Exposure to passive smoking is linked to increased prevalence of
chronic obstructive pulmonary disease (COPD) and this association
could cause 1.9 million deaths among non-smokers in China,
according to a study published in this week's edition of The
Lancet.
It is the largest study ever in China showing a strong
relationship between passive smoking and COPD, a lung disease in
which the lungs are damaged making it hard to breathe.
Dr Peyman Adab and Professor K K Cheng, University of
Birmingham, the United Kingdom, and colleagues from the Hong Kong
School of Public Health and Guangzhou 12th Hospital used data from
the Guangzhou Biobank Cohort Study to do their research. A total of
15,379 non-smokers aged over 50 were included in this analysis.
The researchers found that people exposed to high levels of
passive smoking, equivalent to 40 hours a week for more than five
years, were on average 48 percent more likely to develop COPD.
There were also significant associations between reported
respiratory symptoms and increasing passive smoking exposure,
generally a 16 percentage increased risk for any respiratory
symptom.
The authors conclude: "If our risk estimates are correct, and
assuming that current mortality and passive smoking exposure
patterns continue, of the 240 million people aged over 50 alive
today in China, high exposure to passive smoking would result in
about 1.9 million excess deaths from COPD among those who have
never smoked."
The prevalence of COPD ranged from 0.23 percent to 18.3 percent
worldwide. A recent large epidemiological survey estimated the
prevalence of COPD in China was 8.2 percent.
Figures from the Ministry of Health show that China has an
estimated 350 million smokers, almost a third of the world's 1.1
billion smokers. According to Cheng, in China smoking is a major
risk factor for COPD, and also the proportion of non-smokers who
develop COPD is much higher than in most other countries.
Though passive smoking poses a smaller risk compared to active
smoking, the impact is quite considerable. According to a study
published in the 2005 Chinese Journal of Epidemiology,
more than 460 million Chinese are regularly exposed to second-hand
smoking, the majority being women and children.
Generally, most women are non-smokers and they are exposed to
high levels of passive smoking at home, at work and other public
places.
"This is a big public health problem as 100,000 people died due
to passive smoking each year in China, with COPD contributing about
half of them," says Cheng.
Except for smoking and passive smoking, occupational exposure,
some genetic variants and indoor air pollution from biomass
combustion may contribute to COPD.
"Not smoking is the main way to prevent COPD. Many lives of
non-smokers could be saved if they are not exposed to passive
smoking," suggests Cheng.
Due to relaxed smoking laws and a strong smoking culture, few
restrictions exist to forbid passive smoking in many public places
in China.
The upcoming Olympics is regarded as a good opportunity to
promote smoking ban in public places. All Olympic stadiums, the
Olympic village and all restaurants with The Beijing Organizing
Committee for the Games of the XXIX Olympiad (BOCOG) contracts will
be smoke-free zones.
It is also estimated that by the end of the year Ministry of
Health will complete the revision on Regulations on Hygienic
Management in Public Places, which will supposedly support a
smoking ban in public places.
(China Daily September 5, 2007)