Emilie Courtin

Background: Parental leave policies have been hypothesized to benefit mothers’ mental health. We assessed the impact of a 6-week extension of parental leave in Denmark on maternal mental health. Methods: We linked individual-level data from Danish national registries on maternal sociodemographic characteristics and psychiatric diagnoses. A regression discontinuity design was applied to study the increase in parental leave duration after 26 March 1984. We included women who had given birth between 1 January 1981 and 31 December 1987. Our outcome was a first psychiatric diagnosis following the child’s birth, ascertained as the first day of inpatient hospital admission for any psychiatric disorder. We presented cumulative incidences for the 30-year follow-up period and reported absolute risk differences between women eligible for the reform vs not, in 5-year intervals. Results: In all, 291 152 women were followed up until 2017, death, emigration or date of first psychiatric diagnosis. The median follow-up time was 29.99 years, corresponding to 10 277 547 person-years at risk. The cumulative incidence of psychiatric diagnoses at 30 years of follow-up was 59.5 (95% CI: 57.4 to 61.6) per 1000 women in the ineligible group and 57.5 (95% CI: 55.6 to 59.4) in the eligible group. Eligible women took on average 32.85 additional days of parental leave (95% CI: 29.20 to 36.49) and had a lower probability of having a psychiatric diagnosis within 5 years [risk difference (RD): 2.4 fewer diagnoses per 1000 women, 95% CI: 1.5 to 3.2] and up to 20 years after the birth (RD: 2.3, 95% CI: 0.4 to 4.2). In subgroup analyses, the risk reduction was concentrated among low-educated, low-income and single women. Conclusions: Longer parental leave may confer mental health benefits to women, in particular to those from disadvantaged backgrounds.

We thank Rojas-Saunero et al. for their commentary ( 1) on our article, which assessed the mental health effects of expanding the Earned Income Tax Credit for low-income Americans without dependent children in a randomized controlled trial (RCT) ( 2). We agree that evaluating the health effects of experimental social interventions presents challenges that extend beyond those of, for example, drug trials. As Rojas-Saunero et al. point out, follow-up was 69% at 3 years into our study ( 2), so we do not know how the other 31% of participants would have responded to the intervention. Provided that there is no differential attrition, it is not implausible to assume that treatment effects were observed at random. Linkages to administrative data can both fill in these gaps for trials in progress and be used to assess the long-term impacts of trials conducted in the past ( 3). The United States’ unique history of conducting social policy RCTs since the 1960s is actually a treasure trove for social epidemiologists interested in assessing the long-term effects of social policy interventions, and administrative data offer superior follow-up to most clinical trials. Mortality data are one example of administrative data that can be linked to older trials, providing of course that the original identifiers can be found and that the consent process allows for the linkage.

Antipoverty policies have the potential to improve mental health. We conducted a randomized trial (Paycheck Plus Health Study Randomized Controlled Trial, New York, New York) to investigate whether a 4-fold increase in the Earned Income Tax Credit for low-income Americans without dependent children would reduce psychological distress relative to the current federal credit. Between 2013 and 2014, a total of 5,968 participants were recruited; 2,997 were randomly assigned to the treatment group and 2,971 were assigned to the control group. Survey data were collected 32 months postrandomization (n = 4,749). Eligibility for the program increased employment by 1.9 percentage points and after-bonus earnings by 6% ($635/year), on average, over the 3 years of the study. Treatment was associated with a marginally statistically significant decline in psychological distress, as measured by the 6-item Kessler Psychological Distress Scale, relative to the control group (score change = −0.30 points, 95% confidence interval (CI): −0.63, 0.03; P = 0.072). Women in the treated group experienced a half-point reduction in psychological distress (score change = −0.55 points, 95% CI: −0.97, −0.13; P = 0.032), and noncustodial parents had a 1.36-point reduction (95% CI: −2.24, −0.49; P = 0.011). Expansion of a large antipoverty program to individuals without dependent children reduced psychological distress for women and noncustodial parents—the groups that benefitted the most in terms of increased after-bonus earnings.

Antipoverty policies may hold promise as tools to improve health and reduce mortality rates among low-income Americans. We examined the health effects of the New York City Paycheck Plus randomized ...

Policy Points: Social policies might not only improve economic well‐being, but also health. Health policy experts have therefore advocated for investments in social policies both to improve population health and potentially reduce health system costs. Since the 1960s, a large number of social policies have been experimentally evaluated in the United States. Some of these experiments include health outcomes, providing a unique opportunity to inform evidence‐based policymaking. Our comprehensive review and meta‐analysis of these experiments find suggestive evidence of health benefits associated with investments in early life, income support, and health insurance interventions. However, most studies were underpowered to detect health outcomes. Context: Insurers and health care providers are investing heavily in nonmedical social interventions in an effort to improve health and potentially reduce health care costs.Methods: We performed a systematic review and meta‐analysis of all known randomized social experiments in the United States that included health outcomes. We reviewed 5,880 papers, reports, and data sources, ultimately including 61 publications from 38 randomized social experiments. After synthesizing the main findings narratively, we conducted risk of bias analyses, power analyses, and random‐effects meta‐analyses where possible. Finally, we used multivariate regressions to determine which study characteristics were associated with statistically significant improvements in health outcomes.Findings: The risk of bias was low in 17 studies, moderate in 11, and high in 33. Of the 451 parameter estimates reported, 77% were underpowered to detect health outcomes. Among adequately powered parameters, 49% demonstrated a significant health improvement, 44% had no effect on health, and 7% were associated with significant worsening of health. In meta‐analyses, early life and education interventions were associated with a reduction in smoking (odds ratio [OR] = 0.92, 95% confidence interval [CI] 0.86‐0.99). Income maintenance and health insurance interventions were associated with significant improvements in self‐rated health (OR = 1.20, 95% CI 1.06‐1.36, and OR = 1.38, 95% CI 1.10‐1.73, respectively), whereas some welfare‐to‐work interventions had a negative impact on self‐rated health (OR = 0.77, 95% CI 0.66‐0.90). Housing and neighborhood trials had no effect on the outcomes included in the meta‐analyses. A positive effect of the trial on its primary socioeconomic outcome was associated with higher odds of reporting health improvements. We found evidence of publication bias for studies with null findings.Conclusions: Early life, income, and health insurance interventions have the potential to improve health. However, many of the included studies were underpowered to detect health effects and were at high or moderate risk of bias. Future social policy experiments should be better designed to measure the association between interventions and health outcomes.

In this quasiexperimental study, we examined whether the introduction of an age-friendly transportation policy—free bus passes for older adults—increased public transport use and in turn affected cognitive function among older people in England. Data came from 7 waves (2002–2014) of the English Longitudinal Study of Ageing (n = 17,953), which measured total cognitive function, memory, executive function, and processing speed before and after the bus pass was introduced in 2006. The analytical strategy was an instrumental-variable approach with fixed effects, which made use of the age-eligibility criteria for free bus passes and addressed bias due to reverse causality, measurement error, and time-invariant confounding. Eligibility for the bus pass was associated with a 7% increase in public transport use. The increase in public transportation use was associated with a 0.346 (95% confidence interval: 0.017, 0.674) increase in the total cognitive function z score and with a 0.546 (95% confidence interval: 0.111, 0.982) increase in memory z score. Free bus passes were associated with an increase in public transport use and, in turn, benefits to cognitive function in older age. Public transport use might promote cognitive health through encouraging intellectually, socially, and physically active lifestyles. Transport policies could serve as public health tools to promote cognitive health in aging populations.

Background Longer schooling is associated with better physical, mental and cognitive functioning, but there is controversy as to whether these associations are causal. We examine the long-term health impact of a policy that increased compulsory schooling by 2 years in France for cohorts born on or after January 1953, offering a natural experiment. Methods Data came from Constances, a randomly selected cohort of the French population assessed for cognition, depressive symptoms and physical functioning at ages 45 and older (n=18 929). We use a Regression Discontinuity Design to estimate the impact of increased schooling duration on health. Cognition was measured based on five validated neuropsychological tests and combined into an overall score. The Center for Epidemiological Studies Depression scale was used to assess depressive symptoms levels. Physical functioning was included as finger tapping, hand grip strength and walking speed. Results The reform increased average schooling, particularly among participants from disadvantaged families. Estimates suggest that for men, this reform improved cognitive scores (β=0.15, 95% CI 0.02 to 0.27), but had no impact on physical functioning. Among women, the reform did not increase cognitive scores or physical functioning but led to higher levels of depressive symptoms (β=1.52, 95% CI 0.32 to 2.72). Results were robust to a range of sensitivity analyses. Conclusion These findings highlight the need to carefully consider the potential limits of policies that increase the length of compulsory schooling as strategies to improve population health.

Opportunity NYC–Family Rewards was the first conditional cash transfer, randomized controlled trial for low-income families in the United States. From 2007 to 2010, Family Rewards offered 2,377 New York City families cash transfers that were conditional upon their investments in education, preventive health care, and parental employment. Their health and other outcomes were compared to those of a control group of 2,372 families. The experiment led to a modest improvement in health insurance coverage and a large increase in the use of preventive dental care. It improved parents’ perception of their own health and levels of hope, mainly through improvements in reported financial well-being. While the program’s impacts on physical health were weaker, our study might not have captured effects on chronic disease risk that take longer to accrue. In the context of New York City’s operating social-safety-net programs, conditional cash transfers may have led to positive, albeit modest, improvements in the health o...