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. Author manuscript; available in PMC: 2020 Sep 1.
Published in final edited form as: Environ Res. 2019 Jun 24;176:108553. doi: 10.1016/j.envres.2019.108553

Table 4:

Associations between mean nitrate exposure 12 months pre-birth (MG/L) and specific limb, cardiac, and neural tube defects in Missouri, 2004–2008.

Condition Model a % Well
Restriction b 		Births
(Cases)		 RR (95% CI) c p-value
Limb Deficiencies
Upper Limb Crude n/a 348,250 (100) 1.28 (1.04, 1.59) 0.021
Adjusted n/a 342,514 (99) 1.31 (1.06, 1.62) 0.013
Crude < 20 233,990 (75) 1.26 (1.01, 1.57) 0.042
Adjusted < 20 229,104 (74) 1.28 (1.03, 1.59) 0.026
Crude < 10 210,297 (63) 1.30 (0.96, 1.77) 0.091
Adjusted < 10 205,994 (63) 1.36 (1.01, 1.84) 0.045
Lower Limb Crude n/a 348,250 (65) 1.22 (0.98, 1.52) 0.072
Adjusted n/a 342,514 (65) 1.25 (1.02, 1.53) 0.030
Crude < 20 233,990 (49) 1.20 (0.96, 1.51) 0.109
Adjusted < 20 229,104 (49) 1.24 (1.00, 1.52) 0.046
Crude < 10 210,297 (42) 1.29 (0.96, 1.74) 0.093
Adjusted < 10 205,994 (42) 1.35 (1.03, 1.77) 0.032
Heart Defects
HLHS Crude n/a 348,250 (127) 1.17 (0.89, 1.53) 0.256
Adjusted n/a 342,514 (124) 1.23 (0.95, 1.59) 0.123
Crude < 20 233,990 (82) 1.26 (0.99, 1.62) 0.058
Adjusted < 20 229,104 (80) 1.32 (1.04, 1.67) 0.021
Crude < 10 210,297 (72) 1.25 (0.89, 1.74) 0.204
Adjusted < 10 205,994 (70) 1.34 (0.96, 1.86) 0.087
TGA & ToF Crude n/a 348,250 (341) 1.01 (0.86, 1.19) 0.858
Adjusted n/a 342,514 (333) 1.04 (0.88, 1.22) 0.606
Crude < 20 233,990 (212) 1.02 (0.85, 1.24) 0.808
Adjusted < 20 229,104 (207) 1.04 (0.86, 1.25) 0.695
Crude < 10 210,297 (187) 1.10 (0.88, 1.37) 0.390
Adjusted < 10 205,994 (182) 1.13 (0.90, 1.42) 0.283
Neural Tube Defects
Anencephaly Crude n/a 348,250 (47) 1.02 (0.71, 1.48) 0.915
Adjusted n/a 342,514 (47) 1.07 (0.75, 1.52) 0.705
Crude < 20 233,990 (33) 1.06 (0.74, 1.51) 0.745
Adjusted < 20 229,104 (33) 1.10 (0.78, 1.54) 0.582
Crude < 10 210,297 (26) 1.16 (0.74, 1.82) 0.510
Adjusted < 10 205,994 (26) 1.20 (0.79, 1.82) 0.394
Spina Bifida Crude n/a 348,250 (149) 0.97 (0.75, 1.27) 0.837
Adjusted n/a 342,514 (144) 1.02 (0.79, 1.31) 0.883
Crude < 20 233,990 (88) 1.09 (0.84, 1.39) 0.523
Adjusted < 20 229,104 (84) 1.12 (0.89, 1.41) 0.332
Crude < 10 210,297 (71) 1.12 (0.82, 1.54) 0.460
Adjusted < 10 205,994 (68) 1.18 (0.88, 1.57) 0.266
Oral Cleft Defects
Cleft Lip with or without Cleft Palate Crude n/a 348,250 (415) 0.86 (0.72, 1.02) 0.083
Adjusted n/a 342,514 (410) 0.88 (0.74, 1.05) 0.144
Crude < 20 233,990 (256) 0.77 (0.62, 0.96) 0.021
Adjusted < 20 229,104 (254) 0.82 (0.66, 1.01) 0.060
Crude < 10 210,297 (235) 0.81 (0.64, 1.02) 0.078
Adjusted < 10 205,994 (234) 0.86 (0.68, 1.08) 0.199
Cleft Palate without Cleft Lip Crude n/a 348,250 (279) 0.97 (0.80, 1.17) 0.760
Adjusted n/a 342,514 (277) 0.99 (0.82, 1.20) 0.952
Crude < 20 233,990 (177) 0.96 (0.78, 1.18) 0.680
Adjusted < 20 229,104 (175) 0.98 (0.80, 1.20) 0.825
Crude < 10 210,297 (150) 1.00 (0.78, 1.27) 0.972
Adjusted < 10 205,994 (149) 1.02 (0.80, 1.30) 0.883

Note: “HLHS” indicates hypoplastic left heart syndrome, “TGA” indicates transposition of the great arteries, and “ToF” indicates tetralogy of Fallot

a

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

b

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.

c

Rate Ratio for one mg/L of nitrate in water

Bold indicates statistical significance (i.e. p<0.05)