Influence of Place of Birth on Adult Mortality: The Case of Spain.

We use a unique data set from Spain and we estimate life expectancy at age 50 for males and females by place of residence and place of birth. We show that, consistent with expectations regarding the influence of early conditions on adult health and mortality, the effects of place of birth on adult mortality are very strong, irrespective of place of residence. Furthermore, we find that mortality levels observed in a place are strongly influenced by the composition of migrants by place of birth. This is reflected in a new measure of heritability of early childhood conditions that attains a value in the range 0.42-0.43, implying that as much as 43 percent of the variance in Spain's life expectancy at age 50 is explained by place of birth. Finally, we find evidence of the healthy migrant effect, that is, positive health selection of migrants, at a regional level.

Gene-environment interactions and the case of body mass index and obesity: How much do they matter?

We investigate the demographic and population health implications of gene-environment interactions (GxE) in the case of body mass index (BMI) and obesity. We seek to answer two questions: (a) what is the first-order impact of GxE effects on BMI and probability of obesity, e.g. the direct causal effect of G in different E's? and (b) how large is the impact of GxE effects on second-order health outcomes associated with BMI and obesity, such as type 2 diabetes (T2D) and disability? In contrast to most of the literature that focuses on estimating GxE effects, we study the implications of GxE effects for population health outcomes that are downstream of a causal chain that includes the target phenotype (in this case BMI) as the initial cause. To limit the scope of the paper, we focus on environments defined by birth cohorts. However, extensions to other environments (education, socioeconomic status (SES), early conditions, and physical settings) are straightforward.

Understanding Geographic Disparities in Mortality.

A rich literature shows that early-life conditions shape later-life outcomes, including health and migration events. However, analyses of geographic disparities in mortality outcomes focus almost exclusively on contemporaneously measured geographic place (e.g., state of residence at death), thereby potentially conflating the role of early-life conditions, migration patterns, and effects of destinations. We employ the newly available Mortality Disparities in American Communities data set, which links respondents in the 2008 American Community Survey to official death records, and estimate consequential differences based on the method of aggregation we use: the unweighted mean absolute deviation of the difference in life expectancy at age 50 measured by state of birth versus state of residence is 0.58 years for men and 0.40 years for women. These differences are also spatially clustered, and we show that regional inequality in life expectancy is higher based on life expectancies by state of birth, implying that interstate migration mitigates baseline geographic inequality in mortality outcomes. Finally, we assess how state-specific features of in-migration, out-migration, and nonmigration together shape measures of mortality disparities by state (of residence), further demonstrating the difficulty of clearly interpreting these widely used measures.

Empirical evidence of predictive adaptive response in humans: systematic review and meta-analysis of migrant populations.

Meta-analysis is used to test a variant of a Developmental Origins of Adult Health and Disease (DOHaD)'s conjecture known as predictive adaptive response (PAR). According to it, individuals who are exposed to mismatches between adverse or constrained in utero conditions, on the one hand, and postnatal obesogenic environments, on the other, are at higher risk of developing adult chronic conditions, including obesity, type 2 diabetes (T2D), hypertension and cardiovascular disease. We argue that migrant populations from low and middle to high-income countries offer a unique opportunity to test the conjecture. A database was constructed from an exhaustive literature search of peer-reviewed papers published prior to May 2021 contained in PUBMED and SCOPUS using keywords related to migrants, DOHaD, and associated health outcomes. Random effects meta-regression models were estimated to assess the magnitude of effects associated with migrant groups on the prevalence rate of T2D and hypertension in adults and overweight/obesity in adults and children. Overall, we used 38 distinct studies and 78 estimates of diabetes, 59 estimates of hypertension, 102 estimates of overweight/obesity in adults, and 23 estimates of overweight/obesity in children. Our results show that adult migrants experience higher prevalence of T2D than populations at destination (PR 1.48; 95% CI 1.35-1.65) and origin (PR 1.80; 95% CI 1.40-2.34). Similarly, there is a significant excess of obesity prevalence in children migrants (PR 1.22; 95% CI 1.04-1.43) but not among adult migrants (PR 0.89; 95% CI 0.80-1.01). Although the total effect of migrant status on prevalence of hypertension is centered on zero, some migrant groups show increased risks. Finally, the size of estimated effects varies significantly by migrant groups according to place of destination. Despite limitations inherent to all meta-analyses and admitting that some of our findings may be accounted for alternative explanations, the present study shows empirical evidence consistent with selected PAR-like conjectures.

Ready-Willing-Able: Early childhood mortality decline in Turkey.

We test a conjecture to explain Turkey's decades-long 'underachievement' in early child mortality improvements. We argue that it is largely a consequence of cultural barriers to embracing available modern medical technology and healthcare practices. The empirical test rests on a reformulation of Coale's Ready-Willing-Able (RWA) framework for explaining fertility changes, which makes it suitable to understand mortality changes. We use structural equation modelling and Demographic and Health Surveys spanning 1993-2013 to estimate basic parameters of the reformulated framework. These parameters are then used to classify mothers into four groups with different configurations of RWA dimensions and different probabilities of adopting modern medical practices. We find that observed behaviours in these groups were consistent with RWA expectations. In addition, we find that an important contributor to Turkey's lagging mortality decline was a population distribution biased towards groups more reticent to adopting modern healthcare.

Early Exposure to County Income Mobility and Adult Individual Health in the United States.

OBJECTIVES: Previous research in the United States suggests contextual income mobility may play a role in explaining the disparities between life expectancy in the United States and peer countries. This article aims to extend previous research by estimating the consequences of average individual exposure to mobility regimes during childhood and adolescence on adult health. METHODS: This study draws its data from two longitudinal datasets that track the county of residence of respondents during childhood and adolescence, the Panel Study of Income Dynamics and the National Longitudinal Survey of Youth 1997. We implement marginal structural models to assess the association of the average exposure to county income mobility on five health outcomes and behaviors. RESULTS: The results are only partially consistent with a systematic association between exposure to income mobility and health outcomes. Evidence obtained from the National Longitudinal Survey of Youth suggests less income mobility might increase the probability of smoking by age 30. DISCUSSION: The paper provides a precise assessment of the hypothesis that childhood exposure to income mobility regimes may influence health status through behavior later in life and contribute to longevity gaps. Only partial evidence on smoking suggests an association between income mobility and health, so we discuss potential reasons for the disparities in results with previous research.

Population-level impact of adverse early life conditions on adult healthy life expectancy in low- and middle-income countries.

Evidence from theories of Developmental Origins of Health and Disease (DOHaD) suggests that experiencing adverse early life conditions subsequently leads to detrimental adult health outcomes. The bulk of empirical DOHaD literature does not consider the nature and magnitude of the impact of adverse early life conditions at the population level. In particular, it ignores the distortion of age and cohort patterns of adult health and mortality and the increased load of chronic illness and disability that ensues. In this paper, we use a microsimulation model combined with empirical estimates of incidence and prevalence of obesity, type 2 diabetes, and associated disability in low- and middle-income countries to assess the magnitude of delayed effects on adult healthy life expectancy and on compression (or expansion) of morbidity at older ages. The main goal is to determine if, in what ways, and to what extent delayed effects due to early conditions can influence cohorts' chronic illness and disability profiles.

Modeling biological age and its link with the aging process.

Differences in health status at older ages are a result of genetic predispositions and physiological responses to exposure accumulation over the lifespan. These vary across individuals and lead to health status heterogeneity as people age. Chronological age (CA) is a standard indicator that reflects overall risks of morbidity and mortality. However, CA is only a crude proxy for individuals' latent physiological deterioration. An alternative to CA is biological age (BA), an indicator of accumulated age-related biological change reflected in markers of major physiological systems. We propose and validate two BA estimators that improve upon existing ones. These estimators (i) are based on a structural equation model (SEM) that represents the relation between BA and CA, (ii) circumvent the need to impose arbitrary assumptions about the relation between CA and BA, and (iii) provide tools to empirically test the validity of assumptions the researcher may wish to invoke. We use the US National Health and Nutrition Examination Survey 1988-1994 and compare results with three commonly used methods to compute BA (principal components-PCA, multiple regression-MLR, and Klemera-Doubal's method-KD). We show that SEM-based estimates of BA differ significantly from those generated by PCA and MLR and are comparable to, but have better predictive power than KD's. The proposed estimators are flexible, allow testing of assumptions about functional forms relating BA and CA, and admit a rich interpretation as indicators of accelerated aging.

Estimation of older-adult mortality from information distorted by systematic age misreporting.

Testing theories about human senescence and longevity demands accurate information on older-adult mortality; this is rare in low- to middle-income countries where raw data may be distorted by defective completeness and systematic age misreporting. For this reason, such populations are frequently excluded from empirical tests of mortality and longevity theories, thus limiting their reach, as they reflect only a small and selected human mortality experience. In this paper we formulate an integrated method to compute estimates of older-adult mortality when vital registration and population counts are defective due to inaccurate coverage and/or systematic age misreporting. The procedure is validated with a simulation study that identifies a strategy to compute adjustments, which, under some assumptions, performs quite well. While the paper focuses on Latin American and Caribbean countries, the method is quite general and, with additional information and some model reformulation, could be applied to other populations with similar problems.

Where and When: Sharpening the lens on geographic disparities in mortality.

Life course theories suggest that geographic disparities in mortality may reflect a history of place-based exposures rather than (or in addition to) contemporaneous exposures; yet, few studies examined early life place exposures and later life mortality in the US due to data limitations. The aim of this study is to assess and compare the importance of state of birth and state of residence in predicting mortality for adults over age 50 in the US. Using nationally representative data of nearly 100,000 adults over age 50 from the National Longitudinal Mortality Study, we estimated individual mortality risk using multi-level logistic regression with state of birth and state of residence as second-level random effects. We assessed whether state of residence and state of birth contributed to the variation in adult mortality. We also decomposed state-of-residence random effects to compare "movers" and "stayers." Our results indicate that state of birth is a stronger predictor of age-, race/ethnicity- and sex-adjusted mortality in the US than state of residence at the time of death. The adult mortality profiles of many states are substantially impacted by the composition of "movers." Failing to account for residential mobility has clouded our understanding of the patterns and causes of geographic differences in adult mortality. Measures of geographic residence across the life course can improve models of adult mortality in the US and inform interventions to address geographic disparities in longevity.

Impacts of the 1918 flu on survivors' nutritional status: A double quasi-natural experiment.

Robust empirical evidence supports the idea that embryonic and, more generally, intrauterine disruptions induced by the 1918-flu pandemic had long-term consequences on adult health status and other conditions. In this paper we assess the 1918-flu long-term effects not just of in utero exposure but also during infancy and early childhood. A unique set of events that took place in Puerto Rico during 1918-1919 generated conditions of a "double quasi-natural experiment". We exploit these conditions to empirically identify effects of exposure to the 1918 flu pandemic and those of the devastation left by an earthquake-tsunami that struck the island in 1918. Because the earthquake-tsunami affected mostly the Western coast of the island whereas early (in utero and postnatal) exposure to the flu was restricted to those born in the interval 1917-1920, we use geographic variation to identify the effects of the quake and timing of birth variation to identify those of the flu. We benefit from availability of information on markers of nutritional status in a nationally representative sample of individuals aged 75 and older in 2002. We make two contributions. First, unlike most fetal-origins research that singles out early nutritional status as a determinant of adult health, we hypothesize that the 1918 flu damaged the nutritional status of adult survivors who, at the time of the flu, were in utero or infants. Second, we target markers of nutritional status largely set when the adult survivors were infants and young children. Estimates of effects of the pandemic are quite large mostly among females and those who were exposed to the earthquake-tsunami. Impacts of the flu in areas less affected by the earthquake are smaller but do vary by area flu severity. These findings constitute empirical evidence supporting the conjecture that effects of the 1918 flu and/or the earthquake are associated not just with disruption experienced during the fetal period but also postnatally.

The Consequences of Incarceration for Mortality in the United States.

Previous research has suggested that incarceration has negative implications for individuals' well-being, health, and mortality. Most of these studies, however, have not followed former prisoners over an extended period and into older adult ages, when the risk of health deterioration and mortality is the greatest. Contributing to this literature, this study is the first to employ the Panel Study of Income Dynamics (PSID) to estimate the long-run association between individual incarceration and mortality over nearly 40 years. We also supplement those analyses with data from the National Longitudinal Survey of Youth 1979 (NLSY79). We then use these estimates to investigate the implications of the U.S. incarceration regime and the post-1980 incarceration boom for the U.S. health and mortality disadvantage relative to industrialized peer countries (the United Kingdom).

Early Poverty and Future Life Expectancy with Disability among the Elderly in Argentina: Pobreza Temprana y Esperanza de Vida Futura con Discapacidad entre los Adultos Mayores de la Argentina.

Two aspects of the ageing process in Latin America should be specially taken into account in order to evaluate future perspectives of morbidity among the elderly in the region: 1) Cohorts who will compose the bulk of the elderly population in the 21st century in Latin America survived to old age largely because of improvements in medicine and to a much lesser extent to amelioration of living standards, as is the case in high income countries; 2) a high proportion of the Latin American population still live in poor economic conditions and even these vulnerable individuals continue to experience gains in (adult and older adult) survival. We aim to evaluate to what an extent recent levels of poverty and indigence among young children in Argentina could impact future levels of disability and demands for long-term care of older people. Our results show that given the levels of poverty and indigence in childhood observed between 1988 and 1994 and given the relationship between poor early conditions and the risk of being disabled among the elderly in Argentina, life expectancy with disability at age 60 old would increase substantially between 2000 and 2040 both in absolute and relative terms.

Impact of delayed effects on human old-age mortality1.

BACKGROUND: There is growing empirical evidence supporting theories of developmental origins of health and disease (DOHaD). However, the implications of DOHaD conjectures for aggregate population patterns of human disease, disability, mortality and aging are poorly understood. OBJECTIVE: We empirically test two predictions derived from a formal model of aggregate population-level impacts of DOHaD. This model predicts that populations potentially influenced by delayed effects should experience singularities in their adult mortality patterns that can be empirically detected from aggregate data. METHODS: We test predictions using a large mortality database for populations in the Latin American and Caribbean region (LAC) spanning nearly one hundred years of mortality history. RESULTS: Results are consistent. within explicit bounds of uncertainty, with expected patterns. We find that younger cohorts in countries whose mortality decline starts more recently experience deceleration in survival gains at older ages, attenuation of the rate of aging at older ages and a decline in the association between early childhood and adult mortality. CONCLUSIONS: Results point to the importance of adverse early conditions for human longevity. Future research should shed light on the impact on morbidity, disability and healthy life expectancy. CONTRIBUTION: To our knowledge this is the first time that implications of DOHaD conjectures for populations' mortality patterns are formulated precisely and empirically tested with aggregate population data.

Close social relationships correlate with human gut microbiota composition.

Social relationships shape human health and mortality via behavioral, psychosocial, and physiological mechanisms, including inflammatory and immune responses. Though not tested in human studies, recent primate studies indicate that the gut microbiome may also be a biological mechanism linking relationships to health. Integrating microbiota data into the 60-year-old Wisconsin Longitudinal Study, we found that socialness with family and friends is associated with differences in the human fecal microbiota. Analysis of spouse (N = 94) and sibling pairs (N = 83) further revealed that spouses have more similar microbiota and more bacterial taxa in common than siblings, with no observed differences between sibling and unrelated pairs. These differences held even after accounting for dietary factors. The differences between unrelated individuals and married couples was driven entirely by couples who reported close relationships; there were no differences in similarity between couples reporting somewhat close relationships and unrelated individuals. Moreover, married individuals harbor microbial communities of greater diversity and richness relative to those living alone, with the greatest diversity among couples reporting close relationships, which is notable given decades of research documenting the health benefits of marriage. These results suggest that human interactions, especially sustained, close marital relationships, influence the gut microbiota.

Social and population health science approaches to understand the human microbiome.

The microbiome is now considered our 'second genome' with potentially comparable importance to the genome in determining human health. There is, however, a relatively limited understanding of the broader environmental factors, particularly social conditions, that shape variation in human microbial communities. Fulfilling the promise of microbiome research - particularly the microbiome's potential for modification - will require collaboration between biologists and social and population scientists. For life scientists, the plasticity and adaptiveness of the microbiome calls for an agenda to understand the sensitivity of the microbiome to broader social environments already known to be powerful predictors of morbidity and mortality. For social and population scientists, attention to the microbiome may help answer nagging questions about the underlying biological mechanisms that link social conditions to health. We outline key substantive and methodological advances that can be made if collaborations between social and population health scientists and life scientists are strategically pursued.

Discrete Barker Frailty and Warped Mortality Dynamics at Older Ages.

We develop a discrete variant of a general model for adult mortality influenced by the delayed impact of early conditions on adult health and mortality. The discrete variant of the model builds on an intuitively appealing interpretation of conditions that induce delayed effects and is an extension of the discrete form of the standard frailty model with distinct implications. We show that introducing delayed effects is equivalent to perturbing adult mortality patterns with a particular class of time-/age-varying frailty. We emphasize two main results. First, populations with delayed effects could experience unchanging or increasing adult mortality even when background mortality has been declining for long periods of time. Although this phenomenon also occurs in a regime with standard frailty, the distortions can be more severe under a regime with Barker frailty. As a consequence, conventional interpretations of the observed rates of adult mortality decline in societies that experience Barker frailty may be inappropriate. Second, the observed rate of senescence (slope of adult mortality rates) in populations with delayed effects could increase, decrease, or remain steady over time and across adult ages even though the rate of senescence of the background age pattern of mortality is time- and age-invariant. This second result implies that standard interpretations of empirical estimates of the slope of adult mortality rates in populations with delayed effects may be misleading because they can reflect mechanisms other than those inducing senescence as conventionally understood in the literature.

Cohort Profile: The Mexican Health and Aging Study (MHAS).

The Mexican Health and Aging Study (MHAS) was designed to prospectively evaluate the impact of disease on the health, function and mortality of adults over the age of 50 in both urban and rural areas of Mexico. The overall goal of the study is to examine the ageing process and its disease and disability burden in a large representative panel of older Mexicans, using a wide socioeconomic perspective. The study protocols and survey instruments are highly comparable to the U.S. Health and Retirement Study (HRS).The MHAS 2001 baseline is a nationally and urban-rural representative survey of individuals born in 1951 or earlier. Three waves of data have been collected so far: baseline in 2001 and follow-ups in 2003 and 2012. In 2012, the study added a representative sample of the population from the 1952-62 birth cohorts. A fourth wave will be collected in 2015.The data files and documentation are available free of charge at the study website [www.MHASweb.org] in English and [www.ENASEM.org] in Spanish.

[Uncertainty of mortality estimators and hypothesis testing: the case of Latin America and the Caribbean, 1850-2010]. / Incertidumbre de los estimadores de mortalidad y pruebas de hipótesis: el caso de América Latina y el Caribe, 1850­2010.

We propose a simple procedure to address the uncertainty that arises when multiple estimators of adult mortality indicators are available in statistical analyses. We consider situations in which there are alternative estimators for the same population parameter, each one depending on a set of potentially overlapping assumptions, and some or all potentially characterizing the target parameter erroneously. Uncertainty arises because of the varying sensitivity of estimators to assumption violations or lack of information about how estimators have been calculated. The proposed procedure allows researchers to use all of the (plausible) estimators, instead of having to choose only one that, ex ante, is considered "the best or right one". This is achieved by assigning a precision score to each estimator depending on: (i) known errors attributable to violation of the assumptions on which the estimator is based, and (ii) (estimated) probability that the assumptions are violated in one particular case. The ensuing inferences on mortality determinants or trends can now be based on all estimators, leading to more robust and conservative hypotheses tests. Notwithstanding its use for mortality in this article, the methodology can be applied to any type of demographic parameter.

SES Gradients Among Mexicans in the United States and in Mexico: A New Twist to the Hispanic Paradox?

Recent empirical findings have suggested the existence of a twist in the Hispanic paradox, in which Mexican and other Hispanic foreign-born migrants living in the United States experience shallower socioeconomic status (SES) health disparities than those in the U.S. POPULATION: In this article, we seek to replicate this finding and test conjectures that could explain this new observed phenomenon using objective indicators of adult health by educational attainment in several groups: (1) Mexican-born individuals living in Mexico and in the United States, (2) U.S.-born Mexican Americans, and (3) non-Hispanic American whites. Our analytical strategy improves upon previous research on three fronts. First, we derive four hypotheses from a general framework that has also been used to explain the standard Hispanic paradox. Second, we study biomarkers rather than self-reported health and related conditions. Third, we use a binational data platform that includes both Mexicans living in Mexico (Mexican National Health and Nutrition Survey 2006) and Mexican migrants to the United States (NHANES 1999-2010). We find steep education gradients among Mexicans living in Mexico's urban areas in five of six biomarkers of metabolic syndrome (MetS) and in the overall MetS score. Mexican migrants living in the United States experience similar patterns to Mexicans living in Mexico in glucose and obesity biomarkers. These results are inconsistent with previous findings, suggesting that Mexican migrants in the United States experience significantly attenuated health gradients relative to the non-Hispanic white U.S. POPULATION: Our empirical evidence also contradicts the idea that SES-health gradients in Mexico are shallower than those in the United States and could be invoked to explain shallower gradients among Mexicans living in the United States.