A recent BMC Public Health journal study investigates the effects of air pollution and lifestyle factors on mortality.
Study: Health impacts of lifestyle and ambient air pollution patterns on all-cause mortality: a UK Biobank cohort study. Image Credit: NadyGinzburg / Shutterstock.com
The crucial role of lifestyle choices on health and well-being
Lifestyle factors such as physical activity, sleep, dietary habits, nicotine exposure, and body mass index (BMI) are crucial to combat the economic and medical implications associated with many diseases.
Previous studies have highlighted that physical inactivity, poor diet, heavy alcohol consumption, and smoking contribute to 60% of premature mortality. These unhealthy lifestyle factors also increase the risk of coronary heart disease, cancer, hypertension, and diabetes; therefore, maintaining a healthy lifestyle is essential for improving the overall quality of life.
Ambient air pollution is closely linked to human health. In fact, one 2018 report indicated that 6% of global deaths were attributed to ambient air pollution. Although humans are exposed to multiple air pollutants simultaneously, most studies have investigated the impact of individual air pollutants on mortality risks.
It is imperative to understand the combined relationship between lifestyle factors, air pollution, and all-cause mortality. Furthermore, more evidence is needed to elucidate how interactions between lifestyles and air pollution impact health.
About the study
The current population-based prospective cohort study was conducted to assess the potential association between various lifestyle factors, air pollutants including particulate matter (PM2.5, PM10, PM2.5−10), nitrogen oxides (NOx), and all-cause mortality risk.
The United Kingdom Biobank data were used to obtain genetic and health information for over 500,000 people between 37 and 73 years of age. For the current study, 271,075 U.K. Biobank participants fulfilled all eligibility criteria.
At baseline, information on five different lifestyle factors, including smoking, alcohol consumption, physical activity, diet, and sleep, was obtained. The Land Use Regression (LUR) models, which were developed from the European Study of Cohorts for Air Pollution Effects projects, were used to estimate annual average PM2.5, PM10, and PM2.5−10 and NOx. Data on mortality rates were obtained from the National Health Service (NHS) Information Center for England and Wales and the NHS Central Register for Scotland.
Study findings
Healthy lifestyles were associated with a reduced risk of all-cause mortality, whereas higher exposure to NOx, PM2.5, and PM10 was positively correlated with an increased risk of all-cause mortality. The strength of the association between unhealthy lifestyles and mortality risk differed across air pollution subgroups, with a stronger association observed in subgroups with lower air pollution levels.
Approximately 23% of the study participants had an unhealthy lifestyle, 61% followed a general lifestyle, and 16% had a healthy lifestyle. The mean age of the participants with a healthy lifestyle was 56 years, most of whom were White and male.
Among the air pollutants, PM2.5 was robustly associated with mortality, possibly due to its small size and ability to remain suspended in the atmosphere for prolonged periods, causing lung damage. Particulate matter also absorbs toxic substances from the air and penetrates the lungs.
PM10 primarily contains natural elements instead of heavy metals and is relatively less toxic than PM2.5. However, the combined exposure to multiple air pollutants was associated with a greater impact than individual exposure.
Consistent with previous reports, the study findings emphasize that good sleep quality, sufficient physical activity, non-smoking, and a healthy diet could positively reduce mortality rates. Among different lifestyle factors, smoking was most strongly associated with mortality, which could be attributed to the fact that nicotine exposure increases inflammation and induces oxidative stress.
Alcohol consumption was not significantly correlated with all-cause mortality. This finding contradicts a previous study that revealed moderate drinking is healthier than non-drinking because wine contains biologically active compounds like anthocyanins and resveratrol that reduce oxidative stress and regulate lipid metabolism. Considering the contradictory findings, more research is needed to better understand the association between alcohol consumption and mortality risks.
Conclusions
Multiple lifestyle factors have a synergistic protective effect on mortality risks; therefore, it is important to maintain a variety of lifestyle factors to promote good health. Conversely, extensive research has documented a cumulative adverse impact of multiple air pollutants on mortality.
The association between mortality risk and unhealthy lifestyles became more significant as the density of air pollution reduced from high to low. These findings emphasize the importance of well-coordinated measures to improve air quality and adopt a healthy lifestyle, which should minimize mortality risk.
The main limitations of the current study include the potential presence of measurement errors and the existence of additional behavioral factors that were not considered. Data were also unavailable to study the effects of ozone, carbon monoxide, and sulfur dioxide exposure on mortality risk. Resid confounding may have also impacted the results despite controlling for multiple covariates.