To investigate the impact of diet, the way of parenting and living environment on recurrent upper respiratory tract infections (rURTIs) in children, and to discuss risk and protective factors in order to explore new method for taking prevention measures.

From December 2008 to May 2009, a total of 230 children aged 3 to 6 years old who were admitted in the Department of Child Health Care, Children Hospital of Shanxi, including 151 boys (65.7%) and 79 girls (34.3%). Among those 230 children, 118 children were diagnosed as recurrent upper respiratory tract infections (case group) according to the diagnostic criteria made by Subspecialty Group of Respiratory Diseases, the Society of Pediatrics, Chinese Medical Association, including 82 boys (69.5%) and 36 girls (30.5%). At the same time, another 112 normal children aged 3 to 6 years old from the same hospital were included into control group, including 69 boys (61.6%) and 43 girls(38.4%). Informed consent was obtained from all participates. The general demographic characteristics, nutritional status, ways of parenting and living environment were analyzed between two groups by single factor and multi-factor non-conditional Logistic regression analysis approach in order to explore risk and protective factors of recurrent upper respiratory tract infections.

The main influencing factors of recurrent upper respiratory tract infections aged 3 to 6 years old included, ① Risk factors: Vegetable consumption at least third times per week[OR=5.195, 95%CI(1.193, 22.624)], nursery school [OR=5.642, 95%CI(1.149, 27.702)], history of recurrent upper respiratory tract infections[OR=8.129, 95%CI(2.725, 24.256)], outdoor activity less than 30 minutes a day [OR=4.583, 95%CI(0.857, 24.499)] or less than 2 hours a day [OR=5.291, 95%CI(1.576, 17.763)]. ②Protective factors: Education level of father [OR=0.134, 95%CI(0.034, 0.527)], fruit consumption at least six times per week [OR=0.231, 95%CI(0.069, 0.775)], application of antibiotics less than three times per year[OR=0.028, 95%CI(0.003, 0.303)]. ③ Nursery and fruit intake: There had interaction effect between children who had history of recurrent upper respiratory tract infections before nursery and fruit intake.

The occurrence of recurrent upper respiratory tract infections could affect by rational diet, vegetable intake, fruit intake, and outdoor activity at least 2 hours a day. The education level, especially the father's, is related with the occurrence of recurrent upper respiratory tract infections. Nursery school should strengthen child health care and prevent cross infection, and children with recurrent upper respiratory tract infections should be treated in time.