Effect Evaluation Of Randomized Controlled Trial Of Salt Reduction Intervention Based On Community And Family

Objective To evaluate the effect of salt reduction intervention and analyze the influencing factors after one year of intensive salt reduction intervention in six regions of China,which provided scientific basis for popularizing the salt intervention in the community in the future.Method In this study,a randomized controlled trial(RCT)was used to design a multi-stage random sampling method.60 communities were randomly selected from six areas with multi-stage random sampling method,including Ren county in Hebei Province,Luobei County in Heilongjiang Province,Guide County in Qinghai Province,Hengfeng County in Jiangxi Province,Jinshi city in Hunan Province and Dongqu city in Sichuan Province.1576 respondents were randomly selected from 60 communities.Baseline survey was conducted from September to November 2018,including questionnaire survey,physical measurement,24-hour urine collection and detection of related indicators such as urine sodium and potassium.60 communities were randomly divided into 30 intervention groups and 30 control groups according to the ratio of 1:1.The intervention group was given 1-year intensive salt reduction intervention,including posters,leaflets,videos,health education lectures,salt reduction support tools and 7-day salt intake monitoring.The control group did not accept special salt reduction interventions.A follow-up survey was carried out one year later.The knowledge,attitude and practice of salt reduction,urine sodium,urine potassium and blood pressure were described and compared between different groups and before and after the intervention in the same group.The measurement data were compared by t test or rank sum test,and the counting data were compared by chi square test or Fisher exact probability method.To construct a three-level variance component model with individual as the first level,family as the second level and community/village as the third level.The intervention effect and influencing factors of salt reduction KAP,24-hour urine sodium,urine potassium and blood pressure were evaluated combined with difference-in-difference analysis.Results In this study,1576 subjects were investigated at baseline.After one year of intervention,a total of 1419 people participated in the follow-up survey,157 people were lost to follow-up,and the lost follow-up rate was 9.96%.In the intervention group,there was a difference in the distribution of alcohol consumption between the lost follow-up group and the follow-up group(P=0.004).In the control group,there were differences in the distribution of age,education level,region,total annual family income and diet taste between the lost and follow-up groups(P<0.05).At baseline,there were differences in the distribution of total family income and waist circumference between the control group and the intervention group(P<0.05).At follow-up,there were differences in the distribution of total family income,family number,taste and exercise between the control group and the intervention group(P<0.05).In the aspect of 24-hoururine sodium,after removing the unqualified urine,the24-hour urine sodium of the control group was 0.09(-0.29,-0.11))g/24 h lower than that before intervention in univariate analysis,but there was no statistical significance(P=0.452).The 24-hour urine sodium of the intervention group decreased by 0.39g/24h(P<0.0001).After the intervention,the 24-hour urine sodium of the intervention group was 0.35(-0.54,-0.16)g/24 h lower than that of the control group(P=0.001).In the analysis of multilevel model combined with multiple difference method,after adjusting the variables of age,gender,education level,city,diet taste,drinking,exercise,BMI and 24-hour urinary potassium,the net effect of intervention was that24-hour urinary sodium decreased by 0.276(-0.467,-0.086)g/24h(P=0.004).Older age,female and no alcohol consumption are beneficial to the decrease of urine sodium,while salty taste and high BMI are not.In terms of KAP of salt reduction,part awareness rate of salt reduction related knowledge in the control group was improved after the intervention,the awareness rate of salt reduction related knowledge and positive holding rate of salt reduction related attitude in the intervention group were improved,and the awareness rate of each knowledge and positive holding rate of salt reduction related attitude in the intervention group were higher than those in the control group after the intervention(P<0.05).The behavior holding rate of "not eating pickled food" and "actively asking for less salt when eating out or ordering takeout" in the intervention group was higher than that before the intervention,and the behavior holding rate of the intervention group was higher than that of the control group after the intervention(P<0.05).Women,40-60 years old and above,high school and above education level,mild taste,no drinking,moderate and above intensity exercise are conducive to the improvement of salt reducing KAP,while those who have not been to school,taste salty,often drinking or drinking are not conducive to the improvement of salt reducing KAP.In the aspect of 24-hour urinary potassium,after removing the unqualified urine,the 24-hour urinary potassium of the control group was 65.51(-128.39,-2.64)mg/24 h lower than that before intervention(P=0.004),and that of the intervention group was51.39(-114.68,11.90)mg/24 h lower than that before intervention(P=0.181).After the intervention,24-hour urinary potassium in the intervention group was 29.48(-34.58,93.54)mg/24 h higher than that in the control group,but there was no statistical significance(P=0.229).In the analysis of multilevel model combined with multiple difference method,after adjusting the variables of age,gender,education level,city,diet taste,drinking,BMI and 24-hour urine sodium,the net effect of urinary potassium was no statistical significance(P=0.124).Older age,no smoking and higher BMI are helpfful to increase urinary potassium,while salty taste is not conducive to increase urinary potassium.In terms of blood pressure,the systolic and diastolic blood pressure of the intervention group and the control group did not change significantly in the univariate analysis.After adjusting for age,gender,education level,outdoor temperature,diet taste,drinking,exercise and BMI,the increase of systolic blood pressure in the intervention group was 1.742(-3.331,-0.153)mmHg lower than that in the control group(P=0.032),and there was no significant change in diastolic blood pressure.Women and accepting education are conducive to the decrease of blood pressure,while older age,salty taste and higher BMI are not conducive to the decrease of blood pressure.Conclusion After one year of salt reduction intervention,the awareness rate of salt reduction related knowledge,the holding rate of positive attitude,and the holding rate of some salt reduction behaviors of the intervention population were significantly improved.The 24-hour urine sodium and systolic blood pressure of the intervention population decreased,but the 24-hour urine potassium and diastolic blood pressure did not change significantly,which proved that the intensive salt reduction intervention measures in this study have certain effect,and can be popularized and implemented in community salt reduction activities in the future.At the same time,we can increase the degree of salt reduction intervention and extend the intervention time on this basis.In order to achieve better intervention effect,salt reduction intervention should be strengthened for men,salty taste,drinkers,overweight and obese people.