Table 4.
Maternal characteristics associated with dietary nitrosamine intake, National Birth Defects Prevention Study Controls, 1997-2004
| Nitrosamine intake μg/day | Odds ratios and 95% confidence intervalsb | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Quartile 1a | Quartile 2 | Quartile 3 | Quartile 4 | |||||||||
| <0.3330 | 0.3330-0.4715 | 0.4716-0.6685 | >0.6685 | p-value | 4th quartile compared to the 1st quartile | |||||||
| n | % | n | % | n | % | n | % | Crude | Adjustedc | |||
| Race/Ethnicity | ||||||||||||
| White non-Hispanic | 761 | 21.8 | 894 | 25.7 | 917 | 26.3 | 912 | 26.2 | <0.0001 | 1.0 | 1.0 | |
| Black non-Hispanic | 203 | 30.8 | 158 | 23.9 | 152 | 23.0 | 147 | 22.3 | 0.60 (0.48,0.76) | 0.36 (0.26,0.50) | ||
| Hispanic | 357 | 27.5 | 315 | 24.2 | 318 | 24.5 | 310 | 23.8 | 0.73 (0.61,0.87) | 0.35 (0.26,0.48) | ||
| Asian/Pacific Islander | 68 | 40.2 | 32 | 18.9 | 29 | 17.2 | 40 | 23.7 | 0.49 (0.33,0.73) | 0.33 (0.19,0.57) | ||
| Other | 53 | 31.6 | 45 | 26.8 | 34 | 20.2 | 36 | 21.4 | 0.57 (0.37,0.87) | 0.42 (0.24,0.74) | ||
| Missing | 9 | 40.9 | 7 | 31.8 | 1 | 4.5 | 5 | 22.7 | ||||
| Area of residence (state) | ||||||||||||
| Texas | 168 | 24.6 | 166 | 24.3 | 176 | 25.7 | 174 | 25.4 | <0.0001 | 1.0 | 1.0 | |
| Arkansas | 151 | 21.4 | 150 | 21.2 | 193 | 27.3 | 213 | 30.1 | 1.4 (1.0,1.8) | 1.0 (0.69,1.6) | ||
| California | 235 | 30.1 | 174 | 22.2 | 171 | 21.9 | 202 | 25.8 | 0.83 (0.63,1.1) | 0.73 (0.51,1.0) | ||
| Georgia | 185 | 30.1 | 158 | 25.7 | 151 | 24.7 | 120 | 19.5 | 2.5 (1.8,3.4) | 3.6 (2.4,5.5) | ||
| Iowa | 100 | 15.5 | 118 | 18.3 | 168 | 26.1 | 258 | 40.1 | 0.55 (0.40,0.75) | 0.66 (0.44,1.0) | ||
| Massachusetts | 208 | 28.0 | 226 | 30.4 | 191 | 25.7 | 118 | 15.9 | 0.84 (0.61,1.2) | 0.87 (0.57,1.3) | ||
| New Jersey | 141 | 25.0 | 160 | 28.4 | 141 | 25.0 | 122 | 21.6 | 0.75 (0.54,1.0) | 0.82 (0.53,1.3) | ||
| New York | 135 | 26.0 | 156 | 30.1 | 123 | 23.7 | 105 | 20.2 | 0.63 (0.46,0.86) | 0.67 (0.44,1.0) | ||
| North Carolina | 84 | 29.0 | 87 | 30.0 | 64 | 22.0 | 55 | 19.0 | 0.63 (0.42,0.94) | 0.49 (0.29,0.83) | ||
| Utah | 44 | 17.2 | 56 | 21.9 | 73 | 28.5 | 83 | 32.4 | 1.8 (1.2,2.8) | 1.8 (1.0,3.0) | ||
| Dietary folate (μg/day) | ||||||||||||
| <319 | 619 | 43.0 | 386 | 26.8 | 273 | 19.1 | 160 | 11.1 | <0.0001 | 1.0 | 1.0 | |
| 319-465 | 362 | 24.9 | 414 | 28.5 | 395 | 27.2 | 281 | 19.4 | 3.0 (2.4,3.8) | 1.7 (1.3,2.3) | ||
| 465 - ≤685.5 | 288 | 19.7 | 368 | 25.2 | 416 | 28.4 | 390 | 26.7 | 5.2 (4.2,6.6) | 2.0 (1.5,2.7) | ||
| > 685.5 | 182 | 12.5 | 283 | 19.5 | 367 | 25.3 | 619 | 42.7 | 13.2 (10.4,16.7) | 3.4 (2.4,4.7) | ||
| Maternal education (years at school) | ||||||||||||
| 16+ | 402 | 22.0 | 508 | 27.8 | 485 | 26.6 | 431 | 23.6 | <0.0001 | 1.0 | 1.0 | |
| 12-15 | 343 | 22.3 | 384 | 24.9 | 404 | 26.2 | 409 | 26.6 | 1.1 (0.91,1.4) | 0.74 (0.58,0.96) | ||
| 12 | 404 | 28.0 | 356 | 24.7 | 330 | 22.8 | 354 | 24.5 | 0.82 (0.67,0.99) | 0.38 (0.29,0.50) | ||
| 9-11 | 209 | 30.0 | 143 | 20.6 | 161 | 23.1 | 183 | 26.3 | 0.82 (0.64,1.0) | 0.33 (0.24,0.47) | ||
| 0-8 | 83 | 29.9 | 57 | 20.5 | 67 | 24.1 | 71 | 25.5 | 0.80 (0.57,1.1) | 0.37 (0.23,0.61) | ||
| Missing | 10 | 52.6 | 3 | 15.8 | 4 | 21.1 | 2 | 10.5 | ||||
| Dietary fat (% of daily calories) | ||||||||||||
| ≤ 30% | 1034 | 31.9 | 871 | 26.9 | 726 | 22.5 | 606 | 18.7 | <0.0001 | 1.0 | 1.0 | |
| >30% | 417 | 16.3 | 580 | 22.5 | 725 | 28.3 | 844 | 32.9 | 3.5 (3.0,4.0) | 8.5 (6.9,10.4) | ||
| Maternal household income (dollars annually) | ||||||||||||
| ≥50,000 | 415 | 22.7 | 517 | 28.2 | 490 | 26.8 | 409 | 22.3 | <0.0001 | 1.0 | --- | |
| 40-49,999 | 92 | 21.8 | 114 | 27.0 | 91 | 21.6 | 125 | 29.6 | 1.4 (1.0,1.9) | --- | ||
| 30-39,999 | 123 | 22.8 | 135 | 25.0 | 141 | 26.1 | 141 | 26.1 | 1.2 (0.88,1.5) | --- | ||
| 20-29,999 | 192 | 25.8 | 182 | 24.4 | 196 | 26.3 | 175 | 23.5 | 0.92 (0.72,1.2) | --- | ||
| 10-19.999 | 173 | 24.0 | 181 | 25.0 | 165 | 22.9 | 203 | 28.1 | 1.2 (0.93,1.5) | --- | ||
| < 10,000 | 267 | 28.6 | 199 | 21.4 | 223 | 23.9 | 243 | 26.1 | 0.92 (0.74,1.2) | --- | ||
| Missing | 189 | 30.9 | 123 | 20.0 | 145 | 23.7 | 154 | 25.2 | --- | --- | ||
| Pre-pregnancy BMI | ||||||||||||
| Normal weight (18.5 - 25.0) | 792 | 25.2 | 772 | 24.6 | 790 | 25.2 | 783 | 25.0 | <0.0001 | 1.0 | --- | |
| Under weight (<18.5) | 89 | 28.3 | 86 | 27.4 | 75 | 23.9 | 64 | 20.4 | 0.73 (0.52,1.0) | --- | ||
| Over weight (25.0 - 30.0) | 291 | 23.5 | 321 | 25.8 | 317 | 25.6 | 311 | 25.1 | 1.1 (0.90,1.31) | --- | ||
| Obese (>30.0) | 206 | 23.3 | 209 | 23.7 | 222 | 25.1 | 246 | 27.9 | 1.2 (0.97,1.5) | --- | ||
| Missing | 73 | 31.9 | 63 | 27.5 | 47 | 20.5 | 46 | 20.1 | --- | --- | ||
| Folic acid containing supplements | ||||||||||||
| No | 715 | 27.5 | 599 | 23.0 | 624 | 24.1 | 661 | 25.4 | <0.0001 | 1.0 | --- | |
| Yes | 725 | 22.8 | 844 | 26.6 | 824 | 25.9 | 783 | 24.7 | 1.2 (1.0,1.4) | --- | ||
| Missing | 11 | 39.3 | 8 | 28.6 | 3 | 10.7 | 6 | 21.4 | --- | --- | ||
| Multivitamin use | ||||||||||||
| No | 864 | 24.3 | 935 | 26.3 | 896 | 25.2 | 860 | 24.2 | 0.0020 | 1.0 | --- | |
| Yes | 579 | 26.0 | 511 | 23.0 | 551 | 24.8 | 582 | 26.2 | 1.0 (0.87,1.2) | --- | ||
| Missing | 8 | 32.0 | 5 | 20.0 | 4 | 16.0 | 8 | 32.0 | --- | --- | ||
| Age at conception | ||||||||||||
| 20-24 | 348 | 25.8 | 317 | 23.5 | 331 | 24.6 | 351 | 26.1 | <0.0001 | 1.0 | --- | |
| <20 | 274 | 33.4 | 171 | 20.9 | 184 | 22.4 | 191 | 23.3 | 0.69 (0.54,0.88) | --- | ||
| 25-29 | 350 | 22.5 | 418 | 26.9 | 391 | 25.1 | 397 | 25.5 | 1.1 (0.91,1.4) | --- | ||
| 30-34 | 330 | 23.2 | 375 | 26.4 | 356 | 25.1 | 359 | 25.3 | 1.1 (0.87,1.3) | --- | ||
| 35+ | 149 | 22.6 | 170 | 25.8 | 189 | 28.6 | 152 | 23.0 | 1.0 (0.77,1.3) | --- | ||
aReferent category is nitrosamine intake at the lowest quartile of intake (<0.33299 μg/day)
bOnly presented for variables included in the final multinomial logistic regression model
cAdjusted for tertiles of daily caloric intake, race/ethnicity, maternal education, state of residence, dietary fat intake, and dietary folate as dietary folate equivalents. intake, pre-pregnancy body mass index, and folic acid supplementation
Note: p-value excludes missing values