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.

The neighborhood context and all-cause mortality among older adults in Puerto Rico.

Background: Recent efforts have been made to collect data on neighborhood-level attributes and link them to longitudinal population-based surveys. These linked data have allowed researchers to assess the influence of neighborhood characteristics on the health of older adults in the US. However, these data exclude Puerto Rico. Because of significantly differing historical and political contexts, and widely ranging structural factors between the island and the mainland, it may not be appropriate to apply current knowledge on neighborhood health effects based on studies conducted in the US to Puerto Rico. Thus, we aim to (1) examine the types of neighborhood environments older Puerto Rican adults reside in and (2) explore the association between neighborhood environments and all-cause mortality. Methods: We linked data from the 2000 US Census to the longitudinal Puerto Rican Elderly Health Conditions Project (PREHCO) with mortality follow-up through 2021 to examine the effects of the baseline neighborhood environment on all-cause mortality among 3,469 participants. Latent profile analysis, a model-based clustering technique, classified Puerto Rican neighborhoods based on 19 census block group indicators related to the neighborhood constructs of socioeconomic status, household composition, minority status, and housing and transportation. The associations between the latent classes and all-cause mortality were assessed using multilevel mixed-effects parametric survival models with a Weibull distribution. Results: A five-class model was fit on 2,477 census block groups in Puerto Rico with varying patterns of social (dis)advantage. Our results show that older adults residing in neighborhoods classified as Urban High Deprivation and Urban High-Moderate Deprivation in Puerto Rico were at higher risk of death over the 19-year study period relative to the Urban Low Deprivation cluster, controlling for individual-level covariates. Conclusions: Considering Puerto Rico's socio-structural reality, we recommend that policymakers, healthcare providers, and leaders across industries to (1) understand how individual health and mortality is embedded within larger social, cultural, structural, and historical contexts, and (2) make concerted efforts to reach out to residents living in disadvantaged community contexts to understand better what they need to successfully age in place in Puerto Rico.

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.

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.

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.

Displacement due to armed conflict and violence in childhood and adulthood and its effects on older adult health: The case of the middle-income country of Colombia.

Large population displacement in developing economies due to internal armed conflict and violence is of international concern. There has been relatively little research on the long-term consequences of displacement on older adult health among populations characterized by rapid demographic, epidemiological, and nutritional transitions during the 20th century. We examine displacement in the middle-income country of Colombia, which experienced these rapid transitions and a large population displacement over the last 50-60 years due to internal armed conflict and violence. Using a nationally representative survey of adults 60 years and older, SABE-Colombia (2014-2015, n = 23,694), we estimate the degree to which displacement relative to those never displaced is associated with older adult health (self-reported health, major illness/stress, at least one chronic condition, heart disease), controlling for age, gender, SES (socioeconomic status), residence, early life conditions (infectious diseases, poor nutrition, health, SES, family violence), and adult behavior (smoking, exercise, nutrition). We found (1) strong associations between poor early life conditions and older adult health with little attenuation of effects after controlling for displacement, adult SES, and lifestyle; (2) strong associations between displacement and self-reported health; along with poor early life conditions, displacement increases the chances of poor health at older ages; (3) significant positive interaction effects between childhood infections and displacement during young adulthood for older adult stress/major illness, suggesting the importance of the timing of displacement; (4) significant interaction effects between childhood infections and being displaced during childhood, indicating lower levels of older adult stress/major illness and suggesting the possibility of resilience due to childhood adversity. We conclude that displacement compounds the effects of poor early life conditions and that timing of displacement can matter. The results raise the possibility of similar patterns in the health of aging populations in low-income countries that also experience displacement and rapid demographic and epidemiological transitions.

Patterns of SES Health Disparities Among Older Adults in Three Upper Middle- and Two High-Income Countries.

OBJECTIVES: To examine the socioeconomic status (SES) health gradient for obesity, diabetes, and hypertension within a diverse group of health outcomes and behaviors among older adults (60+) in upper middle-income countries benchmarked with high-income countries. METHOD: We used data from three upper middle-income settings (Colombia-SABE-Bogotá, Mexico-SAGE, and South Africa-SAGE) and two high-income countries (England-ELSA and US-HRS) to estimate logistic regression models using age, gender, and education to predict health and health behaviors. RESULTS: The sharpest gradients appear in middle-income settings but follow expected patterns found in high-income countries for poor self-reported health, functionality, cognitive impairment, and depression. However, weaker gradients appear for obesity, hypertension, diabetes, and other chronic conditions in Colombia and Mexico and the gradient reverses in South Africa. Strong disparities exist in risky health behaviors and in early nutritional status in the middle-income settings. DISCUSSION: Rapid demographic and nutritional transitions, urbanization, poor early life conditions, social mobility, negative health behavior, and unique country circumstances provide a useful framework for understanding the SES health gradient in middle-income settings. In contrast with high-income countries, the increasing prevalence of obesity, an important risk factor for chronic conditions and other aspects of health, may ultimately change the SES gradient for diseases in the future.

Early Life Displacement Due to Armed Conflict and Violence, Early Nutrition, and Older Adult Hypertension, Diabetes, and Obesity in the Middle-Income Country of Colombia.

Objective: We examine the importance of early life displacement and nutrition on hypertension (HTN) and diabetes in older Colombian adults (60+ years) exposed to rapid demographic, epidemiological, and nutritional transitions, and armed conflict. We compare early life nutritional status and adult health in other middle- and high-income countries. Method: In Colombia (Survey of Health, Wellbeing and Aging [SABE]-Bogotá), we estimate the effects of early life conditions (displacement due to armed conflict and violence, hunger, low height, and not born in the capital city) and obesity on adult health; we compare the effects of low height on adult health in Mexico, South Africa (Study on Global Ageing and Adult Health [SAGE]), the United States, and England (Health and Retirement Study [HRS], English Longitudinal Study of Ageing [ELSA]). Results: Early life displacement, early poor nutrition, and adult obesity increase the risk of HTN and diabetes in Colombia. Being short is most detrimental for HTN in Colombian males. Discussion: Colombian data provide new evidence into how early life conditions and adult obesity contribute to older adult health.

Promises and Pitfalls of Anchoring Vignettes in Health Survey Research.

Data harmonization is a topic of growing importance to demographers, who increasingly conduct domestic or international comparative research. Many self-reported survey items cannot be directly compared across demographic groups or countries because these groups differ in how they use subjective response categories. Anchoring vignettes, already appearing in numerous surveys worldwide, promise to overcome this problem. However, many anchoring vignettes have not been formally evaluated for adherence to the key measurement assumptions of vignette equivalence and response consistency. This article tests these assumptions in some of the most widely fielded anchoring vignettes in the world: the health vignettes in the World Health Organization (WHO) Study on Global AGEing and Adult Health (SAGE) and World Health Survey (WHS) (representing 10 countries; n = 52,388), as well as similar vignettes in the Health and Retirement Study (HRS) (n = 4,528). Findings are encouraging regarding adherence to response consistency, but reveal substantial violations of vignette equivalence both cross-nationally and across socioeconomic groups. That is, members of different sociocultural groups appear to interpret vignettes as depicting fundamentally different levels of health. The evaluated anchoring vignettes do not fulfill their promise of providing interpersonally comparable measures of health. Recommendations for improving future implementations of vignettes are discussed.

Early-Life Conditions, Rapid Demographic Changes, and Older Adult Health in the Developing World.

The demographic transition of the 1930s-1960s dramatically improved life expectancy in some developing countries. Cohorts born during this time are increasingly characterized by their survivorship of poor early-life conditions, such as poor nutrition and infectious diseases. As a result, they are potentially more susceptible to the effects of these conditions at older ages. This study examines this conjecture by comparing obesity, diabetes, and hypertension in older adults born in the beginning portion of the 1930s-1960s across different mortality regimes using a subset of harmonized cross-national data from seven low- and middle-income countries (RELATE, n = 16,836). Using birthplace and height as indicators of early-life conditions, the results show (1) higher prevalence of obesity and diabetes and higher likelihood of obesity, diabetes, and hypertension in middle-income countries, but (2) no convincing evidence to indicate stronger effects of early-life conditions on health in these countries. However, shorter adults living in urban areas were more likely to be obese, indicating the overall importance of early-life conditions and the potential negative impact of urban exposures during adulthood. Obesity results may foreshadow the health of future cohorts born in the later portion of the 1930s-1960s as they reach older ages (60+).

Infant mortality, season of birth and the health of older Puerto Rican adults.

The increasing prevalence of heart disease and diabetes among aging populations in low and middle income countries leads to questions regarding the degree to which endogenous early life exposures (exposures in utero) are important determinants of these health conditions. We devised a test using infant mortality (IMR) to verify if season of birth is a good indicator of early life (in utero) conditions that precipitate adult onset of disease. We linked annual IMR at the municipality (municipio) level from the late 1920s to early 1940s with individual birth year and place using a representative sample of older Puerto Rican adults (n = 1447) from the Puerto Rican Elderly: Health Conditions (PREHCO) study. We estimated the effects of season of birth on adult heart disease and diabetes for all respondents and then for respondents according to whether they were born when IMR was lower or higher, controlling for age, gender, obesity, respondent's educational level, adult behavior (smoking and exercise) and other early life exposures (childhood health, knee height and childhood socioeconomic status (SES)). The pattern of effects suggests that season of birth reflects endogenous causes: (1) odds of heart disease and diabetes were strong and significant for those born during the lean season in years when IMR was lower; (2) effects remained consistent even after controlling for other childhood conditions and adult behavior; but (3) no seasonality effects on adult health for adults born when IMR was higher. We conclude that in this population of older Puerto Rican adults there is continued support that the timing of adverse endogenous (in utero) conditions such as poor nutrition and infectious diseases is associated with adult heart disease and diabetes. It will be important to test the validity of these findings in other similar populations in the developing world.

Planning and creating a new bi-state nursing workforce center through unique partnerships.

Multiple strategies are needed to address the complex issues related to the nursing shortage. It is not enough to focus on increasing the number of students in the pipeline unless this is met with complimentary work to improve the professional practice environments of nursing staff. In addition, nurse-driven improvement projects that address specific patient and organizational outcomes will elevate the role of nurses from trusted professional to quality agents. The authors describe a partnership that has launched a new type of workforce center with core missions to create work environment improvements and point-of-care change led by staff nurses.

Early life exposure to poor nutrition and infectious diseases and its effects on the health of older Puerto Rican adults.

OBJECTIVES: We examined the effects of early life exposure to poor nutrition and infectious diseases on adult heart disease and diabetes using season of birth as an indicator to help disentangle the effects on health of early life exposure from effects associated with other childhood conditions. METHODS: Using data from 60- to 74-year-old Puerto Ricans who lived in rural areas during childhood (n = 1,457), we estimated the effects of seasonal exposure during late gestation on the probability of diabetes and heart disease, controlling for adult obesity and other childhood conditions (health, socioeconomic status, knee height). RESULTS: We found (a) strong associations between exposure and heart disease; (b) weaker associations between exposure and diabetes, although significant negative interaction effects between exposure and having a family member with diabetes suggest the possibility of either strong gene-environment or early adult-environment interactions; (c) virtually no attenuation of effects of self-reported childhood health with controls for exposure. DISCUSSION: Timing of birth may reveal conditions experienced perinatally that affect adult heart disease and diabetes. The results suggest that examination of the effects of season of birth on these chronic conditions among older Puerto Rican adults and among older adults from similar populations deserves deeper scrutiny.

Aging and health status of elderly in Latin America and the Caribbean: preliminary findings.

Aging in Latin America and the Caribbean will not proceed along known paths already followed by more developed countries. In particular, the health profile of the future elderly population is less predictable due to factors associated with their demographic past that may haunt them for a long time and make them more vulnerable, even if economic and institutional conditions turn out to be better than what they are likely to be. This paper answers a set of questions regarding the nature and determinants of health status among the elderly in Latin America and the Caribbean using SABE (Survey on Health and Well-Being of Elders), a cross-sectional representative sample of over 10,000 elderly aged 60 and above in private homes in seven major cities in Latin America and the Caribbean. We examine health outcomes such as self-reported health, functional limitations-Activities of Daily Living (ADL's) and Instrumental Activities of Daily Living (IADL's), obesity (ratio of weight in kilograms to the square of height in centimeters), and self-reported chronic conditions (including diabetes). The findings include: (a) Countries differ in self-reported health but exhibit much less differences in terms of functional limitations. The number of chronic conditions increase with age and is higher among females than among males; (b) On average SABE countries display levels of self-reported diabetes (and obesity) that are as high if not higher than those found in the US; (c) There is evidence, albeit weaker than expected, suggesting deteriorated health and functional status in the region; (d) There is important evidence pointing toward rather strong inequalities (by education and income) in selected health outcomes. Preliminary findings from SABE confirm that Latin America and the Caribbean display peculiarities in the health profile of elderly, particularly with regard to diabetes and obesity. It is important that new policy initiatives begin to seriously target the region's elderly, especially with an emphasis on the prevention and treatment of diabetes and obesity.

The tide to come: elderly health in Latin America and the Caribbean.

This article introduces a conjecture and reviews partial evidence about peculiarities in the aging of populations in Latin America and the Caribbean (LAC) that may impact future elderly health status. Using Survey on Health and Well-Being of Elders data (SABE; n = 10,902), the authors estimated effects of early childhood conditions on adult diabetes and heart disease. Using Waaler-type surfaces, the authors obtained expected mortality risks for SABE and also U.S. elderly (Health and Retirement System, n = 12,527). Expected mortality risks using Waaler-type surfaces among elderly in LAC reflected excesses supporting our conjecture. There was partial evidence of a relation between various indicators of early childhood nutritional status (knee height, waist-to-hip ratio) and diabetes and even stronger evidence of a relation between rheumatic fever and adult heart disease. There is some evidence, albeit weak, to suggest that the conjecture regarding elderly health status' connection to early conditions has some merit.

The influence of early conditions on health status among elderly Puerto Ricans.

The demographic origins of aging in Puerto Rican and other Latin American and Caribbean (LAC) countries may have important implications for the profile of health status and mortality of elderly people. For this article we tested a general conjecture about the relation between early childhood conditions and adult health status among Puerto Rican elderly using a rich data set recently collected through an island-wide survey (N = 4,293). We examined the association between markers of early nutritional status, self-reports of health and on socioeconomic conditions during early childhood, and the prevalence of 3 conditions during adult ages: obesity, diabetes, and cardiovascular diseases. Although we found that obesity and diabetes are associated with markers of early malnutrition, that heart disease is associated with early deprivations and selected early childhood conditions, the evidence we were able to tease out from the data provides only fragile support for the conjecture.