Tobacco use and caries risk among adolescents – a longitudinal study in Sweden

BACKGROUND Smoking and the use of smokeless tobacco have a detrimental impact on general and oral health. The relationship to dental caries is however still unclear. As caries is a multi-factorial disease with clear life-style, socio-economic and socio-demographic gradients, the tobacco use may be a co-variable in this complex rather than a direct etiological factor. Our aim was to analyze the impact of tobacco use on caries incidence among adolescents, with consideration to socio-economic variables by residency, using epidemiological data from a longitudinal study in the region of Halland, Sweden. METHODS The study population consisted of 10,068 adolescents between 16-19 years of age from whom yearly data on caries and tobacco use (cigarette smoking and use of smokeless tobacco) were obtained during the period 2006-2012. Reported DMFS increment between 16 and 19 years of age (∆DMFS) for an individual was considered as the primary caries outcome. The outcome data were compared for self-reported never vs. ever users of tobacco, with consideration to neighborhood-level socio-economy (4 strata), baseline (i.e., 16 years of age) DMFS and sex. The region consists of 65 parishes with various socio-economic conditions and each study individual was geo-coded with respect to his/her residence parish. Neighborhood (parish-level) socio-economy was assessed by proportion of residing families with low household purchasing power. RESULTS ∆DMFS differed evidently between ever and never users of tobacco (mean values: 1.8 vs. 1.2; proportion with ∆DMFS > 0: 54.2% vs. 40.5%; p < 0.0001). Significant differences were observed in each neighborhood-level socio-economic stratum. Even after controlling for baseline DMFS and sex, ∆DMFS differed highly significantly between the ever and never users of tobacco (overall p < 0.0001). CONCLUSION Tobacco use was clearly associated with increased caries increment during adolescence. Hence, this factor is relevant to consider in the clinical caries risk assessment of the individual patient as well as for community health plans dealing with oral health.