Raises risk
Secondhand smoke
breathing other people's tobacco smoke. Home & environment.
- Verdict
- Raises riskStudies link it to higher cancer risk.
- How sure
- Rung 5 · EstablishedLarge randomized trials or overwhelming, consistent human evidence; reflected in major guidelines.
- How big
- 20% to 30% higher lung cancer risk in nonsmokers who are exposed, per the CDC.
The rung shows how sure the science is, not how big the effect is. How to read these ratings
Cancers affected
Lung
What the evidence shows
The CDC says nonsmoking adults exposed to secondhand smoke raise their lung cancer risk by 20% to 30%, and that it causes more than 7,300 lung cancer deaths a year among U.S. adults who don't smoke. There is no safe level of exposure.
What to do
Keep your home and car smoke-free.
Sources
To take it to your doctor, print this page.
Step by step
For the whole picture, from prevention and screening to treatment and life after, see the lung cancer page.