[Risk factors associated with bronchiolitis in children under 2 years of age].

Introduction: The objective of this study was to determine the risk factors associated to bronchiolitis in infants less than two years of age.

Materials And Methods: Prospective case-control study was performed in a hospital of second level of attention. The sample size was calculated for a level of confidence of 95%, a power of 90%, and a difference of exposure of 15% between cases and controls.