Salivary matrix metalloproteinase-8 in smoker and non-smoker adolescents

Objectives: Matrix metalloproteinase-8 (MMP-8) is a neutrophil collagenase precursor associated with inflammation and degradation of extracellular matrix components. The activity of MMP-8 is increased also in oral inflammation (Sorsa et al. Ann NY Acad Sci 1994). We hypothesized that there would be a difference in MMP-8 among smokers and non-smokers indicating a difference in the degree of inflam-mation of oral mucosa. Methods: The subjects were 15-year old 139 boys and 153 girls participating in a comprehensive oral health study in Kotka Health Center with emphasis on smoking prevention. A structured questionnaire was used to enquire the subjects health habits. Paraffin-wax stimulated saliva samples were taken and analyzed by immunofluorescence assay for MMP-8 levels. A sub-sample of subjects who reported quitting smoking (n=31) was also analysed. The results were studied by cross tabulation and Studentxs t-test. Results: Of the subjects reported beeing daily smokers (n=64) were 55% girls and 45% boys. Of smokers 25%, of non-smokers 36%, respectively, reported tooth brushing once daily. The mean MMP-8 levels were 235.7µg/l in smokers, 241.0µg/l in non-smokers (n.s.). There was no differ-ence between sexes in the MMP-8 values. No correlation between tooth brushing frequency and salivary MMP-8 level could either be found. Conclusion: This study failed to show any association between salivary MMP-8 level and smoking status in the 15-year old subjects. Consequently, smoking did not seem to reflect in inflammation of oral mucosa as indirectly assessed by use of the salivary MMP-8 analysis. Supported by grant TYH3245 from the Helsinki University Central Hospital.