Risk factors for severe bronchiolitis caused by respiratory virus infections among Mexican children in an emergency department

Robledo-Aceves, Mireya; Moreno-Peregrina, María de Jesús; Velarde-Rivera, Fernando; Ascencio-Esparza, Elba; Preciado-Figueroa, Francisco M.; Caniza, Miguela A.; Escobedo-Melendez, Griselda

The medical records of children included in this study were independently reviewed by 2 pediatricians, and the information was recollected using a standardized questionnaire in the moment that the child was present at Emergency or Preventative Departments for evaluation. The following demographic data were investigated: age, sex, date of birth, gestational age, birth weight, birth length, previous hospitalizations, history of previous respiratory disease, and birthplace. All mothers were interviewed to determine their children's exposure to potential or known risk factors for severe bronchiolitis, including the following: history of inadequate prenatal and neonatal care (e.g., whether mother was evaluated by a medical doctor at least 9 times during the pregnancy [24] ), intake of vitamins and calcium during of pregnancy, exposure to cigarette smoke, [26] delivery by elective caesarean section, [23] premature birth (gestational age < 37 weeks [15] ), requirement of mechanical ventilation during the neonatal period, [15] congenital abnormality (e.g., persistent ductus arteriosus, Down syndrome [15, 19] ); children's health history: breastfed for at least 6 months [21] (if the children were less than 6 months of age and they were being breastfed, was considered to have this criteria), completed vaccination schedule for the child's age (Bacillus Calmette-Guerin and hepatitis B vaccines at birth and hepatitis B vaccine at 2, 4, and 6 months of age; pentavalent acellular pertussis, rotavirus, and pneumococcus vaccines at 6 and 7 months of age; and annual influenza vaccines [27] ), daycare, [28] or malnutrition (i.e., deficiency of weight/age, index weight/age, height/age, and weight/height were obtained from the children, and then the nutrition indexes were analyzed [29] ); family health history: asthma, allergies, atopy, and rhinitis in family members [18] ; and environmental factors: passive exposure to house smoking, [30] excessive moisture in the house (coexistence of molds or black spots on the walls), overcrowding, [12] pest infestation in the house, and coexistence with pets. [18, 30]