|  | Unadjusted odds ratios (95% CI) | Adjusted odds ratios* (95% CI) | ||||
---|---|---|---|---|---|---|---|
 |  Outcome | Quartile 1 vs Quartile 2 | Quartile 1 vs Quartile 3 | Quartile 1 vs Quartile 4 | Quartile 1 vs Quartile 2 | Quartile 1 vs Quartile 3 | Quartile 1 vs Quartile 4 |
Nitrate | Â | Â | Â | Â | Â | Â | Â |
 | anencephaly | 0.93 (0.68-1.27) | 0.72 (0.52-1.01) | 0.90 (0.66-1.23) | 0.97 (0.71-1.34) | 0.81 (0.56-1.17) | 0.99 (0.67-1.45) |
 | spina bifida | 0.93 (0.74-1.16) | 0.96 (0.77-1.20) | 0.77 (0.61-0.97) | 0.93 (0.73-1.17) | 0.98 (0.77-1.26) | 0.78 (0.59-1.04) |
 | encephalocele | 0.80 (0.48-1.32) | 1.00 (0.62-1.60) | 0.74 (0.45-1.24) | 0.75 (0.45-1.26) | 0.87 (0.52-1.48) | 0.59 (0.32-1.08) |
Total Nitrite | Â | Â | Â | Â | Â | Â | |
 | anencephaly | 0.83 (0.59-1.18) | 1.11 (0.80-1.54) | 1.31 (0.96-1.79) | 0.82 (0.57-1.18) | 1.04 (0.73-1.49) | 1.06 (0.69-1.64) |
 | spina bifida | 0.96 (0.76-1.22) | 1.08 (0.86-1.36) | 1.18 (0.94-1.48) | 0.96 (0.76-1.23) | 1.02 (0.79-1.32) | 1.00 (0.73-1.38) |
 | encephalocele | 1.00 (0.60-1.66) | 0.95 (0.56-1.59) | 1.20 (0.74-1.97) | 0.97 (0.57-1.64) | 0.83 (0.47-1.47) | 0.96 (0.49-1.89) |
Animal Nitrite | Â | Â | Â | Â | Â | Â | |
 | anencephaly | 1.01 (0.72-1.43) | 1.27 (0.92-1.76) | 1.27 (0.91-1.75) | 1.00 (0.71-1.42) | 1.22 (0.86-1.73) | 1.12 (0.76-1.67) |
 | spina bifida | 1.07 (0.85-1.34) | 1.16 (0.92-1.46) | 1.07 (0.85-1.35) | 1.06 (0.83-1.34) | 1.12 (0.88-1.43) | 1.00 (0.75-1.33) |
 | encephalocele | 0.59 (0.34-1.02) | 0.88 (0.54-1.43) | 1.04 (0.66-1.66) | 0.59 (0.34-1.03) | 0.86 (0.51-1.44) | 0.98 (0.55-1.74) |
Plant Nitrite | Â | Â | Â | Â | Â | Â | |
 | anencephaly | 1.13 (0.81-1.56) | 0.87 (0.62-1.23) | 1.26 (0.92-1.73) | 1.18 (0.84-1.66) | 0.86 (0.59-1.26) | 0.95 (0.60-1.50) |
 | spina bifida | 0.95 (0.75-1.19) | 0.82 (0.65-1.05) | 1.14 (0.92-1.43) | 0.94 (0.74-1.20) | 0.81 (0.62-1.05) | 0.90 (0.65-1.24) |
 | encephalocele | 1.02 (0.61-1.71) | 1.23 (0.75-2.02) | 1.05 (0.63-1.76) | 0.99 (0.58-1.70) | 1.04 (0.59-1.82) | 0.61 (0.30-1.25) |
Nitrosamine | Â | Â | Â | Â | Â | Â | |
 | anencephaly | 1.01 (0.73-1.40) | 1.10 (0.80-1.52) | 1.03 (0.74-1.43) | 1.10 (0.78-1.55) | 1.18 (0.82-1.68) | 1.06 (0.70-1.60) |
 | spina bifida | 0.81 (0.65-1.03) | 0.87 (0.69-1.09) | 0.98 (0.78-1.22) | 0.82 (0.64-1.04) | 0.85 (0.66-1.10) | 0.91 (0.69-1.21) |
 | encephalocele | 0.98 (0.60-1.60) | 0.79 (0.47-1.33) | 1.03 (0.63-1.68) | 1.01 (0.60-1.68) | 0.82 (0.47-1.46) | 1.13 (0.60-2.11) |