Table 5:

Associations between mean first trimester nitrate exposure (mg/L) and birth defects in Missouri, 2004–2008.

Condition	Model ^a	% Well Restriction ^b	Births (cases)	RR₁ (95% CI) ^c	p-value

Neural Tube Defects	Crude	n/a	134,556 (86)	1.00 (0.78, 1.29)	0.994
	Adjusted	n/a	132,475 (85)	1.02 (0.80, 1.30)	0.897
	Crude	< 20	79,478 (51)	1.12 (0.88, 1.43)	0.920
	Adjusted	< 20	77,839 (50)	1.14 (0.91, 1.42)	0.264
	Crude	< 10	69,812 (37)	1.04 (0.73, 1.50)	0.818
	Adjusted	< 10	68,422 (36)	1.07 (0.76, 1.49)	0.708
Congenital Heart Defects	Crude	n/a	134,556 (178)	1.17 (1.00, 1.36)	0.037
	Adjusted	n/a	132,475 (174)	1.17 (1.01, 1.36)	0.041
	Crude	< 20	79,478 (104)	1.29 (1.09, 1.52)	0.003
	Adjusted	< 20	77,839 (101)	1.28 (1.09, 1.52)	0.003
	Crude	< 10	69,812 (87)	1.33 (1.12, 1.58)	0.001
	Adjusted	< 10	68,422 (84)	1.33 (1.12, 1.58)	0.001
Oral Cleft Defects	Crude	n/a	134,556 (267)	0.98 (0.81, 1.19)	0.832
	Adjusted	n/a	132,475 (264)	1.00 (0.84, 1.20)	0.976
	Crude	< 20	79,478 (132)	0.88 (0.67, 1.16)	0.366
	Adjusted	< 20	77,839 (131)	0.91 (0.71, 1.17)	0.471
	Crude	< 10	69,812 (116)	0.90 (0.66, 1.22)	0.495
	Adjusted	< 10	68,422 (115)	0.93 (0.70, 1.24)	0.625
Limb Deficiencies	Crude	n/a	134,556 (46)	1.17 (0.88, 1.54)	0.285
	Adjusted	n/a	132,475 (46)	1.18 (0.90, 1.54)	0.242
	Crude	< 20	79,478 (27)	1.27 (0.92, 1.74)	0.140
	Adjusted	< 20	77,839 (27)	1.28 (0.95, 1.73)	0.105
	Crude	< 10	69,812 (22)	1.32 (0.93, 1.88)	0.115
	Adjusted	< 10	68,422 (22)	1.35 (0.97, 1.88)	0.077
Gastroschisis	Crude	n/a	134,556 (95)	1.15 (0.95, 1.39)	0.150
	Adjusted	n/a	132,475 (92)	1.12 (0.91, 1.38)	0.273
	Crude	< 20	79,478 (58)	1.20 (0.96, 1.51)	0.117
	Adjusted	< 20	77,839 (56)	1.20 (0.95, 1.51)	0.130
	Crude	< 10	69,812 (53)	1.25 (0.99, 1.57)	0.056
	Adjusted	< 10	68,422 (51)	1.26 (1.00, 1.58)	0.054
Hypospadias ^d	Crude	n/a	68,815 (615)	1.01 (0.92, 1.12)	0.771
	Adjusted	n/a	67,759 (607)	1.00 (0.90, 1.11)	0.978
	Crude	< 20	40,422 (345)	1.05 (0.94, 1.17)	0.350
	Adjusted	< 20	39,575 (338)	0.92 (0.78, 1.08)	0.309
	Crude	< 10	35,537 (313)	1.09 (0.97, 1.22)	0.132
	Adjusted	< 10	34,817 (307)	0.98 (0.84, 1.14)	0.808
Down Syndrome	Crude	n/a	134,556 (195)	1.03 (0.84, 1.26)	0.768
	Adjusted	n/a	132,475 (190)	1.04 (0.85, 1.23)	0.689
	Crude	< 20	79,478 (119)	0.99 (0.78, 1.23)	0.842
	Adjusted	< 20	77,839 (115)	0.98 (0.77, 1.24)	0.852
	Crude	< 10	69,812 (109)	1.02 (0.82, 1.28)	0.839
	Adjusted	< 10	68,422 (105)	1.02 (0.81, 1.30)	0.842

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

Models 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.

Rate Ratio for one mg/L of nitrate in water.

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