Table 3. Neonatal and maternal characteristics and the prevalence of neural tube defects before and after mandatory folic acid fortification of flour, Brazil, 2001–2014.
| Characteristic | Pre-fortificationa |
Post-fortificationb |
Prevalence change % | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| No. of births (% of total) | No. of NTD | Prevalence |
No. of births (% of total) | No. of NTD | Prevalence |
|||||
| NTD per 1000 births | Ratio (95% CI) |
NTD per 1000 births | Ratio (95% CI) |
|||||||
| Maternal age, years c | ||||||||||
| < 20 | 971 805 (19.5) | 915 | 0.94 | 1.34 (1.2–1.4) | 2 221 078 (17.0) | 1 302 | 0.59 | 1.13 (1.1–1.2) | –37.7 | |
| 20–34d | 3 488 203 (70.0) | 2 449 | 0.70 | 1 | 9 232 150 (70.5) | 4 780 | 0.52 | 1 | –26.3 | |
| > 34 | 526 589 (10.6) | 371 | 0.70 | 1.00 (0.9–1.1) | 1 640 707 (12.5) | 938 | 0.57 | 1.10 (1.0–1.2) | –18.9 | |
| Total | 4 986 597 (100.0) | – | – | – | 13 093 935 (100.0) | – | – | – | – | |
| Sex of neonate or stillbirthe | ||||||||||
| Female | 2 437 225 (48.8) | 2 264 | 0.93 | 1.44 (1.3–1.5) | 6 393 203 (48.8) | 3 769 | 0.59 | 1.18 (1.1–1.2) | –36.5 | |
| Malef | 2 560 657 (51.2) | 1 656 | 0.65 | 1 | 6 718 656 (51.2) | 3 368 | 0.50 | 1 | –22.5 | |
| Total | 4 997 882 (100.0) | – | – | – | 13 111 859 (100.0) | – | – | – | – | |
| Race of neonateg | ||||||||||
| White | 3 505 035 (77.4) | 1 983 | 0.57 | 1.1 (1.0–1.2) | 8 730 308 (69.4) | 3 895 | 0.45 | 1.05 (1.0–1.1) | –21.1 | |
| Brown h | 880 425 (19.5) | 439 | 0.50 | 1 | 3 347 507 (26.6) | 1 422 | 0.42 | 1 | –14.8 | |
| Black | 122 622 (2.7) | 73 | 0.60 | 1.2 (0.9–1.5) | 454 023 (3.6) | 204 | 0.45 | 1.06 (0.8–1.3) | –24.5 | |
| Indigenous | 15 930 (0.3) | 13 | 0.82 | 1.6 (0.9–2.8) | 41 980 (0.3) | 21 | 0.50 | 1.18 (0.8–1.8) | –38.7 | |
| Total | 4 524 012 (100.0) | – | – | – | 12 573 818 (100.0) | – | – | – | – | |
CI: confidence interval; NTD: neural tube defects.
a The pre-fortification study period ran from 1 January 2001 to 31 December 2004 – although fortification became mandatory in June 2014.
b The post-fortification study period ran from 1 January 2005 to 31 December 2014.
c Maternal age was missing in 0.22% of the records.
d Used as the reference category in the calculation of prevalence ratios for maternal age.
e Sex of neonate or stillbirth was missing in 0.06% of the records.
f Used as the reference category in the calculation of prevalence ratios for sex of neonate or stillbirth.
g As no data on race were available for stillbirths, the data reported for race refer only to live births.
h Used as the reference category in the calculation of prevalence ratios for race of neonate.