ABSTRACT
Objective To examine the impact of single nucleotide polymorphisms (SNPs) in obesity-related genes on the incidence and durative of obesity in childhood and adolescence.Methods Based on the Beijing Child and Adolescent Metabolic Syndrome (BCAMS) Study,780 school children aged 6 to 16 years were followed-up in 2010,and assessed for body size parameters.Venipuncture blood samples were collected after a 12-hour overnight fast.Genomic DNA was isolated from peripheral blood white cells under the salt fractionation method.SNPs were genotyped by ABI 5700 real time PCR (FTO rs9939609) and TaqMan Allelic Discrimination Assays with the GeneAmp 7900 Sequence Detection System (Applied Biosystems,Foster City,CA,USA) (FTO rs6499640,FAIM2 rs7138803,NPC1 rs1805081,MC4R rs17782313,BDNF rs6265,GNPDA2 rs10938397).Both overweight and obesity were diagnosed by the Chinese age-and sex-specific body mass index (BMI)cutoffs.Two independent sample t-test,Chi-square test and multiple logistic regression analysis were performed.Results During the 6 years follow-up period,the incidence of obesity in the total sample 8.5％,and 65.1％ individuals had persisted their obese status.The genotypes of the SNPs except BDNF rs6265 were in Hardy-Weinberg equilibrium in each group (P＞0.05).The incidence rates of obesity increased with FTO rs9939609 TT,TA and AA genotypes (x2 for trend=8.030,P＜0.05).In the non-obese sub-cohort,after adjusted for sex,age at the initial time of follow up and residential area,when compared with children carrying FTO rs9939609 T-allele,a significantly relative risk of obesity was observed for children carrying the rs9939609 A-allele (OR=2.42,95％CI:1.31-4.47,P=0.005).In the obese sub-cohort,FTO rs9939609 A-allele was significantly associated with durative of obesity (OR=1.72,95％CI:1.07-2.77,P=0.026).However,no statistical significant associations were seen between other SNPs (FTO rs6499640,FAIM2 rs7138803,NPCI rs1805081,MC4R rs17782313,GNPDA2 rs10938397) and the incidence or durative of obesity (all P＞0.05).The genetic risk scorewas associated with the risk of occurrence of obesity (OR=16.42,95％ CI:3.59-75.10,P＜0.001)after adjusted for residential area,sex,age at the initial time of follow up and baseline BMI.Conclusion We confirmed the association of FTO rs9939609 with incidence and durative of obesityin children.Early intervention was recommended on the high risk individuals who carrying more riskalleles in obesity-related genes.
ABSTRACT
<p><b>OBJECTIVE</b>To explore the impact of obesity level and the level change in childhood on hypertension incidence.</p><p><b>METHODS</b>A perspective cohort study was conducted. As part of Beijing Child and Adolescent Metabolic Syndrome Study, 2189 aged 6 - 16 year non-hypertensive children was followed up in December, 2010. In this study, height, weight, waist circumference (WC) and blood pressure was measured at follow-up, and body mass index (BMI) and WC was respectively used to assess overweight, obesity and abdominal obesity. Non-conditional logistic regression was used to evaluate the association between baseline obesity status, change of obesity status and hypertension incidence. OR and 95%CI were computed in the model using obese status as dummy variable and hypertension at follow up visit as dependent variable.</p><p><b>RESULTS</b>The total hypertension incidence of 1184 subjects during 6 years follow-up was 19.9% (236/1184). The hypertension incidence in male (23.2%, 149/643) was higher than that in female (16.1%, 87/541) (χ(2) = 9.257, P = 0.002). The hypertension incidence of non-overweight, overweight and obese children at baseline was 8.7% (45/519), 19.3% (35/181) and 32.4% (156/484) respectively (χ(2) = 9.332, P < 0.001), and the incidence of non-obese and abdominal obese children at baseline was respectively 10.3% (63/613) and 30.7% (173/567) (χ(2) = 77.753, P < 0.001). Hypertension incidence in the baseline obesity group was higher than the non-overweight (BMI: OR = 4.9, 95%CI: 3.4 - 7.0) and non-obese group (WC: OR = 3.9, 95%CI: 2.8 - 5.3). The hypertension incidence increased with the follow-up BMI/WC level, based on the same baseline level of BMI and WC. The hypertension risk increased to 0.21 and 0.07 times respectively with elevation of baseline BMI level by 1 kg/m(2) and WC level by 1 cm, and OR (95%CI) were 1.21 (1.16 - 1.26) and 1.07 (1.05 - 1.09), respectively. Similarly, the hypertension risk increased 0.16 and 0.05 times respectively with the elevation of BMI level change by 1 kg/m(2) and 1 cm, and OR (95%CI) were 1.16 (1.11 - 1.22) and 1.05 (1.03 - 1.07), respectively.</p><p><b>CONCLUSION</b>Obesity and increased obesity level change in childhood can increase the risk of incident hypertension.</p>