Air pollution linked to lung cancer, heart failure

News and analysis by Dan Telvock, Investigative Post's environmental reporter

Air pollution can cause lung cancer and increase the risk of heart failure, according to two studies published Tuesday in The Lancet Journal.

The first study found that extended exposure to particulate air pollution commonly called soot can increase the risk of lung cancer even at concentrations below European Union limits, which are stricter than U.S. limits in some instances. The research led the authors to question whether there are safe levels of air pollution.

The second study found that heart failure or death was associated with increases in a number of air pollutants.

These studies have some meaning locally because of the renewed focus on air quality in neighborhoods surrounding the Peace Bridge, which attracts an average 13,000 cars and 3,500 trucks per day. State Health Department data shows elevated cases of lung cancer among men in the ZIP Code closest to the bridge and slightly elevated for women. The Health Department does not break down heart failure hospitalization and mortality rates by ZIP codes in a publicly available format.

Ole Raaschou-Nielsen from the Danish Cancer Society Research Center and a team of researchers focused on the risk of lung cancer with longterm exposure to nitrogen oxides and particulate matter pollution emitted from traffic, industry and heating homes.

The researchers used data from 17 similar studies in nine countries in Europe that included more than 300,000 people exposed to a wide range of pollution levels. Among the participants, 2,095 developed lung cancer over 13 years. The study took into account whether people smoked, their diets and where they worked.

They discovered that for every five micrograms per cubic meter of PM2.5 pollution, the risk of lung cancer rose by 18 perent. PM2.5  particles are less than 2.5 micrometers in diameter.

For every increase of 10 micrograms per cubic meter of PM10 pollution, the risk increased by 22 percent. PM10 particles are less than 10 micrometers in diameter.

There was no association found between nitrogen oxides and lung cancer.

“At this stage, we might have to add air pollution, even at current concentrations, to the list of causes of lung cancer and recognise that air pollution has large effects on public health,” both Takashi Yorifuji of Okayama University Graduate School of Environmental and Life Science and Saori Kashima of Hiroshima University in Japan said in a prepared statement.

The team of researchers also noted that the association between particulate matter air pollution and lung cancer persisted even at annual concentrations below European Union limits for PM10 (40 micrograms per cubic meter  for annual exposure in Europe and 50 micrograms per cubic meter in the United States) and PM2.5 (25 micrograms per cubic meter in Europe  for annual exposure and 12 micrograms per cubic meter in the United States).

“We found no threshold below which there was no risk; the results showed a picture that ‘the more the worse, the less the better,'” said the authors in a press release.

The second study reviewed data from 35 studies in 12 countries, including the United States, for exposure to sulfure dioxide, carbon monoxide, ozone and particulate matter.

The researchers found that hospitalizations and deaths attributed to heart failure were associated with increases in all types of the pollutants but ozone. Patients were at most risk the day they breathed in the polluted air. Heart failure affects more than 20 million people worldwide and is one of the most common reasons for hospital admission, the authors said.

The authors concluded that a mean reduction in  PM2.5 of 3.9 micrograms per cubic meter for a daily exposure would prevent 7,978 heart failure hospitalizations and save $333 million in health care costs per year. That would be an 11 percent drop in the 24-hour standard for PM2.5 in the United States, which is 35 micrograms per cubic meter. Europe does not have a 24-hour standard for these small particles.

“While the role of air pollution is well recognised as a risk factor for heart attacks, it has been less clear whether exposure increases the risk of adverse events in patients with other cardiovascular conditions like heart failure,” Nicholas Mills of the University of Edinburgh said in a prepared statement.

“Since the entire population is exposed to air pollution, even modest reductions in air pollution could have major cardiovascular health benefits and substantial healthcare cost savings.”