Harmful effects of secondhand smoke

The harmful effects of second-hand smoke have been
recorded since 1928.1 In the 1970s, scientific interest in
potential adverse health effects of second-hand smoke
expanded.2,3 Since then, evidence about ill health because
of second-hand smoke has accumulated from many
studies done in different parts of the world. However,
second-hand smoke remains a common indoor air
pollutant in many regions. Comprehensive legislation to
protect non-smokers from exposure to second-hand smoke
in all indoor workplaces and public places has been
implemented in some countries and subnational
jurisdictions, but 93% of the world’s population is still
living in countries not covered by fully smoke-free public
health regulations.4–8
Knowledge about the links between second-hand
smoke and specific diseases has been summarised in
comprehensive assessments or reviews by the International
Agency for Research on Cancer,9 WHO,10 the
California Environmental Protection Agency,11 and the
US Surgeon General.12 Studies of the effects of smokefree
laws have drawn attention to the importance of
second-hand smoke as a preventable cause of disease
and disability. The International Agency for Research on
Cancer reported in 2009 that “wide-ranging bans on
smoking in the workplace are followed by as much as a
10–20% reduction in acute coronary events in the first
year post-ban”.13,14 The 171 countries that are parties to the
WHO Framework Convention on Tobacco Control
“recognize that scientific evidence has unequivocally
established that exposure to tobacco smoke causes death,
disease, and disability”.15 Furthermore, they recognise
that there is no safe level of exposure to tobacco smoke
and therefore recommend effective measures to provide
protection from exposure to tobacco smoke, as envisioned
by Article 8 of the WHO Framework Convention. The
guidelines for implementation
of Article 8 stipulate that
smoking and tobacco smoke be totally eliminated in all
indoor workplaces, indoor public places, and on public
transport, and be eliminated as appropriate in other
public places.16
Some country-specific studies of the health effects
attributable to second-hand smoke have been reported;17–19
however, this study provides the first assessment of the
worldwide burden of disease from second-hand smoke.
Information about the magnitude and distribution of the
burden of disease from second-hand smoke is particularly
important for policy makers to plan preventive strategies.
We aimed to estimate the worldwide burden of disease
attributable to second-hand smoke, measured as deaths
and disability-adjusted life-years (DALYs) lost for children
and adult non-smokers.