Objective To explore the effects of indoor environmental factors on the respiratory symptoms in children aged 4-17 years. Methods A cross-sectional survey of indoor environmental factors related respiratory symptoms in 6 551 children and teenagers aged 4-17 years was conducted throughout urban area of Shanghai in 2007. The information was obtained on certain aspects of the family socioeconomic status (SES) and other confounding factors,and the associations between indoor environmental factors and respiratory symptoms were analyzed. Results After controlling confounders,parent smoking,the house or the classroom nearby roads (

ObjectiveTo analyze the prevalence of reduced visual acuity of young children in Changning district of Shanghai and to explore the influencing factors， so as to provide a reference basis for formulating prevention and control measures for children’s reduced visual acuity. MethodsVisual acuity examination and questionnaire survey were conducted on 5 772 middle class children in kindergartens and first grade children in primary schools who participated in the refractive screening in Changning District in 2019. χ² test and logistic regression analysis were used to explore the influencing factors of reduced visual acuity. ResultsThe overall prevalence of reduced visual acuity among lower-aged children was 10.4% （596/5 772）. The prevalence of reduced visual acuity in the first grade children was 10.1% （284/2 822）， and that in the middle class children of kindergarten was 10.8% （312/2 900）. The prevalence of reduced visual acuity was 10.2% （298/2 933） in boys and 10.7% （298/2 789） in girls. 98.1% of young children had one or more bad habits when using eyes. Multivariate logistic regression analysis showed that frequent excessive head lowering （OR=1.713） and sometimes too close to the screen （OR=1.294） were independent risk factors for reduced visual acuity in young children； After stratification by age， frequent excessive head lowering （OR=1.997） increased the risk of reduced visual acuity of children in the first grade of primary school. Premature birth （OR=1.841）， sometimes excessive head lowering （OR=1.363） and frequent excessive head lowering （OR=2.002） increased the risk of reduced visual acuity of children in the middle class of kindergarten. ConclusionFor young children， we should pay more attention to their daily eye use distance， correct their bad behaviors for using eyes such as excessively lowering their head when using eyes and too close to the video screen when using electronic products， so as to prevent and delay the occurrence and development of reduced visual acuity.

ObjectiveTo evaluate the caries prevention effect of different fluoride application frequencies in 3-year-old children with active caries. MethodsA total of 337 3-year-old children with dental caries from 12 kindergartens in Changning District of Shanghai were divided into three groups： group 1 received fluoride application once every three months， group 2 received fluoride application once every six months， and the control group received no fluoride application. At baseline， parents completed a questionnaire survey， and oral examinations were conducted at baseline， 7 months， and 16 months after the fluoride intervention to assess the incidence of new dental caries， new dmft， and new dmfs of children. Multivariate logistic regression analysis was used to analyze the relationship between fluoride application and new dental caries， with new dental caries as the dependent variable and local fluoride application， child's gender， age in months， parents' highest education level， frequency of sugary intake （desserts， candies， sweet beverages）， age of toothbrushing initiation， frequency of daily toothbrushing， use of fluoride toothpaste， parental assistance in child’s toothbrushing， and daily use of dental floss as the independent variables. ResultsThere were no significant differences in baseline general conditions and oral health behaviors among group 1 （121 cases）， group 2 （123 cases） and the control group （93 cases） （all P>0.05）. After 16 months' intervention， three children were lost to follow-up due to transferring schools. The new caries rates of group 1 （120 cases）， group 2 （121 cases） and the control group （93 cases） were 5.83%， 24.79% and 52.69%， respectively. The incidence of new caries was significantly lower in group 1 compared to group 2 and the control group （P<0.001）， and it was also significantly lower in group 2 compared to the control group （P<0.001）. The newly-increased caries of group 1， group 2 and the non-fluoride control group were all 0.12 0.52， 0.36 0.68 and 1.16 1.39， respectively. The mean increment of new caries was lower in group 1 compared to group 2 （P=0.040） and the non-fluoride control group （P<0.001）， and it was lower in group 2 compared to the non-fluoride control group （P<0.001）. After adjusting for factors such as gender， parents' education level and child's oral health behaviors by multivariate logistic regression， the results showed that fluoride application once every three months could significantly reduce the risk of dental caries （OR=0.04， P<0.001）. ConclusionLocal use of fluoride has a certain effect on the prevention and treatment of dental caries in children with active caries. Fluoride application once every three months effectively reduces the incidence of new caries and slows down the progression of caries lesions. It is suggested that local application of fluoride should be implemented once every three months for children with active caries.