Table 4.
Potential risk factors for microcephaly: number (percentage) exposed for cases and controls, and odds ratio adjusted for maternal age and education (95% CI)
| Exposure | All microcephaly cases | Neural only microcephaly | |||||
|---|---|---|---|---|---|---|---|
| Cases (n=546)* | Controls (n=2176) | Adjusted odds ratio (95% CI) | Cases (n=230) | Controls (n=917) | Adjusted odds ratio (95% CI) | ||
| Maternal age: | |||||||
| <20 years | 104 (19.0) | 444 (20.4) | 0.81 (0.62 to 1.0) | 49 (21) | 209 (22.8) | 0.77 (0.53 to 1.1) | |
| 20-34 years | 360 (65.9) | 1263 (58.0) | 1.0 | 156 (68) | 547 (59.7) | 1.0 | |
| ≥35 years | 82 (15.0) | 241 (11.1) | 1.2 (0.88 to 1.6) | 25 (11) | 97 (10.6) | 0.84 (0.51 to 1.4) | |
| Not specified | 0 | 228 (10.5) | – | 0 | 64 (7.0) | – | |
| Maternal education: | |||||||
| <6 years | 111 (20.3) | 345 (15.9) | 1.2 (0.92 to 1.6) | 37 (16) | 147 (16.0) | 1.0 (0.64 to 1.5) | |
| 6-12 years | 358 (65.6) | 1364 (62.7) | 1.0 | 161 (70) | 597 (65.1) | 1.0 | |
| ≥13 years | 55 (10.1) | 186 (8.5) | 1.1 (0.77 to 1.5) | 25 (11) | 91 (9.9) | 1.0 (0.59 to 1.6) | |
| Not specified | 22 (4.0) | 281 (12.9) | – | 7 (3) | 82 (8.9) | – | |
| Consanguinity: | |||||||
| Yes | 11 (2.0) | 15 (0.7) | 3.1 (1.4 to 7.0) | 7 (3) | 10 (1.1) | 3.1 (1.1 to 8.9) | |
| No | 535 (98.0) | 1865 (85.7) | 1.0 | 216 (94) | 818 (89.2) | 1.0 | |
| Not specified | 0 | 296 (13.6) | – | 7 (3) | 89 (9.7) | – | |
| STORCH: | |||||||
| Yes | 21 (3.8) | 21 (1.0) | 4.4 (2.3 to 8.3) | 15 (7) | 15 (1.6) | 6.3 (2.6 to 15.1) | |
| No | 525 (96.2) | 2155 (99.0) | 1.0 | 215 (93) | 902 (98.4) | 1.0 | |
| Not specified | 0 | 0 | – | 0 | 0 | – | |
| Diabetes: | |||||||
| Yes | 13 (2.4) | 52 (2.4) | 1.0 (0.53 to 1.9) | 5 (2) | 5 (0.5) | 1.0 (0.38 to 2.9) | |
| No | 533 (97.6) | 2124 (97.6) | 1.0 | 225 (98) | 912 (99.5) | 1.0 | |
| Not specified | 0 | 0 | – | 0 | 0 | – | |
| Influenza: | |||||||
| Yes | 26 (4.8) | 57 (2.6) | 1.9 (1.1 to 3.3) | 12 (5) | 12 (1.3) | 2.7 (1.8 to 6.4) | |
| No | 520 (95.2) | 2119 (97.4) | 1.0 | 218 (95) | 905 (98.7) | 1.0 | |
| Not specified | 0 | 0 | – | 0 | 0 | – | |
STORCH=syphilis, toxoplasmosis, other including HIV, rubella, cytomegalovirus, and herpes simplex.
*Six cases were removed as matched controls could not be identified owing to cases being intersex (4) or having unspecified sex (2).