Demographic and clinical information
Study personnel completed case report forms by interviewing parents or
guardians and extracting clinical information from medical records,
including radiographic and laboratory data. Demographic and clinical
information collected included: underlying medical conditions (UMCs),
gestational age, birth weight, mode of birth delivery [Caesarean
section (C-section) or normal spontaneous vaginal delivery (NSVD)],
child’s medical history including vaccination history, feeding,
including supplemental vitamins, atopic history (asthma, allergic
rhinitis or eczema) using the International Study of Asthma and
Allergies in Childhood questionnaire12, family history of
asthma, allergic rhinitis or eczema, current or history of
breastfeeding, number of siblings, day care attendance, indoor pets, and
household smoke exposure. Smoke exposure includes cigarette smoke and
nargila, a form of smoking traditionally found in Middle Eastern
cultures, in which tobacco is heated with charcoal and the resultant
smoke is passed through a water basin before inhalation13. Subjects were
considered to have UMCs if they had any of the following conditions:
diabetes, heart disease, Down syndrome, kidney disease, sickle cell
disease, cystic fibrosis, cancer, genetic/metabolic, cerebral palsy,
neurological, mental retardation/developmental delay, seizure disorder,
chronic diarrhoea (eg, >2 weeks), gastro-oesophageal reflux
disease, immunodeficiency, asthma/reactive airway disease (RAD), liver
disease and/or other. Data were entered into a standardized, secured
database - REDCap (Research Electronic Data Capture) system
(www.project-redcap.org)14.