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One key objective of the population health sciences is to understand why one social group has different levels of health and well-being compared with another. Whereas several methods have been developed in economics, sociology, demography, and epidemiology to answer these types of questions, a recent method introduced by Jackson and VanderWeele (2018) provided an update to decompositions by anchoring them within causal inference theory. In this paper, we demonstrate how to implement the causal decomposition using Monte Carlo integration and the parametric g-formula. Causal decomposition can help to identify the sources of differences across populations and provide researchers with a way to move beyond estimating inequalities to explaining them and determining what can be done to reduce health disparities. Our implementation approach can easily and flexibly be applied for different types of outcome and explanatory variables without having to derive decomposition equations. We describe the concepts of the approach and the practical steps and considerations needed to implement it. We then walk through a worked example in which we investigate the contribution of smoking to sex differences in mortality in South Korea. For this example, we provide both pseudocode and R code using our package, cfdecomp. Ultimately, we outline how to implement a very general decomposition algorithm that is grounded in counterfactual theory but still easy to apply to a wide range of situations.

ObjectiveTo estimate the causal impact of community based blood pressure screening on subsequent blood pressure levels among older adults in China.DesignRegression discontinuity analysis using data from a national cohort study.Setting2011-12 and 2014 waves of the Chinese Longitudinal Healthy Longevity Survey, a national cohort of older adults in China.Participants3899 older adults who had previously undiagnosed hypertension.InterventionCommunity based hypertension screening among older adults in 2011-12.Main outcome measureBlood pressure two years after initial screening.ResultsThe intervention reduced systolic blood pressure: −6.3 mm Hg in the model without covariates (95% confidence interval −11.2 to −1.3) and −8.3 mm Hg (−13.6 to −3.1) in the model that adjusts additionally for demographic, social, and behavioural covariates. The impact on diastolic blood pressure was smaller and non-significant in all models. The results were similar when alternative functional forms were used to estimate the impact and the bandwidths around the intervention threshold were changed. The results did not vary by demographic and social subgroups.ConclusionsCommunity based hypertension screening and encouraging people with raised blood pressure to seek care and adopt blood pressure lowering behaviour changes could have important long term impact on systolic blood pressure at the population level. This approach could address the high burden of cardiovascular diseases in China and other countries with large unmet need for hypertension diagnosis and care.

Over the coming decades, middle-income countries are expected to undergo substantial demographic changes. We estimated the consequences of these changes on the number of adults in need of hypertension care between 2015 and 2050 using nationally representative household-survey data collected in Brazil, China, India, Indonesia, Mexico, and South Africa (N=770 121). To reflect unmet need for healthcare, we defined hypertension as systolic blood pressure ≥140 mm Hg or diastolic blood pressure ≥90 mm Hg regardless of treatment status. Using a mathematical disease projection equation, we calculated the change in the number of individuals in need of hypertension care in each country that was due to changes in population size, age composition, and age-specific prevalence under various epidemiological scenarios. If the current age-specific prevalence schedule of hypertension remains unchanged until 2050, demographic changes alone will increase the number of adults in need of hypertension care by 319.7 million individuals, ranging from a relative growth of 55% in China to 151% in Mexico. Even if the age-specific prevalence of hypertension is reduced by 25% by 2050 among adults aged ≥40 years, the number of individuals in need of hypertension care will still increase by 145.9 million individuals, with relative increases ranging from 16% in China to 88% in Mexico. Overall, our results suggest that coming demographic changes in middle-income countries will overpower even ideal prevention efforts. Middle-income countries will need to massively expand healthcare services for aging-related diseases, such as hypertension, if they are to meet the virtually inevitable future increase in care needs for these conditions.

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Background: Current hypertension guidelines vary substantially in their definition of who should be offered blood-pressure-lowering medications. Understanding the impact of guideline choice on the proportion of adults who require treatment will be crucial for planning and scaling up hypertension care in low- and middle-income countries (LMICs). Methods: We extracted cross-sectional data on age, sex, blood pressure, hypertension treatment and diagnosis status, smoking, and body mass index for adults ages 30-70 from nationally representative surveys in 50 LMICs (N = 1,037,215). Our main objective was to determine the impact of hypertension guideline choice on the proportion of adults in need of blood-pressure-lowering medications. We considered four hypertension guidelines: the 2017 American College of Cardiology/American Heart Association (ACC/AHA) guideline, the commonly used 140/90 mmHg threshold, the 2016 World Health Organization HEARTS guideline (WHO), and the 2019 United Kingdom National Institute for Health and Care Excellence (NICE) guideline. Results: The proportion of adults in need of blood-pressure-lowering medications was highest under the ACC/AHA followed by the 140/90, NICE, and WHO guidelines (ACC/AHA: women, 27.7% [95% CI: 27.2%, 28.2%], men, 35.0% [34.4%, 35.7%]; 140/90: women: 26.1% [25.5%, 26.6%], men, 31.2% [30.6%, 31.9%]; NICE: women, 11.8% [11.4%, 12.1%]; men, 15.7% [15.3%, 16.2%]; WHO: women, 9.2% [8.9%, 9.5%], men, 11.0% [10.6%,11.4%]). Individuals who were unaware that they have hypertension were the primary contributor to differences in the proportion needing treatment under different guideline criteria. Differences in the proportion needing blood-pressure-lowering medications were largest in the oldest, 65-69, age group (ACC/AHA: women, 60.2% [58.8%, 61.6%], men, 70.1% [68.8%, 71.3%]; WHO: women, 20.1% [18.8%, 21.3%], men, 24.1.0% [22.3%, 25.9%]). For both women and men and across all guidelines, countries in the European and Eastern Mediterranean regions had the highest proportion of adults in need of blood-pressure-lowering medicines while the South and Central Americas had the lowest. Conclusions: There was substantial variation in the proportion of adults in need of blood-pressure-lowering medications depending on which hypertension guideline was used. Given the great implications of this choice for health system capacity, policymakers will need to carefully consider which guideline they should adopt when scaling up hypertension care in their country.

BackgroundDiabetes is an important contributor to global morbidity and mortality. The contributions of population aging and macroeconomic changes to the growth in diabetes prevalence over the past 20 years are unclear.MethodsWe used cross-sectional data on age- and sex-specific counts of people with diabetes by country, national population estimates, and country-specific macroeconomic variables for the years 1990, 2000, and 2008. Decomposition analysis was performed to quantify the contribution of population aging to the change in global diabetes prevalence between 1990 and 2008. Next, age-standardization was used to estimate the contribution of age composition to differences in diabetes prevalence between high-income (HIC) and low-to-middle-income countries (LMICs). Finally, we used non-parametric correlation and multivariate first-difference regression estimates to examine the relationship between macroeconomic changes and the change in diabetes prevalence between 1990 and 2008.ResultsGlobally, diabetes prevalence grew by two percentage points between 1990 (7.4 %) and 2008 (9.4 %). Population aging was responsible for 19 % of the growth, with 81 % attributable to increases in the age-specific prevalences. In both LMICs and HICs, about half the growth in age-specific prevalences was from increasing levels of diabetes between ages 45–65 (51 % in HICs and 46 % in LMICs). After age-standardization, the difference in the prevalence of diabetes between LMICs and HICs was larger (1.9 % point difference in 1990; 1.5 % point difference in 2008). We found no evidence that macroeconomic changes were associated with the growth in diabetes prevalence.ConclusionsPopulation aging explains a minority of the recent growth in global diabetes prevalence. The increase in global diabetes between 1990 and 2008 was primarily due to an increase in the prevalence of diabetes at ages 45–65. We do not find evidence that basic indicators of economic growth, development, globalization, or urbanization were related to rising levels of diabetes between 1990 and 2008.Electronic supplementary materialThe online version of this article (doi:10.1186/s12963-015-0065-x) contains supplementary material, which is available to authorized users.

Previous research has documented intergenerational transmission of human capital from children to parents. Less is known, however, about heterogeneity in this 'upward transmission' in low-resource settings. We examine whether co-resident adult children's education is associated with improved health among older parents in India, using nationally representative data from the 2014 Indian National Sample Survey. Parents of children with tertiary education had a lower probability of reporting poor health than parents of children with less than primary education. The benefits of children's education persisted after controlling for economic factors, suggesting that non-pecuniary pathways-such as health knowledge or skills-may play an important role. The association was more pronounced among economically dependent parents and those living in the North and West regions. Taken together, our results point to a strong positive association between children's education and parental health, the role of non-pecuniary pathways, and the importance of subnational heterogeneity in India.