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.

Adults prenatally exposed to the Dutch Famine exhibit a metabolic signature associated with a broad spectrum of common diseases.

Background: Exposure to famine in the prenatal period is associated with an increased risk of metabolic disease, including obesity and type-2 diabetes. We employed nuclear magnetic resonance (NMR) metabolomic profiling to provide a deeper insight into the metabolic changes associated with survival of prenatal famine exposure during the Dutch Famine at the end of World War II and explore their link to disease. Methods: NMR metabolomics data were generated from serum in 480 individuals prenatally exposed to famine (mean 58.8 years, 0.5 SD) and 464 controls (mean 57.9 years, 5.4 SD). We tested associations of prenatal famine exposure with levels of 168 individual metabolic biomarkers and compared the metabolic biomarker signature of famine exposure with those of 154 common diseases. Results: Prenatal famine exposure was associated with higher concentrations of branched-chain amino acids ((iso)-leucine), aromatic amino acid (tyrosine), and glucose in later life (0.2-0.3 SD, p < 3x10-3). The metabolic biomarker signature of prenatal famine exposure was positively correlated to that of incident type-2 diabetes (r = 0.77, p = 3x10-27), also when re-estimating the signature of prenatal famine exposure among individuals without diabetes (r = 0.67, p = 1x10-18). Remarkably, this association extended to 115 common diseases for which signatures were available (0.3 ≤ r ≤ 0.9, p < 3.2x10-4). Correlations among metabolic signatures of famine exposure and disease outcomes were attenuated when the famine signature was adjusted for body mass index. Conclusions: Prenatal famine exposure is associated with a metabolic biomarker signature that strongly resembles signatures of a diverse set of diseases, an observation that can in part be attributed to a shared involvement of obesity.

Long-term impact of pre-natal exposure to the Ukraine famine of 1932-1933 on adult type 2 diabetes mellitus.

Importance: The long-term impacts of early-life famine exposure on Type 2 Diabetes Mellitus (T2DM) have been widely documented across countries, but it remains less clear what is the critical time window and if there is a dose-response between famine intensity and risk of T2DM. Objective: To establish the relation between prenatal famine exposure and adult Type 2 diabetes mellitus (T2DM). Design: A national cross-sectional study. Setting: The man-made Ukrainian Holodomor famine of 1932-1933. Participants: A total number of 128,225 T2DM cases diagnosed at age 40 or over from the national diabetes register 2000-2008 in Ukraine. The population at risk includes 10,186,016 Soviet Ukraine births (excepting one oblast/province) between 1930-1938 classified by month and year and oblast of birth. Exposure: Births born in January-June 1934 from oblasts that experienced extreme, severe, or significant famine in 1932-1933. Famine intensity was measured based on the excess mortality during the famine. Main Outcomes and Measures: T2DM diagnosis was based on WHO (1999) criteria. Results: We observed in univariate analysis a 1.8-fold increase in T2DM (OR 1.80; 95% CI 1.74-1.85) among individuals born in the first half-year of 1934 in regions with extreme, severe, or significant famine. We observed no increase among individuals born in regions with no famine. In multivariate analysis across regions and adjusting for season of birth we observed a larger than 2-fold increase (OR 2.21; 95% CI 2.00-2.45). There was a dose-response by famine intensity, with ORs increasing from 1.94 to 2.39 across regions. The pattern was similar in men and women. Conclusions and Relevance: Births in the first half-year of 1934 were conceived at the height of the Ukraine famine in 1933. This relation for T2DM outcomes points to early gestation as a critical time window relating maternal nutrition in pregnancy to offspring health in later life. Further studies of biological mechanisms should focus on this time window for which changes in DNA methylation and later body size have also been observed.

How much schizophrenia do famines cause?

Since the 1970s, famines have been widely invoked as natural experiments in research into the long-term impact of foetal exposure to nutritional shocks. That research has produced compelling evidence for a robust link between foetal exposure and the odds of developing schizophrenia. However, the implications of that research for the human cost of famines in the longer run have not been investigated. We address the connection between foetal origins and schizophrenia with that question in mind. The impact turns out to be very modest-much less than one per cent of the associated famine death tolls-across a selection of case studies.

Genetic analysis of selection bias in a natural experiment: Investigating in-utero famine effects on elevated body mass index in the Dutch Hunger Winter Families Study.

Natural-experiment designs that compare survivors of in-utero famine exposure to unaffected controls suggest that in-utero undernutrition predisposes to development of obesity. However, birth rates drop dramatically during famines. Selection bias could arise if factors that contribute to obesity also protect fertility and/or fetal survival under famine conditions. We investigated this hypothesis using genetic analysis of a famine-exposed birth cohort. We genotyped participants in the Dutch Hunger Winter Families Study (DHWFS, N=950; 45% male), of whom 51% were exposed to the 1944-1945 Dutch Famine during gestation and 49% were their unexposed same-sex siblings or "time controls" born before or after the famine in the same hospitals. We computed body-mass index (BMI) polygenic indices (PGIs) in DHWFS participants and compared BMI PGIs between famine-exposed and control groups. Participants with higher polygenic risk had higher BMIs (Pearson r=0.42, p<0.001). However, differences between BMI PGIs of famine-exposed participants and controls were small and not statistically different from zero across specifications (Cohen's d=0.10, p>0.092). Our findings did not indicate selection bias, supporting the validity of the natural-experiment design within DHWFS. In summary, our study outlines a novel approach to explore the presence of selection bias in famine and other natural experiment studies.

Accelerated biological aging six decades after prenatal famine exposure.

To test the hypothesis that early-life adversity accelerates the pace of biological aging, we analyzed data from the Dutch Hunger Winter Families Study (DHWFS, N=951). DHWFS is a natural-experiment birth-cohort study of survivors of in-utero exposure to famine conditions caused by the German occupation of the Western Netherlands in Winter 1944-5, matched controls, and their siblings. We conducted DNA methylation analysis of blood samples collected when the survivors were aged 58 to quantify biological aging using the DunedinPACE, GrimAge, and PhenoAge epigenetic clocks. Famine survivors had faster DunedinPACE, as compared with controls. This effect was strongest among women. Results were similar for GrimAge, although effect-sizes were smaller. We observed no differences in PhenoAge between survivors and controls. Famine effects were not accounted for by blood-cell composition and were similar for individuals exposed early and later in gestation. Findings suggest in-utero undernutrition may accelerate biological aging in later life.

Infant and child mortality in the Netherlands 1935-47 and changes related to the Dutch famine of 1944-45: A population-based analysis.

Precise estimates of the impact of famine on infant and child mortality are rare due to lack of representative data. Using vital statistics reports on the Netherlands for 1935-47, we examine the impact of the Dutch famine (November 1944 to May 1945) on age-specific mortality risk and cause of death in four age groups (stillbirths, <1 year, 1-4, 5-14) in the three largest famine-affected cities and the remainder of the country. Mortality during the famine is compared with the pre-war period January 1935 to April 1940, the war period May 1940 to October 1944, and the post-war period June 1945 to December 1947. The famine's impact was most visible in infants because of the combined effects of a high absolute death rate and a threefold increase in proportional mortality, mostly from gastrointestinal conditions. These factors make infant mortality the most sensitive indicator of famine severity in this setting and a candidate marker for comparative use in future studies.

Early-Life Exposure to the Chinese Famine of 1959-1961 and Type 2 Diabetes in Adulthood: A Systematic Review and Meta-Analysis.

BACKGROUND: The fast-growing literature suggests that the Chinese famine of 1959-1961 drives current and future type 2 diabetes (T2D) epidemics in China. This conclusion may be premature, as many Chinese famine studies have major methodological problems. We examine these problems, demonstrate how they bias the study results, and formulate recommendations to improve the quality of future studies. METHODS: We searched English and Chinese databases for studies that examined the relationship between prenatal exposure to the Chinese famine and adult T2D from inception to 8 February 2022. We extracted information on T2D cases and study populations of individuals born during the famine (famine births), before the famine (prefamine births), and after the famine (postfamine births). We used random-effects models to compare the odds of T2D in famine births to several control groups, including postfamine births, combined pre- and postfamine births, and prefamine births. We used meta-regressions to examine the impacts of age differences between comparison groups on famine effect estimates and the role of other characteristics, including participant sex, age, and T2D assessments; famine intensity; residence; and publication language. Potential sources of heterogeneity and study quality were also evaluated. RESULTS: Twenty-three studies met our inclusion criteria. The sample sizes ranged from less than 300 to more than 360,000 participants. All studies defined the famine exposure based on the participants' dates of birth, and 18 studies compared famine births and postfamine births to estimate famine effects on T2D. The famine and postfamine births had an age difference of three years or more in all studies. The estimates of the famine effect varied by the selection of controls. Using postfamine births as controls, the OR for T2D among famine births was 1.50 (95% CI 1.34-1.68); using combined pre- and postfamine births as controls, the OR was 1.12 (95% CI 1.02-1.24); using prefamine births as controls, the OR was 0.89 (95% CI 0.79-1.00). The meta-regressions further showed that the famine effect estimates increased by over 1.05 times with each one-year increase in ignored age differences between famine births and controls. Other newly identified methodological problems included the poorly assessed famine intensity, unsuitable study settings for famine research, and poor confounding adjustment. INTERPRETATION: The current estimates of a positive relationship between prenatal exposure to the Chinese famine and adult T2D are mainly driven by uncontrolled age differences between famine births and postfamine births. Studies with more rigorous methods, including age-balanced controls and robust famine intensity measures, are needed to quantify to what extent the famine exposure is related to current T2D patterns in China.

Physical and psychological health at adolescence and home care use later in life.

OBJECTIVES: To examine the relation between physical and psychological health indicators at adolescence (age 18) and household, personal, and nursing home care use later in life at ages 57-69 years. METHODS: Using medical examinations on men born in 1944-1947 who were evaluated for military service at age 18 in the Netherlands, we link physical and psychological health assessments to national administrative microdata on the use of home care services at ages 57-69 years. We postulate a panel probit model for home care use over these years. In the analyses, we account for selective survival through correlated panel probit models. RESULTS: Poor mental health and being overweight at age 18 are important predictors of later life home care use. Home care use at ages 57-69 years is also highly related to and interacts with father's socioeconomic status and recruits' education at age 18. DISCUSSION: Specific health characteristics identified at age 18 are highly related to the later utilization of home-care at age 57-69 years. Some characteristics may be amenable to early life health interventions to decrease the future costs of long-term home care.

Impact of promoting healthy infant feeding practices on energy intake and anthropometric measures of children up to 6 years of age: A randomised controlled trial.

BACKGROUND: The first 2 years of life are the window of opportunity to promote healthy feeding practices. Thus, the present study aimed to assess the impact of a health workers training in infant dietary guidelines on energy intake and anthropometric measurement into childhood. METHODS: Cluster randomised field trial (NCT00635453) was conducted in Porto Alegre, Brazil. Healthcare centres were randomised into intervention (n = 9) and control (n = 11) groups. In intervention sites, health workers were trained to promote healthy feeding practices based on the Brazilian guideline for children's nutrition. Pregnant women who were in the last trimester of pregnancy were registered as potential mothers who would receive dietary counselling from the health workers. Energy and macronutrient intake and anthropometric measurements were obtained from children at ages 6 months, 12 months, 3 years and 6 years from low-income families. RESULTS: At age 3 years, intervention group had lower consumption of energy [-92.5 kcal; 95% confidence interval (CI) = -153.5 to -31.5], carbohydrates (-11.9 g; 95% CI = -19.9 to -2.3), and total fat (-3.9 g; 95% CI = -6.2 to -1.2), compared to the control group. At 6 years of age, children in the intervention group had lower waist circumference (-1.3 cm; 95% CI = -2.7 to -0.0), triceps (-1.3 mm; 95% CI = -2.5 to -0.0) and subscapular skinfolds (-1.3 mm; 16 95% CI = -2.6 to -0.0) thickness measurements compared to those in the control group. CONCLUSIONS: The health workers training to promote infant healthy feeding practices resulted in lower energy, carbohydrates and fat intake at 3 years and lower waist circumference, triceps and subscapular skinfolds measurements at 6 years.

Overweight and obesity at age 19 after pre-natal famine exposure.

BACKGROUND: Weight for height has been used in the past as an indicator of obesity to report that prenatal exposure to the Dutch famine of 1944-1945 determined subsequent obesity. Further evaluation is needed as unresolved questions remain about the possible impact of social class differences in fertility decline during the famine and because being overweight is now defined by a Body Mass Index (BMI: kg/m2) from 25 to <30 and obesity by a BMI of 30 or more. METHODS: We studied heights and weights of 371,100 men in the Netherlands born between 1943 and 1947 and examined for military service at age 19. This group includes men with and without prenatal exposure to the Dutch famine. RESULTS: There was a 1.3-fold increase in the risk of being overweight or obese in young adults at age 19 after prenatal famine exposure in early gestation. The increase was only seen in sons of manual workers born in the large cities of Western Netherlands and not among those born in smaller cities or rural areas in the West. Social class differentials in fertility decline during the famine did not bias study results. CONCLUSIONS: The long-term adverse impact of prenatal famine on later life type 2 diabetes and mortality through age 63 is already showing at age 19 in this population as a significant increase in overweight risk.

Investigating the relationships between unfavourable habitual sleep and metabolomic traits: evidence from multi-cohort multivariable regression and Mendelian randomization analyses.

BACKGROUND: Sleep traits are associated with cardiometabolic disease risk, with evidence from Mendelian randomization (MR) suggesting that insomnia symptoms and shorter sleep duration increase coronary artery disease risk. We combined adjusted multivariable regression (AMV) and MR analyses of phenotypes of unfavourable sleep on 113 metabolomic traits to investigate possible biochemical mechanisms linking sleep to cardiovascular disease. METHODS: We used AMV (N = 17,368) combined with two-sample MR (N = 38,618) to examine effects of self-reported insomnia symptoms, total habitual sleep duration, and chronotype on 113 metabolomic traits. The AMV analyses were conducted on data from 10 cohorts of mostly Europeans, adjusted for age, sex, and body mass index. For the MR analyses, we used summary results from published European-ancestry genome-wide association studies of self-reported sleep traits and of nuclear magnetic resonance (NMR) serum metabolites. We used the inverse-variance weighted (IVW) method and complemented this with sensitivity analyses to assess MR assumptions. RESULTS: We found consistent evidence from AMV and MR analyses for associations of usual vs. sometimes/rare/never insomnia symptoms with lower citrate (- 0.08 standard deviation (SD)[95% confidence interval (CI) - 0.12, - 0.03] in AMV and - 0.03SD [- 0.07, - 0.003] in MR), higher glycoprotein acetyls (0.08SD [95% CI 0.03, 0.12] in AMV and 0.06SD [0.03, 0.10) in MR]), lower total very large HDL particles (- 0.04SD [- 0.08, 0.00] in AMV and - 0.05SD [- 0.09, - 0.02] in MR), and lower phospholipids in very large HDL particles (- 0.04SD [- 0.08, 0.002] in AMV and - 0.05SD [- 0.08, - 0.02] in MR). Longer total sleep duration associated with higher creatinine concentrations using both methods (0.02SD per 1 h [0.01, 0.03] in AMV and 0.15SD [0.02, 0.29] in MR) and with isoleucine in MR analyses (0.22SD [0.08, 0.35]). No consistent evidence was observed for effects of chronotype on metabolomic measures. CONCLUSIONS: Whilst our results suggested that unfavourable sleep traits may not cause widespread metabolic disruption, some notable effects were observed. The evidence for possible effects of insomnia symptoms on glycoprotein acetyls and citrate and longer total sleep duration on creatinine and isoleucine might explain some of the effects, found in MR analyses of these sleep traits on coronary heart disease, which warrant further investigation.

Impact of disease screening on awareness and management of hypertension and diabetes between 2011 and 2015: results from the China health and retirement longitudinal study.

BACKGROUND: There has been a limited recognition of hypertension and diabetes in China which has compromised optimal treatment. It is not clear if a screening program implemented by a national health survey has improved awareness and management of these conditions. METHODS: The China Health and Retirement Longitudinal Study (CHARLS) is an ongoing longitudinal health survey conducted since 2011 among Chinese people aged 45 years and older. Participants have been assessed every two years by interviews, physical examinations, and fasting glucose samples were taken in 2011. In 2013 and 2015, participants were asked about awareness and management of selected chronic diseases, and they first became aware of these conditions. RESULTS: Of the 11,000+ participants screened in 2011, 4594 were identified with hypertension and 1703 with diabetes by medical examinations. Over 80% of the middle-aged and elderly Chinese diagnosed with hypertension and/or diabetes in 2011 reported in 2015 that they were unaware of the disease(s). Although some improvement was observed between 2011 and 2015, the main reason for the increase in awareness was a medical examination initiated by the study participant (over 75%), by their work unit or community (12-15%), and rarely (less than 3%) by the CHARLS examination. Participants with a rural household registration status and lower BMI were the most likely to be unaware and to remain unaware of their condition(s). CONCLUSIONS: Disease screening in CHARLS did not lead to significant improvements in awareness of hypertension and diabetes. Improvements should be made by the systematic feedback of screening results to survey participants and the monitoring of disease awareness over time. This will be essential to improve disease recognition and facilitate optimal management.

RW-2018-Research Workshop: The Effect of Nutrition on Epigenetic Status, Growth, and Health.

The goal of the 2018 American Society for Parenteral and Enteral Nutrition (ASPEN) Research Workshop was to explore the influence of nutrition and dietary exposure to xenobiotics on the epigenome during critical periods in development and how these exposures influence both disease incidence and severity transgenerationally. A growing compendium of research indicates that the incidence and severity of common and costly human diseases may be influenced by dietary exposures and deficiencies that modify the epigenome. The greatest periods of vulnerability to these exposures are the periconception period and early childhood. Xenobiotics in the food chain, protein malnutrition, and methyl donor deficiencies could have a profound bearing on the risk of developing heart disease, diabetes, obesity, hypertension, and mental illness over multiple generations. The financial impact and the life burden of these diseases are enormous. These and other aspects of nutrition, epigenetics, and health are explored in this research workshop.

Selective Survival of Embryos Can Explain DNA Methylation Signatures of Adverse Prenatal Environments.

An adverse intrauterine environment is associated with long-term physiological changes in offspring. These are believed to be mediated by epigenomic marks, including DNA methylation (DNAm). Changes in DNAm are often interpreted as damage or plastic responses of the embryo. Here, we propose that stochastic DNAm variation, generated during remodeling of the epigenome after fertilization, contributes to DNAm signatures of prenatal adversity through differential survival of embryos. Using a mathematical model of re-methylation in the early embryo, we demonstrate that selection, but not plasticity, will generate a characteristic reduction in DNAm variance at loci that contribute to survival. Such a reduction in DNAm variance was apparent in a human cohort prenatally exposed to the Dutch famine, illustrating that it is possible to detect a signature of selection on epigenomic variation. Selection should be considered as a possible mechanism linking prenatal adversity to subsequent health and may have implications when evaluating interventions.