RESUMO
Objective@#To investigate the status and influencing factors of health literacy of middle school students in Yinchuan City, to provide reference for health literacy improvement of middle school students in this region.@*Methods@#Using stratified cluster sampling method, 2 003 middle school students from three districts of Yinchuan were investigated to complete the questionnaire survey.The survey included basic characteristics, health literacy and screen time status.@*Results@#The total score of Chinese Adolescent Interactive Health Literacy Questionnaire was(101.3±17.5). The proportion of high, medium and low level of health literacy were 25.0%, 51.2% and 23.9% respectively;the proportion of long screen time exposure among middle school students was 52.5%. The health literacy level of junior middle school students, middle school students with father or mother education level of high school or above and appropriate screen time were higher than those of the corresponding group（χ 2=49.90，14.59，16.53，46.73，P<0.01）. Logistic regression analysis showed that education group, grade, father s or mother s education level and long screen time exposure were associated with middle school students health literacy level(P<0.05).@*Conclusion@#The health literacy level of middle school students in Yinchuan City needs to be further improved and targeted health education should be carried out from school, family and society.
RESUMO
Objective@#To analyze the association between tea drinking during pregnancy and the risk of preterm delivery and abortion,so as to provide basis for prevention of preterm delivery and abortion.@*Methods@#The databases of CNKI,Wanfang,VIP,CBMdisc,PubMed and Web of Science were searched for cohort studies and case-control studies into the association between tea consumption during pregnancy and preterm delivery or abortion until June 30 th,2019. Relative risk（RR）or odds ratio（OR）were used as indicators for the meta-analysis.@*Results@#A total of 1 099 articles were retrieved,14 of them were included in the quantitative study,including 9 cohort studies with 18 295 exposed and 71 890 unexposed individuals and 5 case-control studies with 1 351 cases and 3 059 controls. There was no statistically significant association between tea drinking during pregnancy and preterm birth or abortion（OR/RR=1.08,95%CI：0.99-1.18）. The linear regression model of random effect showed that with the increase of tea consumption during pregnancy,the risk of premature delivery and abortion did not change significantly（OR/RR=1.05，95%CI：0.99-1.11）. There was no publication bias found in Begg's test and Egger's test. @*Conclusion@#Drinking tea during pregnancy is not associated with preterm delivery and abortion.
RESUMO
Objective@#To study the detection rate of Streptococcus mutans in oral cavities of 3-5-year-old Han, Uygur and Mongolian children in Bortala Mongolian Autonomous Prefecture, and the correlation between genotype and dental caries of preschool children.@*Methods @# Ninety children were randomly selected from the sample bank of children′s oral epidemiological survey data in the Bozhou area of Xinjiang. Forty-five children were included in the high caries group (more than 5 missing teeth), and 45 children were included in the noncaries group (0 missing teeth); each group comprised 15 children of each of the Han, Uygur and Mongolian nationalities. Plaque samples were collected and cultured with light saliva-bacillin agar medium and brain-heart infusion medium. Streptococcus mutans were cultured, and clinical isolates were further isolated and identified by Gram staining, biochemical identification and polymerase chain reaction. Genotype distribution was detected by random primer polymerase chain reaction.@*Results @#The detection rate of Streptococcus mutans in the 90 included children was 75.5%. The detection rate of Streptococcus mutans in the high caries group was 86.7%, which was significantly higher than that in the caries-free group (64.4%) (P=0.014). There was no significant difference in the distribution of Streptococcus mutans among Han, Uygur and Mongolian nationalities (P=0.457). A total of 549 clinical strains of Streptococcus mutans were obtained, and 113 different genotypes were found. In the high caries group, 61.5% carried more than one genotype of Streptococcus mutans, and 37.9% of the caries-free group had more than one genotype. The genetic polymorphism of Streptococcus mutans in the high caries group was significantly higher than that in the caries-free group (P=0.035). Spearman correlation analysis showed that there was a positive correlation between oral Streptococcus mutans gene polymorphism and caries sensitivity (r=0.258, P=0.034).@*Conclusion@#The distribution of Streptococcus mutans in children′s oral cavity in the Bozhou area was different between the high caries group and the caries-free group, but there was no difference among nationalities. Streptococcus mutans in the high caries group had more genotypes than those in the caries-free group. The genetic polymorphism of Streptococcus mutans might be related to the caries-causing ability of Streptococcus mutans.