Association of Long-Term Exposure to Fine Particulate Matter and Cardio-Metabolic Diseases in Low- and Middle-Income Countries: A Systematic Review

Abstract

: Background: Numerous epidemiological studies indicated high levels of particulate matter less than2.5 μm diameter (PM2.5) as a major cardiovascular risk factor. Most of the studies have been conducted in high-income countries (HICs), where average levels of PM2.5 are far less compared to low- and middle- income countries (LMICs), and their socio-economic profile, disease burden, and PM speciation/composition are very different. We systematically reviewed the association of long-term exposure to PM2.5 and cardio-metabolic diseases (CMDs) in LMICs. Methods: Multiple databases were searched for English articles with date limits until March 2018. We included studies investigating the association of long-term exposure to PM2.5 (defined as an annual average/average measure for 3 more days of PM2.5 exposure) and CMDs, such as hospital admissions, prevalence, and deaths due to CMDs, conducted in LMICs as defined by World Bank. We excluded studies which employed exposure proxy measures, studies among specific occupational groups, and specific episodes of air pollution. Results: A total of 5567 unique articles were identified, of which only 17 articles were included for final review, and these studies were from Brazil, Bulgaria, China, India, and Mexico. Outcome assessed were hypertension, type 2 diabetes mellitus and insulin resistance, and cardiovascular disease (CVD)-related emergency room visits/admissions, death, and mortality. Largely a positive association between exposure to PM2.5 and CMDs was found, and CVD mortality with effect estimates ranging from 0.24% to 6.11% increased per 10 μg/m3 in PM2.5. CVD-related hospitalizations and emergency room visits increased by 0.3% to 19.6%. Risk factors like hypertension had an odds ratio of 1.14, and type 2 diabetes mellitus had an odds ratio ranging from 1.14–1.32. Diversity of exposure assessment and health outcomes limited the ability to perform a meta-analysis. Conclusion: Limited evidence on the association of long-term exposure to PM2.5 and CMDs in the LMICs context warrants cohort studies to establish the association.

The role of cities in reducing the cardiovascular impacts of environmental pollution in low- and middle-income countries

“…However, most (65%) of these studies were from China and none were conducted in North or sub-Saharan Africa, which represent nearly a fifth of the world's population. Overall, long-term exposure to PM 2.5 was positively associated with cardiovascular mortality (effect estimate range: 0.2-6.1% per 10 μg/m 3 ) and with CVD-related hospitalizations and emergency room visits (effect estimate range: 0.3-19.6% per 10 μg/m 3 ) [41].…”

“…The impacts and magnitude of long-term exposure in LMICs are less understood. A recent systematic review identified just 17 studies of long-term exposure to outdoor PM 2.5 and cardiometabolic disease in LMICs [41]. However, most (65%) of these studies were from China and none were conducted in North or sub-Saharan Africa, which represent nearly a fifth of the world's population.…”

Air Pollution as a Cause of Obesity: Micro-Level Evidence from Chinese Cities

“…Several studies focused on various pollutants in the air and found that these pollutants could negatively affect multiple systems and organs in the human body at a specific concentration, thereby having a significant impact on population mortality and susceptibility to other diseases [4,5,6]. Specifically, most recent literature paid attention to the adverse effects of air pollution on cancer and chronic diseases [7,8,9,10,11,12]. For example, Jaganathan et al (2019) [8] reviewed the relationship between long-term exposure to fine particulate matter and cardio-metabolic diseases in developing countries; Filippini et al (2019) [10] analyzed the association between outdoor air pollution and childhood leukemia based on meta-analysis; and Gaio et al (2019) [11] focused on air pollution and lipid profile.…”

“…Specifically, most recent literature paid attention to the adverse effects of air pollution on cancer and chronic diseases [7,8,9,10,11,12]. For example, Jaganathan et al (2019) [8] reviewed the relationship between long-term exposure to fine particulate matter and cardio-metabolic diseases in developing countries; Filippini et al (2019) [10] analyzed the association between outdoor air pollution and childhood leukemia based on meta-analysis; and Gaio et al (2019) [11] focused on air pollution and lipid profile. A large amount of evidence depicted the adverse effects of air pollution on human health problems.…”

Building capacity for air pollution epidemiology in India

“…An interquartile range (IQR) increase in PM 2.5 (41.1 µg/m 3 ) was associated with increased type 2 diabetes mellitus (T2DM) prevalence ratio (PR) by 1.14 (95% CI = 1.08, 1.20), elevated levels of fasting glucose by 0.26 mmol/L (95% CI = 0.19, 0.32), and hemoglobin A1c/glycated hemoglobin (HbA1c) by 0.08% (95% CI = 0.06, 0.10). 11 …”