DNA Differences May Explain COPD Risk in Both Smokers and Non-smokers, Study Says

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by Santiago Gisler |

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Differences in DNA may explain lung health and the risk of chronic obstructive pulmonary disease (COPD) in both smokers and non-smokers and could help in the future development of preventive and therapeutic strategies against COPD, a large-scale study reports.

The study, “New genetic signals for lung function highlight pathways and chronic obstructive pulmonary disease associations across multiple ancestries,” was published in the journal Nature Genetics.

Although smoking is the leading cause of COPD, 1 in 5 people with the disease have never smoked. Risk factors for the disease that are not related to smoking include occupational exposure to dust, chemicals or fumes, as well as genetics.

A team led by researchers at the University of Leicester in the U.K. analyzed the DNA of 400,000 participants, and assessed their lung function through a breath test. By comparing differences in DNA with lung function test results, the team could associate certain genetic changes with specific lung traits.

“It is well established that smoking is a major risk factor for COPD, yet the mechanisms which cause smokers and non-smokers alike to develop COPD are poorly understood,” Louise Wain, PhD, lead author of the study, said in a university press release.

“Our study provides vital clues as to why some people develop COPD and others don’t, and new knowledge that will help to develop new treatments to halt the decline in lung function observed in patients with COPD,” Wain added.

Out of a total of 20 million differences found in the participants’ DNA, 279 were predictive of lung health and COPD risk in addition to smoking, and 139 of these differences were new.

The researchers then divided the participants into 10 different risk groups according to their genetic profile and lung function.

Based on this classification, eight out of 10 smokers in the highest risk group develop COPD. The team found that although the risk was much lower among non-smokers than smokers, two in 10 non-smokers in the highest genetic risk group developed COPD.

“We are closer to understanding the genetic causes of this condition in people who have never smoked,” said Martin Tobin, PhD, chair of the Leicester Precision Medicine Institute and co-lead author of the study. “People who smoke also appear to have a similar pattern of genetic risk factors, alongside the added risk of tobacco smoking.”

The hope is that the identified genetic differences can aid in the development of new preventive and therapeutic strategies against COPD in both smokers and non-smokers. The genetic differences found in the study include biological pathways that can potentially serve as therapy targets.

Still, co-lead author Ian Hall, PhD, noted that the most important measure to prevent COPD is by avoiding or quitting smoking. Another preventive strategy is reducing exposure to high levels of air pollutants.

“Patients who already have COPD need new treatments,” said Hall, who is the director of the Nottingham Biomedical Research Centre. “We are delighted that our research has brought this a step closer.”

The Wellcome Trust, the Medical Research Council, the British Lung Foundation, and the National Institute for Health Research all provided support for the study.