Population Health

At a Glance Projects Publications Team


Early-Life Determinants of Cognitive Functioning, Health, and Mortality

Mikko Myrskylä, Kieron Barclay, Pekka Martikainen

Detailed Description

Recent research has highlighted the importance of early-life conditions in shaping outcomes across an individual's lifespan, with factors ranging from childhood environmental and family conditions to perinatal health and in utero exposures. The relationship between the length of the birth interval and child outcomes has also received increasing attention, with some studies exploring offspring outcomes across the life course. To gain a deeper understanding of these relationships, our research employs advanced statistical techniques and top-quality data from administrative population registers in Finland and Sweden.

We explore a range of outcomes, including educational achievements such as average points of high school grades, all-cause and cause-specific mortality, and short- and long-term outcomes related to preterm birth, low birth weight, infant mortality, college degree attainment, and occupational status. We compare sibling fixed effects to differentiate the effects of early-life exposures from shared factors that may confound associations. In some studies, we estimate sibling intraclass correlations as a summary measure of all early-life and familial influences.

Our research has already yielded numerous significant findings. For example, we discovered that premature births do not typically harm educational achievement when we account for the degree of prematurity and adjust for shared factors in the family of origin. Only children born extremely preterm have worse outcomes, and extreme prematurity during gestation almost perfectly corresponds to a critical period of in utero brain development. However, even children born extremely preterm can significantly improve their outcomes if they attend the best schools, and this underscores the importance of contextual factors. Because extremely preterm births are rare, the overall impact of premature births on later-life outcomes is likely to be modest.

In other work, we examined the influence of birth spacing on outcomes across the life course. Previous research has shown that extremely short birth intervals may increase the probability of poor perinatal outcomes. Consistent with this, our research has found that children born after a birth interval of 9 to12 months have a higher probability of low birth weight, preterm birth, and infant mortality, both with and without sibling comparisons. Short intervals before the birth of the next youngest sibling are also associated with low birth weight, preterm birth, and infant mortality, both with and without sibling comparisons. However, our research highlights that even the very shortest birth intervals are not negatively associated with long-term outcomes related to educational or occupational achievement or long-term mortality. This suggests that the disadvantages associated with extremely short birth intervals disappear over the extended life course.

Overall, our research underscores the complex interplay between early-life conditions and outcomes across the life course, with some factors exerting stronger effects in the short-term, whereas others may have more long-term impacts.

Research Keywords:

Aging, Mortality and Longevity, Family Behavior, Health Care, Public Health, Medicine, and Epidemiology, Life Course

Region keywords:

Finland, Sweden, United Kingdom, USA


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The Max Planck Institute for Demographic Research (MPIDR) in Rostock is one of the leading demographic research centers in the world. It's part of the Max Planck Society, the internationally renowned German research society.