Table 6:

Associations between mean nitrate exposure 12 months pre-birth (mg/L) and birth defects in rural counties of Missouri, 2004–2008.

Condition	Model a	% Well Restriction b	Births (cases)	RR (95% CI) c	p-value
Neural Tube Defects	Crude	n/a	133,081 (95)	0.78 (0.49, 1.21)	0.255
	Adjusted	n/a	131,761 (94)	0.78 (0.50, 1.22)	0.281
	Crude	< 20	52,984 (42)	0.95 (0.71, 1.27)	0.730
	Adjusted	< 20	52,247 (41)	0.97 (0.73, 1.30)	0.835
	Crude	< 10	37,945 (26)	1.03 (0.77, 1.37)	0.858
	Adjusted	< 10	37,504 (26)	1.03 (0.77, 1.39)	0.831
Congenital Heart Defects	Crude	n/a	133,081 (174)	1.07 (0.87, 1.31)	0.519
	Adjusted	n/a	131,761 (171)	1.08 (0.89, 1.32)	0.428
	Crude	< 20	52,984 (67)	1.14 (0.93, 1.40)	0.211
	Adjusted	< 20	52,247 (67)	1.14 (0.92, 1.39)	0.224
	Crude	< 10	37,945 (45)	1.40 (1.07, 1.84)	0.016
	Adjusted	< 10	37,504 (45)	1.38 (1.05, 1.82)	0.019
Oral Cleft Defects	Crude	n/a	133,081 (288)	0.88 (0.72, 1.09)	0.255
	Adjusted	n/a	131,761 (285)	0.86 (0.69, 1.08)	0.190
	Crude	< 20	52,984 (107)	0.61 (0.33, 1.12)	0.112
	Adjusted	< 20	52,247 (107)	0.62 (0.34, 1.12)	0.113
	Crude	< 10	37,945 (81)	0.44 (0.16, 1.19)	0.104
	Adjusted	< 10	37,504 (81)	0.43 (0.15, 1.18)	0.102
Limb Deficiencies	Crude	n/a	133,081 (57)	1.25 (0.98, 1.59)	0.073
	Adjusted	n/a	131,761 (57)	1.25 (0.98, 1.60)	0.070
	Crude	< 20	52,984 (33)	1.19 (0.94, 1.52)	0.148
	Adjusted	< 20	52,247 (33)	1.19 (0.93, 1.51)	0.160
	Crude Adjusted	< 10	37,945 (22)	1.49 (1.08, 2.07)	0.015
		< 10	37,504 (22)	1.48 (1.08, 2.05)	0.016
Gastroschisis	Crude	n/a	133,081 (196)	0.97 (0.71, 1.33)	0.864
	Adjusted	n/a	131,761 (191)	0.90 (0.62, 1.32)	0.602
	Crude	< 20	52,984 (121)	0.98 (0.67, 1.42)	0.909
	Adjusted	< 20	52,247 (117)	0.98 (0.67, 1.42)	0.905
	Crude	< 10	37,945 (97)	1.19 (0.71, 2.02)	0.510
	Adjusted	< 10	37,504 (94	1.21 (0.72, 2.05)	0.475
Hypospadias d	Crude	n/a	68,322 (566)	0.88 (0.76, 1.02)	0.094
	Adjusted	n/a	67,672 (560)	0.88 (0.76, 1.02)	0.100
	Crude	< 20	27,030 (213)	0.82 (0.65, 1.04)	0.098
	Adjusted	< 20	26,671 (210)	0.82 (0.65, 1.04)	0.101
	Crude	< 10	19,453 (166)	0.87 (0.53, 1.46)	0.607
	Adjusted	< 10	19,245 (163)	0.87 (0.53, 1.45)	0.599
Down Syndrome	Crude	n/a	133,081 (172)	0.91 (0.67, 1.22)	0.511
	Adjusted	n/a	131,761 (171)	0.93 (0.67, 1.30)	0.600
	Crude	< 20	52,984 (71)	0.93 (0.67, 1.09)	0.315
	Adjusted	< 20	52,247 (71)	0.93 (0.75, 1.10)	0.680
	Crude	< 10	37,945 (49)	0.88 (0.71, 1.10)	0.259
	Adjusted	< 10	37,504 (49)	0.88 (0.69, 1.09)	0.231

^aAll adjusted models controlled for maternal age, race, ethnicity, and socioeconomic status.

^bModels without private well restriction included 99 Missouri counties, models with < 20% well restriction included 47 MO counties, models with < 10% well restriction included 38 MO counties.

^cRate Ratio for one mg/L of nitrate in water

^dHypospadias models contain only male births Bold indicates statistical significance (i.e. p<0.05)