Page 33 - Sample Moderate prematurity, socioeconomic status, and neurodevelopment in early childhood

Prevalence of behavioural and emotional problems
Second, mean scores were computed for all CBCL scales to identify behavioural
problems associated with moderate prematurity. In addition, differences in mean
CBCL scores by gender were examined between MP and term-born children,
using t-tests. All t-tests were confirmed by nonparametric Mann-Whitney U tests
because of the non-Gaussian distribution of the CBCL scores. Third, we computed
the risk for clinical CBCL problem scores in MP versus term-born children, using
logistic regression analyses. In a multivariate logistic regression model, results
were adjusted for differences in characteristics between the samples. For all
statistical analyses SPSS for Windows 16.0 was used. A P-value of less than 0.05
was considered as statistically significant. A Bonferroni correction for multiple
t-tests in our gender-subgroup would adjust the cut-off for statistical significance 3 to 0.005.
RESULTS
Background characteristics of the preterm and term groups differed with high statistical significance regarding gender, family composition, and number of siblings, and marginally so for maternal age and educational level (Table 1).
Table 2 shows that MP children had higher mean scores on internalizing (mean difference [MD], 95% confidence interval [CI]: 1.33, 0.67-1.98), externalizing (MD 1.41, 95% CI 0.59-2.23), and total problems (MD 4.04, 95% CI 2.08-6.00) than term-born children. For the syndrome scales the greatest differences were seen in withdrawn behaviour (MD 0.29, 95% CI 0.13-0.44) and attention problems (MD 0.59, 95% CI 0.39-0.79). Adjustment for gender, family composition, number of siblings, maternal age, and maternal educational level did not change the computed differences in means (not shown). Nonparametric testing led to similar results.
Differences in mean CBCL scores between groups tended to be greater in boys than in girls, as presented in Table 3. However, the gender-by-group interaction was not statistically significant. Among boys, mean scores on two syndrome scales, sleep problems and attention problems, were significantly higher in MP than in term-born children. Among MP girls, mean scores on all seven syndrome scales, as well as on internalizing, externalizing, and total problems were significantly higher than among term-born girls (Table 3).
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