An alarming analysis has found that Sub-Saharan Africa recorded the largest increase worldwide in deaths from second-hand smoke in 2023, with figures almost doubling since 1990, reports The Independent.
The number of people exposed rose by 98.5% between 1990 and 2023, and according to The Lancet Global Health report, these new statistics contrast sharply with wealthier countries, where figures have declined.
Second-hand smoke was also linked to an estimated 84 000 deaths in the African region in 2023 and 3.9m years of healthy life lost, as well as 1.66m deaths globally.
The analysis looked at second-hand smoke exposure across 204 countries and territories over more than three decades.
The report showed that exposure has fallen sharply in wealthier countries, as smoking rates have declined and smoke-free laws have become more widespread. The proportion of people exposed fell by about a third between 1990 and 2023.
In contrast, some 234m people in sub-Saharan Africa were exposed in 2023, up from 118m three decades earlier.
The Middle East and North Africa also saw a large increase at more than 72%. Qatar saw the largest increase in the absolute number of people exposed, at a huge 558.9%, with the United Arab Emirates at 343.1%.
The report, the Global Burden of Disease Study, does not give a detailed analysis of whether this meant more people were smoking. In many regions, the proportion of people exposed to second-hand smoke has declined since 1990, but population growth means more people are exposed.
However, the exposure does broadly mirror patterns of active smoking, with many low- and middle-income countries still seeing persistently high numbers of smokers.
The leading cause of death associated with adult exposure to second-hand smoke was ischaemic heart disease, with 5.2m years of healthy life lost to lower respiratory infections.
High-income countries have made significant gains, with countries like Denmark and Norway seeing the proportion of people exposed to second-hand smoke fall by almost half since 1990. Canada also fell by 40%, with Latin America and the Caribbean also seeing a steep decline.
Fertility affected
The authors called for stronger tobacco-control measures to protect people, particularly women and children – infertility being 1.4 times higher in women who smoke, while females exposed to second-hand smoke have a 1.2 times higher risk of infertility, according to a WHO report.
Health Policy Watch reports that while it is harder to quantify the effect of smoking on men’s fertility, a recent review of 44 studies – conducted between 2000 and 2026 – involving more than 60 000 men, found that smoking was associated with “an increase in reproductive dysfunction”.
Across different populations, more men who smoked had erectile dysfunction and ejaculation problems than those who did not.
The review also found that smoking may increase the risk of azoospermia (no sperm in semen), asthenozoospermia (poor sperm motility) and teratozoospermia (abnormal sperm shape).
E-cigarettes and hookahs
There is growing evidence of the impact of e-cigarettes on infertility. A study of more than 4 500 women in the United States found that ever use of e-cigarettes was associated with a 20% reduction in fecundability.
Two studies that included women who smoked cigarettes or waterpipes (hookahs or shisha) found a similar increased risk of infertility, but no studies specifically address waterpipe use only.
Some studies have found that waterpipe smoking may be associated with lower sperm quality, such as less semen volume, lower sperm motility and fewer sperm with a normal shape.
A recent study confirmed that hookah smoking may reduce sperm volume, but did not affect motility, so the WHO has recommended more research “to determine the effects of waterpipe smoking on sperm parameters in men”.
Impact on infertility treatment
Smoking may reduce the success of infertility treatments, but there is “some inconsistency across the studies”, according to the report.
Research from 21 studies showed that cigarette smoking was linked to fewer live births and fewer pregnancies, “which indicate that the chances of successful treatment outcomes may be halved by cigarette smoking”.
“A more recent, albeit smaller, study involving about 300 women showed no differences in fertilisation or pregnancy rates between women who did and did not smoke cigarettes or between women who did or did not use e-cigarettes and/or waterpipes.”
The first report of a link between smoking and infertility was published in 1979 by the US Surgeon General, who reported that women who smoked were more likely to be infertile and experience abnormal menstruation and concluded that smoking may impair fertility.
Study details
Global, regional, and national prevalence of second-hand smoke and attributable disease burden in 204 countries and territories, 1990–2023: a systematic analysis for the Global Burden of Disease Study 2023
Published in The Lancet Global Health on 7 September 2026
GBD 2023 Second-hand smoke Collaborators*
Summary
Background
Second-hand smoke (SHS) exposure remains a major source of morbidity and mortality among non-smokers. This study presents the first dedicated Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) publication to systematically quantify SHS prevalence and evaluate its effect as a global risk factor across a broader range of outcomes.
Methods
Using the GBD 2023 comparative risk assessment framework, we estimated SHS exposure prevalence and attributable disease burden across 204 countries and territories from 1990 to 2023, stratified by age and sex. Exposure estimates were derived by synthesising population-based surveys and household composition data through spatiotemporal Gaussian process regression. Relative risks for nine health outcomes, now including asthma, were estimated using the Burden of Proof methodology, and applied to calculate attributable deaths and disability-adjusted life-years (DALYs).
Findings
In 2023, an estimated 2·71 billion (95% UI 2·44–3·02) people worldwide were exposed to SHS, including 767 million (687–858) children aged 0–14 years. Age-standardised prevalence was highest in southeast Asia, east Asia, and Oceania (48·4% [44·0–53·4]), with female individuals in some countries experiencing nearly 1·8 times the exposure prevalence of male individuals. Despite a 22·2% (10·6–32·4) decline in global age-standardised prevalence since 1990, this progress has not been sufficient to reduce the absolute number of exposed individuals, which has remained stable globally and has risen sharply in sub-Saharan Africa (98·5% [62·0–144·4] increase) and North Africa and the Middle East (72·1% [47·8–101·8] increase). In 2023, SHS exposure accounted for 1·66 million (1·33–2·07) deaths and 44·8 million (35·8–54·3) DALYs globally. Ischaemic heart disease was the leading contributor to SHS-attributable DALYs (12·0 million [9·31–15·2]) overall, while lower respiratory infections predominated among children (5·16 million [3·48–7·12]).
Interpretation
We estimated that SHS remains a substantial driver of global health loss, particularly through cardiovascular and paediatric respiratory diseases. Persistent geographical disparities and growing absolute numbers of exposed individuals in several regions underscore the urgent need for accelerated implementation and enforcement of comprehensive tobacco control measures, particularly to protect women and children in both public and domestic environments.
The Independent article – Exposure to second-hand smoke doubles in sub-Saharan Africa (Open access)
Health Policy Watch article – More evidence of link between smoking and infertility (Open access)
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