Early Childhood Conditions and Old-Age Mortality

Early life conditions might determine adult mortality. The literature, however, both support and contradict this proposition. In most studies, the outcome has been the mortality rates in a given period of time. These rates represent the combined result of both previous and current exposures. Therefore, it is more apt to study the rate of improvement as an outcome, rather than mortality rates in a given period of time.

The effects of early-life conditions, assessed as mortality rates at ages 0 and 1-4, and the effects of indicators of available resources in adult life were analysed.

The outcomes were the decrease in the national rates of mortality in three age groups, aged 24-34, 35-54 and 55-74, in 18 OECD countries over the years 1990-2010. The effects were analysed in linear multiple regression models using least squares, controlling for country-specific historical constants, which represent the mortality rates in 1990.

Among the 24-34 and 35-54 year-olds, neither early-life indicators nor resource indicators significantly affected the regression equations. Among the 55-74 year-olds, however, in the model including the mortality rate at age 0 in 1940-49, the explanatory value of the equation in question increased from 65 to 79%, and the effect of mortality rate at age 0 was statistically significant.

Significant effects of early-life conditions on the rate of decrease in mortality were found, but only in the oldest age group. This finding is consistent with Gavrilov’s reliability theory of aging.

Key Points

• Mortality rates have decreased almost linearly in recent decades in OECD countries.

• Most of the variation between countries seemed to be determined by past history and the catch-up of nations that have previously lagged behind.

• A significant effect of early-life conditions on the rate of decrease in mortality was found, but only in the 55-74 year-olds, not in the 24-34 and 35-54 year-olds.