PHIRN: Population Health Improvement Research Network

Executive Summary

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The growing incidence of chronic diseases has, in part, contributed to increased political and societal pressures to ensure public funds are allocated to the provision of services with known effectiveness. In other words, there is a call to action to ensure the programs and services implemented across Canada in population and public health are effective, and that they will result in improved health outcomes for Canadians. There is some evidence to suggest that current practices related to the social determinants of health may not adequately address inequities in health, and may even increase disparities. The purpose of this paper is to identify and summarize research findings on the effectiveness of population based interventions on the social determinants of health, which was identified as a priority topic area in the annual report of the Ontario Chief Medical Officer of Health to the legislative assembly.

The registry was searched for reviews on the social determinants of health in May 2011. A standardized quality assessment tool was used to assess the methodological quality of each identified review by two independent reviewers. All search results were limited to reviews rated as being of strong methodological quality.  Extracted data included age of participants studied in the review, research design, methodological quality rating, details of the interventions evaluated, details describing which outcomes where evaluated as well as how they were measured, and outcome data.

The social determinants of health search identified 31 high quality reviews, 17 of which reported on outcomes relevant to this review. Outcomes reported on most frequently included: health care utilization (N=10), mental health (N=9), physical health (N=6), and behavioural problems (N=6). The participants studied ranged from the general population with low literacy to adults with mental disorders and homeless persons, as well as children, adults, and health professionals. The interventions evaluated can be classified into the following categories: improving health, supportive housing, home visiting/social support programs, improving literacy, after-school programs, gang/violence prevention, monetary incentives, reducing disparities, and the prevention of sexually transmitted infections.

Nursing home visits in the prenatal period were associated with increased awareness of available community services, greater attendance at childbirth education classes, and speaking more frequently with service providers. Furthermore, social support interventions for at-risk pregnant women resulted in significantly fewer hospital admissions during pregnancy.

In contrast, health interventions among those with low literacy had no impact on health-related outcomes and mammography screening rates in the long term, even though positive effects for screening were observed at six months. Assertive community treatment was effective in reducing homelessness and hospitalization outcomes. Results from one study illustrate that case management and subsidized housing combined were associated with reduced inpatient and outpatient health care utilization. However, no impact was observed for substance use, psychiatric symptoms, or outpatient mental health care utilization. Finally, strategies to prevent HIV and other sexually transmitted infections among female sex workers in resource-poor settings were effective in increasing use of preventive services.
The evidence on the impact of interventions targeting the social determinants of heath on mental health outcomes is mixed. For example, some evidence suggests that among homeless persons with severe mental illness, assertive community treatment is associated with a statistically significant reduction in homelessness and improved psychiatric symptom severity. Additional evidence also indicates that intensive case management with access to drop-in centre services, temporary housing, and rehabilitation services is effective in improving psychiatric symptoms and perceived quality of life in comparison to usual care. Amongst those with substance use disorder, case management versus standard care was not found to have a statistically significant effect on reported psychiatric symptoms. However among those with intellectual disability and concurrent physical, mental or behavioural problems, and in homeless populations with concurrent mental illness and substance use disorders, assertive community treatment was not associated with improved psychological and psychiatric function or reduced substance use, compared to standard community treatment. Those receiving housing support were found to spend less time hospitalized, and reported a greater number of days housed, but did not experience fewer psychiatric symptoms or reduced substance use.  
With respect to behavioural problems the evidence indicates that health care services for populations with intellectual disabilities were not effective in improving behavioural issues such as adaptive behaviours. Similarly the provision of financial resources to families with low SES did not lead to significant improvements in problem behaviour among children, and delinquent behaviour among adolescents.

Evidence illustrates that a universal school-based program to prevent violent and aggressive behaviour resulted in a 15% reduction in violent behaviour school wide, with the greatest impact observed in pre-kindergarten, kindergarten, and high school students. Intervention components included the provision of educational materials; cognitive therapy; social skills training; environmental changes to the whole school as well as the classroom; peer mediation and behaviour modification. Specific topics covered in the intervention included: general violence; disruptive or anti-social behaviour; bullying; gang activity; and dating violence. The greatest impact was observed when the intervention was implemented by peers/students.  The intervention was equally effective in schools located in low SES, high-crime environments as in all environments.
Among teenage mothers with low SES, a postnatal home visiting intervention resulted in statistically significant greater weight and height gain in infants, as well as better Denver development scores at four months, compared to infants of mothers receiving standard care. Among very low-weight infants, telephone support and home visiting in combination resulted in statistically significantly fewer re-hospitalizations, acute care visits, lower incidence of failure to thrive, less child abuse, and less foster placement. Among high risk mothers with low SES receiving pre- and post-natal home visits, reductions in bladder infections and number of cigarettes smoked daily, as well as improved nutrition, were observed. Provision of financial resources to families with low SES generally did not result in decreased rates of child maltreatment, physical/emotional/sexual abuse, visits to the emergency department, and injuries reported in the previous year.
This review of the literature represents many systematic reviews and meta-analyses, primary studies and thousands of people. To some extent, the results illustrate that many population health and public health programs are associated with benefits to various populations, particularly related to outcomes such as healthy eating, physical activity, mental health symptoms, more stable housing, and, in some populations, substance use. However, there remains cause for concern given some of the evidence suggests that various interventions may in fact widen health disparities. As a result, higher SES and white populations benefit more from certain interventions than those from low SES and non-white populations. Much more research is needed to fully explore if and how interventions impact heath outcomes in different sub populations.  However, the evidence presented here provides some direction for moving forward with practice, draws attention to some areas that require ongoing evaluation, and identifies some practices that may not be producing the expected impact and therefore should be examined critically in terms of future investment. While a great deal has been accomplished in population and public health programs there is still much work to be done!

Last Updated ( Wednesday, 18 April 2012 14:53 )