Association Of Dairy Intake Frequency With Carotid Intima-Media Thickness And Left Ventricular Hypertrophy In Chinese Children

BackgroundCardiovascular disease(CVD)is the biggest threat to the health of Chinese residents.CVD risk factors also have a great impact on the health of children and adolescents in China.There is evidence that adulthood CVD is closely associated with risk factors of CVD in childhood and CVD originates in childhood.CVD risk factors of children can lead to target organ damage such as damage of heart,blood vessels,and kidneys,thereby increasing the risk of CVD in adulthood.Short-term subclinical cardiovascular damage in childhood,namely high carotid intima-media thickness(cIMT)and left ventricular hypertrophy(LVH),diagnosed based on cIMT and left ventricular mass index(LVMI),has been proved to be early predictive indicators of CVD.A healthy lifestyle,especially a healthy diet,is known to prevent CVD.Childhood nutrition plays an important role in the development of CVD.As an important source of energy,protein and micronutrients for normal growth and development of children and adolescents,dairy products are associated with childhood obesity and cardiovascular structural changes.Childhood dairy intake is also associated with lower all-cause mortality and CVD mortality in adulthood.The implementation of early detection and intervention against LVH and high cIMT in children has important public health significance for preventing and controlling children's TOD and alleviating the burden of CVD in adulthood.However,previous researches mainly focused on the effects of dairy intake of childhood obesity or the effects of obesity on children's TOD.There is limited data regarding whether dairy intake is associated with childhood short-term cardiovascular damage such as high cIMT and LVH.This study based on the baseline survey of "Huantai Children Cardiovascular Health Cohort",aimed to evaluate the association of dairy intake frequency with high cIMT and LVH and the joint effect of dairy intake and obesity on cIMT and LVH in children,in order to provide a scientific evidence for early warning of cardiovascular structural damage in Chinese children.Objectives(1)To analyze the association of dairy intake frequency with cIMT and high cIMT.(2)To analyze the association of dairy intake frequency with LVMI and LVH.(3)To analyze the association of joint effect of dairy intake and obesity with high cIMT and LVHSubjects and methods1 SubjectsThis study was based on baseline data of "Huantai Children Cardiovascular Health Cohort in children" conducted from November 2017 to January 2018 in Zibo,China.Using the convenience cluster sampling method,1516 participants were recruited from one public primary school.All participants were invited to undergo physical examination,ultrasonic measurement and questionnaire.Excluding 199 participants whose related variables are missing,a total of 1317 school children with complete data were included in this study.2 MethodsPhysical examinations include height,weighty and blood pressure.Ultrasonic measurement was performed to assess cIMT and LVMI.Participants completed the questionnaire on demographic characteristics,physical activity,screen time,sleep duration,frequency of consumption of fruits and vegetables,carbonated drinks and dairy products in the past 12 months.In the analyses of the association between dairy intake frequency and children's cIMT and LVH,children's dairy intake frequency was divided into the following groups:never,?3 times per month,1-5 times per week,and almost every day.In the analysis of the association of joint effect of dairy intake and obesity with cIMT and LVH in children,participants were divided into four groups according to the dairy intake frequency and obesity status.High cIMT and LVH was respectively defined as cIMT and LVMI greater than the sex-and age-specific 90th percentile values in this population.3 Statistical analysesAll analyses were performed using SAS version 9.4 software.The independent samples t-test was used for comparison of continuous variables between two groups,and the general linear model for multiple groups,and chi-square test for categorical variables.Chi-square trend tests were used to analyze the trend P in the rate of high cIMT and LVH across the dairy intake frequency groups.Multivariable linear regression model was used to analyze the linear trend between cIMT and LVMI levels across groups of dairy intake frequency.Adjusted odds ratios(ORs)and 95%confidence intervals(CIs)of high cIMT and LVH were calculated using multivariate logistic regression model.Based on the different covariates,two different models were developed in Multivariable linear regression analysis and multivariate logistic regression analysis to examine the association of dairy intake frequency with cIMT and LVH.Model 1 included sex,age,consumption of fruits and vegetables,and carbonated drinks,sleep duration,screen time,physical activity,and elevated BP.Model 2 additionally adjusted for obesity.Two-sided P values<0.05 were considered statistically significant.Results1 Association of dairy intake frequency with cIMT levels and high cIMTAfter adjusting for sex,age,consumption of fruits and vegetables,and carbonated drinks,sleep duration,screen time,physical activity and elevated BP,cIMT levels decreased with the increase of frequency of dairy intake(Ptrend=0.005).Results were consistent when further adjusting obesity.Compared with no dairy intake group,the ORs for high cIMT were 0.30(95%CI:0.12-0.78)and 0.34(95%CI:0.14-0.84),respectively for dairy intake frequency groups of 1-5 times per week and almost every day.When obesity was further adjusted,the ORs for high cIMT became none in the 1-5 times per week(OR=0.51,95%CI:0.18-1.50)and almost every day group(OR=0.53,95%CI:0.19-1.44).2 Association of dairy intake frequency with LVMI levels and LVHAfter adjusting for potential covariates,participants' LVMI levels decreased with the increase of dairy intake frequency(Ptrend=0-006).Results were consistent when further adjusting obesity.Compared with no dairy intake group,the ORs for LVH were 0.38(95%CI:0.15-0.96)in the ?3 times per month group,0.30(95%CI:0.12-0.70)in the 1-5 times per week group,0.22(95%CI:0.10-0.50)in the almost every day group,respectively.When obesity was further adjusted,having dairy intake almost every day(OR=0.28,95%CI:0.11-0.70)was still associated with LVH.3 Association of joint effect of dairy intake and obesity with high cIMT and LVHAfter adjusting for potential covariates,compared with frequent dairy intake and non-obese group,the association with high cIMT was stronger among participants with infrequent dairy intake and obesity(OR=14.42,95%CI:7.16-29.02)than participants with frequent dairy intake and obesity(OR=11.92,95%CI:7.53-18.86).In addition,the association with LVH was stronger among participants with infrequent dairy intake and obesity(OR=18.90,95%CI:9.77-36.55)than participants with frequent dairy intake and obesity(OR=6.70,95%CI:4.33-10.37).Conclusions(1)Dairy intake frequency is associated with cIMT and LVMI levels,and both cIMT and LVMI levels decrease with the increase of dairy intake frequency in children.(2)Dairy intake frequency is associated with high cIMT and LVH,and having dairy intake once a week or more is associated with the lower risk of high cIMT and LVH.(3)Infrequent dairy intake in combination with obesity is associated with the higher risk of high cIMT and LVH in children.