Intertwined depressive and cognitive trajectories and the risk of dementia and death in older adults: a competing risk analysis

Background

Depressive symptoms and cognitive impairment often interact, rendering their associations controversial. To date, their joint trajectories and associations with dementia and death remain underexplored.

Aims

To explore the interactions between depressive symptoms and cognitive function, their developmental trajectories and the associations with all-cause dementia, Alzheimer's disease (AD) and all-cause death in older adults.

Methods

Data were from the Health and Retirement Study. Depressive symptoms and cognitive function were measured using the 8-item Centre for Epidemiologic Studies Depression Scale and the Telephone Interview of Cognitive Status, respectively. All-cause dementia and AD were defined by self-reported or proxy-reported physician diagnoses. All-cause death was determined by interviews. The restricted cubic spline, group-based trajectory modelling and subdistribution hazard regression were used.

Results

Significant interactions between depressive symptoms and cognitive function in 2010 in their association with new-onset all-cause dementia and AD from 2010 to 2020 were found, especially in women (p for interaction <0.05). Independent trajectory analysis showed that emerging or high (vs no) depressive trajectories and poor or rapidly decreased cognitive trajectories (vs very good) from 1996 to 2010 were at significantly higher risk of subsequent all-cause dementia, AD and all-cause death. 15 joint trajectories of depressive symptoms and cognitive function from 1996 to 2010 were determined, where rapidly decreased cognitive function was more common in those with no depressive symptoms. Compared with older adults with the trajectory of no depressive symptoms and very good cognitive function, those with the trajectory of no depressive symptoms but rapidly decreased cognitive function were much more likely to develop new-onset all-cause dementia and death, with subdistribution hazard ratios (95% confidence intervals) of 4.47 (2.99 to 6.67) and 1.84 (1.43 to 2.36), especially in women.

Conclusions

To effectively mitigate the risk of dementia and death, it is crucial to acknowledge the importance of preventing cognitive decline in older adults without depressive symptoms, particularly in women.

The role of primary health care in improving health status, financial protection and health equity in the context of China's health system reform

BACKGROUND

Stronger primary health care (PHC) is critical to achieving the United Nations' Sustainable Development Goals. However, there is scarce evidence on the impact of PHC on health system performance in developing countries. Since 2009, China has implemented an ambitious health system reform, among which PHC has received unprecedented attention. This study investigates the role of PHC resource in improving health status, financial protection and health equity.

METHODS

We obtained province-level and individual-level data to conduct a longitudinal study across the period of China's health system reform. The dependent variables included health outcomes and financial protection. The independent variables were the number of PHC physicians and share of PHC physicians in all physicians. Mixed-effect models were used for adjusted associations.

RESULTS

From 2003 to 2017, the number of PHC physicians slightly increased by 31.75 per 100,000 persons and the share of PHC physicians in all physicians increased by 3.62 percentage points. At the province level, greater PHC physician density was positively associated with life expectancy, negatively associated with age-standardized excess mortality, infectious disease mortality, perinatal mortality low birth weight, as well as the share of health expenses in total consumption expenses. At the individual and household level, greater PHC physician density was positively associated with self-assessed health, and negatively associated with incidence of catastrophic health expenditures. Compared to other quintiles, the poorest quintile benefited more from PHC physician density.

CONCLUSIONS

In China, an increased PHC physician supply was associated with improved health system performance. While China's PHC system has been strengthened in the context of China's health system reforms, further effective incentives should be developed to attract more qualified PHC workers.

Effects of retirement on inpatient healthcare utilisation: an observational study in China

OBJECTIVE

Previous studies have presented mixed evidence on retirement and inpatient healthcare utilisation. We aimed to examine the causal effect of retirement on inpatient healthcare utilisation in China and explore the heterogenous effects of sex, disease types and ways of hospital admission.

DESIGN

This was a retrospective observational study from the electronic medical record at 376 tertiary hospitals in China between 2013 and 2018.

SETTING

Nationwide data from China.

PARTICIPANTS

We included the male sample aged between 50 and 70, and the female sample aged between 40 and 60 and with basic medical insurance system or public medical insurance. Observations with total expenditures per visit at the top or bottom 1% were excluded.

PRIMARY AND SECONDARY OUTCOME MEASURES

Inpatient expenditures per visit and inpatient days per visit.

METHODOLOGY

We examined the effects by a non-parametric fuzzy regression discontinuity design, exploiting the mandatory retirement age as a source of exogenous variation in retirement status.

RESULTS

Retirement reduced drug expenditures (β=-467.46, p<0.05) and inpatient days per visit (β=-0.99, p<0.05). The mitigation effect was concentrated on people admitted into hospital due to chronic diseases (β=-551.28, p<0.05 for drug expenditures; β=-1.08, p<0.05 for inpatient days per visit) and people admitted into hospital through outpatient services (β=-353.75, p<0.001 for drug expenditures). For males, retirement significantly reduced diagnostic tests expenditures (β=-302.38, p<0.05) and drug expenditures (β=-728.31, p<0.05). Retirement significantly reduced inpatient days per visit (β=-1.13, p<0.05) for females.

CONCLUSION

The empirical findings suggested that retirement may lead to a reduction in inpatient healthcare utilisation, which underlined the importance for policy-makers to consider the externalities of retirement policies on inpatient healthcare utilisation.

Willingness to vaccinate against herpes zoster in Chinese urban population: a mixed-methods study

OBJECTIVE

Although the herpes zoster vaccine has been available in mainland China since June 2020, residents' knowledge of herpes zoster and the herpes zoster vaccine is poor, and vaccination rates are low, especially among the elderly, who are at high risk for herpes zoster. This study assessed willingness to be vaccinated against herpes zoster and factors associated with vaccination among urban residents in China.

METHODS

A mixed-methods study was conducted in community health centres from August 2022 to September 2022. We used convenience sampling to select 2864 residents from 9 Chinese cities for the quantitative study and 67 adults for the qualitative study. A structured questionnaire was used for the quantitative study, and data were collected through face-to-face interviews. Multinomial logistic regression was used to analyse factors associated with willingness to vaccinate. Qualitative data were analysed using thematic analysis of barriers to herpes zoster vaccination.

RESULTS

A total of 2864 eligible respondents were included in the study. Of these, 42.67% intended to receive the herpes zoster vaccine, 21.44% refused and 35.89% were hesitant. The results of the quantitative and qualitative analyses showed that the factors associated with respondents' willingness to be vaccinated against herpes zoster included: personal characteristics such as gender, age and income; knowledge and attitudes about herpes zoster and the vaccine; vaccine characteristics such as efficacy, safety and price; and other factors such as pain tolerance and accessibility to vaccination.

CONCLUSION

The low willingness to vaccinate, especially among the elderly, is mainly related to their poor knowledge and negative attitude towards the infection and vaccination. Therefore, health education about herpes zoster, immunisation promotion, and improvement of accessibility and affordability would be valuable in China.

Characteristics of Chinese Lottery Consumers' Financial Literacy and its Relationship with Problem Lottery Gambling

Problem lottery gambling among lottery consumers has increased globally over the years, rendering it necessary to explore their financial literacy characteristics and to answer whether financial literacy inhibits problem lottery gambling. In the present research, a total of 316 Chinese lottery consumers, who constitute the culturally underrepresented samples in the extant literature, completed a survey about financial literacy and problem lottery gambling. Using the propensity score matching method, we compared financial literacy between Chinese lottery consumers and Chinese general population (N = 10,058). The results showed that the five facets of financial literacy (i.e., financial knowledge, financial capacity, financial management values, financial ethics, and wealth values) among Chinese lottery consumers were significantly lower than Chinese general population. Among Chinese lottery consumers, their Homo sociologicus index (including financial ethics and wealth values) negatively predicted problem lottery gambling, but the Homo economicus index (including financial knowledge, financial capacity, and financial management values) was not significantly associated with problem lottery gambling. The theoretical and practical implications of these findings were discussed.

Internet use, cardiometabolic multimorbidity, and death in older adults: a multi-cohort study spanning developing and developed countries

BACKGROUND

Internet use is a double-edged sword for older adults' health. Whether internet use can prevent cardiometabolic diseases and death in older adults remains controversial.

METHODS

Four cohorts across China, Mexico, the United States, and Europe were utilized. Internet use was defined using similar questions. Cardiometabolic diseases included diabetes, heart diseases, and stroke, with 2 or more denoting cardiometabolic multimorbidity. Depressive symptoms were assessed using the Center for Epidemiological Studies Depression Scale and Europe-depression scale. The competing risk analysis based on subdistribution hazard regression, random-effects meta-analysis, and mediation analysis were utilized.

RESULTS

A total of 104,422 older adults aged 50 or older were included. Internet users (vs. digital exclusion) were at lower risks of diabetes, stroke, and death, with pooled sHRs (95% CIs) of 0.83 (0.74-0.93), 0.81 (0.71-0.92), and 0.67 (0.52-0.86), respectively, which remained significant in sensitivity analyses. The inverse associations of internet use with new-onset cardiometabolic diseases and death were progressively significant in Mexico, China, the United States, and Europe. For instance, older internet users in Europe were at 14-30% lower cardiometabolic risks and 40% lower risk of death. These associations were partially mediated by reduced depressive symptoms and were more pronounced in those with high socioeconomic status and women. Furthermore, patients with prior cardiometabolic conditions were at about 30% lower risk of death if they used the internet, which was also mediated by reduced depressive symptoms. However, certain cardiometabolic hazards of internet use in those aged < 65 years, with low socioeconomic status, men, and single ones were also observed.

CONCLUSION

Enhancing internet usage in older adults can reduce depressive symptoms and thus reduce the risks of cardiometabolic diseases and death. The balance of internet use, socioeconomic status, and health literacy should be considered when popularizing the internet in older adults.

Adverse childhood experiences from family and society contribute to increased risk of depressive symptoms and cognitive impairment: a cross-sectional study

Background

Family environments can shape children's personalities and social networks, rendering distinguishing adverse childhood experiences (ACEs) from family and society essential, but related evidence remains limited.

Aims

This cross-sectional study aimed to investigate the correlations between intrafamilial and social ACEs, their associations with depressive symptoms and cognitive impairment and the (education-moderated) mediating role of social ACEs.

Methods

Data for this cross-sectional study were from the China Health and Retirement Longitudinal Study. Nine intrafamilial (0, 1, 2, 3, and 4 or more) and three social (0, 1, and 2 or more) ACEs were identified. Depressive symptoms were assessed using the 10-item Center for Epidemiological Studies Depression Scale. Global cognition, including episodic memory and mental intactness, was calculated as z scores. Binary and ordered logistic regressions, generalised linear models with Gaussian family and identity link, and mediation analysis were used.

Results

13 435 participants aged 59.0 (51.0-66.0) were included. Compared with participants with no intrafamilial ACEs, those with 1, 2, 3, and 4 or more intrafamilial ACEs tended to develop more social ACEs, with odds ratios (ORs) of 1.55 (95% confidence interval (CI): 1.36 to 1.76), 2.36 (95% CI: 2.08 to 2.68), 3.46 (95% CI: 3.02 to 3.96) and 6.10 (95% CI: 5.30 to 7.02), respectively. Both intrafamilial and social ACEs were associated with depressive symptoms (OR >3 for four or more intrafamilial ACEs and two or more social ACEs) and global cognition (β=-0.26 for four or more intrafamilial ACEs and β=-0.29 for two or more social ACEs). Social ACEs mediated the associations of intrafamilial ACEs with depressive symptoms and global cognition by 12.3% and 13.1%, respectively. Furthermore, as education levels increased, the impact of intrafamilial ACEs on depressive symptoms was increasingly mediated through social ACEs, while the mediating role of social ACEs between intrafamilial ACEs and cognitive impairment gradually diminished.

Conclusions

Improving children's social environments and elevating general education can prevent later-life depressive symptoms and cognitive impairment attributed to ACEs in China.

Community-based integrated care for patients with diabetes and depression (CIC-PDD): study protocol for a cluster randomized controlled trial

BACKGROUND

Managing the multimorbidity of diabetes and depression remains a clinical challenge for patients and healthcare professionals due to the fragmented healthcare delivery system. To effectively cope with multimorbidity, there is an urgent need for the health system to transform into people-centered integrated care (PCIC) system globally. Therefore, this paper describes the protocol of community-based integrated care for patients with diabetes and depression (CIC-PDD) project, an integrated and shared-care intervention project.

METHODS/DESIGN

CIC-PDD project is conducted in two phases, namely "care model development" and "implementation and evaluation." In the first phase, CIC-PDD model was designed and developed based on the four criteria of collaborative care model (CCM) and was subsequently adjusted to align with the context of China. The second phase entails a pragmatic, two-arm, cluster randomized controlled implementation trial, accompanied by parallel mixed-methods process evaluation and cost-effectiveness analysis.

DISCUSSION

We anticipate CIC-PDD project will facilitate the development and innovation of PCIC model and related theories worldwide, particularly in low- and middle-income countries (LMICs). In addition, CIC-PDD project will contribute to the exploration of primary health care (PHC) in addressing the multimorbidity of physical and mental health issues.

TRIAL REGISTRATION

ClinicalTrials.gov registration ChiCTR2200065608 (China Clinical Trials Registry https://www.chictr.org.cn ). Registered on November 9, 2022.

The shattered "Iron Rice Bowl": effects of Chinese state-owned enterprise reform on depressive symptoms in later life

OBJECTIVES

The SOE reform was the first time that economic insecurity was introduced since 1949 in China, with hundreds of million employees affected by the laid off. This study took the State-Owned Enterprises (SOE) reform in China as a natural experiment to explore the impact of economic insecurity on depressive symptoms in later life.

METHODS

Data were obtained from the China Health and Retirement Longitudinal Survey (CHARLS), 2014 and 2015. CHARLS is a nationally representative survey covering 28 provinces in China. CHARLS used the probabilities proportional to size (PPS) sampling method and involved 450 villages/resident committees, 150 counties/districts and 12,400 households. A total of 5113 urban dwellers born earlier than 1971 (aged 25 years old and above at the start of the SOE reform, 1995) were involved. Using the province-level  economic loss from the layoffs, we examined the impact of economic insecurity exposure on the score of depressive symptoms using a difference-in-differences model (DID).

RESULTS

Individuals with economic insecurity exposure had a significantly increased risk of higher depressive symptoms scores, in which a 1 percentage point increase in expected economic loss would increase the CESD-10 score by 0.10. For an individual at the median distribution (CESD-10 = 5), this implies a shift to the 58th percentile (CESD-10 = 6). Given that the average intensity of expected economic loss is 10.22% and the mean CESD-10 is 6.92, exposure to the SOE reform led to an average increase in the CESD-10 score by 1.02 and by at least 14.74%. The heterogeneity analyses showed that the role of SOE reform in depressive symptoms scores was robust in both female and male groups and groups with different educational attainment.

CONCLUSIONS

Economic insecurity exposure increased the depressive symptoms score later in life in the context of China. Programs, such as adequate unemployment insurance benefits, can protect individuals against the risk of financial loss, thereby reducing their negative impact on depressive symptoms. Providing mental symptoms surveillance and psychological counseling to those experienced at a time of great uncertainty is important for preventing depression in times of economic insecurity.

Data envelopment analysis on the efficiency of vaccination services and its influencing factors in Beijing, China

OBJECTIVES

Vaccination is an important part of public health services. We aim to assess the efficiency of vaccination services in Beijing, the capital of China, and to further study the influencing factors of efficiency.

METHODS

Using the immunization service data of Beijing, China in 2020, we firstly developed a data envelopment analysis (DEA) model to calculate the score of vaccination efficiency. Secondly, we used DEA model scenario simulations with different combinations of input-output factors to derive the magnitude of the effect of each input factor on the efficiency. Finally, combined with the data from the Beijing Regional Statistical Yearbook 2021, we developed the Tobit model to examine the effect of external social environmental factors on efficiency.

RESULTS

The average scores of efficiency of POVs (Point of Vaccination) in different areas of Beijing vary greatly. Different input factors had different degrees of positive effects on the efficiency score. In addition, the number of populations served by POV was positively associated with efficiency, the GDP and financial allocation of the POVs' district was also positively associated with efficiency score, while the total dependency ratio of the POVs' district was negatively associated with efficiency score.

CONCLUSION

The efficiency of vaccination services varied considerably across POVs. Constrained by limited resources, efficiency scores can be increased by increasing input factors that have a larger impact on efficiency score and reducing those that have a smaller impact on efficiency. In addition, the social environment should be considered in allocating vaccination resources, and more resources should be invested in areas with low levels of economic development, low financial allocation, and high population.

[A study on knowledge, attitude, and vaccination behavior of herpes zoster vaccine among urban residents in selected areas of China]

Objective: To understand the knowledge, attitude, and current status of vaccination of herpes zoster vaccination among urban residents aged 25 years and above in China. Methods: In August to October 2022, a convenience sampling method was used to survey residents aged 25 years and above at 36 community centers in 9 cities across China. Questionnaires were used to collect basic information, knowledge, and attitude toward herpes zoster and its vaccination, as well as vaccination status and reasons for non-vaccination among residents. Results: A total of 2 864 urban residents were included in the study. The total score of residents' cognition of herpes zoster and its vaccine was 3.01±2.08, and the total score of their attitude was 18.25±2.76. Factors such as being male (β=-0.45, P<0.001), older than 40-59 years (β=-0.34, P=0.023) or ≥60 years (β=-0.68, P<0.001), married (β=-0.69, P=0.002) were negatively associated with knowledge score. The educational level of high school or secondary school (β=0.44, P=0.036), college (β=0.65, P=0.006), bachelor's degree and above (β=1.20, P<0.001), annual net household income ≥120 000 Yuan in 2021 (β=0.42, P=0.020), having urban employee medical insurance (β=0.62, P=0.030), having public or commercial medical insurance (β=0.65, P=0.033), and having a history of chickenpox (β=0.29, P=0.025) were positively associated with knowledge scores. Being male (β=-0.38, P=0.008) and not remembering a history of chickenpox (β=-0.49, P=0.012) were negatively associated with attitude scores. Annual net household income in 2021 was between 40 000-80 000 Yuan (β=0.44, P=0.032) or between 80 000-120 000 Yuan (β=0.62, P=0.002) or ≥120 000 Yuan (β=0.93, P<0.001), and a history of herpes zoster (β=0.59, P=0.004) were positively associated with attitude scores. Of the 2 864 residents surveyed, only 29 (1.01%) had received the herpes zoster vaccine, with a vaccination rate of 1.70% for those aged 50 years and above, with the main reason for non-vaccination being lack of knowledge about the herpes zoster vaccine, followed by the high price. 42.67% of the population said they would consider getting the herpes zoster vaccine in the future. Conclusion: Low knowledge of herpes zoster and its vaccine, positive attitudes towards the preventive effects of herpes zoster and its vaccine, and extremely low vaccination rates among the urban population in China call for multiple measures to strengthen health education and vaccination recommendations for residents, especially for the elderly, low-education and low-income populations.

How socioeconomic status affected the access to health facilities and malaria diagnosis in children under five years: findings from 19 sub-Saharan African countries

BACKGROUND

Prompt and appropriate clinical management of malaria is critical for reducing the continued high burden of malaria among children under five years in sub-Saharan countries. However, more remains to be known about how a patient's socioeconomic status (SES) would affect the access to diagnosis of malaria.

METHODS

In this cross-sectional study using the Demographic and Health Survey and Malaria Indicators Survey, we pooled the data of 38,567 febrile under-five children in 2016-2018 from 19 sub-Saharan countries. Multivariable logistic regression was used to assess the associations between SES and two binary outcomes: the visit to a health facility and a blood test for fever. Stratified analyses were further conducted by the type of health facilities (public hospitals/public primary healthcare facilities/private hospitals/private primary healthcare facilities) for the latter outcome.

RESULTS

Fifty-eight percent of the febrile children were taken to health facilities, among whom only 55% took blood tests. Compared to children from households in the highest wealth quintile, children in the lowest quintile were less likely to be taken to medical facilities [adjusted odds ratio (aOR) = 0.775, 95% confidence interval (CI): 0.675-0.889]. Parents with more than secondary education were more likely to seek care (aOR = 1.830, 95% CI: 1.561-2.145) and to have blood tests (aOR = 1.729, 95% CI:  1.436-2.082) for their febrile children than parents without formal education. The probabilities of receiving blood tests at public hospitals and public primary healthcare facilities stayed relatively high across parental education levels and wealth quintiles, while these probabilities remained the lowest at private primary healthcare facilities, ranging from 0.100 (95% CI: 0.074-0.127) to 0.139 (95% CI: 0.083-0.194) across parental education levels and from 0.104 (95% CI: 0.078-0.130) to 0.125 (95% CI: 0.090-0.160) across wealth quintiles.

CONCLUSIONS

Significant socioeconomic disparities existed both in the access to health facilities and laboratory diagnosis of malaria in children in sub-Saharan African countries. These disparities were particularly evident in the private sector. Universal health coverage needs to be further strengthened to make formal healthcare in general and the laboratory diagnosis of malaria more accessible and affordable.

Mitigating COVID-19 Transmission in Schools With Digital Contact Tracing

Precision mitigation of COVID-19 is in pressing need for postpandemic time with the absence of pharmaceutical interventions. In this study, the effectiveness and cost of digital contact tracing (DCT) technology-based on-campus mitigation strategy are studied through epidemic simulations using high-resolution empirical contact networks of teachers and students. Compared with traditional class, grade, and school closure strategies, the DCT-based strategy offers a practical yet much more efficient way of mitigating COVID-19 spreading in the crowded campus. Specifically, the strategy based on DCT can achieve the same level of disease control as rigid school suspensions but with significantly fewer students quarantined. We further explore the necessary conditions to ensure the effectiveness of DCT-based strategy and auxiliary strategies to enhance mitigation effectiveness and make the following recommendation: social distancing should be implemented along with DCT, the adoption rate of DCT devices should be assured, and swift virus tests should be carried out to discover asymptomatic infections and stop their subsequent transmissions. We also argue that primary schools have higher disease transmission risks than high schools and, thereby, should be alerted when considering reopenings.

Microblog credibility indicators regarding misinformation of genetically modified food on Weibo

The considerable amount of misinformation on social media regarding genetically modified (GM) food will not only hinder public understanding but also mislead the public to make unreasoned decisions. This study discovered a new mechanism of misinformation diffusion in the case of GM food and applied a framework of supervised machine learning to identify effective credibility indicators for the misinformation prediction of GM food. Main indicators are proposed, including user identities involved in spreading information, linguistic styles, and propagation dynamics. Results show that linguistic styles, including sentiment and topics, have the dominant predictive power. In addition, among the user identities, engagement, and extroversion are effective predictors, while reputation has almost no predictive power in this study. Finally, we provide strategies that readers should be aware of when assessing the credibility of online posts and suggest improvements that Weibo can use to avoid rumormongering and enhance the science communication of GM food.

PM2.5 exposure and anxiety in China: evidence from the prefectures

BACKGROUND

Anxiety disorders are among the most common mental health concerns today. While numerous factors are known to affect anxiety disorders, the ways in which environmental factors aggravate or mitigate anxiety are not fully understood.

METHODS

Baidu is the most widely used search engine in China, and a large amount of data on internet behavior indicates that anxiety is a growing concern. We reviewed the annual Baidu Indices of anxiety-related keywords for cities in China from 2013 to 2018 and constructed anxiety indices. We then employed a two-way fixed effect (FE) model to analyze the relationship between PM2.5 exposure and anxiety at the prefectural level.

RESULTS

The results indicated that there was a significant positive association between PM2.5 and anxiety index. The anxiety index increased by 0.1565258 for every unit increase in the PM2.5 level (P < 0.05), which suggested that current PM2.5 levels in China pose a considerable risk to mental health.

CONCLUSION

The enormous impact of PM2.5 exposure indicates that the macroscopic environment can shape individual mentality and social behavior, and that it can be extremely destructive in terms of societal mindset.

Exposure to outdoor air pollution and its human health outcomes: A scoping review

Despite considerable air pollution prevention and control measures that have been put into practice in recent years, outdoor air pollution remains one of the most important risk factors for health outcomes. To identify the potential research gaps, we conducted a scoping review focused on health outcomes affected by outdoor air pollution across the broad research area. Of the 5759 potentially relevant studies, 799 were included in the final analysis. The included studies showed an increasing publication trend from 1992 to 2008, and most of the studies were conducted in Asia, Europe, and North America. Among the eight categorized health outcomes, asthma (category: respiratory diseases) and mortality (category: health records) were the most common ones. Adverse health outcomes involving respiratory diseases among children accounted for the largest group. Out of the total included studies, 95.2% reported at least one statistically positive result, and only 0.4% showed ambiguous results. Based on our study, we suggest that the time frame of the included studies, their disease definitions, and the measurement of personal exposure to outdoor air pollution should be taken into consideration in any future research. The main limitation of this study is its potential language bias, since only English publications were included. In conclusion, this scoping review provides researchers and policy decision makers with evidence taken from multiple disciplines to show the increasing prevalence of outdoor air pollution and its adverse effects on health outcomes.