Objective: We investigated the association of lip pigmentation with smoking and melanin pigmentation in the gingiva.
Design: Case-control study.
Setting: Health check-up in an institute.
Subjects and methods: Photos of 213 males employed in an institution were assessed in terms of pigmentation in lip and gingiva.
Main outcome measures: Prevalence and scores of lip and gingival pigmentation and smoking status.
Results: Among subjects displaying lip and gingival pigmentation, 73% and 87% respectively, were current smokers, whereas 33% and 27% of individuals lacking pigmentation were current smokers respectively. Odds ratios of current smoking relative to lip and gingival pigmentation were 5.6 (95% confidence interval: 2.8-11.1) and 17.0 (8.1-36.0) respectively. Daily consumption, duration of smoking and lifetime exposure exhibited significant correlation with scores of lip and gingival pigmentation (P<0.0001). Odds ratios increased in lip and gingival pigmentation upon exposure. In current smokers, scores of lip and gingival pigmentation demonstrated meaningful correlation (P<0.0001); moreover, 95% of participants with lip pigmentation were positive for gingival pigmentation.
Conclusion: These results indicated the presence of a striking association between smoking and pigmentation in the lip and gingiva, which was stronger with respect to gingival pigmentation. Health professionals could educate smokers, utilizing visible symptoms in the lip and gingiva.