| BackgroundYing Yang Bao(YYB,nutrition sachet)is a complementary food supplement made of soybean powder and micronutrient fortificants.It has been widely used in early childhood nutrition intervention in low-income areas in China,and is considered suitable for infant and Young Children(IYC)nutrition intervention in developing countries,so it has attracted the attention of nutritional fields at home and abroad.Observation data showed YYB intervention benefit IYC by reduction of anemia,however,related studies conducted comparative analysis on before and after the intervention data based on cross-sectional survey.There are needs sophisticated analysis that consider possible confounding factors such as region,month age,gender,in addition,and scientifically set the intervention group and control group,to establish YYB dose-response relationship is needed.Therefore,it requires further systematic in-depth study to evaluate YYB's nutritional intervention effect,make evidence based YYB consumption guidance,explore the role of YYB dose-response relationship and evaluate project result.ObjectiveThe monitoring data of IYC nutrition improvement project in low-income areas were used.On the basis of general statistical analysis,PSM matching method was used to eliminate the interference of region,month age and gender confounding factors,IYC in the baseline period and intervention period after matching was used to study the intervention effect of YYB by month age hierarchy.The integrated clustering grouping method was adopted to scientifically set the intervention group and control group,and the effects of YYB were obtained by grouping them into different age groups to get the results after removing the confounding factors.Factors analysis and dose-effect regression analysis were conducted to further study effect and dose-effect relationship of YYB intervention on growth and nutrition status of IYC.The objective of the study is to provide a scientific basis for the sustainable development of child nutrition improvement projects in low-income areas.MethodsIn 6 counties of Shan Xi,Hu Bei and Yun Nan,PPS sampling was adopted to extract townships/towns and villages,and random isometric sampling was used to select monitored IYC.A baseline survey of 1840 IYC aged 6-23 months was completed from November to December 2012.YYB was widely given out,registered and counted from March to July 2013.From March to July 2014 and April to July 2015,1789 and 1893 IYC aged 6-23 months were monitored and evaluated for the intervention effect of YYB.Monitoring indicators include height,weight,hemoglobin(Hb)and questionnaire of which investigation items including IYC born and feeding status,parents personal details and IYC feeding knowledge,complementary food and 24 hr feeding,two-week morbidity,receipt and consumption of YYB etc.,so as to explore the influence of YYB on the biological characteristics of IYC.1.Data clearing on demographic data,IYC feeding,nutrition and feeding knowledge of parents,anthropometric measurements,hemoglobin and diseases data.Excluding those individuals who were lack demographic data,the single index was not included if it was judged abnormal by more or less than mean ± 5 SD.Establishing the basic database after data cleaning.2.The sample size,mean,standard deviation,statistical difference and percentile distribution were given by general statistical analysis of the data.3.PSM matching method was used in the analysis of monitoring indexes,and the difference between the intervention of YYB and the baseline was observed.4.Using synthetic clustering grouping method,the population was divided into baseline group,YYB intervention group and quasi-control group for comparative analysis to eliminate the influence of confounding interference factors and further analyze the nutrition effect of YYB intervention.5.After single factor related analysis done,Correlation analysis and logistics regression analysis were used to establish the dose-effect relationship between YYB intervention and main nutrition indexes.The overall study was comprehensively discussed to determine the effect of YYB and the limitations of this study.ResultsA total data of 5,522 individuals were collected in this study,among which data of 1840 individuals were collected in the baseline period during the intervention period,3,682 data were collected.The surveyed family numbers reached the design requirement.After data cleaning,the qualified rate of data in 2012,2014 and 2015 was 99.62%,87.26%and 93.03%respectively,all meeting the expectation of the qualified rate of>80%.In this study,the feeding rate of YYB use was 85.22%,and the median number of sachets of YYB used per week was 4.46 packets.76.61%of the infants caretakers were mothers and the caregivers' occupation was mainly housework,accounting for 73.99%.The acceptable feeding rate was 53.72%.The awareness rates of anemia were 35.73%at baseline and 44.31%after intervention.In baseline and after intervention,the underweight rate,stunting rate,wasting rate,overweight rate and obesity rate were 3.98%,4.46%;9.82%,7.38%;2.56%,3.61%;2.67%,2.16%and 0.38%,0.30%respectively;Hb levels 11.69±The matched data showed that the highest proportion of caregivers with education background was junior high school,and the highest proportion with occupation was housework.After analysis and matching of KAP,the response rates of nutritional knowledge of caregivers in the intervention period were 35.73%and 43.17%,which were significantly higher than those in the baseline period after the intervention,indicating that the level of nutritional knowledge was improved.After matching the data from baseline period and intervention period,in baseline period and intervention period of IYC investigated,the birth weight,WHZ and HAZ were 3288.2 g and 3256.4 g;0.02,0.12;0.55,0.38 respectively,while P values were 0.0255,<0.0001 and<0.0001,respectively,and the differences were statistically significant.However,there were no significant differences in birth length,weight and WAZ,in low body weight rate,growth retardation rate,emaciation rate,overweight rate and obesity rate.Matching comparison showed that the Hb level and anemia rate were 11.7 g/dL and 12.0 g/dL and 25%,14.7%respectively in the baseline and intervention periods.The difference was statistically significant(P<0.0001),indicating that YYB can significantly promote the Hb level of IYC and reduce the incidence of anemia.The diarrhea rate decreased significantly in the past two weeks,from 257 infants at baseline to 192 infants after intervention,which was statistically significant(P=0.0026).The comparison between the baseline period and the intervention period showed that there was a significant increase in food types and food tyspe qualification in the baseline period and the intervention period,which were 4.30 kinds/person/day and 4.58 kinds/person/day,P<0.0001;1127 persons,1203 persons,P=0.0083 respectively.However,the feeding frequency was 3.16 times/day in baseline and 3.03 times/day respectively after intervention and the intervention period was lower than the baseline period,P=0.0009.1.21 g/dL.The results showed that YYB intervention significantly reduced anemia prevalence,stunting rate,diarrhea rate and increased food types in complementary feed.The data showed that YYB intervention may have a negative effect on wasting rate and daily feed frequency,which requires in-depth observation and research.The body length of YYB-FG and YYB-NG was 77.6cm and 75.9cm,respectively.The difference is significant(t=-9.36,P<0.001).However,there was no significant difference in body weight between the groups(P>0.05).Stunting rates of YYB-FG and YYG-NG were 6.78%and 10.29%,respectively,with statistically significant difference(?2=19.131,P<0.001).Wasting rates of YYB-FG and YYB-NG were 2.55%and 3.71%,respectively.The difference was significant(?2=5.223,P=0.022),but there was no significant difference among subgroups grouped by ages.Hb levels and anemia rates of YYB-FG and YYB-NG were 12.13 g/dL,11.71 g/dL and 21.18%,32.12%respectively,with statistically significant difference(t=-12.73,P<0.0001;?2=73.943,P<0.0001).YYB-FG compared with matching YYB-NG,with feeding packets from 1 to 7 per week for 7 groups,increased increments of the body length average respectively to 0.7cm.1.1cm?1.1cm?0.9cm?0.3cm?0.6cm?0.6cm,Hb average respectively to 0.30g/dL?0.29 g/dL?0.51g/dL?0.39g/dL?0.41g/dL?0.36g/dL?0.22g/dL,HAZ respectively to 0.28?0.40?0.40?0.35?0.15?0.18?0.24,and WHZ respectively to-0.15?-0.32?-0.08?-0.09?-0.21?-0.16?-0.18,most groups with statistically significant difference(P<0.05)?Multiple linear regression showed that the regression coefficient and test P values of total YYB feed sachet numbers,intervention weeks and number of YYB sachet feed per week were 0.002982,0.000;0.12596,0.000;0.058866 and 0.010,respectively.Hb:0.001278,0·000;0.004162,0.001;0.33632,0.000;HAZ:0.000998,0.000;0.003779,0.002;0.024291,0.005;WHZ:-0.00075,0.000;-0.00172,0.111;-0.0.02397,0.001.Logistics regression analysis showed that the regression coefficient and test P values of total YYB feed sachet numbers,intervention weeks and number of YYB sachet feed per week were-0.00333,0.000;-0.00867,0.003;-0.0.07178 and 0.000,respectively.Stunting rate:-0.00119,0.026;-0.00451,0.269;-0.0.04846,0.117.It shows that YYB intervention has a significant quantitative relationship with body length,Hb,HAZ and anemia rate,which can be used for the quantitative estimation of the effect of YYB.YYB intervention had a negative effect on WHZ,which was consistent with the results of other parts of this study.It was considered that lower wasting related with-2 WHZ score is a relatively serious malnutrition,which is usually not only determined by feeding factors,but also related to diseases or health conditions.Therefore,it is not certain that YYB will increase wasting,which needs to be further discussed.According to the multiple linear regression formula and assuming that other influencing factors are fixed,the calculation by adjusting the dosage of YYB shows that for each additional 10 sachets of YYB,the body length of IYC during the intervention is estimated to increase by 0.03cm,and the HAZ score of IYC is estimated to increase by 0.01.This indicates that if increase the YYB feed sachets,body length and anemia of intervened infants could be further increased and the effect can be estimated quantitatively.The total YYB feed sachets in the intervention period showed no significant effect on body weight,WAZ,emaciation rate and low body weight rate.Innovations1.PSM matching is adopted for the first time in China to get high-quality and standard random distribution data,improve the balance of covariates,eliminate the interference of region,age and gender confounding factors,and ensure the authenticity and accuracy of the results.IYC in the baseline period and intervention period after matching was used to study the intervention effect of YYB by month age hierarchy,confirming that YYB could not only significantly improve the Hb of IYC and reduce the anemia rate,but also significantly improve body length,HAZ and reduce the diarrhea rate in the past two weeks.2.For the first time in China,the integrated clustering grouping method was adopted to scientifically set the intervention group and control group,and the effects of YYB were obtained by grouping them into different age groups to get the results after removing the confounding factors.It was confirmed that YYB could not only significantly improve the Hb of IYC and reduce the anemia rate,but also significantly improve the body length and HAZ,and reduce the stunting rate.3.For the first time,a dose-effect model for the effect of YYB was proposed,and it was found that for each additional 10 packets of YYB,the body length of IYC increased by about 0.03cm,the HAZ increased by about 0.01,the Hb increased by 0.01g/dL,and the anemia rate decreased by 0.03%as well as the stunting rate decreased by 0.01%.The intervention effect of YYB can be estimated preliminarily under conditional assumptions.Conclusion1.Intervention data showed that stunting,anemia and other major nutritional problems existed in infants aged 6-24 months.Caregivers are generally unemployed,poorly educated,and nearly one-fifth of caregivers were grandparents.The rate of Minimum acceptable diet was about 53%and less than 44%of parents do not have basic nutrition knowledge.The continued breastfeeding until age 1 and 2 were 0.2.YYB intervention can effectively improve the Hb level and anemia of IYC in the intervention area.The anemia rate dropped from 25%t before the intervention to 14%after the intervention.3.YYB intervention can effectively improve the body length and HAZ,while reduce stunting rate and two-week diarrhea rate of IYC in the intervention area.4.The total amount,duration and weekly sachets of YYB had a positive quantitative relationship with IYC body length,HAZ and Hb level,but a negative quantitative relationship with stunting rate and anemia rate.It can be used for conditional YYB intervention effect estimation.5.YYB intervention showed a negative effect on WHZ and a reverse quantization relationship,which needs specific study suggested by the author. |
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