Affiliation: | 1. Department of Pediatrics, Second Affiliated Hospital of Kunming Medical University, Kunming, China;2. Department of Women and Child Health, School of Public Health, Kunming Medical University, Kunming, China;3. Department of Pediatrics, Kaiser Permanente Los Angeles Medical Center, Los Angeles, California, USA;4. Department of Health Care, Kunming Maternal and Child Health Hospital, Kunming, China |