Income gains and very low-weight birth among low-income black mothers in California

Family cash transfers in childhood and birthing persons and birth outcomes later in life

Much literature in the US documents an intergenerational transmission of birthing person and perinatal morbidity in socioeconomically disadvantaged groups. A separate line of work indicates that family cash transfers may improve life chances of low-income families well into adulthood. By exploiting a quasi-random natural experiment of a large family cash transfer among a southeastern American Indian (AI) tribe in rural North Carolina, we examine whether a "perturbation" in socioeconomic status during childhood improves birthing person/perinatal outcomes when they become parents themselves. We acquired birth records on 6805 AI and non-AI infants born from 1995 to 2018. Regression methods to examine effect modification tested whether the birthing person's American Indian (AI) status and exposure to the family cash transfer during their childhood years corresponds with improvements in birthing person and perinatal outcomes. Findings show an increase in age at childbearing (coef: 0.15 years, 95% confidence interval [CI]: 0.05, 0.25) and a decrease in pre-pregnancy body mass index (BMI; coef: -0.42, 95% CI: -0.76, -0.09) with increased duration of cash transfer exposure during childhood. The odds of large-for-gestational age at delivery, as well as mean infant birthweight, is also reduced among AI births whose birthing person had relatively longer duration of exposure to the cash transfer. We, however, observe no relation with other birthing person/perinatal outcomes (e.g., tobacco use during pregnancy, preterm birth). In this rural AI population, cash transfers in one generation correspond with improved birthing person and infant health in the next generation.

Estimating the effect of timing of earned income tax credit refunds on perinatal outcomes: a quasi-experimental study of California births

BACKGROUND

The largest poverty alleviation program in the US is the earned income tax credit (EITC), providing $60 billion to over 25 million families annually. While research has shown positive impacts of EITC receipt in pregnancy, there is little evidence on whether the timing of receipt may lead to differences in pregnancy outcomes. We used a quasi-experimental difference-in-differences design, taking advantage of EITC tax disbursement each spring to examine whether trimester of receipt was associated with perinatal outcomes.

METHODS

We conducted a difference-in-differences analysis of California linked birth certificate and hospital discharge records. The sample was drawn from the linked CA birth certificate and discharge records from 2007-2012 (N = 2,740,707). To predict eligibility, we created a probabilistic algorithm in the Panel Study of Income Dynamics and applied it to the CA data. Primary outcome measures included preterm birth, small-for-gestational age (SGA), gestational diabetes, and gestational hypertension/preeclampsia.

RESULTS

Eligibility for EITC receipt during the third trimester was associated with a lower risk of preterm birth compared with preconception. Eligibility for receipt in the preconception period resulted in improved gestational hypertension and SGA.

CONCLUSION

This analysis offers a novel method to impute EITC eligibility using a probabilistic algorithm in a data set with richer sociodemographic information relative to the clinical and administrative data sets from which outcomes are drawn. These results could be used to determine the optimal intervention time point for future income supplementation policies. Future work should examine frequent income supplementation such as the minimum wage or basic income programs.

Association of the 2021 Child Tax Credit Advance Payments With Low Birth Weight in the US

IMPORTANCE

Infants and pregnant people in the US fare worse on almost all health measures compared with those in peer nations. Families in the US are more likely to live in poverty and have a less generous social safety net, which has generated debate over the contribution of economic conditions to this disparity.

OBJECTIVE

To assess the association between temporary increases in income during pregnancy through the 2021 expanded Child Tax Credit (CTC) and birth outcomes.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study applied a comparison-population, interrupted time series design to data from US birth certificates (January 1, 2014, through December 31, 2021) to test whether the log odds of low birth weight (LBW) among monthly cohorts of births exposed to the CTC would coincide with a decreased incidence of LBW. All singleton live births to US residents aged 15 to 49 years with available data were included.

EXPOSURE

Monthly birth cohorts exposed to the CTC were defined as those born to parous people during the CTC advance payment period from July through December 2021.

MAIN OUTCOMES AND MEASURES

The main outcome was the natural logarithm of the odds of LBW (<2500 g) among monthly birth cohorts.

RESULTS

Among included births (n = 28 866 466), 61.2% were to parous people, the majority were to people aged 20 to 39 years (91.7%), and 6.5% were born LBW. The odds of LBW increased above expected values in 5 of the 6 months of the CTC payments (range of increases, 3.3%-5.4% across the 5 months). The outlier-adjusted odds of LBW increased, on average, by 4.2% (95% CI, 2.7%-5.7%) among the monthly birth cohorts exposed to the CTC.

CONCLUSIONS AND RELEVANCE

This study found that the odds of LBW among birth cohorts exposed to the CTC increased above expected values in 5 of the 6 months of the CTC advance payments. Additional research is needed to evaluate rival explanations for this increase in LBW among births exposed to the CTC payments.

Structural interventions that affect racial inequities and their impact on population health outcomes: a systematic review

Structural racism is the historical and ongoing reinforcement of racism within society due to discriminatory systems and inequitable distribution of key resources. Racism, embedded within institutional structures, processes and values, perpetuates historical injustices and restricts access to structural factors that directly impact health, such as housing, education and employment. Due to the complex and pervasive nature of structural racism, interventions that act at the structural level, rather than the individual level, are necessary to improve racial health equity. This systematic review was conducted to evaluate the effects of structural-level interventions on determinants of health and health outcomes for racialized populations. A total of 29 articles are included in this review, analyzing interventions such as supplemental income programs, minimum wage policies, nutrition safeguard programs, immigration-related policies, and reproductive and family-based policies. Most studies were quasi-experimental or natural experiments. Findings of studies were largely mixed, although there were clear benefits to policies that improve socioeconomic status and opportunities, and demonstrable harms from policies that restrict access to abortion or immigration. Overall, research on the effects of structural-level interventions to address health inequities is lacking, and the evidence base would benefit from well-designed studies on upstream policy interventions that affect the structural determinants of health and health inequities and improve daily living conditions.

Effects of the revised WIC food package on women's and children's health: a quasi-experimental study

BACKGROUND

The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) was revised in 2009 to be more congruent with national dietary guidelines. There is limited research examining effects of the revision on women's and children's health. The objective of this study was to evaluate whether the revised WIC food package was associated with various indicators of physical and mental health for women and children.

METHODS

We used 1998-2017 waves of the National Health Interview Survey (N = 81,771 women and 27,780 children) to estimate effects of the revised WIC food package on indicators of health for both women (self-reported health and body mass index) and children (anemia, mental health, and parent-reported health). We used difference-in-differences analysis, a quasi-experimental technique that assessed pre-post differences in outcomes among WIC-recipients while "differencing out" the secular underlying trends among a control group of non-recipients.

RESULTS

For all outcomes evaluated for women and children, we were unable to rule out the null hypothesis that there was no effect of receiving the revised WIC food package. These findings were confirmed across several secondary analyses conducted to assess heterogeneity of effects and robustness of results.

CONCLUSION

While we did not find effects of the revised WIC food package on downstream health indicators, studies using similarly robust methods in other datasets have found shorter-term effects on more proximal outcomes related to diet and nutrition. Effects of the modest WIC revisions may be less impactful on longer-term indicators of health, and future studies should examine the larger COVID-19-era expansion.

State-Level Social and Economic Policies and Their Association With Perinatal and Infant Outcomes

Policy Points State-level social and economic policies that expand tax credits, increase paid parental leave, raise the minimum wage, and increase tobacco taxes have been demonstrated to reduce adverse perinatal and infant health outcomes. These findings can help prioritize evidence-based legislated policies to improve perinatal and infant outcomes in the United States.

CONTEXT

Rates of preterm birth and infant mortality are alarmingly high in the United States. Legislated efforts may directly or indirectly reduce adverse perinatal and infant outcomes through the enactment of certain economic and social policies.

METHODS

We conducted a narrative review to summarize the associations between perinatal and infant outcomes and four state-level US policies. We then used a latent profile analysis to create a social and economic policy profile for each state based on the observed policy indicators.

FINDINGS

Of 27 articles identified, nine focused on tax credits, eight on paid parental leave, four on minimum wages, and six on tobacco taxes. In all but three studies, these policies were associated with improved perinatal or infant outcomes. Thirty-three states had tax credit laws, most commonly the earned income tax credit (n = 28, 56%). Eighteen states had parental leave laws. Two states had minimum wage laws lower than the federal minimum; 14 were equal to the federal minimum; 29 were above the federal minimum; and 5 did not have a state law. The average state tobacco tax was $1.76 (standard deviation = $1.08). The latent profile analysis revealed three policy profiles, with the most expansive policies in Western and Northeastern US states, and the least expansive policies in the US South.

CONCLUSIONS

State-level social and economic policies have the potential to reduce adverse perinatal and infant health outcomes in the United States. Those states with the least expansive policies should therefore consider enacting these evidence-based policies, as they have shown a demonstratable benefit in other states.

Racial Differences in the Association between the U.S. Earned Income Tax Credit and Birthweight

OBJECTIVE

We examined whether the largest U.S. poverty alleviation program for families, the Earned Income Tax Credit (EITC), has different associations with birthweight among women of different racial backgrounds.

DESIGN

We analyzed data from the 1985-2015 waves of the Panel Study of Income Dynamics, a longitudinal cohort study of U.S. families (N = 5,230 infants born to 3,672 women). The primary outcome was a continuous measure of birthweight, with secondary outcomes including low birthweight (LBW) and very LBW. Using rich sociodemographic data available in the Panel Study of Income Dynamics, we calculated the amount of EITC benefit for which women were eligible. We then examined the association of EITC benefit size with each outcome using multivariable regressions, examining the sample overall as well as racial subgroups (White, Black, or other).

RESULTS

We found that larger EITC benefits were not associated with increased infant birthweight for the overall sample (18.37 g per $1,000 of EITC; 95% confidence interval [CI], -2.62 to 33.36). There was an increase in birthweight for Black women (40.17 g; 95% CI: 7.32 to 73.02), but not for White women (-1.86 g; 95% CI, -33.33 to 29.60) or women of other races (-13.26 g; 95% CI, -75.90 to 49.38). There was no association between EITC benefit size and the probability of LBW or very LBW. Results were robust to alternative model specifications.

CONCLUSIONS

Social policies to address poverty may be effective at decreasing racial disparities in birthweight. Future work should examine potential mechanisms and the benefits of improved health outcomes for children later in life.

Short-term effects of the earned income tax credit on children's physical and mental health

PURPOSE

Child poverty is associated with worsened health, although there is limited research on whether U.S. poverty alleviation policies improve children's health. We examined the short-term effects of the earned income tax credit (EITC), among the largest U.S. poverty alleviation programs, on children's food insecurity, weight status, and mental health.

METHODS

Using data from the National Health Interview Survey (NHIS, 1998-2016), we examined the effects of the EITC using a quasi-experimental difference-in-differences methodology. About 90% of EITC-eligible individuals receive tax refunds in February-April, while NHIS interviews occur throughout the year. We took advantage of this timing of refund receipt to compare EITC-eligible families interviewed in February-April with those interviewed in the other months, "differencing out" seasonal trends in outcomes among noneligible families. Analyses involved multivariable linear regressions.

RESULTS

We found that food insecurity decreased in the months following EITC refund receipt, with no effects for weight status or mental health. Results were robust to alternative specifications.

CONCLUSION

While these findings suggest that food insecurity among vulnerable children was reduced immediately after EITC refund receipt, this also means that the EITC may contribute to cyclical food insecurity. Policies to enhance income stability may be one solution to address these findings.

The Health Effects Of Expanding The Earned Income Tax Credit: Results From New York City

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 controlled trial. Paycheck Plus tests the impact of a potential fourfold increase in the Earned Income Tax Credit for low-income Americans without dependent children. Starting in 2015, Paycheck Plus offered 5,968 study participants a credit of up to $2,000 at tax time (treatment) or the standard credit of about $500 (control). Health-related quality of life and other outcomes for a representative subset of these participants (n = 3,289) were compared to those of a control group thirty-two months after randomization. The intervention had a modest positive effect on employment and earnings, particularly among women. It had no effect on health-related quality of life for the overall sample, but women realized significant improvements.

Income dividends and subjective survival in a Cherokee Indian cohort: a quasi-experiment

Persons with high temporal discounting tend to value immediate gratification over future gains. Low self-reported lifespan (SRL)-an individual's assessment of a relatively short future lifespan-concentrates in low-income populations and may reflect high temporal discounting. We use casino-based cash dividends among the Eastern Band of Cherokee Indians (EBCI) as a quasi-experiment to test whether large income gains among EBCI members translate into increased SRL. We used SRL data for EBCI and White youth, aged 19 to 28, participating in two waves of the Life Time Trajectory of Youth (LTI-Y) survey from 2000 to 2010. We controlled for unobserved confounding across individuals, time, and region through a longitudinal design using a difference-in-difference analytic approach (N = 294). We conducted all analyses separately by gender and by quartile of socioeconomic status. Cash dividends correspond with a 15.23 year increase in SRL among EBCI men below the lowest socio-economic quartile at baseline relative to Whites (standard error = 5.39, p < .01). Results using other socio-economic cut-points support improved SRL among EBCI men (but not women). The large magnitude of this result among EBCI men indicates that a non-trivial cash dividend to a low-income population may confer long-term benefits on perceptions of future lifespan and, in turn, reduce temporal discounting.Abbreviations: EBCI: Eastern Band of Cherokee Indians; SES: Socioeconomic Status; LTI-Y: Life Trajectory Interview for Youth; GSMS: Great Smoky Mountains Study; SRL: Self-Reported Lifespan; SSS: Subjective Social Status.

Immigrant apprehensions and birth outcomes: Evidence from California birth records 2008-2015

While several studies find adverse birth outcomes among Latina mothers after discrete immigration enforcement events, it is unknown whether day-to-day enforcement activities precede adverse birth outcomes. This study examines birth outcomes among Latinas following local immigrant apprehensions-48-h holds on suspected undocumented immigrants by local law enforcement-over an 8-year period. County-level apprehensions, scaled to 1000 of the population, were averaged across the third trimester. We analyzed the association between county-level apprehensions and low birth weight (LBW) and preterm birth (PTB) between 2008 and 2015 in California using spline logistic regression models with knots at the quartiles of apprehensions and included covariates, county fixed-effects, and a time propensity variable to account for trend and seasonality in LBW and PTB. We performed these regressions for non-Hispanic White, all Latina, and foreign-born (FB) Latina mothers. There were no significant associations between apprehensions and LBW. For all Latina women, there were no differences in PTB between zero apprehensions and levels that were below the median. Latina mothers exposed to moderately high apprehensions had lower odds for PTB compared to zero apprehensions. At the highest levels of apprehensions, however, Latina women showed significantly elevated odds of PTB (at 0.71 apprehensions: OR = 1.06, 95% CI 1.01-1.12). PTB responded differentially to localized enforcement threats. At lower and moderate levels, Latino communities may have mobilized in ways that reduced the risk for PTB. Risks emerged at the highest levels of enforcement, underlying the intense fear and anxiety in hyper-surveilled areas.

The earned income tax credit and infant health revisited

Hoynes, Miller, and Simon (2015), henceforth HMS, report that the national expansion of the Earned Income Tax Credit (EITC) is associated with decreases in low birth weight. We question their findings. HMS's difference-in-differences estimates are unidentified in some comparisons, while failed placebo tests undermine others. Their effects lack a plausible mechanism as the association between the EITC and prenatal smoking also fails placebo tests. We contend that the waning of the crack epidemic is a possible confound, but we show that any number of policies directed at poor women also eliminate the effect of the EITC when aggregated to the national level. Identifying small, causal effects of a national policy at a single point in time is exceedingly challenging.

The Impact of the Revised WIC Food Package on Maternal Nutrition During Pregnancy and Postpartum

The Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) provides nutritional support for pregnant and postpartum women and young children. The typical food package provided to recipient families was revised in October 2009 to include more whole grains, fruits, vegetables, and low-fat milk. Little is known about whether these revisions improved nutrition among women during this critical period of the life course. We conducted a quasiexperimental difference-in-differences analysis, comparing WIC recipients ("treatment" group) before and after the WIC policy change, while accounting for temporal trends among nonrecipients ("control" group). We examined nutritional outcomes among a cohort of 1,454 women recruited during pregnancy in 2006-2011 in Memphis and surrounding Shelby County, Tennessee. We found improvements in several measures of dietary quality and nutrient intake during pregnancy, although these did not persist into the postpartum period. Results were robust to numerous sensitivity analyses. At a time when federal WIC funding is threatened, this study provides some of the first evidence of the benefits of recent WIC revisions among low-income women.

Effects of State-Level Earned Income Tax Credit Laws on Birth Outcomes by Race and Ethnicity

Purpose: Health disparities persist in birth outcomes by mother's income, education, and race in the United States. Disadvantaged mothers may experience benefit from supplements to family income, such as the earned income tax credit (EITC). We examined the effects of state-level EITCs on birth outcomes among women with a high school education or less, stratified by race and ethnicity.

Methods: A quasi-experimental multistate and multiyear difference-in-differences design is used to assess effects of the presence and generosity of 23 state-level EITC laws on birth outcomes from 1994 to 2013. The methods utilized the U.S. National Vital Statistics System birth data for the outcomes: birth weight, probability of low birth weight (LBW; <2500 g), and gestation weeks.

Results: Across all subgroups, any level of state EITC is associated with better birth outcomes with the largest effects seen among states with more generous EITCs. Black mothers experience larger percentage point reductions in the probability of LBW and increases in gestation duration. Among mothers with a high school education or less, results translate into 3760 fewer LBW babies with black mothers and 8364 fewer LBW babies with white mothers per year at the most generous state EITC level (i.e., 10% or more of federal and refundable). Hispanic and non-Hispanic mothers display relatively similar effects.

Conclusions: The EITC at the federal and state level is an effective policy tool to reduce poverty and improve birth outcomes across racial and ethnic subgroups. Given the historically higher risk among black mothers, state-level EITC expansions offer one policy option to address this persistent health disparity.

Estimating the Short-Term Effects of the Earned Income Tax Credit on Child Health

The Earned Income Tax Credit (EITC) is the largest US poverty-alleviation program, yet few studies examine its effects on the health of recipients' children. We employed quasiexperimental techniques to test the hypothesis that EITC refund receipt is associated with short-term improvements in child health. The data set included children in families surveyed in the Third National Health and Nutrition Examination Survey (n = 7,444). We employed a difference-in-differences approach, exploiting the seasonal nature of EITC refund receipt. We compared children of EITC-eligible families interviewed immediately after refund receipt (February to April) with those interviewed during other months (May to January), differencing out seasonal variation among non-EITC-eligible families. We examined outcomes that were likely to be affected immediately after refund receipt, including general health, nutrition, metabolic and inflammatory biomarkers, and test scores. There were improvements in physician-reported overall health after refund receipt but no changes in infection, serum metabolic or inflammatory markers, or test scores, and there were contradictory findings for food insufficiency. In summary, EITC refunds are not strongly associated with most short-term health outcomes among recipients' children, although numerous previous studies have demonstrated impacts on longer-term outcomes. This highlights the importance of examining the effects of public policies on beneficiaries and their children using varying study designs.

Do cash transfer programmes yield better health in the first year of life? A systematic review linking low-income/middle-income and high-income contexts

INTRODUCTION

Decades of research unequivocally demonstrates that no matter the society, socioeconomic resources are perhaps the most fundamental determinants of health throughout the life course, including during its very earliest stages. As a result, societies have implemented 'cash transfer' programmes, whichprovide income supplementation to reduce socioeconomic disadvantage among the poorest families with young children. Despite this being a common approach of societies around the world, research on effects of these programmes in low-income/middle-income countries, and those in high-income countries has been conducted as if they are entirely distinct phenomena. In this paper, we systematically review the international literature on the association between cash transfer programmes and health outcomes during the first year of life.

METHODS

We conducted a systematic review based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol. Using a variety of relevant keywords, we searched MEDLINE, EMBASE, CINAHL, Cochrane Reviews, EconLit and Social Sciences Citations Index.

RESULTS

Our review yielded 14 relevant studies. These studies suggested cash transfer programmes that were not attached to conditions tended to yield positive effects on outcomes such as birth weight and infant mortality. Programmes that were conditional on use of health services also carried positive effects, while those that carried labour-force participation conditionalities tended to yield no positive effects.

DISCUSSION

Given several dynamics involved in determining whether children are healthy or not, which are common worldwide, viewing the literature from a global perspective produces novel insights regarding the tendency of policies and programmes to reduce or, to exacerbate, the effects of socioeconomic disadvantage on child health.

Cohort Variation in Selection During Pregnancy and Risk of Selected Birth Defects Among Males

BACKGROUND

The literature theorizes, but does not test, that variation over time in selective loss in utero affects the observed count of live-born birth defects cases. We test the hypothesis that the risk of birth defects among live-born males varies inversely with the strength of selection against males in utero.

METHODS

We identified a subset of six birth defect phenotypes among males from the California Birth Defects Monitoring Program, an active surveillance system for over 490,000 male singletons born in eight California counties from 1986 to 2004. We assigned each birth defect case infant to a monthly conception cohort at risk of selection in utero. We used the monthly sex ratio at birth (M:F), derived from each conception cohort, as the indicator of selection against males. We analyzed the odds ratio of birth defects with both individual-level logistic regression and aggregate time-series methods.

RESULTS

Consistent with selection in utero, male infants from conception cohorts with low outlying sex ratios (i.e., stronger selectivity) exhibit fewer than expected birth defects (adjusted odds ratio [OR] = 0.86; 95% confidence interval [CI] = 0.76, 0.98). Aggregate time-series tests also yield similar findings (OR = 0.81; 95% CI = 0.71, 0.90).

CONCLUSIONS

Our findings among males indicate that variation in the strength of selectivity in utero accounts for a portion of observed cohort differences in morbidity due to birth defects. These findings suggest that "revealed prevalence" of morbidity across birth cohorts varies, at least in part, from selective loss in utero. See video abstract at, http://links.lww.com/EDE/B209.

Family Economic Security Policies and Child and Family Health

In this review, we examine the effects of family economic security policies (i.e., minimum wage, earned income tax credit, unemployment insurance, Temporary Assistance to Needy Families) on child and family health outcomes, summarize policy generosity across states in the USA, and discuss directions and possibilities for future research. This manuscript is an update to a review article that was published in 2014. Millions of Americans are affected by family economic security policies each year, many of whom are the most vulnerable in society. There is increasing evidence that these policies impact health outcomes and behaviors of adults and children. Further, research indicates that, overall, policies which are more restrictive are associated with poorer health behaviors and outcomes; however, the strength of the evidence differs across each of the four policies. There is significant diversity in state-level policies, and it is plausible that these policy variations are contributing to health disparities across and within states. Despite increasing evidence of the relationship between economic policies and health, there continues to be limited attention to this issue. State policy variations offer a valuable opportunity for scientists to conduct natural experiments and contribute to evidence linking social policy effects to family and child well-being. The mounting evidence will help to guide future research and policy making for evolving toward a more nurturing society for family and child health and well-being.

Improving population health by reducing poverty: New York's Earned Income Tax Credit

Despite the established relationship between adverse health outcomes and low socioeconomic status, researchers rarely test the link between health improvements and poverty-alleviating economic policies. New research, however, links individual-level health improvements to the Earned Income Tax Credit (EITC), a broad-based income support policy. We build on these findings by examining whether the EITC has ecological, neighborhood-level health effects. We use a difference-in-difference analysis to measure child health outcomes in 90 low- and middle- income neighborhoods before and after the expansion of New York State and New York City's EITC policy between 1997-2010. Our study takes advantage of the relatively exogenous source of income variation supplied by the EITC-legislative changes to EITC policy parameters. This feature minimizes the endogeneity problem in studying the relationship between income and health. Our estimates link a 15-percentage-point increase in EITC benefit rates to a 0.45 percentage-point reduction in the low birthweight rate. We do not observe any measurable link between EITC benefits and prenatal health or asthma-related pediatric hospitalization. The magnitude of the EITC's impact on low birthweight rates suggests ecological effects, and an additional channel through which anti-poverty measures can serve as public health interventions.

The EARN-Health Trial: protocol for a randomised controlled trial to identify health effects of a financial savings programme among low-income US adults

INTRODUCTION

A theory within the social epidemiology field is that financial stress related to having inadequate financial savings may contribute to psychological stress, poor mental health and poor health-related behaviours among low-income US adults. Our objective is to test whether an intervention that encourages financial savings among low-income US adults improves health behaviours and mental health.

METHODS AND ANALYSIS

A parallel group two-arm controlled superiority trial will be performed in which 700 participants will be randomised to the intervention or a wait list. The intervention arm will be provided an online Individual Development Account (IDA) for 6 months, during which participants receive a $5 incentive (£3.2, €4.5) for every month they save $20 in their account (£12.8, €18), and an additional $5 if they save $20 for two consecutive months. Both groups will be provided links to standard online financial counselling materials. Online surveys in months 0 (prior to randomisation), 6 and 12 (6 months postintervention) will assess self-reported health behaviours and mental health among participants in both arms. The surveys items were tested previously in the US Centers for Disease Control and Prevention national health interviews and related health studies, including self-reported overall health, health-related quality of life, alcohol and tobacco use, depression symptoms, financial stress, optimism and locus of control, and spending and savings behaviours. Trial data will be analysed on an intent-to-treat basis.

ETHICS AND DISSEMINATION

This protocol was approved by the Institutional Review Board of Stanford University (Protocol ID: 30641). The findings of the trial will be disseminated through peer-reviewed publication.

TRIAL REGISTRATION NUMBER

Identifier NCT02185612; Pre-results.

Poverty, Pregnancy, and Birth Outcomes: A Study of the Earned Income Tax Credit

BACKGROUND

Economic interventions are increasingly recognised as a mechanism to address perinatal health outcomes among disadvantaged groups. In the US, the earned income tax credit (EITC) is the largest poverty alleviation programme. Little is known about its effects on perinatal health among recipients and their children. We exploit quasi-random variation in the size of EITC payments to examine the effects of income on perinatal health.

METHODS

The study sample includes women surveyed in the 1979 National Longitudinal Survey of Youth (n = 2985) and their children born during 1986-2000 (n = 4683). Outcome variables include utilisation of prenatal and postnatal care, use of alcohol and tobacco during pregnancy, term birth, birthweight, and breast-feeding status. We first examine the health effects of both household income and EITC payment size using multivariable linear regressions. We then employ instrumental variables analysis to estimate the causal effect of income on perinatal health, using EITC payment size as an instrument for household income.

RESULTS

We find that EITC payment size is associated with better levels of several indicators of perinatal health. Instrumental variables analysis, however, does not reveal a causal association between household income and these health measures.

CONCLUSIONS

Our findings suggest that associations between income and perinatal health may be confounded by unobserved characteristics, but that EITC income improves perinatal health. Future studies should continue to explore the impacts of economic interventions on perinatal health outcomes, and investigate how different forms of income transfers may have different impacts.

Systematic assessment of the correlations of household income with infectious, biochemical, physiological, and environmental factors in the United States, 1999-2006

A fuller understanding of the social epidemiology of disease requires an extended description of the relationships between social factors and health indicators in a systematic manner. In the present study, we investigated the correlations between income and 330 indicators of physiological, biochemical, and environmental health in participants in the US National Health and Nutrition Examination Survey (NHANES) (1999-2006). We combined data from 3 survey waves (n = 249-23,649 for various indicators) to search for linear and nonlinear (quadratic) correlates of income, and we validated significant (P < 0.00015) correlations in an independent testing data set (n = 255-7,855). We validated 66 out of 330 factors, including infectious (e.g., hepatitis A), biochemical (e.g., carotenoids, high-density lipoprotein cholesterol), physiological (e.g., upper leg length), and environmental (e.g., lead, cotinine) measures. We found only a modest amount of association modification by age, race/ethnicity, and gender, and there was no association modification for blacks. The present study is descriptive, not causal. We have shown in our systematic investigation the crucial place income has in relation to health risk factors. Future research can use these correlations to better inform theory and studies of pathways to disease, as well as utilize these findings to understand when confounding by income is most likely to introduce bias.

The short-term impacts of Earned Income Tax Credit disbursement on health

BACKGROUND

There are conflicting findings regarding long- and short-term effects of income on health. Whereas higher average income is associated with better health, there is evidence that health behaviours worsen in the short-term following income receipt.Prior studies revealing such negative short-term effects of income receipt focus on specific subpopulations and examine a limited set of health outcomes.

METHODS

The United States Earned Income Tax Credit (EITC) is an income supplement tied to work, and is the largest poverty reduction programme in the USA. We utilize the fact that EITC recipients typically receive large cash transfers in the months of February,March and April, in order to examine associated changes in health outcomes that can fluctuate on a monthly basis. We examine associations with 30 outcomes in the categories of diet, food security, health behaviours, cardiovascular biomarkers, metabolic biomarkers and infection and immunity among 6925 individuals from the U.S. National Health and Nutrition Survey. Our research design approximates a natural experiment,since whether individuals were sampled during treatment or non-treatment months is independent of social, demographic and health characteristics that do not vary with time.

RESULTS

There are both beneficial and detrimental short-term impacts of income receipt.Although there are detrimental impacts on metabolic factors among women, most other impacts are beneficial, including those for food security, smoking and trying to lose weight.

CONCLUSIONS

The short-term impacts of EITC income receipt are not universally health promoting, but on balance there are more health benefits than detriments.