefficient of variation (CV) France (1.40)10.9% Italy (1.46)11.6% Spain (1.56)12.1% United Kingdom (1.54)12.0% Greece (1.52)11.5% Source: Onland-Moret et al., American Journal of Epidemiology (7):

Mean age at menarche, its standard deviation and coefficient of variation for European women (continue) CountryBirth yearsMean age at menarche (SD) Coefficient of variation (CV) The Netherlands (1.56)11.8% Germany (1.48)11.2% Sweden (1.41)10.4% Denmark (1.53)11.3% Greece (1.52)11.5% Source: Onland-Moret et al., American Journal of Epidemiology (7):

Age at menarche in other countries Iran: Mean age (SD) in the urban areas was 12.4 (1.1) years and in rural areas it was 12.6 (1.1) years (Delavar and Hajian-Tilaki, 2008) Korea: Mean age at menarche of girls born between 1986 and 1995 was (1.49) (Cho et al., 2010)

What about boys? Third National Health and Nutrition Examination Survey (NHANES III) Sexual maturity stages based on the recommendations of Tanner were assigned to each maturity indicator Pubic hair development using stages from 1 (immaturity) to 5 (complete maturity) Genitalia development using stages from 1 (immaturity) to 5 (complete maturity)

Mean age (SD) of some characteristics of sexual maturation for U.S. boys (NHANES study) CharacteristicNon-Hispanic whites Non-Hispanic blacks Mexican Americans Pubic hair development, stage (1.50)16.67 (1.23)17.14 (1.45) Genitalia development, stage (1.64)16.42 (1.43)16.85 (1.92) Source: Sun et al., PEDIATRICS, 2002, 110:

Age at natural menopause as a marker of reproductive aging

Mean age (SD) at natural menopause PopulationMean age (SD) at menopause, years Source South Korean women46.9 (4.9)Hong et al., MATURITAS, 2007 Viennese women aged 47 to (3.6)Kirchengast et al., International Journal of Anthropology, 1999 Mexico: Puebla Mexico city 46.7 (4.77) 46.5 (5.00) Sievert, Hautaniemi, Human Biology, 2003 Black women in South Africa: rural urban 49.5 (4.7) 48.9 (4.2) Walker et al., International Journal of Obstetrics & Gynaecology, 2005

Our results using the MIDUS study

National survey conducted in 1994/95 Americans aged core national sample (N=3,485) city oversamples (N=957) Additional samples: twins, siblings Subsample used in this study : women having natural menopause (no surgeries affecting the age at menopause) aged 60-74

A minute telephone survey A 114 page mail survey Number of respondents: 4,242 Number of respondents: 3,690

Women Aged (n=2,087) AGE RACE/ETHNICITY White86.9 African-American7.7 Other8.9 RELATIONSHIP STATUS Married54.2 Other intimate relationship4.7 MIDUS SAMPLE POPULATION DISTRIBUTIONS (%)

DISTRIBUTION OF AGE AT MENARCHE IN THE MIDUS SAMPLE

DISTRIBUTION OF AGE AT MENOPAUSE IN THE MIDUS SAMPLE

DISTRIBUTION OF AGE AT DEATH, SWEDISH FEMALES, 1995 Data source: Human Mortality Database

Variation for characteristics of human aging and development CharacteristicMean age (SD) years Coefficient of variation Source Age at onset of menarche 12.9 (1.6)12.4%MIDUS data Age at onset of menopause 49.7 (5.2)10.5%MIDUS data Age at death78.7 (16.1)20.5%USA, women, Human mortality database

Variation of age at onset of menarche and age at death (in 2005) CountryMean age (SD) for onset of menarche CV % Mean age (SD) at death CV % France12.84 (1.40) (13.8)16.6 Italy12.54 (1.46) (13.1)15.7 Sweden13.59 (1.41) (12.9)15.7 UK12.89 (1.54) (14.0)17.5 USA12.9 (1.60) (16.1)20.5

Variation of age at onset of menarche and age at death (in 2005) after 10 years CountryMean age (SD) for onset of menarche CV % Mean age (SD10) at death after 10 CV10 % France12.84 (1.40) (12.7)15.2 Italy12.54 (1.46) (11.9)14.2 Sweden13.59 (1.41) (12.0)14.5 UK12.89 (1.54) (12.6)15.5 USA12.9 (1.60) (14.3)18.0

Mean Values and Standard Deviations for Human Developmental Characteristics

Conclusions Standard deviations for age at onset of menarche are about 10 times lower than standard deviations for ages at death Coefficients of variation for ages at onset of menarche and ages at death for contemporary populations are of the same order of magnitude

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