Statistical analyses
Continuous variables were represented using mean, standard deviation,
median, minimum, and maximum value while categorical ones using absolute
and relative frequencies. Fasting and postprandial TSBA
2.5th and 97.5th percentiles and
their 95% confidence intervals were reported.
In order to assess the association between fasting or postprandial TSBA
and maternal and neonatal characteristics the Pearson’s correlation
coefficient was used. To evaluate the difference in fasting or
postprandial TSBA between groups a T-test, Satterthwaite T-test or
Mann-Whitney test were used according to Shapiro-Wilk test and F-Test
for normality and homoschedasticity respectively.
The Kruskal-Wallis test was used to assess the difference in fasting or
postprandial TSBA between seasons, according to Shapiro-Wilk test for
normality.
The statistical analyses were conducted using statistical software
package SAS 9.3 and the significance level was set at 5%.
Ethical approval
This study was performed according to the principles of the Declaration
of Helsinki and was approved by the ethics committee of Careggi
University Hospital (reference number 18008_bio).