Severe prenatal shocks and adolescent health: Evidence from the Dutch Hunger Winter

This paper investigates health impacts at the end of adolescence of prenatal exposure to multiple shocks, by exploiting the unique natural experiment of the Dutch Hunger Winter. At the end of World War II, a famine occurred abruptly in the Western Netherlands (November 1944-May 1945), pushing the previously and subsequently well-nourished Dutch population to the brink of starvation. We link high-quality military recruits data with objective health measurements for the cohorts born in the years surrounding WWII with newly digitised historical records on calories and nutrient composition of the war rations, daily temperature, and warfare deaths. Using difference-in-differences and triple differences research designs, we first show that the cohorts exposed to the Dutch Hunger Winter since early gestation have a higher Body Mass Index and an increased probability of being obese at age 18. We then find that this effect is partly moderated by warfare exposure and a reduction in energy-adjusted protein intake. Lastly, we account for selective mortality using a copula-based approach and newly-digitised data on survival rates, and find evidence of both selection and scarring effects. These results emphasise the complexity of the mechanisms at play in studying the consequences of early conditions.

Dairying, diseases and the evolution of lactase persistence in Europe

In European and many African, Middle Eastern and southern Asian populations, lactase persistence (LP) is the most strongly selected monogenic trait to have evolved over the past 10,000 years1. Although the selection of LP and the consumption of prehistoric milk must be linked, considerable uncertainty remains concerning their spatiotemporal configuration and specific interactions2,3. Here we provide detailed distributions of milk exploitation across Europe over the past 9,000 years using around 7,000 pottery fat residues from more than 550 archaeological sites. European milk use was widespread from the Neolithic period onwards but varied spatially and temporally in intensity. Notably, LP selection varying with levels of prehistoric milk exploitation is no better at explaining LP allele frequency trajectories than uniform selection since the Neolithic period. In the UK Biobank4,5 cohort of 500,000 contemporary Europeans, LP genotype was only weakly associated with milk consumption and did not show consistent associations with improved fitness or health indicators. This suggests that other reasons for the beneficial effects of LP should be considered for its rapid frequency increase. We propose that lactase non-persistent individuals consumed milk when it became available but, under conditions of famine and/or increased pathogen exposure, this was disadvantageous, driving LP selection in prehistoric Europe. Comparison of model likelihoods indicates that population fluctuations, settlement density and wild animal exploitation-proxies for these drivers-provide better explanations of LP selection than the extent of milk exploitation. These findings offer new perspectives on prehistoric milk exploitation and LP evolution.

Fleeing mass starvation: what we (do not) know about the famine-migration nexus

The relationship between famine and migration has not been studied adequately to date. A systematic review of scholarship centred on famine and its demographic, political, and socioeconomic effects demonstrates the paucity of academic attention to the issue. This paper surveys the dominant hypotheses and findings regarding the connection between famine and migration. It delineates key questions that an interdisciplinary and case-based exploration of the subject should address, highlighting gaps in the literature with respect to population-level analyses. Primary observations about the literature reviewed include tenuous generalisations about the linkage between famine and migration and partial examination of the role of politics in enabling or prohibiting mobility during hunger-related crises. In addition, disciplinary silos influence which particular aspects of a famine are scrutinised and which are not appraised. In view of these concerns, international legal and humanitarian norms governing migration also need to pay closer attention to its association with famine.

Association Between Fetal Exposure to Famine and Anthropometric Measures in Adulthood: A Regression Discontinuity Approach

OBJECTIVE

The aim of this study was to investigate the differences in six anthropometric measurements of people born during and immediately after the 1959 to 1961 Great Chinese Famine using a regression discontinuity approach.

METHODS

Data were drawn from the baseline of the China Kadoorie Biobank study, and a subset of data from 76,912 participants was analyzed. We performed regression discontinuity among participants who were born during the famine (October 1959 to October 1962) and immediately after the famine period (November 1962 to October 1964) by using local linear and parametric regressions. All analyses were conducted by sex and study area.

RESULTS

Significantly, there were increases of 0.30 kg/m² (P = 0.007) in BMI, 0.81 kg (P = 0.028) in weight, 8.57 mm (P = 0.004) in waist circumference, and 5.07 mm (P = 0.004) in hip circumference for rural women who were exposed to famine during their fetal period compared with those who were not exposed to famine in utero. However, such statistically significant increases in anthropometric values were not observed in local linear regression and most parametric models among rural men or in the urban population.

CONCLUSIONS

Rural Chinese women who were exposed to famine during the fetal period were observed to have higher levels of BMI, weight, waist circumference, and hip circumference in adulthood.

Adult body height as a mediator between early-life conditions and socio-economic status: the case of the Dutch Potato Famine, 1846-1847

Adult body height appears to be a relatively accurate summary variable of early-life exposures' influence on health, and may be a useful indicator of health in populations where more traditional health-related indicators are lacking. In particular, previous studies have shown a strong, positive relationship between environmental conditions in early life (particularly nutritional availability and the disease environment) and adult height. Research has also demonstrated positive associations between height and socioeconomic status. We therefore hypothesize that height mediates the relationship between early-life conditions and later-life socio-economic outcomes. We also hypothesize that the period of exposure in early life matters, and that conditions during pregnancy or the first years of life and/or the years during puberty have the largest effects on height and socio-economic status. To test these relationships, we use a sample of 1817 Dutch military conscripts who were exposed during early life to the Dutch Potato Famine (1846-1847). We conduct mediation analyses using structural equation modelling, and test seven different time periods in early-life. We use potato prices and real wages to proxy early-life environmental conditions, and occupational status (using the HISCAM scale) to proxy socioeconomic status. We find no evidence of mediation, partial or full, in any models. However, there are significant relationships between potato prices in adolescence, height and socio-economic status. To determine causality in these relationships, further research is needed.