[Mediating effect of milk intake between family socioeconomic status and body mass index of children and adolescents].

OBJECTIVE: To examine the association between family socioeconomic status (SES) and body mass index (BMI) z-score of children and adolescents, and the mediating effect of milk intake in this association. METHODS: In the study, 2 496 students and their parents were selected from 16 schools (4 urban middle schools, 4 rural middle schools, 4 urban primary schools, and 4 rural primary schools) using a stratified cluster sampling method. The frequency and amount of weekly milk intake from the 7-day Food Records reported by the students were extracted. The parents' education and household income were the indicators of family SES. The mediating effect of milk intake between family SES and BMI z-score of children and adolescents were tested using the PROCESS add-on SPSS software. RESULTS: Parents' education level and household income were positively correlated with BMI z-score of children and adolescents (P=0.001 and 0.038, respectively). The overall average daily intake of milk was (0.92±0.84) servings, and the frequency was (4.43±2.70) days per week. The students of primary school, in urban areas, with higher parents' education level, with higher household income, and being non-obese were likely to have higher frequency and amount of milk intake. Milk intake was one of the mediating factors in the relationship between family SES and BMI z-score of children and adolescents. Specifically, the mediating effect of the frequency of milk intake accounted for -6.57% and -10.21% of the total effects of the association between the parents' education and the household income with BMI z-score of children and adolescents, respectively. The mediating effect of the daily intake of milk accounted for -3.63% and -5.86% of the total effects of the association between the parents' education and the household income with BMI z-score of children and adolescents, respectively. CONCLUSION: The milk intake of Chinese children and adolescents still needs to be improved. High family SES was found to contribute to high BMI z-score, mediated by the milk intake which was the protective factors of BMI z-score. Further research is needed to study other dietary or physical exercise behaviors that mediate the relationship between family SES and BMI z-score of children and adolescents in order to adopt more targeted interventions.

[Research on knowledge status and relevant factors of breastfeeding among medical staff in China based on network platform].

From August 1(st) to 7(th), 2017, the breastfeeding knowledge of medical staff were collected from 52 medical health institutions in 29 provinces through a network system. A total of 35 243 questionnaires were included in the study to analyze the current status of breastfeeding knowledge and related factors. The qualified rate of breastfeeding knowledge questionnaires for medical staff in this study was 75.3% (26 546/35 243). Compared with those in the eastern region and those who were mothers, the qualified rate of breastfeeding knowledge of medical staff in the central region or the western region and medical staff who were fathers or expectant parents was lower, with OR (95%CI) values about 0.71 (0.67-0.75), 0.66 (0.61-0.72), 0.63 (0.55-0.72) and 0.87 (0.80-0.95), respectively. Compared with those attaining high school education or below and those with children aged<1 month, the qualified rate of breastfeeding knowledge was higher in medical staff with bachelor's degree, graduate degree or above, and with children aged 1-5, 6-23 and ≥24 months, with OR (95%CI) values about 1.92 (1.80-2.05), 2.16 (1.94-2.42), 2.28 (1.93-2.70), 2.41 (2.06-2.83) and 1.99 (1.72-2.32), respectively.

Surface roughening of glass ionomer cements by neutral NaF solutions.

The objective of this study was to investigate the effect of repeated applications of a neutral NaF solution on the surface roughness of four conventional glass ionomer cements (GIC) (ChemFil Superior encapsulated, Fuji Cap II, Ketac-Fil and Hi Dense), three resin-modified (RM-) GIC (Fuji II LC encapsulated, Photac-Fil and Vitremer) and one polyacid-modified composite resin (PAM-C) (Dyract). Matured specimens were four times alternately eluted in water and exposed to 2% neutral NaF aqueous solutions for 1h. Control specimens were only subjected to elution in water for the same time period. After the treatment the surface roughness R(a) was determined using non-contact surface profilometry and selected samples were examined with SEM. Except for the PAM-C, R(a) increased drastically for the fluoride-treated samples compared to water-stored samples, the effect being most pronounced for the GIC. Surface roughening apparently is caused by a progressive disintegration or chemical erosion of the polysalt matrix of (RM-)GIC.