Climate and fertility amid a public health crisis.

One line of enquiry in demographic research assesses whether climate affects fertility. We extend this literature by examining the ramifications of climate conditions on fertility over a period of public health crisis in a highly unequal, urban middle-income country. We use monthly data for Brazil's 5,564 municipalities and apply spatial fixed-effects models to account for unobserved municipal heterogeneity and spatial dependence. Findings suggest that increases in temperature and precipitation are associated with declines in births. We also show that changes in response to climate conditions became greater during the Zika epidemic, particularly in urban areas. Combined, findings highlight the value of understanding the intersections between climate and fertility across geographic boundaries and during this public health crisis. Epidemics have become more important in people's lives with the recurring emergence of novel infectious disease threats, such as Zika and Covid-19.

Tuning Random Forests for Causal Inference under Cluster-Level Unmeasured Confounding.

Recently, there has been growing interest in using machine learning methods for causal inference due to their automatic and flexible ability to model the propensity score and the outcome model. However, almost all the machine learning methods for causal inference have been studied under the assumption of no unmeasured confounding and there is little work on handling omitted/unmeasured variable bias. This paper focuses on a machine learning method based on random forests known as Causal Forests and presents five simple modifications for tuning Causal Forests so that they are robust to cluster-level unmeasured confounding. Our simulation study finds that adjusting the default tuning procedure with the propensity score from fixed effects logistic regression or using variables that are centered to their cluster means produces estimates that are more robust to cluster-level unmeasured confounding. Also, when these parametric propensity score models are mis-specified, our modified machine learning methods remain robust to bias from cluster-level unmeasured confounders compared to existing parametric approaches based on propensity score weighting. We conclude by demonstrating our proposals in a real data study concerning the effect of taking an eighth-grade algebra course on math achievement scores from the Early Childhood Longitudinal Study.

Later-life transitions and changes in prescription medication use for pain and depression.

BACKGROUND: Over the past two decades, prescription medication use for pain and depression increased dramatically. Most studies consider the early life course, despite a similar increase among those in later life. In this paper, we examine whether and how later life transitions may relate to changes in medication use. METHODS: We draw on data from the Health and Retirement Study and fixed-effects models to examine whether work, family, and civic transitions in later life are related to changes in the usage of prescription pain and depression medication. RESULTS: Results show that individuals had higher odds of regularly using prescription pain and depression medications in periods when out of the labor market. Higher odds of depression medication use were also associated with periods of widowhood, and lower odds of use when frequently volunteering. Such relations persist adjusting for reported levels of pain and depression. CONCLUSION: Our findings call attention to the importance of social ties and the presence of actors that may regulate health behaviors, as well as a change in social context, that may shape medication use in later life.

Do prescription drug monitoring programs encourage prescription - or illicit - opioid abuse?

BACKGROUND: Prescription drug monitoring programs (PDMPs) are tools that states can use to fight prescription opioid misuse within their jurisdiction. However, because PDMPs make prescription opioids more difficult to access, these programs may have the unintended consequence of increasing deaths related to illicit opioids. Methods: This study uses fixed effects models to estimate how PDMP regulatory strength is associated with both prescription opioid- and heroin-related deaths between 1999 and 2016. PDMP regulatory strength is measured by creating a score using multiple correspondence analysis (MCA). Additional models replace the MCA score with a binary indicator for the presence of one particular regulation requiring physicians to access the system before writing opioid prescriptions. Results: Results show that continuous measures of PDMP strength are not generally associated with prescription opioid- or heroin-related death rates. Yet, one model does show that PDMP scores are positively associated with the heroin-related death rate. The models using the binary mandatory access variable show a strong positive association with both prescription opioid and heroin deaths. Conclusions: This study supports the theory that more stringent state PDMPs are associated with higher rates of heroin-related deaths, potentially due to decreases in prescription opioid availability.

Does school learning shape gender ideology? Academic performance and adolescents' attitudes toward gender practices.

Despite research linking education to values, our understanding of the effects of academic learning on gender attitudes is still limited. Using sibling data collected over time, we investigate how learning in school, measured by achievement test scores, affects adolescents' views on gender issues both with and without direct implications for women's economic mobility. With fixed-effects models accounting for unobserved heterogeneity between high and low achievers, we show that the relationship between academic achievement and gender ideology is not spurious, but learning does not enlighten adolescents on all gender-related beliefs, either. Rather, school learning socializes both boys and girls into more liberal views on issues clearly related to women's economic opportunities. For views concerning dating practices or boy-girl interactions, which are irrelevant to the meritocracy-based mainstream values, academic performance has less consistent effects, with higher achievement scores sometimes associated with more conservative views among boys. Our results generally support the socialization and reproduction model of the role of school learning, although self-interest also explains high and low achievers' different attitudes on dating and other personal-realm gender practices.

Changing family relationships and mental health of Chinese adolescents: the role of living arrangements.

OBJECTIVE: This study examined the association between changing family relationships (marital relationships and parent-child relationships) and adolescents' mental health in transitional China. It further explored the potential moderating role of living arrangements in the abovementioned associations. STUDY DESIGN: The study design used in the study is a longitudinal study. METHODS: Data were derived from wave 1 (academic year: 2013-2014, grade 7) and wave 2 (academic year: 2014-2015, grade 8) of the China Education Panel Survey (CEPS). We used fixed-effects models in the longitudinal data analysis (N = 7237). RESULTS: Descriptive analysis indicated significant changes in both adolescents' mental health and self-reported family relationships during the transition from grade 7 to grade 8. The fixed-effects models showed that high marital quality and close parent-child relationships improved the mental health of adolescents. Interaction analysis suggested that paternal living arrangements significantly moderated the association between the father-child relationships and adolescents' mental health: effects of the father-child relationships were weaker among those living away from their biological fathers than among those living with their biological fathers. CONCLUSIONS: Family relationships play an important role in shaping Chinese adolescents' psychological status. However, the effect of the father-child relationships varies based on the paternal living arrangements. This finding highlights the importance of considering the context in examining the effects of family relationships on adolescents' well-being.

Fast Genome-Wide QTL Association Mapping on Pedigree and Population Data.

Since most analysis software for genome-wide association studies (GWAS) currently exploit only unrelated individuals, there is a need for efficient applications that can handle general pedigree data or mixtures of both population and pedigree data. Even datasets thought to consist of only unrelated individuals may include cryptic relationships that can lead to false positives if not discovered and controlled for. In addition, family designs possess compelling advantages. They are better equipped to detect rare variants, control for population stratification, and facilitate the study of parent-of-origin effects. Pedigrees selected for extreme trait values often segregate a single gene with strong effect. Finally, many pedigrees are available as an important legacy from the era of linkage analysis. Unfortunately, pedigree likelihoods are notoriously hard to compute. In this paper, we reexamine the computational bottlenecks and implement ultra-fast pedigree-based GWAS analysis. Kinship coefficients can either be based on explicitly provided pedigrees or automatically estimated from dense markers. Our strategy (a) works for random sample data, pedigree data, or a mix of both; (b) entails no loss of power; (c) allows for any number of covariate adjustments, including correction for population stratification; (d) allows for testing SNPs under additive, dominant, and recessive models; and (e) accommodates both univariate and multivariate quantitative traits. On a typical personal computer (six CPU cores at 2.67 GHz), analyzing a univariate HDL (high-density lipoprotein) trait from the San Antonio Family Heart Study (935,392 SNPs on 1,388 individuals in 124 pedigrees) takes less than 2 min and 1.5 GB of memory. Complete multivariate QTL analysis of the three time-points of the longitudinal HDL multivariate trait takes less than 5 min and 1.5 GB of memory. The algorithm is implemented as the Ped-GWAS Analysis (Option 29) in the Mendel statistical genetics package, which is freely available for Macintosh, Linux, and Windows platforms from http://genetics.ucla.edu/software/mendel.

Gender Differences in the Consequences of Divorce: A Study of Multiple Outcomes.

In this study, I examined gender differences in the consequences of divorce by tracing annual change in 20 outcome measures covering four domains: economic, housing and domestic, health and well-being, and social. I used data from the German Socio-Economic Panel Study (SOEP) and fixed-effects panel regression models on a sample of N = 18,030 individuals initially observed in a marital union, N = 1,220 of whom divorced across the observation period (1984-2015). Three main findings emerged from the analysis. First, men were more vulnerable to short-term consequences of divorce for subjective measures of well-being, but postdivorce adaptation alleviated gender differences in these outcomes. Second, a medium-term view on multiple outcomes showed more similarity than differences between women and men. The medium-term consequences of divorce were similar in terms of subjective economic well-being; mental health, physical health, and psychological well-being; residential moves, homeownership, and satisfaction with housework; and chances of repartnering, social integration with friends and relatives, and feelings of loneliness. Third, the key domain in which large and persistent gender differences emerged were women's disproportionate losses in household income and associated increases in their risk of poverty and single parenting. Taken together, these findings suggest that men's disproportionate strain of divorce is transient, whereas women's is chronic.

Sparse meta-analysis with high-dimensional data.

Meta-analysis plays an important role in summarizing and synthesizing scientific evidence derived from multiple studies. With high-dimensional data, the incorporation of variable selection into meta-analysis improves model interpretation and prediction. Existing variable selection methods require direct access to raw data, which may not be available in practical situations. We propose a new approach, sparse meta-analysis (SMA), in which variable selection for meta-analysis is based solely on summary statistics and the effect sizes of each covariate are allowed to vary among studies. We show that the SMA enjoys the oracle property if the estimated covariance matrix of the parameter estimators from each study is available. We also show that our approach achieves selection consistency and estimation consistency even when summary statistics include only the variance estimators or no variance/covariance information at all. Simulation studies and applications to high-throughput genomics studies demonstrate the usefulness of our approach.

Do Immigrants Suffer More From Job Loss? Unemployment and Subjective Well-being in Germany.

This study asks whether immigrants suffer more from unemployment than German natives. Differences between these groups in pre-unemployment characteristics, the type of the transition into unemployment, and the consequences of this transition suggest that factors intensifying the negative impact of unemployment on subjective well-being are more concentrated in immigrants than in natives. Based on longitudinal data from the German Socio-Economic Panel Study (1990-2014; N = 34,767 persons aged 20 to 64; N = 210,930 person-years), we used fixed-effects models to trace within-person change in subjective well-being across the transition from employment into unemployment and over several years of continued unemployment. Results showed that immigrants' average declines in subjective well-being exceeded those of natives. Further analyses revealed gender interactions. Among women, declines were smaller and similar among immigrants and natives. Among men, declines were larger and differed between immigrants and natives. Immigrant men showed the largest declines, amounting to one standard deviation of within-person change over time in subjective well-being. Normative, social, and economic factors did not explain these disproportionate declines. We discuss alternative explanations for why immigrant men are most vulnerable to the adverse effects of unemployment in Germany.

Health trends in the wake of the financial crisis-increasing inequalities?

AIM: The financial crisis that hit Europe in 2007-2008 and the corresponding austerity policies have generated concern about increasing health inequalities, although impacts have been less salient than initially expected. One explanation could be that health inequalities emerged first a few years into the crisis. This study investigates health trends in the wake of the financial crisis and analyses health inequalities across a number of relevant population subgroups, including those defined by employment status, age, family type, gender, and educational attainment. METHODS: This study uses individual-level panel data (EU-SILC, 2010-2013) to investigate trends in self-rated health. By applying individual fixed effects regression models, the study estimates the average yearly change in self-rated health for persons aged 15-64 years in 28 European countries. Health inequalities are investigated using stratified analyses. RESULTS: Unemployed respondents, particularly those who were unemployed in all years of observation, had a steeper decline in self-rated health than the employed. Respondents of prime working age (25-54 years) had a steeper decline than their younger (15-24) and older (55-64) counterparts, while single parents had a more favorable trend in self-rated health than dual parents. We did not observe any increasing health inequalities based on gender or educational attainment. CONCLUSIONS: Health inequalities increased in the wake of the financial crisis, especially those associated with employment status, age, and family type. We did not observe increasing health inequalities in terms of levels of educational attainment and gender.

Quantifying Variation in Gait Features from Wearable Inertial Sensors Using Mixed Effects Models.

The emerging technology of wearable inertial sensors has shown its advantages in collecting continuous longitudinal gait data outside laboratories. This freedom also presents challenges in collecting high-fidelity gait data. In the free-living environment, without constant supervision from researchers, sensor-based gait features are susceptible to variation from confounding factors such as gait speed and mounting uncertainty, which are challenging to control or estimate. This paper is one of the first attempts in the field to tackle such challenges using statistical modeling. By accepting the uncertainties and variation associated with wearable sensor-based gait data, we shift our efforts from detecting and correcting those variations to modeling them statistically. From gait data collected on one healthy, non-elderly subject during 48 full-factorial trials, we identified four major sources of variation, and quantified their impact on one gait outcome-range per cycle-using a random effects model and a fixed effects model. The methodology developed in this paper lays the groundwork for a statistical framework to account for sources of variation in wearable gait data, thus facilitating informative statistical inference for free-living gait analysis.

Single-parent households and mortality among children and youth.

Although many studies have examined associations between family structure and child outcomes, few have considered how the increase in single-parent households since the 1960s may have affected child mortality rates. We examined state-level changes in the percentage of children living with single parents between 1968 and 2010 and state-level trends in mortality among children and youth (age 19 or younger) in the United States. Regression models with state and year fixed effects revealed that increases in single parenthood were associated with small increments in accidental deaths and homicides.

CLME: An R Package for Linear Mixed Effects Models under Inequality Constraints.

In many applications researchers are typically interested in testing for inequality constraints in the context of linear fixed effects and mixed effects models. Although there exists a large body of literature for performing statistical inference under inequality constraints, user friendly statistical software for implementing such methods is lacking, especially in the context of linear fixed and mixed effects models. In this article we introduce CLME, a package in the R language that can be used for testing a broad collection of inequality constraints. It uses residual bootstrap based methodology which is reasonably robust to non-normality as well as heteroscedasticity. The package is illustrated using two data sets. The package also contains a graphical interface built using the shiny package.

Social participation and depression in old age: a fixed-effects analysis in 10 European countries.

We examined whether changes in different forms of social participation were associated with changes in depressive symptoms in older Europeans. We used lagged individual fixed-effects models based on data from 9,068 persons aged ≥50 years in wave 1 (2004/2005), wave 2 (2006/2007), and wave 4 (2010/2011) of the Survey of Health, Ageing and Retirement in Europe (SHARE). After we controlled for a wide set of confounders, increased participation in religious organizations predicted a decline in depressive symptoms (EURO-D Scale; possible range, 0-12) 4 years later (ß = -0.190 units, 95% confidence interval: -0.365, -0.016), while participation in political/community organizations was associated with an increase in depressive symptoms (ß = 0.222 units, 95% confidence interval: 0.018, 0.428). There were no significant differences between European regions in these associations. Our findings suggest that social participation is associated with depressive symptoms, but the direction and strength of the association depend on the type of social activity. Participation in religious organizations may offer mental health benefits beyond those offered by other forms of social participation.

Income inequality, life expectancy and cause-specific mortality in 43 European countries, 1987-2008: a fixed effects study.

Whether income inequality is related to population health is still open to debate. We aimed to critically assess the relationship between income inequality and mortality in 43 European countries using comparable data between 1987 and 2008, controlling for time-invariant and time-variant country-level confounding factors. Annual data on income inequality, expressed as Gini index based on net household income, were extracted from the Standardizing the World Income Inequality Database. Data on life expectancy at birth and age-standardized mortality by cause of death were obtained from the Human Lifetable Database and the World Health Organization European Health for All Database. Data on infant mortality were obtained from the United Nations World Population Prospects Database. The relationships between income inequality and mortality indicators were studied using country fixed effects models, adjusted for time trends and country characteristics. Significant associations between income inequality and many mortality indicators were found in pooled cross-sectional regressions, indicating higher mortality in countries with larger income inequalities. Once the country fixed effects were added, all associations between income inequality and mortality indicators became insignificant, except for mortality from external causes and homicide among men, and cancers among women. The significant results for homicide and cancers disappeared after further adjustment for indicators of democracy, education, transition to national independence, armed conflicts, and economic freedom. Cross-sectional associations between income inequality and mortality seem to reflect the confounding effects of other country characteristics. In a European context, national levels of income inequality do not have an independent effect on mortality.

Maternal heavy alcohol use and toddler behavior problems: a fixed effects regression analysis.

Using data from the longitudinal Norwegian Mother and Child Cohort Study, the aims of the current study were to examine associations between postnatal maternal heavy alcohol use and toddler behavior problems, taking both observed and unobserved confounding factors into account by employing fixed effects regression models. Postnatal maternal heavy alcohol use (defined as drinking alcohol 4 or more times a week, or drinking 7 units or more per alcohol use episode) and toddler internalizing and externalizing behavior problems were assessed when the toddlers were aged 18 and 36 months. Maternal psychopathology, civil status and negative life events last year were included as time-variant covariates. Maternal heavy alcohol use was associated with toddler internalizing and externalizing behavior problems (p < 0.001) in the population when examined with generalized estimating equation models. The associations disappeared when observed and unobserved sources of confounding were taken into account in the fixed effects models [(p = 0.909 for externalizing behaviors (b = 0.002, SE = 0.021), p = 0.928 for internalizing behaviors (b = 0.002, SE = 0.023)], with an even further reduction of the estimates with the inclusion of time-variant confounders. No causal effect was found between postnatal maternal heavy alcohol use and toddler behavior problems. Increased levels of behavior problems among toddlers of heavy drinking mothers should therefore be attributed to other adverse characteristics associated with these mothers, toddlers and families. This should be taken into account when interventions aimed at at-risk families identified by maternal heavy alcohol use are planned and conducted.

Single-parent households and children's educational achievement: A state-level analysis.

Although many studies have examined associations between family structure and children's educational achievement at the individual level, few studies have considered how the increase in single-parent households may have affected children's educational achievement at the population level. We examined changes in the percentage of children living with single parents between 1990 and 2011 and state mathematics and reading scores on the National Assessment of Educational Progress. Regression models with state and year fixed effects revealed that changes in the percentage of children living with single parents were not associated with test scores. Increases in maternal education, however, were associated with improvements in children's test scores during this period. These results do not support the notion that increases in single parenthood have had serious consequences for U.S. children's school achievement.

Transitioning into and out of precarious employment and life satisfaction: Evidence from asymmetric fixed effects models.

Previous studies have found that those with precarious jobs report lower levels of life satisfaction than those with non-precarious jobs. However, it is unclear whether transitioning into and out of precarious jobs has differential effects on life satisfaction. This study examines the association between employment status transitions and life satisfaction, as well as gender differences in these associations. Data from the Korean Welfare Panel Study (N = 9,792) from 2006 to 2020 were used in this study. A novel asymmetric fixed effects model was employed to separately estimate the association for transitioning into and out of precarious employment. Gender heterogeneity was estimated by including an interaction term of gender and employment transition. Standard fixed effects estimates showed that precarious employment is negatively associated with life satisfaction (b = -0.048). Asymmetric fixed effects models revealed that transitioning out of precarious employment is associated with increased life satisfaction (b = 0.051), while transitioning into a precarious job is not significantly associated with life satisfaction. These asymmetric associations were more pronounced for men than women. This study provides evidence that, especially for men, the association for transitioning out of precarious employment is significantly larger than the association for transitioning into precarious employment. Policies that facilitate the transition into stable employment are likely to enhance the quality of life for employed individuals.

Beyond the Situation: Hanging Out with Peers now is Associated with Short-Term Mindsets Later.

It is well-established that unstructured unsupervised socializing with peers (UUS) motivates deviance while in that specific context. In this article, we extend this situational view by arguing that repeated UUS may also gradually shape adolescents' norms and decision making beyond the situation. Specifically, we argue that UUS promotes short-term mindsets, i.e., an increased focus on present rewards at the expense of considering future consequences. We test this hypothesis with fixed-effects models, using longitudinal data from a representative sample of 1,675 adolescents from Zurich, Switzerland. Consistent with our preregistered predictions, more frequent UUS is associated with increased short-term mindsets. Thus, our finding suggests that the effects of UUS on later deviance might be driven by becoming more present-oriented. This link offers new insights into the developmental pathways toward adolescent delinquency and offers a potential target for intervention. Supplementary Information: The online version contains supplementary material available at 10.1007/s40865-024-00249-2.