Moderate laws were those that covered just public places but excluded workplaces like manufacturing facilities. Weak laws covered some public places but left many out.
Individuals living in the counties with the most comprehensive smoke-free policies had a significantly lower risk for lung cancer compared with counties that had no smoke-free laws (P = .002). The people living in these counties were 7.9% less likely to be diagnosed with lung cancer compared with people living in counties with no protection.
“We believe that smoke-free laws, when comprehensive and strong, have a really good chance of reducing the number of lung cancer cases,” Dr Hahn said. “If you extrapolate the data we had over a 20-year period, if we had smoke-free ordinances in every county of our state we would see 325 fewer lung cancer cases a year.”
The study did not, however, show differences in lung cancer incidence among people in counties with only moderate or weak laws and those with no protection.
“Even the moderate laws did not have an effect on risk,” Dr Hahn said. “These laws leave people behind, such as those in manufacturing facilities or other workplaces not open to the public.”
Dr Hahn compared it with antibiotics: “if you do not take enough antibiotics, for example for bronchitis, you are probably not going to get better,” she said.
“Smoke-free laws are like public health vaccines. If you don’t have the proper dose you are not going to have the expected result.”
- Hahn EJ, Rayens MK, Wiggins AT, Gan W, Brown HM, Mullett TW. Lung cancer incidence and the strength of municipal smoke-free ordinances. Cancer. 2017 Nov 28. doi: 10.1002/cncr.31142 [Epub ahead of print]