Secondhand Smoke

Secondhand Smoke is one of the modifiable risk factors tracked by the IHME Global Burden of Disease Study. The attributable deaths shown here represent the estimated number of deaths that could be prevented if exposure to this risk factor were eliminated or reduced to optimal levels. Understanding risk factor contributions helps prioritize public health interventions and policy decisions.

Risk factor attribution uses comparative risk assessment methodology. A single death may be partially attributed to multiple risk factors, so attributable death counts should not be summed across risk factors. Data covers 204 countries from 1990 to the latest available year.

Secondhand smoke (environmental tobacco smoke) exposure causes approximately 1.2 million deaths annually among non-smokers, including both adults and children. Secondhand smoke contains over 7,000 chemicals, of which at least 70 are known carcinogens. In adults, it increases the risk of coronary heart disease by 25-30%, stroke by 20-30%, and lung cancer by 20-30%. In children, it causes sudden infant death syndrome (SIDS), acute respiratory infections, ear infections, worsened asthma, and impaired lung development. Approximately 40% of children, 33% of male non-smokers, and 35% of female non-smokers worldwide are exposed to secondhand smoke regularly. Exposure is highest in countries with weak tobacco control legislation and where indoor smoking remains common — particularly in East Asia, Eastern Europe, and parts of the Middle East.

Secondhand Smoke contributes to mortality from ischaemic heart disease, stroke, lung cancer, COPD, and 1 other conditions. The magnitude of impact varies by country depending on exposure levels, population demographics, and the availability of preventive and treatment services.

Comprehensive smoke-free legislation in all indoor workplaces, public places, and public transport is the most effective intervention. Article 8 of the WHO Framework Convention on Tobacco Control (FCTC) mandates such laws. Smoke-free homes and cars protect children. Enforcement of smoke-free policies, public education about secondhand smoke harms, and cessation support for smokers complement legislative measures. Smoke-free policies do not merely shift smoking outdoors — they also motivate quit attempts and reduce overall consumption.