Association Between Smoking Intensity and Duration and Tooth Loss Among Finnish Middle-aged Adults

The Northern Finland Birth Cohort 1966 Project

Toni Similä; Jorma I. Virtanen


BMC Public Health. 2015;15(1141) 

In This Article


Tobacco smoking is a risk factor for both general and oral diseases.[1,2] Researchers have identified cigarette smoking as the most important behavioral risk factor for periodontal disease, which in turn is the main cause of tooth loss among the middle-aged and elderly.[3–5] Studies have shown that cigarette smoking associates with fewer remaining teeth and a higher prevalence of edentulousness.[6–8]

In addition, researchers have found an exposure-dependent relation between cigarette smoking and tooth loss among young adults.[9,10] Moreover, a recent study of health professionals revealed a dose-dependent relation, but failed to investigate smoking duration or intensity among current smokers.[6] Among middle-aged Danes who were daily and former smokers, the number of cigarettes smoked associated with tooth loss, and smoking duration associated with tooth loss.[11]

When analyzing the effect of smoking, its duration and intensity are the most important aspects to take into account. However, most studies have focused on either the average daily number of cigarettes smoked or years of smoking rather than combining these two measures to represent smoking history. Recently, pack-years have begun to find favor, because this measure takes into account both aspects of smoking with equal weighting (pack-years = years of smoking * the daily consumption of cigarettes/cigarettes per pack (e.g., 20)). Moreover, pack-years or its derivatives have served to reflect the burden of smoking history when the outcome is tooth loss.[9,10] Few studies have examined the association between different metrics of smoking history (e.g., intensity and duration) and tooth loss with a clinically determined number of missing teeth.[4,11]

In Finland, a National Health Act in the 1970s entitled all young people to free dental care; since then, all Finns have enjoyed access to subsidized dental care, which has greatly improved the oral health of the population. Our aim was to examine the association between smoking and tooth loss among middle-aged Finns with a specific focus on the intensity and duration of smoking history. We used data from the Northern Finland Birth Cohort 1966 Project (NFBC1966), a valuable source of comprehensive information on public and individual health in general.[12] We also examined the association of smoking with tooth loss by gender, education and tooth brushing frequency.