Effect Of App-Based School-Family Salt Reduction Health Education On Knowledge,Attitudes,Practices And 24-Hour Urinary Sodium Of Primary School Students And Their Parents

Background Dietary salt intake is the main factor affecting the increase of blood pressure.Evidences have shown that hypertension in adulthood can be traced back to childhood.Reducing sodium intake from childhood can reduce blood pressure that increases with age,thus preventing hypertension and cardiovascular disease.Health education is the main strategy to reduce salt intake.At present,intervention studies have adopted the traditional teaching method,that was,school teachers impart salt reduction knowledge to students and parents face to face.However,many schools lack specially trained health education teachers,and there is an obvious shortage of teachers.This way not only increases the burden of teachers,but also can’t guarantee the completeness and accuracy of intervention information.As a result,sustainability and extensibility are severely limited.Objective This study conducted a comprehensive salt reduction health education intervention based on an App.The effect of comprehensive intervention on salt reduction was evaluated and the influencing factors were analyzed by comparing the changes of salt and health-related knowledge,attitudes and practices and 24 h urinary sodium between students and parents in the intervention group and the control group before and after the intervention.In addition,this study will also explore the feasibility of school-family comprehensive salt reduction health education intervention model based on App.Method(1)Sampling.This study was a randomized controlled trial.Using the method of multi-stage random sampling,54 primary schools were randomly selected from three cities: Shijiazhuang City in Hebei Province,Luzhou City in Sichuan Province,and Yueyang City in Hunan Province.594 students and 1188 parents were randomly selected from 54 primary schools to participate in the baseline and final survey.(2)Grouping.54 primary schools were randomly assigned to the intervention group and the control group according to the proportion of 1:1.The primary school students in the control group learned the original health education curriculum,while the intervention group increased the health education course of “salt and health”on the basis.(3)Intervention of health education.Primary school students and their parents in the intervention group were given an one-year App-based school-family comprehensive salt reduction health education intervention.During the intervention,they should regularly take online courses and participate in “Salt and Health” theme activities,such as “Salt and Health”handwritten newspaper competition,family salt reduction achievement sharing meeting and experiments to test salt content,and create a supportive environment for salt reduction in schools and families.(4)Contents of investigation.Every survey included questionnaire,physical measurement and two 24 h urine collection.(5)Statistical analysis.T-test and ANOVA were used to compare the differences of measurement data between different groups and before and after health education in the same group;chi-square test was used to compare the difference of rates.Combined with difference-in-differences(DID),24 h urinary sodium was analyzed by multivariate analysis,in order to evaluate the effect of intervention and explore the relevant factors affecting 24-hour urinary sodium.Results In this study,592 students and 1184 parents were investigated at baseline(2 students and 4 parents dropped out of the study),after the intervention,565 students and 1072 parents were investigated,and the lost follow-up rate of 4.6% and 9.5%,respectively.(1)Changes of knowledge,attitude and practice related to salt and health in primary school studentsAfter the intervention,the awareness rate of some knowledge of primary school students in the control group increased,and the awareness rate of each item of knowledge in the intervention group increased significantly.The awareness rates of “recommended daily salt intake for adults”,“children’s salt intake should be lower than adults”,“nutrition labels that represent salt in food” and “eating too much salt is harmful to health” in the intervention group and the control group were 77.7% and 23.2%,98.2% and84.6%,79.5% and 49.3%,98.5% and 87.1%,respectively(P<0.05).The proportion of self-rated salty taste in the two groups decreased to 8.1% and22.1%,respectively(P<0.05).The proportion of students in the intervention group who didn’t eat salty snacks was 15.8% higher than that at baseline(P<0.05).(2)Changes of 24 h urinary sodium of primary school studentsAt baseline,the average of 24 h urinary sodium in the intervention group and the control group were both 2.17g/d(P>0.05).After intervention,the average of 24 h urinary sodium in the two groups was 2.07g/d and2.38g/d,respectively(P<0.05).Compared to baseline,the mean 24 h urinary sodium was 0.10 g/d lower in the intervention group(P<0.05)and 0.21 g/d higher in the control group(P<0.05).(3)Changes of knowledge,attitude and practice related to salt and health among parentsIn terms of salt and health related knowledge,after intervention,the knowledge awareness rate of parents both in the intervention group and the control group were improved,and the increase in the intervention group was higher than that in the control group.The awareness rates of “recommended daily salt intake for adults” and “low-sodium salt” in the intervention group and the control group were 64.1% and 40.8%,77.7% and 68.1%,respectively(P<0.05).In terms of salt and health-related attitudes,after intervention,the recognition rates increased in both the intervention and control groups.The recognition rates of “long-term excessive salt may lead to hypertension” and“eating less salt will not make people weak” in the intervention group and the control group were 86.4% and 78.3%,64.9% and 42.0%,respectively(P<0.05).In terms of salt and health-related practices,after intervention,the positive holding rate of some salt reduction behaviors of parents in the intervention group was significantly increased,and the positive holding rate of each behavior in the intervention group was higher than that in the control group.The proportion of parents who used low-sodium salt when cooking,not ate pickled foods,not ate salty snacks,and actively asked for less salt when eating out or ordering takeout in the intervention group and control group were 44.6% and 28.4%,71.6% and 65.6%,93.1% and 87.4%,45.1%and 18.5%,respectively(P<0.05).(4)Changes of 24 h urinary sodium of parentsAt baseline,the average of 24 h urinary sodium in the intervention group and the control group were 3.93g/d and 3.92g/d,respectively(P>0.05).After intervention,the average of 24 h urinary sodium in the two groups was3.48g/d and 3.82g/d,respectively(P<0.05).Compared to baseline,the 24 h urinary sodium in the intervention group decreased 0.45g/d(P<0.05).The 24 h urinary sodium was the highest in those with salty taste,followed by those with moderate taste,and the lowest in those with the light taste(P<0.05).In the intervention group,the frequency of eating pickled food and salty snacks was different,and the average of 24 h urinary sodium was different(P<0.05).The results of multivariate analysis combined with DID method showed that region,sex,age,education level and practice scores were all influencing factors of 24 h urinary sodium.Conclusion After one year of salt reduction health education,the awareness rate of salt-related knowledge,the recognition rate of attitudes and the positive holding rate of some salt reduction practices of students and parents have been greatly improved.The 24 h urinary sodium of students and parents in the intervention group decreased significantly.Above all,App-based salt reduction program for primary school children and their families can effectively improve the level of knowledge,attitudes and practices of students and parents,and reduce salt intake.Therefore,this intervention model has good feasibility and generalizability.