Objective: To investigate whether insufficient nutritional health knowledge can increase the risk of obesity conferred by the surrounding environment, so as to provide a basis for improving the physical health of primary school students by their knowledge of nutritional health. Methods: From May to June 2017, a stratified cluster random sampling method was used to select 3 669 primary school students from 2 primary schools in Shenyang for anthropometric measurements and a student questionnaire survey. School neighborhood environment data were obtained from geospatial analyses conducted by using SuperMap GIS 9D. A self designed questionnaire based on the Chinese Dietary Guidelines (2016) was used to assess individual nutritional health knowledge levels.The frequency of fruit and vegetable intake was divided into four quartiles ( Q 1- Q 4), and the land use efficiency was divided into three quintiles ( T 1- T 3). Multiple Logistic regression and linear regression analyses were employed to examine the relationships between insufficient nutritional health knowledge, school neighborhood environment, and the frequency of fruit and vegetable intake, body mass index (BMI), and perirenal fat thickness (PrFT) among primary school students. Results: After adjusting for age, sex, place of residence, family annual income, parental education level, and physical activity, multiple Logistic regression analysis showed that higher land use efficiency around school ( T 2 and T 3)( OR =1.37, 2.45), the presence of ≥1 shopping mall ( OR =1.43), and ≥1 fruit and vegetable store ( OR =1.51) were associated with a higher frequency of fruit and vegetable intake ( Q 4) (all P <0.05). Multiple linear regression analysis revealed that students attending schools with higher land use ( T 3: β = -0.72 ), ≥1 shopping mall ( β = -0.45 ), and multiple fruit and vegetable stores ( β =-0.33) had lower PrFT (all P <0.05). Interaction analysis indicated that the positive association between school neighborhood environment and fruit and vegetable intake frequency was attenuated by insufficient nutritional health knowledge [ T 3 land use×insufficient nutritional knowledge score ( OR = 0.05); ≥1 shopping mall × insufficient nutritional knowledge score ( OR =0.06); ≥1 fruit and vegetable store×insufficient nutritional knowledge score( OR =0.07)] (all P < 0.05). The negative association between school neighborhood environment and the extreme quartile of PrFT was attenuated by insufficient nutritional health knowledge [ T 3 land use mix×insufficient nutritional knowledge score ( β =2.31); ≥1 shopping mall×insufficient nutritional knowledge score( β =3.59)](both P <0.05). Conclusions The healthy food environment around schools is negatively correlated with the obesity risk among primary school students.However, the association is affected by their insufficient nutritional knowledge. Comprehensive intervention strategies should be implemented to prevent the prevalence of obesity by addressing both individual and environmental factors influencing dietary habits.

[Objective] To explore the accuracy and feasibility of non-invasive prenatal diagnosis of fetal RhE genotype using cell-free fetal DNA (cff-DNA) from maternal peripheral blood. [Methods] A total of 134 pregnant women with single fetuses and RhE-negative blood group were selected from our hospital from November 2023 to August 2024. Free DNA extraction kit was used to extract free DNA from peripheral blood of pregnant women, and the RhE blood group genotype of free DNA was detected by real-time fluorescent quantitative PCR (RT-qPCR). If the qPCR amplification signal of the sample was negative, the methylated RASSF1A gene was amplified, and the positive amplification result was used as a sign of successful extraction of cff-DNA. Serological microcolumn gel method was used to detect the phenotype of RhE blood group in neonatal peripheral blood. [Results] Among the 134 maternal peripheral blood samples, the cff-DNA detection of RhE blood group phenotypes was consistent with the RhE blood group genotyping of neonatal peripheral blood in 133 cases, including 90 cases of Rhee genotype and 43 cases of RhE genotype, with diagnostic concordance rate of 99.3%, sensitivity of 97.7%, specificity of 100%, youden index of 0.977, area under ROC curve of 0.995, the Kappa value of 0.983, positive predictive value of 100%, and negative predictive value of 98.9%. The sample of 1 case failed to be detected. After the amplification of methylated RASSFIA gene, it was confirmed that the reason for the failure was that no cff-DNA was extracted from the sample. The diagnostic concordance rates of the first, second and third trimesters were 93.8% (15/16), 100% (51/51) and 100% (67/67), respectively. Fisher's exact test method was used to calculate the P value, which was P>0.05, indicating that there was no statistical significance in the difference of diagnostic concordance rate among the three pregnancy periods, and there was no difference in the detection concordance rate of this method in different pregnancy periods. [Conclusion] The use of cff-DNA in maternal peripheral blood for the detection of fetal RhE blood group genotype is an accurate and highly feasible non-invasive prenatal diagnostic method, which is helpful for the clinical diagnosis of fetal and neonatal hemolytic disease caused by anti-E antibody.