Years of Life
Three common assumptions about inflammation, aging, and health that are probably wrong
Thomas McDade
Proceedings of the National Academy of Sciences, 19 December 2023
Abstract:
Chronic inflammation contributes to the onset and progression of cardiovascular disease and other degenerative diseases of aging. But does it have to? This article considers the associations among inflammation, aging, and health through the lens of human population biology and suggests that chronic inflammation is not a normal nor inevitable component of aging. It is commonly assumed that conclusions drawn from research in affluent, industrialized countries can be applied globally; that aging processes leading to morbidity and mortality begin in middle age; and that inflammation is pathological. These foundational assumptions have shifted focus away from inflammation as a beneficial response to infection or injury and toward an understanding of inflammation as chronic, dysregulated, and dangerous. Findings from community-based studies around the world -- many conducted in areas with relatively high burdens of infectious disease -- challenge these assumptions by documenting substantial variation in levels of inflammation and patterns of association with disease. They also indicate that nutritional, microbial, and psychosocial environments in infancy and childhood play important roles in shaping inflammatory phenotypes and their contributions to diseases of aging. A comparative, developmental, and ecological approach has the potential to generate novel insights into the regulation of inflammation and how it relates to human health over the life course.
Limited psychological and social effects of lifetime cannabis use frequency: Evidence from a 30-year community study of 4,078 twins
Stephanie Zellers et al.
Journal of Psychopathology and Clinical Science, January 2024, Pages 115-128
Method: In a sample of 4,078 American adult twins first assessed decades ago, we used cotwin control mixed effects models to evaluate the effect of lifetime average frequency of cannabis consumption measured on substance use, psychiatric, and psychosocial outcomes.
Results: On average, participants had a lifetime cannabis frequency of about one to two times per month, across adolescence and adulthood. As expected, in individual-level analyses, cannabis use was significantly associated with almost all outcomes in the expected directions. However, when comparing each twin to their cotwin, which inherently controls for shared genes and environments, we observed within-pair differences consistent with possible causality in three of the 22 assessed outcomes: cannabis use disorder symptoms (βW-Pooled = .15, SE = .02, p = 1.7 × 10−22), frequency of tobacco use (βW-Pooled = .06, SE = .01, p = 1.2 × 10−5), and illicit drug involvement (βW-Pooled = .06, SE = .02, p = 1.2 × 10−4). Covariate specification curve analyses indicated that within-pair effects on tobacco and illicit drug use, but not cannabis use disorder, attenuated substantially when covarying for lifetime alcohol and tobacco use.
Growth in Suicide Rates Among Children During the Illicit Opioid Crisis
David Powell
Demography, December 2023, Pages 1843-1875
Abstract:
This article documents child suicide rates from 1980 to 2020 in the United States using the National Vital Statistics System Multiple Cause of Death database. After generally declining for decades, suicide rates among children aged 10-17 accelerated from 2011 to 2018 in an unprecedented rise in both duration and magnitude. I consider the role of the illicit opioid crisis in driving this mental health crisis. In August 2010, an abuse-deterrent version of OxyContin was introduced and the original formulation was removed from the market, leading to a shift to illicit opioids and stimulating growth in illicit opioid markets. Areas more exposed to reformulation -- as measured by pre-reformulation rates of OxyContin misuse in the National Survey on Drug Use and Health -- were more affected by the transition to illicit opioids and experienced sharper growth in child suicide rates. The evidence suggests that children's illicit opioid use did not increase, implying that the illicit opioid crisis engendered higher suicide propensities by increasing suicidal risk factors for children, such as increasing rates of child neglect and altering household living arrangements. In complementary analyses, I document how living conditions declined for children during this time period.
Opium Price Shocks and Prescription Opioids in the USA
Claudio Deiana, Ludovica Giua & Roberto Nisticò
Oxford Bulletin of Economics and Statistics, forthcoming
Abstract:
We investigate the effect of international opium price shocks on the per capita dispensation of prescription opioids in the USA. Using quarterly county-level data for 2002q4–2016q4, three main results emerge. First, reductions in opium prices significantly increase the quantity of opioids prescribed, and more so in counties with a larger pre-existing market for pain relief, as captured by the incidence of mining sites. Second, the increase involves only natural and semi-synthetic, but not fully-synthetic, opioids, suggesting that the effect is moderated by the amount of raw material contained in the products. The impact is larger prior to 2010, when overdose deaths were more related to the use of legally prescribed opioids. Third, advertising expenses, stock prices and the profits of opioid producers increase following negative opium price shocks, suggesting an important role of supply-side economic incentives.
Morphine Exposure During Adolescence Induces Enduring Social Changes Dependent on Adolescent Stage of Exposure, Sex, and Social Test
David King’uyu et al.
Behavioral Neuroscience, forthcoming
Abstract:
Drug exposure during adolescence, when the “reward” circuitry of the brain is developing, can permanently impact reward-related behavior into adulthood. Epidemiological studies show that opioid treatment during adolescence, such as pain management for a dental procedure or surgery, increases the incidence of psychiatric illness including substance use disorders. Moreover, the opioid epidemic currently in the United States is affecting younger individuals raising the impetus to understand the pathogenesis of the negative effects of opioids. One reward-related behavior that develops during adolescence is social behavior. We previously demonstrated that developmental changes in the nucleus accumbens reward region regulate social development in rats during sex-specific adolescent periods: early to mid-adolescence in males (postnatal day, P30–40) and preearly adolescence in females (P20–30). We thus hypothesized that the developmental stage of morphine exposure will differentially impact social behavior development such that drug administered during the female critical period would result in adult sociability deficits in females, but not males, and morphine administered during the male critical period would result in adult sociability deficits in males, but not females. We found that morphine exposure during the female critical period primarily resulted in deficits in sociability in females, while morphine exposure during the male critical period primarily resulted in deficits in sociability primarily in males. However, depending on the test performed and the social parameter measured, social alterations could be found in both sexes that received morphine exposure at either adolescent stage. These data indicate that when drug exposure occurs during adolescence, and how the endpoint data are measured, will play a large role in determining the effects of drug exposures on social development.
“Rational overeating” in a feast-or-famine world: Economic insecurity and the obesity epidemic
Trenton Smith, Steven Stillman & Stuart Craig
Southern Economic Journal, forthcoming
Abstract:
Obesity has risen dramatically in the United States since the 1980s, but incidence varies across demographic groups. We investigate the potential role of economic insecurity -- defined, roughly, as the extent to which a household faces the threat of catastrophic income loss -- in explaining these changes. We construct a synthetic panel of demographic groups for 1988–2016 by combining the Economic Security Index (which measures the probability of a year-on-year drop in adjusted household income of 25% or more) with data from the NHANES surveys. This gives us a plausibly exogenous group-level measure of economic insecurity while allowing us to control for both individual characteristics and various interactions of group and year fixed effects. We find robust evidence of a link between economic insecurity and obesity, suggesting a nearly one-to-one correspondence in percentage point changes in ESI and obesity, for both men and women. We further show that if we instead measure economic insecurity based on the changing occupational exposure of each demographic group to trade with China over time, we find similar qualitative results for men, but not for women. Taken together, these results are supportive of a causal interpretation of our findings.
Vaccine Nationalism Counterintuitively Erodes Public Trust in Leaders
Clara Colombatto et al.
Psychological Science, December 2023, Pages 1309-1321
Abstract:
Global access to resources like vaccines is key for containing the spread of infectious diseases. However, wealthy countries often pursue nationalistic policies, stockpiling doses rather than redistributing them globally. One possible motivation behind vaccine nationalism is a belief among policymakers that citizens will mistrust leaders who prioritize global needs over domestic protection. In seven experiments (total N = 4,215 adults), we demonstrate that such concerns are misplaced: Nationally representative samples across multiple countries with large vaccine surpluses (Australia, Canada, United Kingdom, and United States) trusted redistributive leaders more than nationalistic leaders -- even the more nationalistic participants. This preference generalized across different diseases and manifested in both self-reported and behavioral measures of trust. Professional civil servants, however, had the opposite intuition and predicted higher trust in nationalistic leaders, and a nonexpert sample also failed to predict higher trust in redistributive leaders. We discuss how policymakers’ inaccurate intuitions might originate from overestimating others’ self-interest.
'13 Reasons Why' Probably Increased Emergency Room Visits for Self-Harm among Teenage Girls
Chris Felton
Sociological Science, December 2023
Abstract:
I present evidence that the release of Netflix’s 13 Reasons Why -- a fictional series about the aftermath of a teenage girl’s suicide -- caused a temporary spike in emergency room (ER) visits for self-harm among teenage girls in the United States. I conduct an interrupted time series analysis using monthly counts of ER visits obtained from a large, nationally representative survey. I estimate that the show caused an increase of 1,297 self-harm visits (95 percent CI: 634 to 1,965) the month it was released, a 14 percent (6.5 percent, 23 percent) spike relative to the predicted counterfactual. The effect persisted for two months, and ER visits for intentional cutting -- the method of suicide portrayed in the series -- were unusually high following the show’s release. The findings indicate that fictional portrayals of suicide can influence real-life self-harm behavior, providing support for contagion-based explanations of suicide. Methodologically, the study showcases how to make credible causal claims when effect estimates are likely biased.