Smoking increases risk of tooth loss: A meta-analysis of the literature

Table 1 Baseline characteristics of patients of the 24 included studies

Author (yr)	Country	Study design	Base population	Sex	n	Mean age (yr) of subjects	Measure of association	Pattern of comparison (vsnever smokers)	Relative risk	Adjustment for socioeconomic status	Adjustment for behavior associated with oral health3	Definition, No. of tooth loss
Eklund et al[16] (1994)	United States	Cohort	General population	M/F	2207	42.0	RR	Ever	1.88 (1.04-3.38)1	Yes	Yes	Incidence of tooth loss
Norlén et al[18] (1996)	Sweden	Cross-sectional	General population	M	483	68.0	OR	Former	2.60 (1.34-5.03)	Yes	Yes	> 16 loss
								Current	3.02 (1.50-6.07)
								Ever	2.79 (1.73-4.52)2
Slade et al[30] (1997)	Australia	Cohort	General population	M/F	693	73.0	RR	Former	2.55 (1.48-4.40)	No	Yes	Incidence of tooth loss
								Current	2.06 (0.92-4.62)
								Ever	2.39 (1.52-3.74)2
Suominen-Taipale et al[31] (1999)	Finland	Cross-sectional	General population	M/F	213	40.0	OR	Ever	1.4 (1.0-2.0)	Yes	No	28 loss
Xie et al[17] (1999)	Finland	Cross-sectional	General population	M/F	293	81.0	OR	Ever	3.12 (1.56-6.23)	No	No	28 loss
Yoshida et al[33] (2001)	Japan	Cross-sectional	Petroleum chemical plant employees	M	2015	39.5	OR	Former	1.27 (0.89-1.81)	No	Yes	> 1 loss
								Current	1.54 (1.20-1.96)
								Ever	1.45 (1.18-1.77)2
Randolph et al[32] (2001)	United States	Cross-sectional	General population	M/F	3050	74.1	OR	Former	1.26 (1.04-1.54)	Yes	No	> 14 loss
								Current	1.69 (1.31-2.20)
								Ever	1.40 (1.20-1.63)2
Ylöstalo et al[19] (2004)	Finland	Cross-sectional	General population	M/F	8409	31.0	OR	Ever	1.73 (1.39-2.15)2	Yes	Yes	> 6 loss
Cunha-Cruz et al[22] (2004)	Brazil	Cross-sectional	University employees	M/F	3840	40.0	OR	Ever	1.62 (1.35-1.96)	Yes	Yes	> 26 loss
Klein et al[34] (2004)	United States	Cross-sectional	General population	M/F	2794	65.0	OR	Former	1.57 (1.25-1.98)	Yes	No	> 1 loss
								Current	4.04 (2.52-6.49)
								Ever	1.88 (1.53-2.31)2
Tanaka et al[35] (2005)	Japan	Cross-sectional	Hospital	F	1002	29.8	OR	Former	1.42 (0.91-2.20)	Yes	No	> 1 loss
								Current	1.56 (1.18-2.06)2
								Ever	1.52 (1.20-1.93)2
Susin et al[20] (2005)	Brazil	Cross-sectional	General population	M/F	974	48.7	OR	Ever	1.50 (1.18-1.90)2	No	No	> 7 loss
Susin et al[37] (2006)	Brazil	Cross-sectional	General population	M/F	612	21.5	OR	Ever	1.30 (1.02-1.66)2	Yes	No	> 1 loss
Okamoto et al[36] (2006)	Japan	Cross-sectional	Hospital	M	1332	43.5	OR	Former	1.11 (0.68-1.85)	No	No	> 1 loss
								Current	1.59 (1.21-2.08)2
								Ever	1.46 (1.15-1.85)2
Krall et al[23] (2006)	United States	Cohort	People who received dental care	M	789	49.0	HR	Former	1.3 (0.9-1.7)	Yes	Yes	Incidence of tooth loss
								Current	2.1 (1.5-3.1)
								Ever	1.7 (1.3-2.2)2
Ojima et al[40] (2007)	Japan	Cross-sectional	General population	M/F	1314	30.0	OR
				Total				Former	0.80 (0.45-1.43)2	No	Yes	> 1 loss
								Current	1.91 (1.41-2.59)2
								Ever	1.58 (1.21-2.07)2
				M				Former	1.25 (0.55-2.86)
								Current	2.21 (1.40-3.50)
								Ever	1.93 (1.30-2.88)2
				F				Former	0.52 (0.23-1.18)
								Current	1.70 (1.13-2.55)
								Ever	1.34 (0.93-1.93)2
Mundt et al[24] (2007)	Germany	Cross-sectional	General population	M/F	2501	49.5	OR	Former	1.71 (1.27-2.30)	Yes	Yes	> 26 loss
								Current	2.58 (2.03-3.27)
								Ever	2.19 (1.82-2.64)2
Dietrich et al[25] (2007)	United States	Cohort	Health professional	M	43112	56.0	HR	Former	1.57 (1.53-1.62)2	Yes	Yes	Incidence of tooth loss
								Current	2.25 (2.14-2.37)2
								Ever	1.75 (1.69-1.80)2
Hanioka et al[38] (2007)	Japan	Cross-sectional	General population	M/F	3999	60.0	OR
				Total				Former	1.18 (0.87-1.59)	No	Yes	> 20 loss
								Current	2.19 (1.71-2.80)
								Ever	1.70 (1.40-2.05)2
				M				Former	1.29 (0.92-1.80)
								Current	2.22 (1.61-3.06)
								Ever	1.72 (1.36-2.17)2
				F				Former	0.86 (0.46-1.60)
								Current	2.14 (1.45-3.15)
								Ever	1.66 (1.19-2.31)2
Musacchio et al[39] (2007)	Italy	Cross-sectional	General population	M	1226	76.8	OR	Former	3.42 (2.42-4.82)	Yes	No	28 loss
								Current	4.01 (2.59-6.20)
								Ever	3.64 (2.77-4.77)2
Haugejorden et al[26] (2008)	Norway	Cross-sectional	General population	M/F	1092	47.9	OR	Ever	2.2 (1.3-3.7)	Yes	Yes	> 20 loss
Cunha-Cruz et al[41] (2008)	United States	Cohort	People who received dental care	M/F	12631	51.0	RR	Former	1.3 (1.1-1.4)	No	Yes	Incidence of tooth loss
								Current	2.3 (2.0,2.6)
								Ever	1.8 (1.6-2.0)2
Moedano et al[21] (2009)	United States	Cross-sectional	Hospital	M/F	166	69.1	OR	Ever	1.19 (0.49-2.87)	Yes	No	> 10 loss
Yanagisawa et al[42] (2010)	Japan	Cross-sectional	General population	M	1088	59.6	OR	Former	1.35 (0.94-1.94)	No	Yes	> 8 loss
								Current	1.67 (1.12-2.50)
								Ever	1.49 (1.14-1.94)2

¹Relative risk was calculated from coefficient and standard error;

²Within-study summary estimate by meta-analysis with fixed effect model;

³Behaviors associated with oral health include tooth brushing frequencies, existence of periodontal disease at the baseline survey, use of floss, frequency of dental clinic visit and reason for visit and occupation (dentist or not), use of interdental brush, self-check of teeth and gum a using mirror, and experience of tooth brushing instruction. M: Male; F: Female.