Biodemography Soc Biol
· 2018 · PMID 31852335
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This study uses the micro-simulation method to investigate the role of cohort forces in age-dependent mortality pattern. We test the micro mechanisms for cohort evolution and mortality selection, and how these two biolog...This study uses the micro-simulation method to investigate the role of cohort forces in age-dependent mortality pattern. We test the micro mechanisms for cohort evolution and mortality selection, and how these two biological and demographic forces may interact with epidemiologic transition to shape the cohort age-dependence of mortality pattern in both early- and later-transition countries. We show that cohort evolution is due to the declining rate of mortality acceleration at the individual level, which is associated with lower initial mortality rates but not smaller variance of frailty distribution in later birth cohorts. The steeper slope of mortality acceleration at the population level among later birth cohorts is due to mortality selection mechanism associated with smaller variance of frailty distribution but not lower initial mortality rates. These two forces jointly shape the non-crossover cohort age-dependence of mortality pattern regardless of the differential mechanisms of epidemiologic transition in early- and later-transition countries.
Biodemography Soc Biol
· 2018 · PMID 31852334
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, the recent book by Catherine Bliss on the development and state of the field of sociogenomics, is far from perfect. Yet, this flawed book levies a mixture of erroneous and compelling questions about the state of the fi..., the recent book by Catherine Bliss on the development and state of the field of sociogenomics, is far from perfect. Yet, this flawed book levies a mixture of erroneous and compelling questions about the state of the field of sociogenomics, many of which we as a field would benefit from considering: How should we bring the environment back in the post-GWAS era? How do the publication and funding incentives of our field influence the evolution of our research agenda? What role should social scientific theory play in motivating our research and interpreting our findings? How can we promote greater diversity in our research community and subjects? And how can we work to better control media and popular narratives of our research? The authors do not attempt to answer all of these questions definitively, but do argue that we as a field must grapple with them seriously to ensure that our ideals and reality as a field are more congruent.
Biodemography Soc Biol
· 2018 · PMID 31852333
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People living in socially cohesive neighborhoods generally have better health. We extend this research by evaluating the hypothesis that perceived neighborhood cohesion may influence health by attenuating genetic liabili...People living in socially cohesive neighborhoods generally have better health. We extend this research by evaluating the hypothesis that perceived neighborhood cohesion may influence health by attenuating genetic liability for cardiometabolic risk factors. Using data from the Health and Retirement Study ( = 6,615; mean age 69.7), we conducted a gene × environment interaction study hypothesizing that perceived neighborhood cohesion would attenuate the link between polygenic scores for waist-to-hip ratio (WHR) and body mass index and a measure of multisystem cardiometabolic risk (systolic blood pressure [SBP] and diastolic blood pressure [DBP], heart rate, A1c, C-reactive protein, and total and high-density lipoprotein cholesterol). In support of the hypothesis, results indicated that among people perceiving low neighborhood cohesion, higher WHR polygenic scores were associated with greater cardiometabolic risk. In contrast, the genetic-cardiometabolic risk link was much attenuated among those living in neighborhoods perceived as socially cohesive. Our results support community-level interventions to enhance the social cohesiveness of individuals' neighborhoods which may provide health benefits by reducing the risks associated with known genetic risk factors.
Results from a genome-wide association study (GWAS) can be used to generate a polygenic score (PGS), an individual-level measure summarizing identified genetic influence on a trait dispersed across the genome. For comple...Results from a genome-wide association study (GWAS) can be used to generate a polygenic score (PGS), an individual-level measure summarizing identified genetic influence on a trait dispersed across the genome. For complex, behavioral traits, the association between an individual's PGS and their phenotype may contain bias (from geographic, ancestral, and/or socioeconomic confounding) alongside the causal effect of the individual's genes. We formalize the introduction of a different source of bias in regression models using PGSs: the effects of parental genes on offspring outcomes, known as genetic nurture. GWAS do not discriminate between the various pathways through which genes become associated with outcomes, meaning existing PGSs capture both direct genetic effects and genetic nurture effects. We construct a theoretical model for genetic effects and show that the presence of genetic nurture biases PGS coefficients from both naïve OLS (between-family) and family fixed effects (within-family) regressions. This bias is in opposite directions; while naïve OLS estimates are biased away from zero, family fixed effects estimates are biased toward zero. We quantify this bias using two novel parameters: (1) the genetic correlation between the direct and nurture effects and (2) the ratio of the SNP heritabilities for the direct and nurture effects.
Biodemography Soc Biol
· 2018 · PMID 29741416
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To understand the education-mortality association among U.S. adults, recent studies have documented its national functional form. However, the functional form of education-mortality relationship may vary across geographi...To understand the education-mortality association among U.S. adults, recent studies have documented its national functional form. However, the functional form of education-mortality relationship may vary across geographic contexts. The four U.S. Census regions differ considerably in their social and economic policies, employment opportunities, income levels, and other factors that may affect how education lowers the risk of mortality. Thus, we documented regional differences in the functional form of the education-mortality association and examined the role of employment and income in accounting for regional differences. We used data on non-Hispanic white adults (2,981,672, person years) aged 45-84 in the 2000-2009 National Health Interview Survey, with Linked Mortality File through 2011 (37,598 deaths) and estimated discrete-time hazard models. The functional form of education and adult mortality was best characterized by credentialism in the Midwest, Northeast, and for Western men. For Western women, the association was linear, consistent with the human capital model. In the South, we observed a combination of mechanisms, with mortality risk declining with each year of schooling and a step change with high school graduation, followed by steeper decline thereafter. Our work adds to the increasing body of research that stresses the importance of contexts in shaping the education-mortality relationship.
This study evaluates the validity of subjective health measurement for racial/ethnic comparisons in the United States, by assessing whether allostatic load (AL) is equally associated with poor/fair self-rated health (SRH...This study evaluates the validity of subjective health measurement for racial/ethnic comparisons in the United States, by assessing whether allostatic load (AL) is equally associated with poor/fair self-rated health (SRH) for different racial/ethnic groups. This study used data from the National Health and Nutrition Survey (NHANES) for 2006-2010. Multivariable logistic regression models were fit and stratified by race/ethnicity to study the association between AL and poor/fair SRH. Higher levels of AL were associated with higher odds of reporting poor/fair SRH. However, this association differs by race/ethnicity. Analysis of interactions and racial/ethnic-stratified models suggest that AL is less associated with poor/fair SRH status for non-Hispanic Blacks and Hispanics populations. These results demonstrate that subjective health ratings potentially underestimate actual measures of biological health risk, especially for racial/ethnic minorities. As a result, population-based assessments of racial/ethnic health disparities based on SRH may be significantly understated.
Thomas D, Seeman T, Potter A
… +5 more, Hu P, Crimmins E, Herningtyas EH, Sumantri C, Frankenberg E
Biodemography Soc Biol
· 2018 · PMID 29741414
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Glycated hemoglobin (HbA1c) measured using high-performance liquid chromatography (HPLC) assays with venous blood and dried blood spots (DBS) are compared for 143 paired samples collected in Aceh, Indonesia. Relative to...Glycated hemoglobin (HbA1c) measured using high-performance liquid chromatography (HPLC) assays with venous blood and dried blood spots (DBS) are compared for 143 paired samples collected in Aceh, Indonesia. Relative to gold-standard venous-blood values, DBS-based values reported by the HPLC are systematically upward biased for HbA1c<8% and the fraction diabetic (HbA1c ≥ 6.5%) is overstated almost five-fold. Inspection of chromatograms from DBS assays indicates the % glycosylated calculated by the HPLC excludes part of the hemoglobin A which is misidentified as a hemoglobin variant. Taking this into account, unbiased DBS-based values are computed using data from the machine-generated chromatograms. When the DBS are collected in a clinic-like setting, under controlled humidity/temperature conditions, the recalculated values are almost identical to venous-based values. When DBS are collected under field conditions, the recalculated values are unbiased, but only about half the HbA1c values are measured reliably, calling into question the validity of the other half. The results suggest that collection conditions, particularly humidity, affect the quality of the DBS-based measures. Cross-validating DBS-based HbA1c values with venous samples collected under exactly the same environmental conditions is a prudent investment in population-based studies.
Martin CL, Haan MN, Fernandez-Rhodes L
… +2 more, Lee A, Aiello AE
Biodemography Soc Biol
· 2018 · PMID 29741413
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Foreign-born Hispanics have better cardiometabolic health upon arrival in the US than their US-born counterparts, yet this advantage diminishes as duration of residence in the US increases. Underlying mechanisms explaini...Foreign-born Hispanics have better cardiometabolic health upon arrival in the US than their US-born counterparts, yet this advantage diminishes as duration of residence in the US increases. Underlying mechanisms explaining this paradox have been understudied. Using data from the Sacramento Area Latino Study on Aging (SALSA), this study examined immigration history (immigrant generation and duration of US residence) in relation to biomarkers of inflammation (interleukin-6 (IL-6), soluble forms of type 1 and 2 receptors of tumor necrosis factor-alpha (sTNF-R1 and sTNF-R2), C-reactive protein (CRP), leptin, adiponectin) in a sample of 1,290 predominantly Mexican-origin immigrants. Second and ≥3rd generation immigrants had higher IL-6 and leptin levels than 1st generation immigrants living in the US for less than 15 years (2nd generation percent difference = 45.9; 95% CI: 24.7, 70.7 and 3rd generation percent difference = 41.8; 95% CI: 17.7, 70.4). CRP and sTNF-R1 levels were higher among ≥3rd generation immigrants than 1st generation immigrants with less than 15 years of US residency. Worse inflammatory profiles were observed among Mexican-origin immigrants with longer US immigration histories, independent of health, and behavioral factors. Additional research is warranted to understand the factors that shape trajectories of biological risk across generations of Hispanics.
Using data from the 1986 to 2010 National Longitudinal Study of Youth (NLSY) and the NLSY Child and Young Adult Supplement, this research explores how changes in parental socioeconomic status relate to child obesity over...Using data from the 1986 to 2010 National Longitudinal Study of Youth (NLSY) and the NLSY Child and Young Adult Supplement, this research explores how changes in parental socioeconomic status relate to child obesity over time. Results from linear mixed-effects models indicate that maternal educational gains and maternal employment transitions significantly increased their child's body mass index (BMI). This finding suggests that mothers who work may have less time to devote to monitoring their child's food intake and physical activity, which places their children at higher risks of becoming overweight or obese over time. Conversely, father's work transitions and educational gains contribute to decreases in child's BMI. Thus, work instability and increasing educational attainment for the traditional breadwinner of the household corresponds to better child weight outcomes. Results also suggest that there are racial differences in child BMI that remain after adjusting for changes in socioeconomic status, which indicate that the same structural disadvantages that operate to keep minorities in lower social class standings in society also work to hinder minorities from advancing among and out of their social class. Policy implications related to curbing child obesity are discussed.
The evolution of mortality shows a marked deceleration at older ages. This phenomenon is generally thought to be an effect of selection: mortality decelerates because it progressively selects the most robust individuals...The evolution of mortality shows a marked deceleration at older ages. This phenomenon is generally thought to be an effect of selection: mortality decelerates because it progressively selects the most robust individuals in the cohort. Other processes, however, may contribute to mortality deceleration as well. People may not be passive in the face of ageing and may try to counter it by modifying their behaviours and lifestyles. In this paper, I propose a method to test whether selection is to be considered the unique mechanism responsible for mortality deceleration. I applied this method to the life tables of selected female cohorts drawn from the Human Mortality Database. The results indicate mortality decelerates more rapidly than predicted by the selection theory.
Positive psychologists have observed, based on large cross-cultural data, that "most people are happy" and "life is pretty meaningful." Evolutionary and behavior genetic considerations suggest, however, that the human te...Positive psychologists have observed, based on large cross-cultural data, that "most people are happy" and "life is pretty meaningful." Evolutionary and behavior genetic considerations suggest, however, that the human tendency to hold "extreme" opinions significantly above or below the scale midpoint may be more universal. Analyses of all relevant questions in the 2014 General Social Survey ( = 266 questions and 2,538 respondents) and Wave 6 of the World Values Survey ( = 138 questions and 79,805 respondents in 59 countries) show that, no matter what question one asks anywhere in the world, humans hold "extreme" opinions in nearly all (94.6%) cases, and the observed effect is both highly statistically significant (mean = 29.44) and large (mean = .80).
Biodemography Soc Biol
· 2018 · PMID 31274347
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This paper provides new evidence of the impacts of early life exposure to the 1918 pandemic on old-age mortality by analyzing data from the National Longitudinal Mortality Study (n ~ 220,000). The specifications used yea...This paper provides new evidence of the impacts of early life exposure to the 1918 pandemic on old-age mortality by analyzing data from the National Longitudinal Mortality Study (n ~ 220,000). The specifications used year and quarter of birth indicators to assess the effects of timing of pandemic exposure and used Cox proportional hazard models for all-cause mortality outcomes. The findings suggest evidence of excess all-cause mortality for cohorts born during 1918 and mixed evidence for cohorts born in 1917 and 1919. Therefore, contrary to some existing research, the results suggest no consistent evidence of the importance of specific windows of exposure by gestation period.
Biodemography Soc Biol
· 2018 · PMID 31178981
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We investigated the impact of diabetes on US life expectancy by sex and race/ethnicity using a prospective cohort study design. Cohorts were drawn from 1997-2009 waves of the National Health Interview Survey and linked t...We investigated the impact of diabetes on US life expectancy by sex and race/ethnicity using a prospective cohort study design. Cohorts were drawn from 1997-2009 waves of the National Health Interview Survey and linked to death records through December 31, 2011. We combined data on the prevalence of diabetes among decedents with estimates of the hazard ratios of individuals diagnosed with diabetes to calculate population attributable fractions (PAFs) by age, sex, and race/ethnicity at ages 30 and above. These estimates were then applied to deaths in the official US life table for 2010 to estimate effects of diabetes on life expectancy. Diabetes was responsible for a reduction of 0.83 years of life expectancy for men at age 30 and 0.89 years for 30-year-old women. The impact was greatest among Black women at 1.05 years. Estimates based on traditional demographic and actuarial methods using the frequency with which a disease appears as an underlying cause of death on death certificates produced a reduction in life expectancy at age 30 of only 0.33 years. We conclude that diabetes is substantially reducing US longevity and that its effect is seriously underestimated when using data on underlying causes of death.
Biodemography Soc Biol
· 2018 · PMID 31007841
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Aging is a major risk factor for both normal and pathological cognitive decline. However, individuals vary in their rate of age-related decline. We developed an easily interpretable composite measure of cognitive age, an...Aging is a major risk factor for both normal and pathological cognitive decline. However, individuals vary in their rate of age-related decline. We developed an easily interpretable composite measure of cognitive age, and related both the level of cognitive age and cognitive slope to sociodemographic, genetic, and disease indicators and examine its prediction of dementia transition. Using a sample of 19,594 participants from the Health and Retirement Study, cognitive age was derived from a set of performance tests administered at each wave. Our findings reveal different conclusions as they relate to levels versus slopes of cognitive age, with more pronounced differences by sex and race/ethnicity for absolute levels of cognitive decline rather than for rates of declines. We also find that both level and slope of cognitive age are inversely related to education, as well as increased for persons with APOE ε4 and/or diabetes. Finally, results show that the slope in cognitive age predicts subsequent dementia among non-demented older adults. Overall, our study suggests that this measure is applicable to cross-sectional and longitudinal studies on cognitive aging, decline, and dementia with the goal of better understanding individual differences in cognitive decline.
Chernenko A, Hollingshaus M, Robson S
… +2 more, Hanson HA, Smith KR
Biodemography Soc Biol
· 2018 · PMID 30906507
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Women who bear twins may possess a robust phenotype compared to non-twinning mothers. We examine mortality patterns for the singleton offspring of mothers of twins compared to the offspring of non-twinning mothers to det...Women who bear twins may possess a robust phenotype compared to non-twinning mothers. We examine mortality patterns for the singleton offspring of mothers of twins compared to the offspring of non-twinning mothers to determine whether they share the hypothesized robust phenotype of their mothers. Using data from the Utah Population Database, we show that both male and female singleton offspring of twinning mothers experience a survival prior to age 5, no survival benefit or penalty between ages 5 and 49, and - for males only - a statistically significant survival after age 50. We further examine the survival effects on singletons born before and after a twinset. We observe a survival in early life for singleton offspring of twinning mothers born after the twinset for both sexes. In addition, we find a significant survival at older ages in certain categories of male singleton offspring - a likely reflection of mortality selection. The findings suggest that while bearing twins may reflect a robust maternal phenotype, the toll of bearing twins may disadvantage subsequent offspring, especially during infancy.
Biodemography Soc Biol
· 2017 · PMID 29199872
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Inflammation has been linked to clinical cognitive impairment, including Alzheimer's disease. Less is known, however, about the relationship between inflammation and normal, age-associated cognitive decline. An understan...Inflammation has been linked to clinical cognitive impairment, including Alzheimer's disease. Less is known, however, about the relationship between inflammation and normal, age-associated cognitive decline. An understanding of the determinants of all types of cognitive decline is important for improving quality of life in an aging world. This study investigated whether biomarkers of inflammation were associated with cognitive function and decline in older Taiwanese adults. Data were from the Taiwan Longitudinal Study of Aging and the Social Environment and Biomarkers of Aging Study. Inflammation was measured in 2000 and 2006 as C-reactive protein, interleukin-6, soluble e-selectin, soluble intercellular adhesion molecule-1, and white blood cell count. Cognition was assessed by 10 cognitive and memory tasks, measured in 2006, 2007, and 2011. Growth curve models were used to examine the relationship between inflammation and cognitive score over this time period. Higher levels of inflammation were associated with lower baseline cognitive scores, but not with longitudinal change in cognitive score. This study did not support a causal link between inflammation and cognitive decline among this older cohort. The observed cross-sectional relationship could reflect a causal relationship that arises earlier in life, or confounding; additional research across the life course is warranted.
This study investigates the association between body weight and the likelihood that people perceive that they have been the victims of racial discrimination in the workplace among the unemployed. I find that unemployed o...This study investigates the association between body weight and the likelihood that people perceive that they have been the victims of racial discrimination in the workplace among the unemployed. I find that unemployed obese men and women are 8.4 percentage points and 7.7 percentage points, respectively, more likely to have experienced racial discrimination before becoming unemployed than their non-obese counterparts. For unemployed men, the relationship between body weight and perceived racial discrimination does not seem to be associated with race. For unemployed women, being black and obese significantly increases the likelihood of perceiving racial discrimination.
The purpose of this study is to evaluate the relationship between spiritual struggles and levels of interleukin-6 (IL-6) with a subsample (N = 943) of participants who took part in a nationwide survey. This study, which...The purpose of this study is to evaluate the relationship between spiritual struggles and levels of interleukin-6 (IL-6) with a subsample (N = 943) of participants who took part in a nationwide survey. This study, which was completed in 2014, was conducted in the United States. Spiritual struggles refer to difficulties that a person may encounter with his or her faith and include having a troubled relationship with God, encountering difficulties with religious others, and being unable to find a sense of ultimate meaning in life. Based on the notion that spiritual struggles may be associated with personal growth as well physical health problems, it was hypothesized that there is a nonlinear relationship between the two: levels of IL-6 will decline at relatively low levels of spiritual struggles, but levels of IL-6 will increase as spiritual struggles become more severe. The findings support this hypothesis and suggest there is a quadratic relationship between spiritual struggles and IL-6. The clinical implications of these findings are discussed.
Despite accumulating small-sample and clinical evidence on "inflammaging," no population-representative longitudinal studies have specifically examined women's late-life inflammation trends. While a range of studies indi...Despite accumulating small-sample and clinical evidence on "inflammaging," no population-representative longitudinal studies have specifically examined women's late-life inflammation trends. While a range of studies indicates estradiol's immunomodulation role, evidence is contradictory on whether its effects are pro- or antiinflammatory among older women. Using longitudinal data from the first two waves of the National Social Life, Health and Aging Project-a national probability sample of older U.S. adults aged 57 to 85 years at baseline-this study began to fill these gaps. Findings suggested rather than being a lifelong process, older women's inflammaging may have a biological window that closes with senescence. Moreover, their endogenous estradiol plays a proinflammatory rather than immunoprotective role. Nor does this sex steroid modulate age effects on women's inflammation. More sex-specific basic research is needed on causal mechanisms underlying women's late-life inflammaging patterns.