Demographic and clinical characteristics for the subset of term singleton newborns studied,* comparing those having a 22q11.2 deletion with the remainder of the population sampled
| Demographic or clinical variable | Newborn group;* no. (%) of newborns† | OR (95% CI)‡ | |
|---|---|---|---|
| With 22q11.2 deletion (maximum n = 13) | Remaining population (maximum n = 26 305) | ||
| Sex, male | 4 (31) | 13 467 (51) | 0.42 (0.12 to 1.35) |
| Birth weight for gestational age§ | |||
| < 10th percentile | 6 (46) | 2869 (11) | 7.00 (2.36 to 23.18) |
| < 3rd percentile¶ | 2 (15) | 819 (3) | 5.66 (0.90 to 23.80) |
| Neonatal transfusion** | 0 (0) | 12 (0.06) | 0.00 (0.00 to 834.95) |
| Complex neonatal feeding**†† | 2 (18) | 183 (0.8) | 29.41 (4.53 to 134.65) |
| Gestational age, wk, median (IQR) | 39.0 (38.0 to 39.6) | 39.3 (38.5 to 40.2) | −0.3 (−1.1 to 0.2)‡‡ |
| Maternal age,** yr, median (IQR) | 25.5 (24.0 to 29.5) | 32.0 (28.0 to 35.0) | −6.5 (−7 to −2)‡‡ |
Note: CI = confidence interval, IQR = interquartile range, OR = odds ratio.
↵* Only singletons born at term with available data for sex, birth weight and gestational age are included. “Term” was defined as 37 weeks ≤ gestational age < 42 weeks; all multiple births were excluded. Some data were missing for other variables (see details below). Also, for 1 individual of the 13 in the 22q11.2 deletion group and 109 of the 26 305 individuals in the remaining population group, the DNA was obtained before 24 hours of age, which might be considered a less-than-satisfactory sample, given that certain newborn screening tests may be less sensitive with DNA sampled in this period.
↵† Except where indicated otherwise (i.e., for the continuous variables gestational age and maternal age).
↵‡ Except where indicated otherwise (i.e., for the continuous variables gestational age and maternal age), the entries in this column are ORs quantifying the association between each variable of interest and the 22q11.2 deletion, with 95% CI. For ease of interpretation, the following variables were statistically significant with a p value < 0.05: birth weight for gestational age < 10th percentile, complex neonatal feeding and maternal age.
↵§ Percentiles were calculated based on a Canadian reference set of all singletons born in Canada between 1994 and 1996 (with the exception of Ontario).22
↵¶ Among female infants, the proportion with birth weight for gestational age below the third percentile was significantly greater in the 22q11.2 deletion group (n = 2/9 [22%] v. n = 401/12 838 [3%], p = 0.03).
↵** Some data were missing for each of the following variables: neonatal transfusion data were available for n = 11 from the 22q11.2 deletion group and n = 21 699 from the remaining population; neonatal feeding data were available for n = 11 from the 22q11.2 deletion group and n = 24 414 from the remaining population; maternal age data were available for n = 12 from the 22q11.2 deletion group and n = 25 999 from the population group (the latter excluding 1 individual with maternal age recorded as > 60 yr, presumed to be a data entry error).
↵†† “Complex neonatal feeding” refers to neonates who required total parenteral nutrition and those who were designated to receive nothing by mouth (“nil per os” or NPO) as either their sole method of feeding or in combination with another feeding type. The 2 individuals with 22q11.2 deletion and a complex feeding type were both recorded as NPO at birth.
↵‡‡ Entry shown is the difference between medians (22q11.2 deletion group minus population group), with 95% CI.