Biodemography of exceptional longevity: early-life and mid-life predictors of human longevity

Abstract

This study explores the effects of early-life and middle-life conditions on exceptional longevity using two matched case-control studies. The first study compares 198 validated centenarians born in the United States between 1890 and 1893 to their shorter-lived siblings. Family histories of centenarians were reconstructed and exceptional longevity validated using early U.S. censuses, the Social Security Administration Death Master File, state death indexes, online genealogies, and other supplementary data resources. Siblings born to young mothers (aged less than 25 years) had significantly higher chances of living to 100 compared to siblings born to older mothers (odds ratio = 2.03, 95% CI = 1.33-3.11, p = .001). Paternal age and birth order were not associated with exceptional longevity. The second study explores whether people living to 100 years and beyond differ in physical characteristics at a young age from their shorter-lived peers. A random representative sample of 240 men who were born in 1887 and survived to age 100 was selected from the U.S. Social Security Administration database and linked to U.S. World War I civil draft registration cards collected in 1917 when these men were 30 years old. These validated centenarians were then compared to randomly selected controls who were matched by calendar year of birth, race, and place of draft registration in 1917. Results showed a negative association between "stout" body build (being in the heaviest 15 percent of the population) and survival to age 100. Having the occupation of "farmer" and a large number of children (4 or more) at age 30 increased the chances of exceptional longevity. The results of both studies demonstrate that matched case-control design is a useful approach in exploring effects of early-life conditions and middle-life characteristics on exceptional longevity.

Figure 1

Description of Case-Sibling Design in this study

Figure 2

Odds ratio to survive to 100 years as a function of maternal age at person's birth. Data for persons born to mother at 25-29 years are treated as a reference category. Based on logistic regression model, which includes five categories of maternal age and gender as covariates.

Figure 3

Matched case-control design of the study.

Figure 4

Body height at age 30 and survival to age 100. Distribution of cases (future centenarians) and controls by the height category.

Figure 5

Body build at age 30 and survival to age 100. Distribution of cases (future centenarians) and controls by the body build category.