Table 3 Population attributable fractions and 95% confidence interval associated with identified factors for microcephaly and its subtypes
From: Prevalence of congenital microcephaly and its risk factors in an area at risk of Zika outbreaks
Risk factors | Microcephaly | Disproportionate microcephaly | Proportionate microcephaly |
|---|---|---|---|
All risk factors combined | 66.4% (43.9–81.1%) | 47.5% (13.1–71.7%) | 67.7% (47.7–81.1%) |
Specific factors | |||
 Primiparity | 28.9% (10.3–45.5%) | – | 28.2% (7.9–46.3%) |
 HDP | – | – | 1.9% (− 3.2 to 6.9%) |
 Maternal carrier of HBV | 4.8% (−1.2 to 10.8%) | – | – |
 Small for gestational age | 50.6% (38.8–60.8%) | – | 56.5% (44.0–66.9%) |
 Preterm birth | 4.0% (− 1.4 to 9.4%) | 47.5% (13.1–71.7%) | – |