Estimating risk factor attributable burden - challenges and potential solutions when using the comparative risk assessment methodology

Update on numbers of tobacco-attributable deaths by country in the South-East Asia region: implications for policy

BACKGROUND

The WHO South-East Asia Region is home to around 33% of adult tobacco users. To inform tobacco control policy and practice, we conducted a study using the latest available data to update mortality attributable to overall tobacco use, including smoked tobacco, smokeless tobacco (SLT) and secondhand smoke (SHS) exposure, in the 11 countries of the Region.

METHODS

We estimated smoking, SLT use and SHS exposure using the latest available surveys for each country during 2016-2021, and then estimated all-cause and lung cancer-attributable annual deaths for each using the population-attributable fraction method. Finally, we estimated the annual total tobacco-attributable deaths including all three exposures using the multiplicative aggregation method.

RESULTS

We estimated the occurrence of 4 087 920 all-cause deaths and 105 279 lung cancer deaths annually attributable to tobacco use among the 11 countries investigated. India accounted for 63.9% of all-cause tobacco-attributable deaths.

CONCLUSIONS

The high annual number of tobacco-attributable deaths in the Region highlights the need for accelerating progress in reducing tobacco use. Implementation of the WHO Framework Convention on Tobacco Control (FCTC) and MPOWER policy package needs prioritisation at the country level. Tobacco cessation services, supply-side measures and policies to counter tobacco industry interference should be strengthened. Further work is needed to monitor progress towards FCTC implementation and analyse the impacts of policies on tobacco-related outcomes, including attributable mortality and disease burden, to inform advocacy efforts.

Risk and Population Attributable Fraction of Stroke Subtypes in Japan

BACKGROUND

Associations of major risk factors for stroke with total and each type of stroke, as well as subtypes of ischemic stroke, and their population attributable fractions had not been examined comprehensively.

METHODS

Participants of the Japan Public Health Center-based prospective (JPHC) Study Cohort II without histories of cardiovascular disease and cancer (n = 14,797) were followed from 1993 through 2012. Associations of current smoking, hypertension, diabetes, overweight (body mass index ≥25 kg/m2), non-high-density lipoprotein cholesterol (non-HDLC) categories, low HDLC (<40 mg/dL), urine protein, and history of arrhythmia were examined in a mutually-adjusted Cox regression model that included age and sex. Population attributable fractions (PAFs) were estimated using the hazard ratios and the prevalence of risk factors among cases.

RESULTS

Subjects with hypertension were 1.63 to 1.84 times more likely to develop any type of stroke. Diabetes, low HDLC, current smoking, overweight, urine protein, and arrhythmia were associated with risk of overall and ischemic stroke. Hypertension and urine protein were associated with risk of intracerebral hemorrhage, while current smoking, hypertension, and low non-HDLC were associated with subarachnoid hemorrhage. Hypertension alone accounted for more than a quarter of stroke incidence, followed by current smoking and diabetes. High non-HDLC, current smoking, low HDLC, and overweight contributed mostly to large-artery occlusive stroke. Arrhythmia explained 13.2% of embolic stroke. Combined PAFs of all the modifiable risk factors for total, ischemic, and large-artery occlusive strokes were 36.7%, 44.5%, and 61.5%, respectively.

CONCLUSION

Although there are differences according to subtypes, hypertension could be regarded as the most crucial target for preventing strokes in Japan.

Increasing Racial and Ethnic Disparities in Ambient Air Pollution-Attributable Morbidity and Mortality in the United States

BACKGROUND

Ambient nitrogen dioxide (NO 2 ) and fine particulate matter with aerodynamic diameter ≤ 2.5 μ m (PM 2.5 ) threaten public health in the US, and systemic racism has led to modern-day disparities in the distribution and associated health impacts of these pollutants.

OBJECTIVES

Many studies on environmental injustices related to ambient air pollution focus only on disparities in pollutant concentrations or provide only an assessment of pollution or health disparities at a snapshot in time. In this study, we compare injustices in NO 2 - and PM 2.5 -attributable health burdens, considering NO 2 -attributable health impacts across the entire US; document changing disparities in these health burdens over time (2010-2019); and evaluate how more stringent air quality standards would reduce disparities in health impacts associated with these pollutants.

METHODS

Through a health impact assessment, we quantified census tract-level variations in health outcomes attributable to NO 2 and PM 2.5 using health impact functions that combine demographic data from the US Census Bureau; two spatially resolved pollutant datasets, which fuse satellite data with physical and statistical models; and epidemiologically derived relative risk estimates and incidence rates from the Global Burden of Disease study.

RESULTS

Despite overall decreases in the public health damages associated with NO 2 and PM 2.5 , racial and ethnic relative disparities in NO 2 -attributable pediatric asthma and PM 2.5 -attributable premature mortality have widened in the US during the last decade. Racial relative disparities in PM 2.5 -attributable premature mortality and NO 2 -attributable pediatric asthma have increased by 16% and 19%, respectively, between 2010 and 2019. Similarly, ethnic relative disparities in PM 2.5 -attributable premature mortality have increased by 40% and NO 2 -attributable pediatric asthma by 10%.

DISCUSSION

Enacting and attaining more stringent air quality standards for both pollutants could preferentially benefit the most marginalized and minoritized communities by greatly reducing racial and ethnic relative disparities in pollution-attributable health burdens in the US. Our methods provide a semi-observational approach to track changes in disparities in air pollution and associated health burdens across the US. https://doi.org/10.1289/EHP11900.

Climate Change Adaptation Methods for Public Health Prevention in Australia: an Integrative Review

PURPOSE OF REVIEW

Climate change poses a serious threat to human health and well-being. Australia is not immune to the public health impacts and continues to be underprepared, putting the population health at risk. However, there is a dearth in knowledge about how the Australian public health system will address the impacts of climate change.

RECENT FINDINGS

This integrative review synthesises tools, frameworks, and guidance material suitable for climate change adaptation from a preventive public health perspective. The literature search was conducted in electronic databases MEDLINE, PubMed, CINAHL, and Web of Science. Of 4507 articles identified, 19 articles met the inclusion criteria that focused on operational methods in public health and excluded the clinical context and reactive disaster response approaches. This review revealed that Australia is ill-prepared to manage climate change adverse health impacts due to ineffective adaptation strategies. The review highlights that Australia urgently requires effective adaptation strategies such as undertaking a National Adaptation Plan process and an improved understanding in managing complex health risks. Taking this action will strengthen the public health system and build health resilience especially for vulnerable populations. These findings will help understand and develop of the necessary adaptive strategies in Australia.

Income and professional inequalities in chronic diseases: prevalence and incidence in France

OBJECTIVES

In France, almost nine of 10 deaths are caused by non-communicable diseases, and there is significant social inequality in mortality rates. However, it is not easy to collect robust data on the incidence and prevalence of such diseases according to socio-economic status. Based on data from the link between the primary longitudinal population sample and the national health data system, the aim of our study was to compute the standardised incidence and prevalence of seven major groups of chronic diseases according to socio-economic status.

STUDY DESIGN

Descriptive retrospective cohort study.

METHODS

This was a descriptive retrospective cohort study on a weighted representative sample of the French population, comprising 3.4 million individuals from data collected 2016-2017. Main chronic disease categories include diabetes, cancers, psychiatric disorders, liver and pancreatic diseases, neurological conditions, respiratory and cardiovascular diseases, calculated from the 2016-2017 period by combining health care consumption and diagnoses received during hospitalisations and/or associated with specific full healthcare coverage. Socio-economic status was measured by disposable income from the 2013-2014 tax returns and census-derived socioprofessional groups, and findings were standardised for age and sex.

RESULTS

For all disease categories except cancers, standardised incidence rates showed a gradient favouring the wealthiest, with a risk ratio between the first and tenth standard of living deciles ranging from 1.4 (cardiovascular diseases) to 2.8 (diabetes). Incidence of all disease categories, except cancers, was higher for all groups compared with executives and higher academic professions (risk ratios between workers and executives ranged from 2.0 to 1.3 in psychiatric and cardiovascular diseases, respectively). Conversely, cancer incidence rate followed a flat curve, reduced in the two poorest standard of living deciles, and there were no significant differences between socioprofessional groups. Standardised prevalence rates followed the same patterns, although risk ratios were highest for psychiatric diseases, varying according to sex and disease.

CONCLUSIONS

Deep social inequalities in incidence and prevalence of chronic diseases were observed in a large representative sample of the French population. The reverse social inequalities in cancer incidence and prevalence calls for more detailed research into cancer types and selection mechanisms, the data from which would allow the long-term monitoring of such disparities.

Burden of lung cancer and predicted costs of occupational exposure to hexavalent chromium in the EU - The impact of different occupational exposure limits

BACKGROUND

Exposure to hexavalent chromium [Cr(VI)] occurs widely in occupational settings across the EU and is associated with lung cancer. In 2025, the occupational exposure limit is set to change to 5 μg/m³. Current exposure limits are higher, with 10 μg/m³ as a general limit and 25 μg/m³ for the welding industry. We aimed to assess the current burden of lung cancer caused by occupational exposure to Cr(VI) and to evaluate the impact of the recently established EU regulation by analysing different occupational exposure limits.

METHODS

Data were extracted from the literature, the Global Burden of Disease 2019) study, and Eurostat. We estimated the cases of cancer attributable to workplace exposure to Cr(VI) by combining exposure-effect relationships with exposure data, and calculated related DALYs and health costs in scenarios with different occupational exposure limits.

RESULTS

With current EU regulations, 253 cases (95%UI 250.96-255.71) of lung cancer were estimated to be caused by Cr(VI) in 2019, resulting in 4684 DALYs (95%UI 4683.57-4704.08). In case the welding industry adopted 10 μg/m³, a decrease of 43 cases and 797 DALYs from current values is expected. The predicted application of a 5 μg/m³ limit would cause a decrease of 148 cases and 2746 DALYs. Current costs are estimated to amount to 12.47 million euros/year (95%UI 10.19-453.82), corresponding to 39.97 million euros (95%UI 22.75-70.10) when considering costs per DALY. The limits implemented in 2025 would lead to a decrease of 23.35 million euros when considering DALYs, with benefits of introducing a limit value occurring after many decades. Adopting a 1 μg/m³ limit would lower costs to 1.04 million euros (95%UI 0.85-37.67) and to 3.33 million euros for DALYs (95%UI 1.89-5.84).

DISCUSSION

Assessing different scenarios with different Cr(VI) occupational exposure limits allowed to understand the impact of EU regulatory actions. These findings make a strong case for adapting even stricter exposure limits to protect workers' health and avoid associated costs.

Burden of disease attributable to risk factors in European countries: a scoping literature review

OBJECTIVES

Within the framework of the burden of disease (BoD) approach, disease and injury burden estimates attributable to risk factors are a useful guide for policy formulation and priority setting in disease prevention. Considering the important differences in methods, and their impact on burden estimates, we conducted a scoping literature review to: (1) map the BoD assessments including risk factors performed across Europe; and (2) identify the methodological choices in comparative risk assessment (CRA) and risk assessment methods.

METHODS

We searched multiple literature databases, including grey literature websites and targeted public health agencies websites.

RESULTS

A total of 113 studies were included in the synthesis and further divided into independent BoD assessments (54 studies) and studies linked to the Global Burden of Disease (59 papers). Our results showed that the methods used to perform CRA varied substantially across independent European BoD studies. While there were some methodological choices that were more common than others, we did not observe patterns in terms of country, year or risk factor. Each methodological choice can affect the comparability of estimates between and within countries and/or risk factors, since they might significantly influence the quantification of the attributable burden. From our analysis we observed that the use of CRA was less common for some types of risk factors and outcomes. These included environmental and occupational risk factors, which are more likely to use bottom-up approaches for health outcomes where disease envelopes may not be available.

CONCLUSIONS

Our review also highlighted misreporting, the lack of uncertainty analysis and the under-investigation of causal relationships in BoD studies. Development and use of guidelines for performing and reporting BoD studies will help understand differences, avoid misinterpretations thus improving comparability among estimates.

REGISTRATION

The study protocol has been registered on PROSPERO, CRD42020177477 (available at: https://www.crd.york.ac.uk/PROSPERO/ ).

Re-assessing human mortality risks attributed to PM2.5-mediated effects of agricultural ammonia

How can and should epidemiologists and risk assessors assemble and present evidence for causation of mortality or morbidities by identified agents such as fine particulate matter or other air pollutants? As a motivating example, some scientists have warned recently that ammonia from the production of meat significantly increases human mortality rates in exposed populations by increasing the ambient concentration of fine particulate matter (PM2.5) in air. We reexamine the support for such conclusions, including quantitative calculations that attribute deaths to PM2.5 air pollution by applying associational results such as relative risks, odds ratios, or slope coefficients from regression models to predict the effects on mortality or morbidity of reducing PM2.5 exposures. Taking an outside perspective from the field of causal artificial intelligence (CAI), we conclude that these attribution calculations are methodologically unsound. They produce unreliable conclusions because they ignore an essential distinction between differences in outcomes observed at different levels of exposure and changes in outcomes caused by changing exposure. We find that multiple studies that have examined associations between changes over time in particulate exposure and mortality risk instead of differences in exposures and corresponding mortality risks have found no clear evidence that observed changes in exposure help to predict or explain subsequent changes in mortality risks. We conclude that there is no sound theoretical or empirical reason to believe that reducing ammonia emissions from farms has reduced or would reduce human mortality risks. More generally, applying CAI principles and methods can potentially improve current widespread practices of unsound causal inferences and policy-relevant causal claims that are made without the benefit of formal causal analysis in air pollution health effects research and in other areas of applied epidemiology and public health risk assessment.

Global burden of cardiovascular disease from 1990 to 2019 attributable to dietary factors

BACKGROUND

While dietary factors play a crucial role in the incidence of cardiovascular disease, the specific dietary risk factors vary across regions and require further investigation.

OBJECTIVE

The burden of cardiovascular disease (CVD) due to different dietary factors was analyzed by determining sex, age, and sociodemographic index (SDI) values for 204 countries and territories between 1990 and 2019.

METHODS

Data were extracted from the Global Burden of Disease (GBD) 2019 and analyzed to determine population attributable fractions (PAFs), mortality, and disability-adjusted life years (DALYs), and trends thereof, for CVDs attributable to dietary risk factors from 1990 to 2019. We used a generalized linear model with a Gaussian distribution to calculate the estimated annual percentage changes (EPACs) in CVD mortality and DALY rates attributable to dietary risk factors. We also used a comparative risk-assessment framework to estimate the CVD mortality and DALYs attributable to dietary risk factors.

RESULTS

Approximately 40% of CVD mortality and DALY rates were attributable to dietary risk factors, with high sodium intake, low whole-grain intake, and low legume intake being the greatest dietary risk factors globally. Moreover, high-SDI regions had the highest PAFs for CVD mortality and DALYs associated with high red and processed meat intake, middle-SDI regions had the highest PAFs with high sodium intake, and low-SDI regions had the highest PAFs with low fruit and vegetable intake. The highest PAFs for CVD mortality and DALYs were associated with low whole-grain intake in 13 and 9 regions, respectively.

CONCLUSION

Reducing sodium intake and increasing whole-grain and legume intake should be the top priority worldwide for improving regional diets and thereby decreasing CVD burdens. Other priorities should be set for different SDI-value regions, depending on the predominant dietary risk factors for CVDs in the respective regions.