Table 2.

Higher prevalence of probiotic bacterial taxa among current-smokers than among never-smokers and former-smokers

Probiotic taxa	Prevalence			P value* (PBonferroni†)
	Current-smokers (n=592)	Former-smokers (n=477)	Never-smokers (n=547)	Current-smokers versus never-smokers	Former-smokers versus never-smokers	Current-smokers versus non-smokers‡
Phylum Actinobacteria
Genus Bifidobacterium	85.64%	71.07%	67.28%	2.30×10−6 (1.59×10−4)	0.88 (1.00)	2.09×10−7 (1.44×10−5)
Species Bifidobacterium longum	67.57%	45.07%	39.67%	2.61×10−11 (1.80×10−9)	0.32 (1.00)	2.91×10−12 (2.01×10−10)
Phylum Firmicutes
Genus Lactobacillus	89.36%	73.38%	73.49%	2.62×10−6 (1.81×10−4)	0.46 (1.00)	1.15×10−7 (7.91×10−6)
Species Lactobacillus crispatus	61.15%	35.43%	34.37%	2.60×10−10 (1.80×10−8)	0.72 (1.00)	3.85×10−13 (2.66×10−11)
Species L. fermentum	57.60%	39.83%	35.65%	2.09×10−6 (1.44×10−4)	0.56 (1.00)	4.59×10−7 (3.16×10−5)
Species L. gasseri	72.47%	56.39%	53.02%	6.51×10−6 (4.50×10−4)	0.95 (1.00)	7.51×10−7 (5.18×10−5)
Species L. oris	43.75%	26.83%	20.84%	1.09×10−8 (7.54×10−7)	0.04 (1.00)	3.46×10−8 (2.39×10−6)
Species L. panis	42.23%	26.83%	25.41%	3.74×10−7 (2.58×10−5)	0.81 (1.00)	2.33×10−7 (1.61×10−5)
Species L. reuteri	41.55%	23.27%	20.84%	1.65×10−8 (1.14×10−6)	0.99 (1.00)	5.36×10−10 (3.70×10−8)

^*P values were calculated by logistic regression. Sequencing batch as well as other covariates (age, sex, race, BMI, alcohol consumption, oral health and disease status at the first follow-up and total energy intake) were adjusted for.

^†Bonferroni correction, adjusted for 69 independent tests.

^‡Non-smokers includes former-smokers and never-smokers.

BMI, body mass index.