| BackgroundRecently,the prevalence of overweight and obesity has increased in the pediatric population.Studies have shown that overwight and obesity lead to subclinical target organ damages among children,such as high carotid intima-media thickness(cIMT)and left ventricular hypertrophy(LVH).High cIMT and LVH reflect the early structural damages of vessel and heart,which are independent risk factors of long-term cardiovascular diseases.Notably,these subclinical target organ damages in childhood could be reversible.Previous studies found that the regression of cIMT and left ventricular mass was associated with the reduction in the risk of cardiovascular diseases.Therefore,it is of public significance to identify the risk factors of subclinical target organ damages in childhood,to prevent and control the target organ damages in the short-term as well as to reduce the risk of cardiovascular diseases in the long-term.Obesity is one of the most important risk factors of cardiovascular diseases.Body mass index(BMI)is widely used to define general obesity;however,BMI cannot distinguish the distribution of body fat.Waist circumference(WC)is a commonly used indicator for abdominal obesity,which can not only reflect the accumulation of abdominal fat,but also correlate with the risk of cardiovascular diseases more closely.It is well documented that overweight/obesity in children is associated with the short-term target organ damages,and increases the risk of cardiovascular diseases in adulthood.A systemic review and meta-analysis found that changes in BMI status from childhood to adulthood were associated with the risk of high cIMT and LVH in adulthood.Compared with individuals with persistently normal BMI in childhood and adulthood,those with normal BMI in childhood but excess BMI in adulthood,or those with persistently excess BMI in childhood and adulthood had higher risk of high cIMT and LVH in adulthood;while no statistically significant risk was found for those with excess BMI in childhood but normal BMI in adulthood.These findings suggest that prevention and control of pediatric obesity would be conducive to the reduction in the risk of cardiovascular diseases in adulthood.However,evidence derived from the child follow-up cohort on the relationship between WC changes and short-term cardiovascular structure is limited.Therefore,this study based on the "Huantai Childhood Cardiovascular Health Cohort Study",aims to examine the associations of WC and its 2-year changes with high cIMT and LVH,providing the theoretical evidence to prevent and control cardiovascular structural damages in childhood.Objectives1.To examine the associations of baseline and follow-up WC with high cIMT and LVH in childhood.2.To examine the associations of 2-year WC changes from baseline to follow-up with follow-up high cIMT and LVH in childhood.MethodsStudy participants were recruited from the "Huantai Childhood Cardiovascular Health Cohort Study" using the convenient cluster sampling method from one public primary school in Huantai County,Shandong Province.A total of 1515 pupils with a baseline age of 6-11 years were included.After excluding children with missing information,a total of 1406 children in the baseline survey(in 2017)and 1190 children in the follow-up survey(in 2019)were included to examine the associations of baseline and follow-up WC with high cIMT and LVH,respectively.A total of 1114 children with complete information in the baseline and follow-up surveys were investigated to examine the associations of 2-year WC changes from baseline to follow-up with the follow-up high cIMT and LVH after further exclusion of those with baseline high cIMT(n=105)or baseline LVH(n=103).All students and their parents/guardians provided the writtern informed consent before participation.The study was approved by the Ethics Committees of Public Health in Shandong University(Approval number:20160308).First,covariance analysis was used to examine the associations of baseline and follow-up WC status and its 2-year changes with the level of cIMT and left ventricular mass index(LVMI).Sex,age,sleep duration,screen time,physical activity,frequency of fruits/vegetables intake,blood pressure,fasting blood glucose,triglycerides,and high-density lipoprotein cholesterol were successively adjusted in three models.Second,binary logistic regression models were used to examine the associations of baseline and follow-up WC status and its 2-year changes with high cIMT and LVH.Finally,restrictive cubic spline(RCS)was used to test the doseresponse associations of baseline and follow-up WC level and its 2-year changes with high cIMT and LVH.Results1.Associations of Baseline WC with High cIMT and LVHThe prevalence of baseline abdominal obesity(high WC status)was 31.3%.Compared with children with normal WC in the baseline,those with high WC had higher level of cIMT(496.4 μm vs.457.6 μm)and LVMI(30.3 g/m2.7 vs.27.5 g/m2.7)and higher prevalence of high cIMT(29.3%vs.2.3%)and LVH(21.8%vs.3.8%).After adjusting for potential covariables,compared with those with normal WC in the baseline,the odds ratios(ORs)and 95%confidence intervals(CIs)of high cIMT and LVH were 11.76(7.07-19.56)and 5.22(3.32-8.21),respectively.There was a linear dose-response relationship between baseline WC level and high cIMT(P for non-linear=0.511),whereas there was a non-linear dose-response relationship between baseline WC level and LVH(P for non-linear<0.001).2.Associations of Follow-up WC with High cIMT and LVHThe prevalence of follow-up abdominal obesity(high WC status)was 36.7%.Compared with children with normal WC in the follow-up,those with high WC had higher level of cIMT(539.2μm vs.510.6 μm)and LVMI(31.7 g/m2.7 vs.29.6 g/m2 7)and higher prevalence of high cIMT(30.7%vs.3.7%)and LVH(22.4%vs.7.4%).After adjusting for potential covariables,compared with those with normal WC in the follow-up,the ORs(95%CIs)of high cIMT and LVH were 7.12(4.41-11.51)and 2.66(1.75-4.04),respectively.There were linear doseresponse relationships between follow-up WC level and high cIMT and LVH(both P for nonlinear>0.05).3.Associations of 2-year WC Changes from Baseline to Follow-up with High cIMT and LVH in the Follow-upDuring 2 years from baseline to follow-up,667(59.9%)children had persistently normal WC,35(3.1%)children had WC lost,103(9.3%)children had WC gain,and 309(27.7%)children had persistently high WC.After adjusting for potential covariables in the baseline,compared with children with persistently normal WC from baseline to follow-up(508.0μm),those with WC gain(531.2 μm)and persistently high WC(546.2 μm)had higher level of cIMT in the follow-up.The prevalence of follow-up high cIMT for those with persistently normal WC,WC lost,WC gain,and persistently high WC was 3.8%,8.6%,14.1%,and 30.6%,respectively.Compared with those with persistently normal WC,those with WC gain and persistently high WC had increased risk of follow-up high cIMT,with ORs(95%CIs)of 3.89(1.93-7.85)and 8.78(5.05-15.29),respectively;however,those with WC lost did not have statistically significant risk of follow-up high cIMT(OR=2.15,95%CI:0.61-7.62).There was a marginal non-linear dose-response relationship between 2-year WC level change and followup high cIMT(P for non-linear=0.049).After adjusting for potential covariables in the baseline,compared with children with persistently normal WC from baseline to follow-up(29.0 g/m2.7),those with WC gain(31.0 g/m2.7)and persistently high WC(31.6 g/m2.7)had higher level of LVMI in the follow-up.The prevalence of follow-up LVH for those with persistently normal WC,WC lost,WC gain,and persistently high WC was 6.1%,3.0%,15.8%,and 18.1%,respectively.Compared with those with persistently normal WC,those with WC gain and persistently high WC had increased risk of follow-up LVH,with ORs(95%CIs)of 3.09(1.60-5.96)and 4.00(2.32-6.92),respectively;however,those with WC lost did not have statistically significant risk of follow-up LVH(OR=0.51,95%CI:0.07-3.90).There was a linear dose-response relationship between 2-year WC level change and follow-up LVH(P for non-linear=0.996).Conclusions1.Baseline or follow-up high WC not only increases the level of cIMT and LVMI,but also increases the risk of high cIMT and LVH.2.Two-year WC changes from baseline to follow-up are associated with high cIMT and LVH in the follow-up.Compared with children with persistently normal WC,those with WC gain or persistently high WC have increased risk of follow-up high cIMT and LVH,while those with WC lost do not have statistically significant risk. |
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