When do we know enough to act on the social determinants of health?

1. Center for Public Health Initiatives University of Pennsylvania Philadelphia February 12, 2013 Paula Braveman, MD, MPH Professor of Family & Community Medicine Director, Center on Social Disparities in Health University of California, San Francisco When do we know enough to act on the social determinants of health?

2. Evidence-based medicine • Long overdue response to basing Rx on opinion • Hierarchy of evidence to infer causation/effectiveness: • Gold standard: RCTs • Cohort studies • Case-control • Other designs considered weak

3. Limitations of evidence-based medicine (EBM) approach in general • Randomization not always feasible or ethical • Quality of RCTs sometimes not considered • A well-designed and conducted observational study vs a poorly designed/executed RCT • Lack of generalizability • Often little information about context

4. UPSTREAM: At or near the source of a cause of ill health DOWNSTREAM: Near where health effects are seen

5. The social determinants of health: considering the causes of the causes Economic & Social Opportunities & Resources (e.g. Income, education, racial inequality) HEALTH Living & Working Conditions in Homes & Communities Medical Care Personal Behavior Robert Wood Johnson Foundation Commission to Build a Healthier America www.commissiononhealth.org

6. How could income affect health? A body of literature supports, for example: • Income can shape options for: • Housing • Neighborhood conditions • Nutrition • Physical activity • Services (e.g., childcare, transportation, repairs, medical care…) • Alleviating stress • Parents’ income shapes • the next generation’s: • Education • Work • Income

7. Education can shape health behaviors by determining knowledge and skills • Health knowledge • Literacy • Problem-solving • Coping skills • Diet • Exercise • Smoking • Health/disease management Educational attainment

8. Other plausible pathways from education to health, e.g., via work & income • Neighborhood environment (including schools) • Diet & exercise options • Stress Income HEALTH Educational attainment Work-related resources • Health insurance • Sick leave • Wellness programs • Stress Work Working conditions • Control / demand imbalance • Stress

9. Income shapes neighborhood options. How could a neighborhood affect health? • Safe places to exercise • Access to healthy food • Ads for harmful substances • Social networks & support • Norms, role models, peer pressure • Fear, anxiety, despair, stress • Quality of schools

10. The stress-health link: Biologically plausible? • Advances in neuro-science & psycho-neuro-immunology help elucidate how social factors like income, education, & racial discrimination can “get into the body” • HPA axis, sympathetic nervous system, and immune/inflammatory mechanisms have been demonstrated as responses to stress • Relative importance of specific mediators/markers (e.g., cortisol, C-reactive protein, cytokines, telomerase) not established • Chronic stress is a plausible and likely major contributor to both socioeconomic and racial/ethnic inequalities in health

11. Psychosocial pathways from education to health • Social & economic resources • Perceived status • Stress Social standing HEALTH • Social & economic resources • Norms • Social support • Stress Educational attainment Social networks Control beliefs (powerlessness, sense/locus of control, fatalism, mastery) • Coping • Response to stressors

12. How could education affect health? Educational attainment HEALTH • Diet • Exercise • Smoking • Health/disease management Health knowledge, literacy, coping & problem solving • Exposure to hazards • Control/demand imbalance • Stress Working conditions HEALTH Educational attainment • Health insurance • Sick leave • Wellness programs • Stress Work-related resources Work Income • Housing • Neighborhood environment • Diet & exercise options • Stress • Coping & problem solving • Response to stressors • Health-related behaviors Control beliefs HEALTH Educational attainment • Social & economic resources • Perceived status • Stress Social standing HEALTH • Social & economic resources • Social Support • Norms for healthy behavior • Stress Social networks

13. What produces and reproduces health disparities across the life course and across generations? SOCIETY INDIVIDUAL Social position by race & class 2.Differential exposure Social Context 1. Social stratification 3. Differential vulnerability Specific exposure 4. Differential consequences Disease Policy Context Social consequences of ill health 5. Further social stratification Adapted from Finn Diderichsen, U. Copenhagen

14. Long, multiple, complex pathways • Pathways from social factors to health are often long and complex • Interactions with characteristics of people and settings, at each step in causal chain • Health effects of social factors may not manifest for decades or generations • Randomization likely to be unfeasible or unethical • Does this mean we will never have good evidence?

15. Should we give up? • Techniques to reduce likelihood of confounding and bias in observational research • Multivariate analysis, stratification, instrumental variables, propensity score matching… • Critical thinking: rigorously looking for potential bias due to unmeasured differences • Connect the dots – knowledge linkage – chains of inference

16. Connect the dots • We may lack evidence directly linking social factor A  health outcome C • But we may have evidence linking A  B (e.g., educational attainment) and B  C • May be from another discipline/field • Build knowledge of SDOH by linking knowledge of pathway segments, acknowledging limitations • Done all the time in medicine --targeting risk factors (e.g., cholesterol, blood pressure)

17. Evidence-based medicine’s hierarchy of evidence is peculiar to medicine • Civil law: preponderance of evidence • Criminal law: beyond a reasonable doubt • Similar approaches in commerce and economic policy • Has the Air Force conducted RCTs to determine whether they should supply parachutes to paratroopers? • Best available knowledge

18. Is lack of evidence always the problem? • Obstacles to translating the knowledge we have into interventions • Often we have knowledge of pathways and mechanisms but don’t know how to translate it into effective, efficient interventions • Political obstacles • Often the obstacle is lack of political will

19. When do we know enough to recommend action on the SDOH? • Need a broader conception of what counts as evidence • Build on and broaden – don’t discard – EBM principles • Require rigor in all study designs • Consider range of sources of evidence, including qualitative • Connect the dots from A  B and B  C • Policy should be informed by best available knowledge & critical thinking; consider long-term consequences • Need bold experiments testing the most promising directions, based on current knowledge • Weigh costs of acting vs. costs of status quo