"When there's a total smoking ban in the home, we found that smokers are more likely to reduce tobacco consumption and attempt to quit than when they're allowed to smoke in some parts of the house," said Wael K. Al-Delaimy, MD, PhD, professor and chief of the Division of Global Health in the UC San Diego Department of Family and Preventive Medicine.

"The same held true when smokers report a total smoking ban in their city or town. Having both home and city bans on smoking appears to be even more effective."

Al-Delaimy said the findings underscore the public health importance of smoking bans inside and outside the home as a way to change smoking behaviors and reduce tobacco consumption at individual and societal levels.

"California was the first state in the world to ban smoking in public places in 1994 and we are still finding the positive impact of that ban by changing the social norm and having more homes and cities banning smoking," he said.

"These results provide quantitative evidence that smoking bans that are mainly for the protection of nonsmokers from risks of secondhand smoke actually encourage quitting behaviors among smokers in California. They highlight the potential value of increasing city-level smoking bans and creating a win-win outcome."

Al-Delaimy and colleagues surveyed 1,718 current smokers identified as a representative sample of the adult population in California. They found that total home smoking bans were significantly associated with reduced consumption and successful quitting, but partial bans were not. Similarly, smokers who report smoking is broadly banned in their city were also more likely to attempt to quit and succeed than in places where smoking is not banned.

The researchers found that total home bans were more effective in reducing smoking among persons 65 years and older and among females, while city smoking bans were significantly associated with quit attempts in males, but not females. Total home bans were more effective in households without children, possibly reflecting the ultimate goal of cessation rather than primarily reducing children's secondhand smoke exposure. Neither race nor income significantly modified relations between total home bans and smoking reductions.