Don’t smoke at home or in the car, and don’t let guests smoke indoors

2. Don’t smoke at home or in the car, and don’t let guests smoke indoors

Cost: There is no monetary cost and it takes little time. The challenge is simply having the conversation with family members and guests to keep them from smoking indoors.

In plain terms: Around 600,000 people worldwide die each year from secondhand smoke exposure; nearly 30% of those are children. Long‑term exposure to secondhand smoke raises the risk of hypertension, heart disease, and stroke by roughly 30% compared to non‑exposed individuals. Smoke inhaled at home is even more harmful than smoke encountered outside.

Benefit: In 2004, secondhand smoke caused 603,000 deaths globally — about 1.0% of all deaths worldwide, with children accounting for 28% of those fatalities. Pooled data from 57 studies show that people exposed to secondhand smoke have a 1.28‑fold higher chance of developing hypertension, a 1.39‑fold higher risk of heart disease, a 1.50‑fold higher risk of myocardial infarction, and a 1.36‑fold higher risk of stroke compared to non‑exposed individuals. The risk is greater when exposure occurs at home rather than outside.

Evidence grade: A

Sources: Öberg M, Jaakkola MS, Woodward A, Peruga A, Prüss-Ustün A (2011). Worldwide burden of disease from exposure to second-hand smoke: a retrospective analysis of data from 192 countries. Lancet: "603,000 deaths were attributable to second-hand smoke in 2004, which was about 1·0% of worldwide mortality. 47% of deaths from second-hand smoke occurred in women, 28% in children, and 26% in men","61% of DALYs were in children". <https://doi.org/10.1016/S0140-6736(10)61388-8>; (2026). The Associations Between Secondhand Smoke Exposure and Various Cardiovascular Diseases: A Meta-Analysis. Nicotine & Tobacco Research: 57 research,"hypertension (OR: 1.28, 95% CI: 1.15 to 1.40), heart disease (OR: 1.39, 95% CI: 1.28 to 1.50), myocardial infarction (OR: 1.50, 95% CI: 1.17 to 1.84), stroke (OR: 1.36, 95% CI: 1.18 to 1.54)""Home exposure has a higher risk of CVD than non-home exposure". <https://doi.org/10.1093/ntr/ntaf111>

Notes: Focus on home environments first, since people spend more time there and pooled research indicates that indoor secondhand smoke is more harmful than outdoor exposure. Children bear 61% of the overall health burden caused by secondhand smoke. For personal smoking cessation, see item 1 in this section.