Table 3:

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

Condition	Model a	% Well Restriction b	Births (cases)	RR (95% CI) c	p-value
Neural Tube	Crude	n/a	348,250 (196)	0.98 (0.79, 1.22)	0.887
Defects	Adjusted	n/a	342,514 (191)	1.03 (0.84, 1.27)	0.770
	Crude	< 20	233,990 (121)	1.08 (0.88, 1.33)	0.475
	Adjusted	< 20	229,104 (117)	1.12 (0.92, 1.35)	0.264
	Crude	< 10	210,297 (97)	1.14 (0.88, 1.47)	0.335
	Adjusted	< 10	205,994 (94)	1.18 (0.93, 1.51)	0.165
Congenital Heart	Crude	n/a	348,250 (442)	1.03 (0.89, 1.19)	0.703
Defects	Adjusted	n/a	342,514 (432)	1.06 (0.92, 1.23)	0.430
	Crude	< 20	233,990 (279)	1.07 (0.92, 1.24)	0.402
	Adjusted	< 20	229,104 (272)	1.09 (0.94, 1.27)	0.267
	Crude	< 10	210,297 (245)	1.09 (0.90, 1.31)	0.366
	Adjusted	< 10	205,994 (238)	1.13 (0.93, 1.38)	0.215
Oral Cleft Defects	Crude	n/a	348,250 (643)	0.91 (0.80, 1.04)	0.178
	Adjusted	n/a	342,514 (637)	0.93 (0.82, 1.06)	0.316
	Crude	< 20	233,990 (405)	0.87 (0.74, 1.01)	0.070
	Adjusted	< 20	229,104 (402)	0.90 (0.77, 1.05)	0.168
	Crude	< 10	210,297 (364)	0.89 (0.75, 1.06)	0.202
	Adjusted	< 10	205,994 (362)	0.93 (0.79, 1.11)	0.431
Limb Deficiencies	Crude	n/a	348,250 (142)	1.23 (1.02, 1.48)	0.024
	Adjusted	n/a	342,514 (141)	1.26 (1.05, 1.51)	0.011
	Crude	< 20	233,990 (106)	1.21 (1.01, 1.47)	0.044
	Adjusted	< 20	229,104 (105)	1.24 (1.03, 1.48)	0.020
	Crude	< 10	210,297 (90)	1.25 (0.97, 1.62)	0.089
	Adjusted	< 10	205,994 (90)	1.31 (1.02, 1.68)	0.032
Gastroschisis	Crude	n/a	348,250 (273)	1.01 (0.84, 1.22)	0.908
	Adjusted	n/a	342,514 (268)	0.94 (0.76, 1.16)	0.582
	Crude	< 20	233,990 (177)	1.03 (0.84, 1.26)	0.758
	Adjusted	< 20	229,104 (173)	0.98 (0.79, 1.22)	0.879
	Crude	< 10	210,297 (161)	1.07 (0.85, 1.36)	0.542
	Adjusted	< 10	205,994 (157)	1.02 (0.80, 1.31)	0.858
Hypospadias d	Crude	n/a	178,295 (1,612)	0.98 (0.91, 1.06)	0.596
	Adjusted	n/a	175,329 (1,591)	0.98 (0.91, 1.06)	0.664
	Crude	< 20	119,400 (1,097)	0.98 (0.91, 1.06)	0.695
	Adjusted	< 20	116,857(1,079)	0.99 (0.91, 1.07)	0.795
	Crude	< 10	107,403 (1,010)	1.02 (0.93, 1.11)	0.675
	Adjusted	< 10	105,159 (994)	1.03 (0.94, 1.13)	0.497
Down Syndrome	Crude	n/a	348,250 (500)	0.91 (0.77, 1.07)	0.247
	Adjusted	n/a	342,514 (491)	0.93 (0.80, 1.10)	0.438
	Crude	< 20	233,990 (346)	0.92 (0.78, 1.08)	0.308
	Adjusted	< 20	229,104 (338)	0.94 (0.79, 1.12)	0.508
	Crude	< 10	210,297 (314)	0.90 (0.74, 1.09)	0.263
	Adjusted	< 10	205,994 (306)	0.91 (0.74, 1.12)	0.377

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

^bModels without private well restriction included 113 Missouri counties, models with < 20% well restriction included 58 MO counties, models with < 10% well restriction included 48 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)