title: Association between dietary fat intake and insulin resistance in Chinese child twins.
abstract: Dietary fat intake is correlated with increased insulin resistance (IR). However, it is unknown whether gene-diet interaction modulates the association. This study estimated heritability of IR measures and the related genetic correlations with fat intake, and tested whether dietary fat intake modifies the genetic influence on type 2 diabetes (T2D)-related traits in Chinese child twins. We included 622 twins aged 7-15 years (n 311 pairs, 162 monozygotic (MZ), 149 dizygotic (DZ)) from south-eastern China. Dietary factors were measured using FFQ. Structural equation models were fit using Mx statistical package. The intra-class correlation coefficients for all traits related to T2D were higher for MZ twins than for DZ twins. Dietary fat and fasting serum insulin (additive genetic correlation (r A) 0·20; 95 % CI 0·08, 0·43), glucose (r A 0·12; 95 % CI 0·01, 0·40), homoeostasis model of assessment-insulin resistance (Homa-IR) (r A 0·22; 95 % CI 0·10, 0·50) and the quantitative insulin sensitivity check index (Quicki) (r A -0·22; 95 % CI -0·40, 0·04) showed strong genetic correlations. Heritabilities of dietary fat intake, fasting glucose and insulin were estimated to be 52, 70 and 70 %, respectively. More than 70 % of the phenotypic correlations between dietary fat and insulin, glucose, Homa-IR and the Quicki index appeared to be mediated by shared genetic influence. Dietary fat significantly modified additive genetic effects on these quantitative traits associated with T2D. Analysis of Chinese twins yielded high estimates of heritability of dietary fat intake and IR. Genetic factors appear to contribute to a high proportion of the variance for both insulin sensitivity and IR. Dietary fat intake modifies the genetic influence on blood levels of insulin and glucose, Homa-IR and the Quicki index.
authors.affiliation: 1Epidemiology Domain,Saw Swee Hock School of Public Health and Department of Medicine,Yong Loo Lin School of Medicine,National University of Singapore,Singapore,021800.
authors.forename: Tao
authors.initials: T
authors.lastname: Huang
authors.affiliation: 3Department of Epidemiology,Johns Hopkins Bloomberg School of Public Health,Baltimore,MD 21205,USA.
authors.forename: Terri
authors.initials: T
authors.lastname: Beaty
authors.affiliation: 2Department of International Health,Johns Hopkins Bloomberg School of Public Health,Baltimore,MD 21205,USA.
authors.forename: Ji
authors.initials: J
authors.lastname: Li
authors.affiliation: 4Jiaxing Maternal and Child Health Hospital,Jiaxing,Zhejiang 314051,People's Republic of China.
authors.forename: Huijuan
authors.initials: H
authors.lastname: Liu
authors.affiliation: 4Jiaxing Maternal and Child Health Hospital,Jiaxing,Zhejiang 314051,People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhao
authors.affiliation: 2Department of International Health,Johns Hopkins Bloomberg School of Public Health,Baltimore,MD 21205,USA.
authors.forename: Youfa
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000293:Adolescent; D044466:Asian People / Q000235:genetics*; D001786:Blood Glucose / Q000378:metabolism*; D002648:Child; D002681:China; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000235:genetics; D004041:Dietary Fats / Q000494:pharmacology*; D005215:Fasting; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D006946:Hyperinsulinism / Q000097:blood / Q000235:genetics; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance / Q000235:genetics*; D008297:Male; D010641:Phenotype; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic
chemical_list: D001786:Blood Glucose; D004041:Dietary Fats; D007328:Insulin
keywords:  DZ dizygotic;  Homa-IR homoeostasis model of assessment–insulin resistance;  IR insulin resistance;  IS insulin sensitivity;  MZ monozygotic;  Quicki quantitative insulin sensitivity check index;  T2D type 2 diabetes;  rA additive genetic correlation; Children; Diabetes; Diet; Fat intake; Gene–diet interactions; Insulin resistance; Insulin sensitivity