Why people born during World War II are healthier

During wars, countless people suffer, even during times without direct exposure to violence, as they are exposed to conditions such as poorer nutritional situations, stress, recessions, and sub optimally functioning health care systems. This was the situation during much of World War II in three occupied countries: France, Belgium and The Netherlands. Biological theory predicts that the health of those who were prenatally exposed to such adverse circumstances will be worse once they have reached old age. But for WWII, such effects have thus far been proven only for famines and other extreme exposures that differed from those experienced by the majority of women in these occupied countries who were pregnant during WWII. We show that – contrary to expectations – prenatal exposure to WWII in the three countries does not lead to poorer health among the older population. We even find a better health among exposed females, but demonstrate that this is due to selective mortality during infanthood among the war cohorts and to selective fertility during WWII. These selection effects are likely to be stronger during more extreme circumstances than the ones studied here. Therefore, previous research on long-term effects of such prenatal exposures may have underestimated effects. Negative health effects as a result of prenatal exposure to WWII in France, Belgium and The Netherlands – outside of the well-known effects of the Dutch famine – are absent or at most very small.