An association between higher educational attainment and better health status has been repeatedly reported in the literature. Similarly, thousands of studies have found a relationship between higher income and better health. However, whether these repeated observations amount to causality remains a challenge, not least because of the practical limitations of randomizing people to receive different amounts of money or schooling. In this essay, we review the potential causal mechanisms linking schooling and income to health, and discuss the twin challenges to causal inference in observational studies, in other words, reverse causation and omitted variable bias. We provide a survey of the empirical attempts to identify the causal effects of schooling and income on health, including natural experiments. There is evidence to suggest that schooling is causally related to improvements in health outcomes. Evidence also suggests that raising the incomes of the poor leads to improvement in their health outcomes. Much remains unknown beyond these crude findings, however; for example, what type of education matters for health, or whether there is a difference between the health impacts of temporary income shocks versus changes in long-term income.

ObjectiveThe authors evaluated the use of conditional cash transfers as an HIV and sexually transmitted infection prevention strategy to incentivise safe sex.DesignAn unblinded, individually randomised and controlled trial.Setting10 villages within the Kilombero/Ulanga districts of the Ifakara Health and Demographic Surveillance System in rural south-west Tanzania.ParticipantsThe authors enrolled 2399 participants, aged 18–30 years, including adult spouses.InterventionsParticipants were randomly assigned to either a control arm (n=1124) or one of two intervention arms: low-value conditional cash transfer (eligible for $10 per testing round, n=660) and high-value conditional cash transfer (eligible for $20 per testing round, n=615). The authors tested participants every 4 months over a 12-month period for the presence of common sexually transmitted infections. In the intervention arms, conditional cash transfer payments were tied to negative sexually transmitted infection test results. Anyone testing positive for a sexually transmitted infection was offered free treatment, and all received counselling.Main outcome measuresThe primary study end point was combined prevalence of the four sexually transmitted infections, which were tested and reported to subjects every 4 months: Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis and Mycoplasma genitalium. The authors also tested for HIV, herpes simplex virus 2 and syphilis at baseline and month 12.ResultsAt the end of the 12-month period, for the combined prevalence of any of the four sexually transmitted infections, which were tested and reported every 4 months (C trachomatis, N gonorrhoeae, T vaginalis and M genitalium), unadjusted RR for the high-value conditional cash transfer arm compared to controls was 0.80 (95% CI 0.54 to 1.06) and the adjusted RR was 0.73 (95% CI 0.47 to 0.99). Unadjusted RR for the high-value conditional cash transfer arm compared to the low-value conditional cash transfer arm was 0.76 (95% CI 0.49 to 1.03) and the adjusted RR was 0.69 (95% CI 0.45 to 0.92). No harm was reported.ConclusionsConditional cash transfers used to incentivise safer sexual practices are a potentially promising new tool in HIV and sexually transmitted infections prevention. Additional larger study would be useful to clarify the effect size, to calibrate the size of the incentive and to determine whether the intervention can be delivered cost effectively.Trial registration numberNCT00922038 ClinicalTrials.gov.

BackgroundTo determine socioeconomic status (SES) gradients in the different dimensions of health among elderly Costa Ricans. Hypothesis: SES disparities in adult health are minimal in Costa Rican society.MethodsData from the Costa Rican Study on Longevity and Healthy Aging study: 8,000 elderly Costa Ricans to determine mortality in the period 2000–2007 and a subsample of 3,000 to determine prevalence of several health conditions and biomarkers from anthropometry and blood and urine specimens.ResultsThe ultimate health indicator, mortality, as well as the metabolic syndrome, reveals that better educated and wealthier individuals are worse off. In contrast, quality of life–related measures such as functional and cognitive disabilities, physical frailty, and depression all clearly worsen with lower SES. Overall self-reported health (SRH) also shows a strong positive SES gradient. Traditional cardiovascular risk factors such as diabetes and cholesterol are not significantly related to SES, but hypertension and obesity are worse among high-SES individuals. Reflecting mixed SES gradients in behaviors, smoking and lack of exercise are more common among low SES, but high calorie diets are more common among high SES.ConclusionsNegative modern behaviors among high-SES groups may be reversing cardiovascular risks across SES groups, hence reversing mortality risks. But negative SES gradients in healthy years of life persist.

Study queStion

This study aims to establish a sociodemographic and personality profile of Canadians who donate internationally, fills the gap in the literature with regard to individual-level determinants of international giving, and compares these determinants with those of domestic donors. Women, volunteers, and individuals of non-Canadian origin, with higher income, higher education, higher level of religiosity, higher political awareness and participation, and higher frequency of extended family participation were more likely to contribute internationally. Higher education and a higher level of religiosity seem to influence international giving more than they did domestic giving. In terms of the variations in amount of international donations the important determinants are income, education, level of religiosity, and feeling of financial security. These results suggest that international charities should probably target their efforts at more-educated, higher-income and more-religious individuals. The other target donors are volunteers, women, individuals of non-Canadian origin, and politically aware and socially involved individuals.

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

Objective We evaluated the effectiveness of short-term cash and food assistance to improve adherence to antiretroviral therapy (ART) and retention in care among people living with HIV (PLHIV) in Tanzania. Methods At three clinics, 805 participants were randomized to three groups in a 3:3:1 ratio, stratified by site: nutrition assessment and counseling (NAC) plus cash transfers (~$11/month, n=347), NAC plus food baskets (n=345), and NAC-only (comparison group, n=113, clinicaltrials.gov NCT01957917). Eligible PLHIV were: ≥18 years, initiated ART ≤90 days prior, and food insecure. Cash or food was provided for ≤6 consecutive months, conditional on visit attendance. The primary outcome was medication possession ratio (MPR) ≥95% at 6 months. Secondary outcomes were appointment attendance and loss to follow-up (LTFU) at 6 and 12 months. Results The primary intent-to-treat analysis included 800 participants. Achievement of MPR≥95% at 6 months was higher in the NAC+cash group compared to NAC-only (85.0% vs. 63.4%), a 21.6 percentage point difference (95% confidence interval (CI): 9.8, 33.4, p<0.01). MPR≥95% was also significantly higher in the NAC+food group versus NAC-only (difference=15.8, 95% CI: 3.8, 27.9, p<0.01). When directly compared, MPR≥95% was similar in the NAC+cash and NAC+food groups (difference=5.7, 95% CI: −1.2, 12.7, p=0.15). Compared to NAC-only, appointment attendance and LTFU were significantly higher in both the NAC+cash and NAC+food groups at 6 months. At 12 months, the effect of NAC+cash, but not NAC+food, on MPR≥95% and retention was sustained. Conclusions Short-term conditional cash and food assistance improves ART possession and appointment attendance and reduces LTFU among food-insecure ART initiates in Tanzania.

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