TABLE 1.

5-Year Associations Between Maternal Age and Risk of Preterm Delivery, by Race, Smoking Status, and Neighborhood Deprivation (n = 182 938): 8 US Geographic Areas, 1995–2001

	Primiparous Women		Multiparous Women
	Unadjusted OR (95% CI)	AORa (95% CI)	Unadjusted OR (95% CI)	AORa (95% CI)
Non-Hispanic White nonsmokers
Nonsmokers	1.08* (1.03, 1.14)	1.11* (1.05, 1.17)	0.95 (0.90, 1.02)	1.00 (0.94, 1.06)
Deprivation scale
Low	1.03 (0.93, 1.14)	1.04 (0.94, 1.15)	0.99 (0.91, 1.06)	1.02 (0.95, 1.10)
Medium	1.16* (1.08, 1.23)	1.18* (1.11, 1.26)	0.98 (0.89, 1.07)	1.02 (0.93, 1.12)
High	1.14 (0.93, 1.41)	1.18 (0.96, 1.45)	1.09 (0.94, 1.27)	1.12 (0.97, 1.30)
Non-Hispanic White smokers
Smokers	1.14* (1.02, 1.28)	1.17* (1.04, 1.32)	1.13* (1.05, 1.21)	1.16* (1.08, 1.25)
Deprivation scale
Low	1.07 (0.78, 1.45)	1.08 (0.79, 1.48)	1.10 (0.86, 1.41)	1.14 (0.90, 1.46)
Medium	1.16* (1.01, 1.34)	1.19* (1.03, 1.38)	1.09 (0.96, 1.25)	1.13 (0.99, 1.28)
High	1.45* (1.04, 2.02)	1.51* (1.08, 2.14)	1.25* (1.08, 1.43)	1.26* (1.10, 1.45)
Non-Hispanic Black nonsmokers
Nonsmokers	1.17* (1.12, 1.23)	1.20* (1.14, 1.26)	1.06* (1.03, 1.11)	1.11* (1.07, 1.15)
Deprivation scale
Low	1.17 (0.98, 1.40)	1.19 (1.00, 1.43)	1.04 (0.95, 1.14)	1.08 (0.98, 1.19)
Medium	1.17* (1.11, 1.23)	1.19* (1.13, 1.25)	1.05* (1.02, 1.09)	1.09* (1.05, 1.13)
High	1.28* (1.18, 1.40)	1.31* (1.20, 1.43)	1.11* (1.02, 1.19)	1.15* (1.08, 1.23)
Non-Hispanic Black smokers
Smokers	1.51* (1.34, 1.69)	1.56* (1.38, 1.75)	1.25* (1.14, 1.36)	1.31* (1.20, 1.43)
Deprivation scale
Low	1.50* (1.06, 2.12)	1.54* (1.09, 2.18)	1.20 (0.90, 1.61)	1.26 (0.94, 1.68)
Medium	1.54* (1.30, 1.83)	1.59* (1.34, 1.89)	1.24* (1.09, 1.41)	1.33* (1.16, 1.54)
High	1.54* (1.29, 1.82)	1.59* (1.34, 1.88)	1.34* (1.26, 1.40)	1.36* (1.30, 1.43)

Note. AOR = adjusted odds ratio; CI = confidence interval.

^aAdjusted for maternal education.

^*P < .05.