Years of Exposure to Air Pollution and Road Traffic Noise May Raise Heart Failure Risk

Exposure to air pollution and road traffic noise over the course of many years may be associated with an increased risk of developing heart failure, and the correlation appears to be even greater in people who are former smokers or have high blood pressure, according to new research published today in the Journal of the American Heart Association, an open access journal of the American Heart Association.

“We found that long-term exposure to specific air pollutants and road traffic noise increased the risk of incident heart failure, especially for former smokers or people with hypertension, so preventive and educational measures are necessary,” said Youn-Hee Lim, Ph.D., lead author of the study and assistant professor in the section of environmental health within the department of public health at the University of Copenhagen in Copenhagen, Denmark. “To minimize the impact of these exposures, broad public tactics such as emissions control measures should be implemented. Strategies like smoking cessation and blood pressure control must be encouraged to help reduce individual risk.”

This analysis examined the impact of long-term environmental exposure, specifically from air pollution and road traffic noise, on the development of heart failure in a group of female nurses in Denmark over a 15-to-20-year period.

Researchers collected data from a prospective study of over 22,000 members of the all-female Danish Nurse Cohort study. The women were 44 years of age and older at study enrollment and living in Denmark. Participants were recruited in 1993 or 1999, and when they enrolled, each woman completed a comprehensive questionnaire on body mass index, lifestyle factors (smoking, alcohol consumption, physical activity and dietary habits), pre-existing health conditions, reproductive health and working conditions. Information on heart failure diagnoses was gathered throughout the 20-year follow by linking study participants to the Danish National Patient Register, which includes records on all health care provided at hospitals in Denmark. Patient data was collected through December 31, 2014.

The study group lived in rural, urban and suburban areas throughout Denmark. To best measure individual exposure to air pollution and road traffic noise, researchers maintained records of each individual’s residential addresses, including any moves to new residences from 1970 and 2014. To determine levels of air pollution, the yearly average concentrations of two components, fine particulate matter (PM2.5) and nitrogen dioxide (NO2), were measured using a Danish air pollution modeling system. Road traffic noise levels within a three-kilometer radius from the participants’ residential addresses were estimated using a validated model system called Nord2000 and measured in decibels (dB), the standard unit for the intensity of sound.

The analysis of various pollutants and their effects on incident heart failure found:

  • For every 5.1 µg/m3 increase in fine particulate matter exposure over three years, the risk of incident heart failure increased by 17%;
  • For every 8.6 µg/m3 increase in NO2 exposure over three years, the risk of incident heart failure increased by 10%;
  • For every 9.3 dB increase in road traffic noise exposure over three years, the risk of incident heart failure increased by 12%; and,
  • Increased exposure to fine particulate matter and status as a former smoker were associated with a 72% increased risk of incident heart failure.

“We were surprised by how two environmental factors – air pollution and road traffic noise – interacted,” Lim said. “Air pollution was a stronger contributor to heart failure incidence compared to road traffic noise; however, the women exposed to both high levels of air pollution and road traffic noise showed the highest increase in heart failure risk. In addition, about 12% of the total study participants had hypertension at enrollment of the study. However, 30% of the nurses with heart failure incidence had a previous history of hypertension, and they were the most susceptible population to air pollution exposure.”

The study has several limitations. Researchers did not have information on additional variables that may have affected the results of the analysis, such as measures for each individual’s exposure to indoor air pollution or occupational noise; the amount of time spent outdoors; glass thickness of the windows of their home, which may influence noise pollution levels; if they had a hearing impairment; or individual socioeconomic status. Additionally, almost one-fourth of the original participants in the Danish Nurse Cohort were excluded from the final analysis because information was missing at the beginning of the study or at the study’s completion, so selection bias may be a contributing factor. The researchers also note that since they investigated Danish female nurses’ exposure levels and health outcomes, a generalization of the results to men or other populations warrants caution.

Previous research has shown an association between air pollution and cardiovascular disease, and the American Heart Association detailed a collection of research on the risks of pollution in a scientific statement in 2004, with additional updated findings added in 2010. In 2020 the American Heart Association American Heart Association published a scientific statement and policy guidance to address the implications of air pollution amid the COVID-19 pandemic and beyond. The policy statement discusses policy guidance at the local, state and federal levels to improve the health of our communities. Short-term exposure to high levels of some air pollutants has also been linked to heart failure.

Source: American Heart Association

Cleaning Up the Air Could Help Prevent Alzheimer’s

Dennis Thompson wrote . . . . . . . . .

Air pollution causes you to gasp and wheeze. Smog puts strain on your hearts and inflames your lungs.

Could dirty air also be costing you your brain health?

A trio of new studies finds that air quality appears linked to a risk of thinking declines and dementia, and bad air might even promote toxic brain proteins that are a hallmark of Alzheimer’s disease.

“This is extremely exciting, because it indicates the potential that improving air quality levels could have on mortality levels, other areas of health, and also perhaps risk of dementia,” said Claire Sexton, director of scientific programs and outreach for the Alzheimer’s Association.

In the first study, researchers found that reduction of fine particulate pollution and smog over a decade was tied to reductions in dementia risk among women.

The study followed more than 2,200 women between the ages of 74 and 92 without dementia who’d enrolled in a long-term study of brain health. Researchers tracked their thinking, reasoning and memory skills as they aged, and compared the results to the air quality of their various communities.

The women’s risk of dementia decreased by up to 26% for every 10% improvement in air quality in their neighborhoods, the researchers concluded. Women in areas with cleaner air had dementia risk similar to that seen in women two to three years younger.

Cleaner air also seems to slow overall decline in cognitive function and memory, similar to women one to two years younger, results showed.

These benefits occurred regardless of age, education or neighborhood, said lead researcher Xinhui Wang, an assistant professor of research neurology at the University of Southern California.

“Air pollution is a modifiable risk factor,” Wang said. “The impact will be great because everybody is exposed to some level of air pollution. If we reduce air pollution, everybody will benefit.”

A second study from researchers led by Noemie Letellier, a postdoctoral scholar at University of California, San Diego, found that reductions in fine particle pollution between 1990 and 2000 caused dementia and Alzheimer’s risk to fall among a group of more than 7,000 people in France.

Dementia risk fell by 15% and Alzheimer’s risk by 17% for every microgram reduction in air pollution per cubic meter of air, researchers found. Again, the changes benefited everyone, regardless of their income or where they lived in a community.

The third study, led by Christina Park, a doctoral student in the University of Washington’s Department of Epidemiology, provided a potential explanation for why air pollution might affect brain health.

Researchers found that people with longer exposure to particle pollution and smog had higher levels of beta amyloid, a sticky protein that can clump in the brain. Amyloid plaques are one of the hallmarks of Alzheimer’s disease.

Air pollution also might increase dementia risk by causing inflammation in the body and by damaging heart and lung health, Wang and Sexton said.

So battling air pollution might not be just a way to stop climate change and protect heart health, but a way to actually reduce dementia among aging folks, experts concluded.

“There’s been improvements in air quality over a number of years and decades, but there’s still so much further to go,” Sexton said. “Globally, more than 90% of people breathe air that fails to meet World Health Organization standards.”

All three studies will be presented Monday at the Alzheimer’s Association annual meeting, held both in Denver and online. Findings presented at medical meetings are considered preliminary until published in a peer-reviewed journal.

Source: HealthDay

Developing Countries Pay Steep Economic and Health Costs Because of High In-car Air Pollution

In an international study published by the journal Environment International, the University of Surrey led an international team of air pollution experts in monitoring pollution hotspots in 10 global cities: Dhaka (Bangladesh); São Paulo (Brazil); Guangzhou (China); Medellín (Colombia); Cairo (Egypt); Addis Ababa (Ethiopia); Chennai (India); Sulaymaniyah (Iraq); Blantyre (Malawi); and Dar-es-Salaam (Tanzania). 

Surrey’s Global Centre for Clean Air Research (GCARE) set out to investigate whether the amount of fine air pollution particles (PM2.5) drivers inhaled is connected to the duration drivers spend in pollution hotspots and socio-economic indicators such as gross domestic product (GDP).

Across all the cities in the study, researchers found that drivers only needed to spend a short amount of time in high-pollution hotspots to inhale a significant amount of PM2.5 particles. For example, drivers in Guangzhou and Addis Ababa spent 26 and 28 per cent of their commute in hotspot areas, which contributed to 54 and 56 per cent of the total amount of air pollution inhaled on their trip.

The researchers found that the cities where drivers were exposed to the highest levels of PM2.5 pollution – Dar-es-Salaam, Blantyre and Dhaka – also experienced higher death rates per 100,000 commuting car population per year. The low PM2.5 levels in Medellín, São Paulo and Sulaymaniyah corresponded with very low death rates.

The international study assessed economic losses by measuring a city’s death rate caused by PM2.5 car exposure against its GDP per capita. It found that, for most cities, lower GDP linked directly to more significant economic losses caused by in-car PM2.5 exposure – with Cairo and Dar-es-Salaam being impacted the most (losses of 8.9 and 10.2 million US dollars per year, respectively).

The team also found that, except for Guangzhou, cities with higher GDP per capita have less hotspot areas during an average route trip, thus decreasing the risk to drivers.

Professor Prashant Kumar, Principal Investigator of CArE-Cities Project, Associate Dean (International) and Founding Director of GCARE at the University of Surrey, said: “Our global collaborative project has confirmed that air pollution disproportionately affects developing countries. Many countries are caught in a vicious cycle where their low GDP leads to higher pollution exposure rate for drivers, which leads to poorer health outcomes, which further damages the economy of those cities. This is discouraging news – but it should galvanise the international community to find and deploy measures that mitigate the health risks faced by the world’s most vulnerable drivers.”

Professor Shi-Jie Cao, a collaborative partner from the Southeast University, said: “If we are ever to make a world where clean air is available to all, it will take a truly global collaborative effort – such as CArE-Cities. We hope to continue to work closely with Surrey and other global partners, sharing knowledge and expertise that will make a cleaner future a reality.”

Professor Adamson Muula, a collaborative partner from formerly University of Malawi and now Head of Public Health at the Kamuzu University of Health Sciences (KUHeS), said: “If developing countries are to not be left behind in the struggle against air pollution and climate change, it is important that we build the capacity and knowledge to gather on-the-ground data. This project is a small but a significant step in the right direction for Malawians; a direction which will lead to better decisions and cleaner air for Malawi.”

Source: University of Surrey

Air Pollution Linked to High Blood Pressure in Children; Other Studies Address Air Quality and the Heart

A meta-analysis of 14 air pollution studies from around the world found that exposure to high levels of air pollutants during childhood increases the likelihood of high blood pressure in children and adolescents, and their risk for high blood pressure as adults. The study is published in a special issue on air pollution in the Journal of the American Heart Association, an open access journal of the American Heart Association.

Other studies look at: the effects of diesel exhaust on the muscle sympathetic nerve; the impact of pollutants on high blood pressure; rates of hospital readmission for heart failure among those exposed to high levels of ambient air pollution; and risk of stroke and heart attack after long-term exposure to high levels of particulate matter. The studies include health outcomes of people who were exposed to pollutants in the United States, China and Europe.

High blood pressure during childhood and adolescence is a risk factor for hypertension and heart disease in adulthood. Studies on air pollution and blood pressure in adolescents and children, however, have produced inconsistent conclusions. This systematic review and meta-analysis pooled information from 14 studies focused on the association between air pollution and blood pressure in youth. The large analysis included data for more than 350,000 children and adolescents (mean ages 5.4 to 12.7 years of age).

“Our analysis is the first to closely examine previous research to assess both the quality and magnitude of the associations between air pollution and blood pressure values among children and adolescents,” said lead study author Yao Lu, M.D., Ph.D., professor of the Clinical Research Center at the Third Xiangya Hospital at Central South University in Changsha, China, and professor in the department of life science and medicine at King’s College London. “The findings provide evidence of a positive association between short- and long-term exposure to certain environmental air pollutants and blood pressure in children and adolescents.”

The analysis included 14 studies published through September 6, 2020, exploring the impact of long-term exposure (≥30 days) and/or short-term exposure (<30 days) of ambient air pollution on blood pressure levels of adolescents and/or children in China and/or countries in Europe.

The studies were divided into groups based upon length of exposure to air pollution and by composition of air pollutants, specifically nitrogen dioxide and particulate matter with diameter ≤10 μm or ≤2.5 μm. (The majority of research linking heart disease with particulate matter focuses on particle matter mass, which is categorized by aerodynamic diameter – μm or PM.) Fine particles are defined as PM2.5 and larger; coarse particles are defined at PM10; and the concentrations of particulate matter are typically measured in their mass per volume of air (μg/m3).

The meta-analysis concluded:

  • Short-term exposure to PM10 was significantly associated with elevated systolic blood pressure in youth (the top number on a blood pressure reading).
  • Periods of long-term exposure to PM2.5, PM10 and nitrogen dioxide were also associated with elevated systolic blood pressure levels.
  • Higher diastolic blood pressure levels (the bottom number on a blood pressure reading) were associated with long-term exposure to PM2.5 and PM10.

“To reduce the impact of environmental pollution on blood pressure in children and adolescents, efforts should be made to reduce their exposure to environmental pollutants,” said Lu. “Additionally, it is also very important to routinely measure blood pressure in children and adolescents, which can help us identify individuals with elevated blood pressure early.”

The results of the analysis are limited to the studies included, and they did not include data on possible interactions between different pollutants, therefore, the results are not generalizable to all populations. Additionally, the analysis included the most common and more widely studied pollutants vs. air pollutants confirmed to have heart health impact, of which there are fewer studies.

Source: American Heart Association

Long-term Exposure to Low Levels of Air Pollution Increases Risk of Heart and Lung Disease

Exposure to what is considered low levels of air pollution over a long period of time can increase the risk of heart attack, stroke, atrial fibrillation and pneumonia among people ages 65 and older, according to new research published today in the American Heart Association’s flagship journal Circulation.

Air pollution can cause harm to the cardiovascular and respiratory systems due to its effect on inflammation in the heart and throughout the body. Newer studies on the impact of air pollution on health are focused on understanding the potential harm caused by long-term exposure and are researching the effects of multiple air pollutants simultaneously. Research on air pollution is critical to informing recommendations for national environmental and health guidelines.

“People should be conscious of the air quality in the region where they live to avoid harmful exposure over long periods of time, if possible,” said Mahdieh Danesh Yazdi, Pharm.D., M.P.H., Ph.D., a post-doctoral research fellow at the Harvard T.H. Chan School of Public Health and lead author of the study. “Since our study found harmful effects at levels below current U.S. standards, air pollution should be considered as a risk factor for cardiovascular and respiratory disease by clinicians, and policy makers should reconsider current standards for air pollutants.”

Researchers examined hospitalization records for more than 63 million Medicare enrollees in the contiguous Unites States from 2000 to 2016 to assess how long-term exposure to air pollution impacts hospital admissions for specific cardiovascular and respiratory issues. The study measured three components of air pollution: fine particulate matter (PM2.5), nitrogen dioxide (NO2) and ozone (O3). Using hundreds of predictors, including meteorological values, satellite measurements and land use to estimate daily levels of pollutants, researchers calculated the study participants’ exposure to the pollutants based upon their residential zip code. Additional analysis included the impact of the average yearly amounts of each of the pollutants on hospitalization rates for non-fatal heart attacks, ischemic strokes, atrial fibrillation and flutter, and pneumonia.

Statistical analyses found thousands of hospital admissions were attributable to air pollution per year. Specifically:

  • The risks for heart attacks, strokes, atrial fibrillation and flutter, and pneumonia were associated with long-term exposure to particulate matter.
  • Data also showed there were surges in hospital admissions for all of the health outcomes studied with each additional unit of increase in particulate matter. Specifically, stroke rates increased by 2,536 for each additional ug/m3 (micrograms per cubic meter of air) increase in fine particulate matter each year.
  • There was an increased risk of stroke and atrial fibrillation associated with long-term exposure to nitrogen dioxide.
  • Pneumonia was the only health outcome in the study that seemed impacted by long-term exposure to ozone; however, researchers note there are currently no national guidelines denoting safe or unsafe long-term ozone levels.

“When we restricted our analyses to individuals who were only exposed to lower concentrations of air pollution, we still found increased risk of hospital admissions with all of the studied outcomes, even at concentration levels below current national standards,” added Danesh Yazdi. “More than half of the study population is exposed to low levels of these pollutants, according to U.S. benchmarks, therefore, the long-term health impact of these pollutants should be a serious concern for all, including policymakers, clinicians and patients.”

The researchers further stratified the analyses to calculate the cardiovascular and respiratory risks associated with each of the pollutants among patient subgroups including gender, race or ethnicity, age and socioeconomic factors, detailed in the study.

The causality in the study could only be interpreted and not proven definitively due to the limitations of the data available, which may have not included other known CVD risk factors. In addition, coding errors can occur in the Medicare database, which would impact the analyses.

Source: American Heart Association