Table 2.

Relationship between reproductive history and DMFT index based on Negative binomial regression analysis

Variable		Unadjusted1			Adjusted
					Model 12			Model 23			Model 34
		IRR5	95% CI	P-value	IRR	95% CI	P-value	IRR	95% CI	P-value	IRR	95% CI	P-value
Frequency of pregnancy	4 ≤	1.34	1.21–1.48	< 0.001	1.07	0.96–1.18	0.21	1.13	1.02–1.26	0.02	1.12	1.01–1.24	0.04
	3	1.04	0.93–1.15	0.49	1.07	0.96–1.19	0.2	1.11	0.99–1.23	0.07	1.09	0.98–1.22	0.10
	2	0.94	0.84–1.05	0.27	1.05	0.94–1.17	0.34	1.08	0.97–1.21	0.16	1.07	0.96–1.19	0.21
	1	0.9	0.78–1.04	0.18	1	0.87–1.16	0.96	1.01	0.87–1.16	0.95	1	1.86–1.16	0.99
	0	Reference
Age at the onset of menstrual (years)	Early (12>)	1.06	0.98–1.16	0.15	0.99	0.91–1.08	0.91	1.01	0.93–1.09	0.84	1.01	0.93–1.09	0.86
	Late (14<)	1.12	1.07–1.18	< 0.001	1.01	0.96–1.06	0.77	1.02	0.97–1.07	0.34	1.03	0.98–1.08	0.25
	Normal (12–14)	Reference
Age at the onset of menopause (years)	Precursor (< 40)	0.95	0.83–1.1	0.51	0.98	0.85–1.14	0.83	0.98	0.85–1.13	0.81	0.98	0.85–1.13	0.81
	Early (40–45)	1	0.93–1.08	0.99	1	0.93–1.08	0.95	1.01	0.94–1.09	0.77	1.01	0.94–1.09	0.75
	Normal (> 45)	Reference
Age at first pregnancy (years)	40–49	0.95	0.65–1.39	0.78	0.89	0.61–32/1	0.58	0.9	0.61–1.32	0.59	0.9	0.62–1.32	0.6
	30–39	0.93	0.83–1.03	0.17	0.98	0.88–1.09	0.75	0.96	0.86–1.08	0.51	0.97	0.86–1.08	0.53
	10–19	1.1	1.05–1.16	< 0.001	1.01	0.96–1.06	0.71	1.01	0.97–1.07	0.55	1.01	0.96–1.06	0.76
	20–29	Reference