Table 3.

DMFS outcome data at baseline and change in DMFS during the follow up period for each tobacco group, residential-area household purchasing power group and baseline DMFS group, with p-values for the tobacco group comparisons of change in DMFS

			DMFS baseline		ΔDMFS
SE group	Baseline DMFS group	Tobacco group	N	Mean	N	Mean	p-value*
< 10	0	Ever users	63	0.0	63	0.4	0.33
		Never users	774	0.0	774	0.4
	1-3	Ever users	49	1.6	49	1.2	0.44
		Never users	492	1.7	492	1.0
	> 3	Ever users	40	7.6	40	2.8	0.20
		Never users	287	6.5	287	1.8
10 – 19.9	0	Ever users	115	0.0	115	0.7	0.05
		Never users	875	0.0	875	0.6
	1-3	Ever users	129	1.9	129	1.6	0.001
		Never users	810	1.8	810	0.9
	> 3	Ever users	138	7.3	138	2.5	0.002
		Never users	610	6.8	610	1.7
20 – 29.9	0	Ever users	206	0.0	206	0.7	0.001
		Never users	1370	0.0	1370	0.5
	1-3	Ever users	241	1.9	241	1.8	0.001
		Never users	1285	1.8	1285	1.1
	> 3	Ever users	308	8.0	308	2.7	0.45
		Never users	1171	7.8	1171	2.5
30+	0	Ever users	45	0.0	45	0.8	0.10
		Never users	287	0.0	287	0.6
	1-3	Ever users	47	2.0	47	2.3	< 0.001
		Never users	293	1.9	293	1.2
	> 3	Ever users	70	8.9	70	3.3	0.57
		Never users	312	8.8	312	2.6

* P-value from the Wilcoxon-Mann–Whitney test comparing the distributions of DMFS between ever vs. never users.

The overall p-value < 0.0001 (stratified Wilcoxon-Mann–Whitney test; with additional stratification by sex).