Ninety eight children with RRI, one hundred and one children
with chronic cough and one hundred and twenty four children
as controls were enrolled. The clinical characteristics of the
study subjects are shown in Table 1. Mean age was 45.9
± 16.2 mo in RRI group, 47.9 ± 15.5 mo in chronic cough
group and 30.1 ± 19.4 mo in control group. There were no
significant differences in baseline variables (age, gender, diet)
between the groups. Duration of exclusive breastfeeding was
similar between cases and controls. Duration of vitamin D
supplementation was lower in RRI group compared to control
group (Table 1) (p