It's been clear for years that smokers have a higher risk of periodontal disease but there's also research showing secondhand smoke can also increase the risk.
Researchers at the University of North Carolina-Chapel Hill, using data from another study that included 2,379 nonsmokers ages 53–74, have concluded that exposure to secondhand tobacco smoke for a few hours each day can double a person’s risk of severe periodontal disease. People exposed to secondhand smoke for 25 hours or less each week had a 29 percent increased chance and for those exposed more than 26 hours the odds were twice as high.
The researchers defined severe periodontitis as five or more periodontal sites with probing pocket depth of 5 millimeters or more and clinical attachment levels of 3 millimeters or more in those sites. Other outcomes were extent of periodontal probing depths of 4 millimeters or more and extent of clinical attachment levels of 3 millimeters or more, according to the study.
The study appears in the December issue of the American Journal of Public Health. It can be found at http://ajph.aphapublications.org/doi/full/10.2105/AJPH.2010.300069.
In 2004, the U.S. surgeon general concluded that the scientific evidence was sufficient to infer a causal relationship between tobacco and periodontal disease. In 2006, the surgeon general stated there is no risk-free level of exposure to secondhand smoke.