Table 4.

Multivariate analysis of decayed teeth, according to year, fluoridation status and socio-economic characteristics^‡

Variable	2008		2010		2012
	IRR	95% CI	IRR	95% CI	IRR	95% CI
Fluoridation status
Fluoridated	1.00†		1.00†		1.00†
Newly fluoridated	1.64***	1.33–2.03	1.19NS	0.92–1.53	1.15NS	0.87–1.52
Unfluoridated	2.29***	1.64–3.21	2.40***	1.83–3.14	2.29***	1.68–3.11
Indigenous status
Non-Aboriginal	1.00†		1.00†		1.00†
Aboriginal	1.30NS	0.88–1.92	1.47*	1.02–2.10	1.89**	1.27–2.83
Cardholder status
Non-cardholder	1.00†		1.00†		1.00†
Cardholder	1.55***	1.26–1.89	1.91***	1.55–2.36	1.73***	1.35–2.20
Maternal country of birth
English speaking	1.00†		1.00†		1.00†
Non-English speaking	1.74**	1.19–2.55	2.21***	1.52–3.21	1.68*	1.11–2.54
Highest educational attainment of parent(s)§
Bachelor’s and higher	–	–	1.00†		1.00†
Certificate/Diploma	–	–	1.21NS	0.94–1.55	1.14NS	0.86–1.51
Year 12 or below	–	–	1.35*	1.01–1.80	1.70**	1.22–2.37
Toothbrushing behaviour
Twice or more a day	1.00†		1.00†		1.00†
Once or less a day	1.14NS	0.92–1.40	1.26*	1.02–1.56	1.48**	1.16–1.88
Sugary drink consumption
None	1.00†		1.00†		1.00†
One or more a day	1.60***	1.29–1.99	1.56***	1.27–1.92	1.58***	1.23–2.01

IRR, incidence rate ratio; NS, not significant.

^*P < 0.05.

^**P < 0.01.

^***P < 0.001.

^†Referent.

^‡Adjusted for age and gender.

^§Highest educational attainment of parents was not asked in 2008.