Understanding income-related differences in distribution of child growth, behaviour and development using a cross-sectional sample of a clinical cohort study

OBJECTIVES

Children from low-income households are at an increased risk of social, behavioural and physical health problems. Prior studies have generally relied on dichotomous outcome measures. However, inequities may exist along the range of outcome distribution. Our objective was to examine differences in distribution of three child health outcomes by income categories (high vs low): body mass index (BMI), behaviour difficulties and development.

DESIGN AND SETTING

This was a cross-sectional study using data from a primary care-based research network with sites in three Canadian cities, and 15 practices enrolling participants.

PARTICIPANTS, INDEPENDENT VARIABLE AND OUTCOMES

The independent variable was annual household income, dichotomised at the median income for Toronto (<$C80 000 or ≥$C80 000). Outcomes were: (1) growth (BMI z-score (zBMI) at 5 years, 1628 participants); (2) behaviour (Strengths and Difficulties Questionnaire (SDQ) at 3-5 years, 649 participants); (3) development (Infant Toddler Checklist (ITC) at 18 months, 1405 participants). We used distributional decomposition to compare distributions of these outcomes for each income group, and then to construct a counterfactual distribution that describes the hypothetical distribution of the low-income group with the predictor profile of the higher-income group.

RESULTS

We included data from 1628 (zBMI), 649 (SDQ) and 1405 (ITC) children. Children with lower family income had a higher risk distribution for all outcomes. For all outcomes, thecounterfactual distribution, which represented the distribution of children with lower-income who were assigned the predictor profile of the higher-income group, was more favourable than their observed distributions.

CONCLUSION

Comparing the distributions of child health outcomes and understanding different risk profiles for children from higher-income and lower-income groups can offer a deeper understanding of inequities in child health outcomes. These methods may offer an approach that can be implemented in larger datasets to inform future interventions.

Is social assistance boosting the health of the poor? Results from Ontario and three countries

INTERVENTION

Social assistance programs supplement incomes of the most income-insecure. Because income is a fundamental source of health, income supplementation is expected to result in a boost to health status. As Canada finds itself in the midst of heated debate regarding the structuring (and restructuring) of social assistance programs, there is little evidence available for policymakers about the effectiveness of current social assistance programs in improving the health of the income-insecure.

RESEARCH QUESTION

In this paper, we evaluate the health effects of social assistance programs in Ontario, Canada-wide and in peer programs from the United States and the United Kingdom.

METHODS

We used nationally representative household panel surveys (e.g., Canadian Survey of Labour and Income Dynamics) which follow individuals over time. Using fixed effects modelling, which controls for time-invariant characteristics of individuals, and further controlling for key time-varying characteristics, we modelled change in health status associated with change in receipt of social assistance in these societies. Health status was measured using self-rated health (fair/poor versus good/very good/excellent).

RESULTS

Our results suggest that the health of social assistance recipients was worse (Ontario, Canada, UK) or no different (US) than the health of non-recipients. For example, in Canada, receipt of social assistance was associated with 52.5% higher odds of reporting fair or poor health.

CONCLUSION

Social assistance programs in Canada and peer countries are currently inadequate for improving the health of the income-insecure. This is likely due to insufficient benefits, exposure to precarious job conditions, or selection factors.

The impact of social assistance programs on population health: a systematic review of research in high-income countries

Background

Socioeconomic disadvantage is a fundamental cause of morbidity and mortality. One of the most important ways that governments buffer the adverse consequences of socioeconomic disadvantage is through the provision of social assistance. We conducted a systematic review of research examining the health impact of social assistance programs in high-income countries.

Methods

We systematically searched Embase, Medline, ProQuest, Scopus, and Web of Science from inception to December 2017 for peer-reviewed studies published in English-language journals. We identified empirical patterns through a qualitative synthesis of the evidence. We also evaluated the empirical rigour of the selected literature.

Results

Seventeen studies met our inclusion criteria. Thirteen descriptive studies rated as weak (n = 7), moderate (n = 4), and strong (n = 2) found that social assistance is associated with adverse health outcomes and that social assistance recipients exhibit worse health outcomes relative to non-recipients. Four experimental and quasi-experimental studies, all rated as strong (n = 4), found that efforts to limit the receipt of social assistance or reduce its generosity (also known as welfare reform) were associated with adverse health trends.

Conclusions

Evidence from the existing literature suggests that social assistance programs in high-income countries are failing to maintain the health of socioeconomically disadvantaged populations. These findings may in part reflect the influence of residual confounding due to unobserved characteristics that distinguish recipients from non-recipients. They may also indicate that the scope and generosity of existing programs are insufficient to offset the negative health consequences of severe socioeconomic disadvantage.

Electronic supplementary material

The online version of this article (10.1186/s12889-018-6337-1) contains supplementary material, which is available to authorized users.

Government social assistance programmes are failing to protect the health of low-income populations: evidence from the USA and Canada (2003–2014)

Background

Social policies that improve the availability and distribution of key socioeconomic resources such as income, wealth and employment are believed to present the most promising avenue for reducing health inequalities. The present study aims to estimate the effect of social assistance recipiency on the health of low-income earners in the USA and Canada.

Methods

Drawing on nationally representative survey data (National Health Interview Survey and the Canadian Community Health Survey), we employed propensity score matching to match recipients of social assistance to comparable sets of non-recipient ‘controls’. Using a variety of matching algorithms, we estimated the treatment effect of social assistance recipiency on self-rated health, chronic conditions, hypertension, obesity, smoking, binge drinking and physical inactivity.

Results

After accounting for underlying differences in the demographic and socioeconomic characteristics of recipients and non-recipients, we found that social assistance recipiency was associated with worse health status or, at best, the absence of a clear health advantage. This finding was consistent across several different matching strategies and a diverse range of health outcomes.

Conclusions

From a public health perspective, our findings suggest that interventions are warranted to improve the scope and generosity of existing social assistance programmes. This may include reversing welfare reforms implemented over the past several decades, increasing benefit levels and untethering benefit recipiency from stringent work conditionalities.

Illustrating a "consequential" shift in the study of health inequalities: a decomposition of racial differences in the distribution of body mass

PURPOSE

We present a conceptual introduction to "distributional inequalities"-differences in distributions of risk factors or other outcomes between social groups-as a consequential shift for research on health inequalities. We also review a companion analytical methodology, "distributional decomposition", which can assess the population characteristics that explain distributional inequalities.

METHODS

Using the 1999-2012 U.S. National Health and Nutrition Examination Survey, we apply statistical decomposition to (a) document gender-specific, black-white inequalities in the distribution of body mass index (BMI) and, (b) assess the extent to which demographic (age), socioeconomic (family income, education), and behavioral predictors (caloric intake, physical activity, smoking, alcohol consumption) are associated with broader distributional inequalities in BMI.

RESULTS

Black people demonstrate favorable or no different caloric intake, smoking, or alcohol consumption than whites, but worse levels of physical activity. Racial inequalities extend beyond the obesity threshold to the broader BMI distribution. Demographic, socioeconomic, and behavioral characteristics jointly explain more of the distributional inequality among men than women.

CONCLUSIONS

Black-white distributional inequalities are present both among men and women, although the mechanisms may differ by gender. The notion of "distributional inequalities" offers an additional purchase for studying social inequalities in health.

Income inequality and self-rated health status: evidence from the European Community Household Panel

We examine the effect of income inequality on individuals' self-rated health status in a pooled sample of 11 countries, using longitudinal data from the European Community Household Panel survey. Taking advantage of the longitudinal and cross-national nature of our data, and carefully modeling the self-reported health information, we avoid several of the pitfalls suffered by earlier studies on this topic. We calculate income inequality indices measured at two standard levels of geography (NUTS-0 and NUTS-1) and find consistent evidence that income inequality is negatively related to self-rated health status in the European Union for both men and women, particularly when measured at national level. However, despite its statistical significance, the magnitude of the impact of inequality on health is very small.