2.4 Statistical analysis
Descriptive analysis of the baseline characteristics, disease phenotypes
and covariates of the study population was performed, stratifying by
presence of FA. Continuous and categorial variables were tested using
one-way ANOVA and Chi2-test, respectively. To
investigate the associations of ever eczema and eczema phenotypes with
FA presence, multinomial logistic regression analysis with and without
adjustment for all covariates (excluding age at baseline) was conducted.
Association of ever eczema and eczema phenotypes with presence of asthma
and hay fever were analyzed using logistic regression analysis with and
without adjustments for all covariates (excluding age at follow-up). The
trajectories of the different allergic diseases in the study population,
stratified by FA presence, was based on the prevalence of eczema, asthma
and hay fever within each age bracket. Differences in prevalence of each
allergic disease between the FA groups were tested using a
Chi2-test with post-hoc group-wise comparison within
each age bracket.
Data management tasks and statistical analysis were carried out using R
Studio (2022.02.0443, based on R version 4.1.2, RStudio Team (2022),
RStudio: Integrated Development Environment for R. RStudio, PBC, Boston,
MA URL http://www.rstudio.com/). Relevant packages are listed in the
supplement. The significance level for all tests conducted was a p-value
of 0.05.