Table 2 Characteristics of the longitudinal studies included in this review (n = 07 studies)

Author/ Country/ Follow-up

Follow-up

Subjects

Assessment of smoking status

Assessment of the outcome

Main findings

Dietrich et al. 2007

(EUA)

16 years

43,112 health men professionals with 40 to 75 years from Heatlth Professionals Follow-up Study

Self-reported questionnaire (mailed questionnaire every 2 years)

Never smokers: < 20 packs of cigarettes in their lives.

Ever smokers: average number of cigarettes per day.

Former smokers: years since cessation (time since cessation (<  1, 1–2, 3–5, 6–9, > 10)

Self-reported questionnaire.

Subjects reported baseline number of teeth and incident tooth loss in two-year intervals thereafter.

Outcome: incident tooth loss

Hazard Ratio (CI 95%) for incidence of first tooth loss:

Never: 1.0 (reference)

Current (+45cig/d): 3.0 (2.4–3.9)

Former (10+ yrs): 1.2 (1.2–1.3)

Dietrich et al. 2015 (Germany)

8.6 years (mean)

21,810 participants from EPIC-Postdam Study with at least 1 natural tooth at baseline

Self-reported questionnaire

Never smokers

Current smokers: (< 15 and ≥ 15 cig/day)

Former smokers: (< 10, 10 to < 20, ≥20 years since cessation)

Self-reported questionnaire.

In the last follow-up, patients reported number of natural teeth and the number of teeth lost since study baseline.

Outcome: incident tooth loss

Odds ratio (CI 95%) for incidence of tooth loss:

Males <50y

Never: 1.0 (reference)

Former smoker ≥20 years: 0.91 (0.66–1.27)

Current smokers ≥15 cig/day: 3.64 (3.00–4.42)

Males 50-59y

Never: 1.0 (reference)

Former smoker ≥20 years: 1.11 (0.94–1.32)

Current smokers ≥15 cig/day: 2.82 (2.36–3.37)

Males 60-70y

Never: 1.0 (reference)

Former smoker ≥20 years: 1.18 (0.98–1.44)

Current smokers ≥15 cig/day: 2.47 (1.85–3.30)

Females <50y

Never: 1.0 (reference)

Former smoker ≥20 years: 0.92 (0.70–1.20)

Current smokers ≥15 cig/day: 2.47 (2.11–2.89)

Females 50-59y

Never: 1.0 (reference)

Former smoker ≥20 years: 1.20 (0.99–1.44)

Current smokers ≥15 cig/day: 2.06 (1.60–2.66)

Females 60-70y

Never: 1.0 (reference)

Former smoker ≥20 years: 0.98 (0.78–1.23)

Current smokers ≥15 cig/day: 1.79 (1.21–2.63)

Jansson & Lavstedt 2002 (Sweden)

20 years

507 subjects from the population of the Country of Stockholm was perfomerd in 1970 (Lavstedt & Eklund 1975)

Interview

Life-time smoking exposure expressed as number of years with a mean consumption of 20 cigarettes per day.

Never smokers: did not smoke in 1970 and 1990

Smokers: smoked in 1970 and 1990

Former smokers: stopped smoking between 1970 and 1990

Clinical examination

Outcome: Number of teeth lost between 1970 and 1990

Number (SD) of tooth lost:

Never smokers (n = 220): 2.2 (3.0)

Smokers (n = 163): 3.7 (4.8)

Former smokers (n = 124): 3.2 (4.0)

Klein et al. 2004 (EUA)

10 years

2764 subjects (53–96 yrs. of age) from Beaver Dam, WI (1998-2000)

Examiner-administered interview

Never smokers: persons who smoked 100 or fewer cigarettes in their lifetime.

Current smokers

Former smokers

Examiner-administered

interview

Outcome: Tooth loss (missing some or all teeth)

Odds ratio (CI 95%) for missing some or all teeth:

Never: 1.0 (reference)

Current: 4.04 (2.52–6.49)

Former: 1.57 (1.25–1.98)

Krall et al. 1997 (EUA) (females)*

6 ± 2 yrs.

(mean)

584 medically healthy post-menopausal females, screened for nutritional intervention trials at the USDA Human Nutrition Research Center on Aging at Tufts University (Dawson-Hughes et al., 1990).

Annually applied questionnaire

Non-smokers (never or former): did not use cigarettes at any time subsequent to baseline.

Continuous smokers: used cigarettes at baseline and at each subsequent examination.

Quitters: smoked cigarettes at baseline but reported no cigarette or other tobacco product use at follow-up examinations

Clinical examination and questionnaire.

Teeth counted by a nurse practitioner at baseline.

Number of teeth lost since baseline and year in which they were lost were assessed by questionnaire at the end of the study.

Outcome: Risk of tooth loss; Tooth loss rate/10 yrs

Relative Risk (CI 95%) of tooth loss:

Non-smokers (n = 225): 1.0 (ref)

Continuous smokers (n = 09): 3.4 (2.1–5.7)

Quitters (n = 14): 0.7 (0.3–1.8)

Tooth loss rate/10 years

Non-smokers (n = 225): 0.8

Continuous smokers (n = 09): 2.73

Quitters (n = 14): 0.55

Krall et al. 2006 (EUA)

35 yrs. (maximum follow-up)

789 men who participated in the Veterans Administration Dental Longitudinal Study from 1968 to 2004.

Interviewer-administered questionnaire

Never smokers: men who had never smoked tobacco (cigarettes, pipes, or cigars) either before baseline or during the study

Former smokers: men who smoked cigarettes before baseline but not during follow-up

Continuous smokers: men who smoked cigarettes before baseline and continued to smoke cigarettes at each evaluation

Quitters: men who smoked cigarettes before baseline and quit smoking and abstained from any type of tobacco product

Clinical examination every 3 years

Outcome: Tooth loss per person, teeth lost per year per 1000 teeth at risk

No of teeth lost per person

Never smokers (n = 264): 1.0 (0.3)

Former smokers (n = 283): 1.0 (0.4)

Continuous smokers (n = 113): 2.0 (0.4)

Quitters (n = 129): 3.0 (1.8)

No of teeth lost per year per 100 teeth at risk:

Never smokers (n = 264): 2 (0.7)

Former smokers (n = 283): 3 (0.11)

Continuous smokers (n = 113): 8 (0.17)

Quitters (n = 129): 7 (2.2)

Okamoto et al. 2006 (Japan)

4 years

1332 (30–59 years) male Japanese

Self-reported questionnaire

Non-smokers: those did not smoke at either check-up.

Smokers: smoked at both the baseline and the second check-up. Subdivided into 3 groups based on the number of cigarettes they smoked per day (1–19, 20, or > 21).

Former smokers: stopped smoking at baseline and had not resumed by the second check-up.

Clinical examination Seven calibrated examiners did the baseline clinical examination and a second examination four years later.

Outcome: Teeth lost during 4 yrs

Odds ratio (CI 95%) for tooth loss during 4 years:

Age group 30–39 years:

Never: 1.0 (reference)

Former smoker: 0.36 (0.04–3.28)

Current smokers 1–20 cig/day: 3.30 (1.09–10.0)

Current smokers > 21 cig/day: 2.47 (0.72–8.53)

Age group 40–49 years:

Never: 1.0 (reference)

Former smoker: 1.14 (0.59–2.21)

Current smokers 1–20 cig/day: 1.48 (0.76–2.91)

Current smokers > 21 cig/day: 2.03 (1.00–4.10)

Age group 50–59 years:

Never: 1.0 (reference)

Former smoker: 1.07 (0.44–2.61)

Current smokers 1–20 cig/day: 1.34 (0.49–3.68)

Current smokers > 21 cig/day: 1.67 (0.56–4.99)