Table 6.
Summarized findings of previous case-control studies evaluating risk factors for isolated microtia
| Present study | Van Bennekom et al, 2013 | Paput et al, 2011 | Mastroiacovo et al, 1995 | Castilla & Orioli, 1986 | |
|---|---|---|---|---|---|
| Population | South America | USA | Hungary | Italy | South America |
| Period | 1982–2011 | 1997–2005 | 1980–1996 | 1983–1992 | 1967–1977 |
| Pregnancy outcome | Livebirth | Livebirth | Live- and stillbirth | Live- and stillbirth | Livebirth |
| N casesa | 1,194 | 304 | 354 | 114 | 184 |
| N controlsb | 1,194 | 6,747 | 38,151 | 648 | 184 |
| Matching | Sex, time and place of birth | Time and place of birth | Sex, time and place of birth | Time and place of birth | Sex, time and place of birth |
| Descriptive measures | |||||
| Maternal age | = | = | = | = | = |
| Paternal age | = | na | = | = | > |
| Birthweight | = | na | < | < | < |
| Gestational age | = | na | = | = | = |
| Sex (male %) | 56.6 | 60.0 | 54.0 | 52.6 | na |
| Measures of Associationc OR (95% CI) | |||||
| Multiple births (≥2) | 1.2 (0.6–2.3) | 1.7 (0.8–3.5) | = | na | na |
| Parity (≥2) | 1.5 (1.2–1.8) | = | > | = | > |
| Maternal use of alcohol | 1.4 (0.9–2.1) | = | = | = | na |
| Maternal smoking | 1.7 (1.1–2.6) | 1.0 (0.5–1.7) | = | = | na |
| Maternal use of medications | |||||
| 1. NSAIDs | 2.1 (0.8–5.7) | 1.3 (1.0–1.8) | na | na | na |
| 2. Antihypertensives | 3.6 (1.0–13.7) | 0.9 (0.3–3.1) | na | na | na |
| 3. Analgesics | 2.2 (1.4–3.4) | na | = | na | na |
| 4. Antibiotics | 1.6 (1.1–2.5) | na | = | na | = |
| Maternal Acute and Chronic diseases (1st trimester) | |||||
| 1. Cold-like symptoms | 2.2 (1.2–3.9) | na | 4.3 (1.9–7.4) | na | na |
| 2. Hypertension | 0.9 (0.3–2.8) | 1.1 (0.6–2.1) | 0.8 (0.5–1.3) | = | na |
| 3. Diabetes mellitus | 2.2 (0.2–24.3) | 3.4 (1.3–8.5) | 1.5 (0.5–4.7) | 8.7 (1.2–96.4) d | na |
| 4. Respiratory infection | 2.5 (0.6–9.7) | na | 1.3 (0.4–2.4) | na | na |
| 5. Urinary infection | 1.0 (0.7–1.6) | na | 1.1 (0.2–2.4) | na | na |
| Race/ethnicity | = | Hispanicse | na | na | = |
| Maternal years of school (≤12) | 1.1 (0.9–1.3) | < | na | = | = |
| Maternal occupation (less skilled) | 1.3 (1.0–1.6) | naf | < skilled workers | = | = |
If odds ratio (OR) were provided in the manuscripts we reported them with the respective confidence intervals (CI).
Otherwise we used: (=) no difference between cases and controls was found; (>) cases had higher values than controls; (<) cases had lower values than controls
All studies also analyzed microtia associated with other defects, but we did not include those results since for this study we analyzed only isolated cases.
All studies used non-malformed infants as controls. Paput et al used an additional set of malformed infants, but we only added in this table the results from the comparisons with the non-malformed infants.
Analysis done on cases with isolated microtia and associated with other congenital anomalies.
Mothers of infants with isolated microtia were more likely to be of Hispanic origin
Mothers of infants with isolated microtia were more likely to have lower household incomes
“na”: data not available/NSAIDs: Non-steroidal antiinflammatories