The influence of smoking and race on adult periodontitis and serum IgG2 levels.

Smoking is a known risk factor for developing periodontal diseases, but the risk appears to be greater for white smokers than black smokers. Furthermore, it has been reported that young white subjects have significantly lower levels of serum IgG2 than their non-smoking counterparts while young black adult subjects are generally not affected by smoking. These relationships prompted the hypothesis that adult white subjects, including periodontitis subjects, who smoked would have more attachment loss than adult black subjects and that smoking would be associated with lower serum IgG2 levels in adult white subjects but not in adult black subjects. Smoking status was established from serum cotinine levels determined by radioimmunoassay. Serum IgG subclass levels were determined using radial immunodiffusion. White adult periodontitis (AP) and non-periodontitis (NP) subjects who smoked had greater mean attachment loss per site than their non-smoking counterparts. Furthermore, smoking white AP subjects and their age-matched NP controls had substantially less IgG2 in their serum. In marked contrast, we were unable to detect any increase in periodontal destruction or a significant decrease in serum IgG2 levels in smoking black AP subjects or their age-matched controls. However, IgG1 and IgG4 levels were reduced in smoking black AP subjects. IgG3 was the only subclass in adults that was unaffected by smoking. IgG2 can be a good opsonin and may help control periodontitis-associated bacteria in adults. Even though a cause-and-effect relationship has not been established, the association between a smoking-related decrease in serum IgG2 and an increase in periodontal destruction in white subjects is striking.