First, the sample sizes of the 2 groups in our study were very different, so some of the differences between the premature and full-term infants may not be apparent in the CBISQ sleep measurement.
There were, however, no significant differences between the premature group and the special population group in terms of proportions of hospitalized infants tested for RSV (79% vs. 85%, χ = 1.179, df = 1, p = 0.327).
The results revealed, as expected, a significant difference between the 2 groups: The premature group preferred a side body position and being held when falling asleep, had more night awakenings, greater subjective mention of presence of a sleep problem by caregivers, louder noisy breathing and more time spent crying during the night.
The mixed linear model [ 25] was used to study potential differences in HRQoL between the premature and the matched term born control children, adjusted for potential confounders, i.e. gender, physical activity, learning and/or attention problems and FEV1.
Another difference between the two phenotypes is the premature differentiation of iASPP−/− keratinocytes, which does not occur with ΔNp63 or full p63 depletion.
Not only did our study validate the CBISQ, but it is also the first study targeting the difference between premature and full-term infants through a reliable and valid screening questionnaire.
There was no sex difference between premature infants at the time of delivery (p=0.2), but after receiving a standard nutrition during 6 weeks the correlation of PI with maternal BMI appeared significantly vice versa compared to full-term infants (p=0.01).
As a pilot study in this field, our results provide new insights into the difference between premature and full-term infants with regard to sleep problems.
There was no significant difference between the two groups with respect to premature birth (p = 0.88), whether mothers took vitamin D supplements during pregnancy (p = 0.92), or maternal milk intake during pregnancy (p = 0.56) (data not shown).
There was little difference between the two ethnic groups in mean gestation, premature births and infant sex.
