Rates of incurable lung disease are higher than
previously thought, a study across 12 countries suggests.
Tests in almost 9,500 adults aged over 40 found
one in 10 had chronic obstructive respiratory disease (COPD),
which causes breathing difficulties.
Rates are set to rise further as the population
ages, reported the US researchers in the Lancet study.
COPD is currently the fifth leading cause of
death worldwide but is set to become the third leading cause
by 2020.
COPD is an umbrella term for a range of conditions
including chronic bronchitis and emphysema.
There are an estimated two million people in
the UK who have COPD but have not been diagnosed.
Smoking link
Researchers from Oregon Health and Science
University carried out spirometry tests to measure breathing
in individuals from 12 countries.
They found 11.8% of men and 8.5% of women had
moderate or higher stage COPD - more than has been reported
in other studies.
There was also a strong link with age with
the risk of the disease almost doubling with every 10 years
over the age of 40.
Smoking is a major factor in developing the
disease and explains much of the difference between rates in
men and women.
But the researchers also found a fairly high
prevalence of COPD in individuals who had never smoked, which
they said raises questions about genetic susceptibility.
"This worldwide study showed higher levels
and more advanced staging of spirometrically confirmed COPD
than have typically been reported," said study leader Dr Sonia
Buist.
Encouraging people to stop smoking was becoming
increasingly important as people were living longer, she concluded.
But she said because of ageing populations
"if every smoker in the world were to stop smoking today, the
rates of COPD would probably continue to increase for the next
20 years".
A separate study in the same issue of the Lancet
found that poor lung function shortly after birth is associated
with poor lung function in early adulthood.
Better understanding of lung development in
the womb may help to prevent COPD in later life, the researchers
concluded.
Dame Helena Shovelton, chief executive of the
British Lung Foundation said: "There are people with COPD who
have never smoked and this research shows that deprivation,
dust exposure and lung development in the womb play a vital
role in causing the disease.
"The research also highlights how much more
work is needed to improve our understanding of how environmental,
socioeconomic and other factors can cause COPD."
