The Relationship of Fertility and Longevity

HE RAPID decline in the birth rate of practically all industrial nations, which has become especially noticeable during the past two decades, has directed attention to the course of the birth rate during the entire nineteenth and early part of the twentieth centuries. Due to the general inaccuracy and incompleteness of the records of births and deaths during the past century, it has been necessary to resort to indirect indices of the birth rate during this period. One of these indices is a comparison of the average number of offspring of women dying at various ages after the close of the childbearing period (I-4).' On the assumption that there is no relationship between fertility and length of life, the difference in the average number of children born to women aged 50-54 years at death and women aged 80-84 years at death is a measure of the difference in the birth rate of the two periods during which these women were in the childbearing ages. It has been generally recognized that the validity of this procedure rests upon the assumption that the ability to survive to an advanced age is independent of the number of children born. All investigations have shown that women dying at advanced ages have borne on the average more children than women dying at younger ages. However, there has been general disagreement concerning the interpretation of this fact. Some have interpreted the generally higher average number of children born to women dying, for example at 75-79 years of age as compared with the average number of children born to women dying at 50-54 years of age, as a measure of the decline in the birth rate, but others accept the same type of data as proof of a positive correlation between fertility and length of life (5-8). All of the studies, with the exception of those using the data to indicate the decline in the birth rate, have concluded that there was a positive correlation between fertility and length of life and that because of this women who died at advanced ages had more children than those who died at younger ages. As a whole, the conclusions have not been well founded since in none of the studies have all the relevant factors been controlled. A critical summary of the studies has been published by Freeman so that detailed criticism will not be undertaken here (9). To indicate the shortcomings of previous studies, it is only necessary to point out that age at death and number of offspring were the usual variables considered and that age at

Fertility · Longevity · Population · Sociology · Birth, Development, and Health · Demography · Insurance, Mortality, Demography, Risk Management · Medicine · Psychology · Gerontology

• The effect of number of births on women's mortality

  L S Hurt, C Ronsmans et al.•Population Studies•2006

  Add to list

• Fertility and Longevity

  Open Access•Walter C Mc Kain•OMEGA - Journal of Death and Dying•1977

  Add to list

• Changing patterns of fertility in the United States

  Clyde V Kiser•Social Biology•1970

  Add to list

• Fertility and post-reproductive longevity

  Kendra R Smith, Ken R Smith et al.•Biodemography and Social Biology•2002

  Add to list