The effects of shocks in early life mortality on later life expectancy and mortality compression: A cohort analysis

Disease exposure in infancy affects women's reproductive outcomes and offspring health in southern Sweden 1905-2000

Ample evidence demonstrates that early-life adversity negatively affects morbidity and survival in late life. We show that disease exposure in infancy also has a continuous impact on reproduction and health across the female life course and even affects early-life health of the next generation. Using Swedish administrative data, obstetric records, and local infant mortality rates as a measure of disease exposure, we follow women's reproductive careers and offspring health 1905-2000, examining a comprehensive set of outcomes. Women exposed to disease in infancy give birth to a lower proportion of boys, consistent with notions that male fetuses are more vulnerable to adverse conditions and are more often miscarried. Sons of exposed mothers are also more likely to be born preterm and have higher birthweight suggesting in utero out-selection. Exposed women have a greater risk of miscarriage and of male stillbirth, but their overall likelihood of giving birth is not affected.

Intergenerational health effects of Medicaid

This paper investigates the effects of the introduction of Medicaid during the 1960s on next generations' birth outcomes. A federal mandate that all states must widen the coverage to all cash welfare recipients generated cross-state variations in Medicaid eligibility, specifically among nonwhites who largely overrepresented the target population. I implement a reduced-form difference-in-differences strategy that compares the birth outcomes of mothers born in states with higher cash welfare recipiency versus low welfare recipiency and different years relative to the Medicaid implementation year. Using Natality data (1970-2004), I find that Medicaid significantly improves birth outcomes. The effects are considerably larger among nonwhites, specifically blacks. The effects do not appear to be driven by preexisting trends in birth outcomes, preexisting trends in households' socioeconomic characteristics, changes in other welfare expenditures, and selective fertility. A back-of-an-envelope calculation points to a minimum of 3.9% social externality of Medicaid through income rises due to next generations' improvements in birth outcomes.

Tracking progress in mean longevity: The Lagged Cohort Life Expectancy (LCLE) approach

Cohort life expectancy is an important but rarely used indicator of mean longevity. In this paper, we show that there are specific advantages in lagging this indicator in time by its own value, an approach termed Lagged Cohort Life Expectancy (LCLE). We discuss the usefulness of LCLE as an indicator for tracking progress in mean longevity and introduce a new interpretation of LCLE as a reference age separating 'early' deaths from 'late' deaths, or, equivalently, as the age above which individuals in a population can be considered 'above-average' survivors. Using data from 15 countries in the Human Mortality Database, we show that current LCLE can be estimated with a relatively high degree of certainty, at least in these low-mortality populations. Results shed new light on levels and trends in mean longevity in these populations.

Early Plasmodium-induced inflammation does not accelerate aging in mice

Aging is associated with a decline of performance leading to reduced reproductive output and survival. While the antagonistic pleiotropy theory of aging has attracted considerable attention, the molecular/physiological functions underlying the early-life benefits/late-life costs paradigm remain elusive. We tested the hypothesis that while early activation of the inflammatory response confers benefits in terms of protection against infection, it also incurs costs in terms of reduced reproductive output at old age and shortened longevity. We infected mice with the malaria parasite Plasmodium yoelii and increased the inflammatory response using an anti-IL-10 receptor antibody treatment. We quantified the benefits and costs of the inflammatory response during the acute phase of the infection and at old age. In agreement with the antagonistic pleiotropy hypothesis, the inflammatory response provided an early-life benefit, since infected mice that were treated with anti-IL-10 receptor antibodies had reduced parasite density and anemia. However, at old age, mice in all treatment groups had similar levels of C-reactive protein, reproductive output, survival rate, and lifespan. Overall, our results do not support the hypothesis that the benefits of a robust response to malaria infection in early life incur longer term fitness costs.

Cognitive Disparities: The Impact of the Great Depression and Cumulative Inequality on Later-Life Cognitive Function

Population aging has driven a spate of recent research on later-life cognitive function. Greater longevity increases the lifetime risk of memory diseases that compromise the cognitive abilities vital to well-being. Alzheimer's disease, thought to be the most common underlying pathology for elders' cognitive dysfunction (Willis and Hakim 2013), is already the sixth leading cause of death in the United States (Alzheimer's Association 2016). Understanding social determinants of pathological cognitive decline is key to crafting interventions, but evidence is inconclusive for how social factors interact over the life course to affect cognitive function. I study whether early-life exposure to the Great Depression is directly associated with later-life cognitive function, influences risky behaviors over the life course, and/or accumulates with other life-course disadvantages. Using growth curve models to analyze the Health and Retirement Study, I find that early-life exposure to the Great Depression is associated with fluid cognition, controlling for intervening factors-evidence for a critical period model. I find little support for a social trajectory model. Disadvantage accumulates over the life course to predict worse cognitive function, providing strong evidence for a cumulative inequality model.

Tendência na incidência de acidentes e doenças de trabalho no Brasil: aplicação do filtro Hodrick-Prescott

Resumo Introdução: analisar a tendência temporal da incidência de acidentes do trabalho é importante para prognósticos de longo prazo. No entanto, alterações cíclicas e sazonais, como o trabalho informal e a subnotificação dos acidentes, podem influenciar e precisam ser consideradas. O método do filtro Hodrick-Prescott (HP), utilizado para avaliar a dinâmica de variáveis macroeconômicas, pode propiciar análise mais precisa da evolução de variáveis sujeitas a essas flutuações do que métodos usualmente utilizados em epidemiologia, como o de médias móveis (MM). Objetivo: testar o filtro HP como método de extração de tendência da variável “incidência de acidentes de trabalho”. Métodos: análise comparativa entre o filtro HP e o método MM para extrair a tendência de longo prazo das variáveis acidente típico, de trajeto, doença do trabalho e total de acidentes no Brasil entre 2008 e 2013. Resultados: ambas metodologias indicaram tendências semelhantes das variáveis ao longo do período. No entanto, a análise da tendência de longo prazo pelo método MM pode ser mais afetada por flutuações de curto prazo. Conclusão: o método HP permite inferir de maneira mais consistente a tendência de médio e longo prazo da variável, o que pode torná-lo mais adequado para a definição e a gestão de políticas públicas.

Sex-Based Differences in the Determinants of Old Age Life Expectancy: The Influence of Perimenopause

Studies using the sensitive periods framework typically examine the effects of early life exposures on later life health, due to the significant growth and development occurring during the first few years of life. The menopausal transition (i.e., perimenopause) is similarly characterized by rapid physiological change, yet rarely has been tested as a sensitive window in adulthood. Cohort mortality data drawn from three historic populations, Sweden (1751-1919), France (1816-1919), and England and Wales (1841-1919), were analyzed using time series methods to assess whether conditions at midlife significantly influenced or "programmed" later life longevity. Results indicated a significant inverse association between mortality at ages 45-49, the average age range in which perimenopause occurred, and life expectancy at age 60 among females in all three countries. Study findings suggest a degree of plasticity associated with women's aging and, in particular, the age group correlated with perimenopause.

Early-life disease exposure and associations with adult survival, cause of death, and reproductive success in preindustrial humans

A leading hypothesis proposes that increased human life span since 1850 has resulted from decreased exposure to childhood infections, which has reduced chronic inflammation and later-life mortality rates, particularly from cardiovascular disease, stroke, and cancer. Early-life cohort mortality rate often predicts later-life survival in humans, but such associations could arise from factors other than disease exposure. Additionally, the impact of early-life disease exposure on reproduction remains unknown, and thus previous work ignores a major component of fitness through which selection acts upon life-history strategy. We collected data from seven 18th- and 19th-century Finnish populations experiencing naturally varying mortality and fertility levels. We quantified early-life disease exposure as the detrended child mortality rate from infectious diseases during an individual's first 5 y, controlling for important social factors. We found no support for an association between early-life disease exposure and all-cause mortality risk after age 15 or 50. We also found no link between early-life disease exposure and probability of death specifically from cardiovascular disease, stroke, or cancer. Independent of survival, there was no evidence to support associations between early-life disease exposure and any of several aspects of reproductive performance, including lifetime reproductive success and age at first birth, in either males or females. Our results do not support the prevailing assertion that exposure to infectious diseases in early life has long-lasting associations with later-life all-cause mortality risk or mortality putatively linked to chronic inflammation. Variation in adulthood conditions could therefore be the most likely source of recent increases in adult life span.

Babies of the War: The Effect of War Exposure Early in Life on Mortality Throughout Life

There is increasing evidence that circumstances very early in our lives, and particularly during pregnancy, can affect our health for the remainder of life. Studies that have looked at this relationship have often used extreme situations, such as famines that occurred during wartime. Here we investigate whether less extreme situations during World War II also affected later-life mortality for cohorts born in Belgium, France, The Netherlands, and Norway. We argue that these occupied countries experienced a considerable deterioration in daily life situations and show that this resulted in strongly increased mortality rates and lower probabilities of survival until age 55 among civilian populations who had been prenatally exposed to wartime circumstances. However, this mortality effect among the prenatally exposed is entirely concentrated in the first years of life, particularly infanthood. Once we condition on having survived the first years of life, those who had been prenatally exposed do not have higher mortality rates. This suggests that "culling" is important and that effects found in earlier studies may have been biased downward substantially.

Early life exposure to the 1918 influenza pandemic and old-age mortality by cause of death

OBJECTIVES

We sought to analyze how early exposure to the 1918 influenza pandemic is associated with old-age mortality by cause of death.

METHODS

We analyzed the National Health Interview Survey (n = 81,571; follow-up 1989-2006; 43,808 deaths) and used year and quarter of birth to assess timing of pandemic exposure. We used Cox proportional and Fine-Gray competing hazard models for all-cause and cause-specific mortality, respectively.

RESULTS

Cohorts born during pandemic peaks had excess all-cause mortality attributed to increased noncancer mortality. We found evidence for a trade-off between noncancer and cancer causes: cohorts with high noncancer mortality had low cancer mortality, and vice versa.

CONCLUSIONS

Early disease exposure increases old-age mortality through noncancer causes, which include respiratory and cardiovascular diseases, and may trigger a trade-off in the risk of cancer and noncancer causes. Potential mechanisms include inflammation or apoptosis. The findings contribute to our understanding of the causes of death behind the early disease exposure-later mortality association. The cancer-noncancer trade-off is potentially important for understanding the mechanisms behind these associations.

No consistent effects of prenatal or neonatal exposure to Spanish flu on late-life mortality in 24 developed countries

We test the effects of early life exposure to disease on later health by looking for differences in late-life mortality in cohorts born around the 1918-1919 flu pandemic using data from the Human Mortality Database for 24 countries. After controlling for age, period, and sex effects, residual mortality rates did not differ systematically for flu cohorts relative to surrounding cohorts. We calculate at most a 20-day reduction in life expectancy for flu cohorts; likely values are much smaller. Estimates of influenza incidence during the pandemic suggest that exposure was high enough for this to be a robust negative result.