International Scholarly Research Network ISRN Pediatrics Volume 2012, Article ID 685151, 9 pages doi:10.5402/2012/685151 Research Article Regional Variation on Rates of Bronchopulmonary Dysplasia and Associated Risk Factors Mar´ ıa Ximena Rojas, 1 Mario Augusto Rojas, 2 Juan Manuel Lozano, 3 Mart´ ın Alonso Rond ´ on, 1 and Laura Patricia Charry 1 1 Department of Clinical Epidemiology and Biostatistics, School of Medicine, Pontificia Universidad Javeriana, Bogot´ a 110001, D.C., Colombia 2 Division of Neonatology, Wake Forest University School of Medicine, Winston-Salem, NC, USA 3 Division of Research and Information, College of Medicine, Florida International University, Miami, FL, USA Correspondence should be addressed to Mar´ ıa Ximena Rojas, mxrojas@javeriana.edu.co Received 6 March 2012; Accepted 9 May 2012 Academic Editors: G. J. Casimir, D. L. Jeppesen, S. K. Patole, and T. F. Yeh Copyright © 2012 Mar´ ıa Ximena Rojas et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Background. An abnormally high incidence (44%) of bronchopulmonary dysplasia with variations in rates among cities was observed in Colombia among premature infants. Objective. To identify risk factors that could explain the observed high incidence and regional variations of bronchopulmonary dysplasia. Study Design. A case-control study was designed for testing the hypothesis that differences in the disease rates were not explained by differences in city-of-birth specific population characteristics or by differences in respiratory management practices in the first 7 days of life, among cities. Results. Multivariate analysis showed that premature rupture of membranes, exposure to mechanical ventilation after received nasal CPAP, no surfactant exposure, use of rescue surfactant (instead of early surfactant), PDA, sepsis and the median daily FIO 2 , were associated with a higher risk of dyspla- sia. Significant differences between cases and controls were found among cities. Models exploring for associations between city of birth and dysplasia showed that being born in the highest altitude city (Bogot´ a) was associated with a higher risk of dysplasia (OR 1.82 95% CI 1.31–2.53). Conclusions. Bronchopulmonary dysplasia was manly explained by traditional risk factors. Findings suggest that altitude may play an important role in the development of this disease. Prenatal steroids did not appear to be protective at high altitude. 1. Introduction Despite all the advances in the care of premature infants with respiratory distress syndrome (RDS), including the use of antenatal steroids and early management with surfactant, bronchopulmonary dysplasia (BPD) continues to be a major cause of chronic morbidity among this population. There are large variations in the incidence and severity of this disease. According to the National Institutes of Health of USA (NICHD) consensus [1], mild BPD is defined as a need for supplemental oxygen for ≥28 days at 36 weeks post- menstrual age (wPMA) or discharge, moderate BPD as sup- plemental oxygen for ≥28 days plus treatment with <30% oxygen at 36 wPMA, and severe BPD as supplemental oxygen for ≥28 days plus ≥30% oxygen and/or positive pressure at 36 wPMA. Currently, the estimated incidence of BPD defined as need for supplemental oxygen at 36 wPMA in the United States is approximately 30% for premature infants with a birth weight <1000 grams and <7% in infants with a birth weight >1250 grams or who were at least 30 weeks of gestation at birth [1, 2]. Previous epidemiological studies have identified prema- turity, oxygen toxicity, and mechanical ventilation as major risk factors associated with BPD [3–7]. Additional risk fac- tors include perinatal or postnatal infection/inflammation [8–12], pulmonary edema resulting from patent ductus arteriosus (PDA) [12, 13] or excess fluid administration [7, 14, 15], vitamin A deficiency [16], early adrenal insufficiency [17], and, more recently, genetic polymorphism [18]. There is little information about trends in the epidemi- ology and pathogenesis of BPD in developing countries.