title: Heritability of factors of the insulin resistance syndrome in women twins.
abstract: The insulin resistance syndrome (IRS) is characterized by a combination of interrelated coronary heart disease (CHD) risk factors, including low high-density lipoprotein cholesterol (HDL-C) levels, obesity and increases in triglyceride (TG), blood pressure, small low-density lipoprotein particles (LDL), and both fasting and postload plasma insulin and glucose. Using factor analysis, we previously identified 3 uncorrelated factors that explained 66% of the variance among these variables, based on data from women participating in examination 2 of the Kaiser Permanente Women Twins Study in Oakland, CA during 1989-1990. The factors were interpreted as: 1) body mass/fat distribution, 2) insulin/glucose, and 3) lipids: TG, HDL-C, LDL peak particle diameter. In this analysis, heritability of each of the factors was estimated based on data from 140 monozygotic and 96 dizygotic pairs of non-diabetic women twins. Heritability estimates were calculated using the classical approach, the analysis of variance (ANOVA) approach, and the maximum likelihood approach. For the body mass/fat distribution factor heritability estimates suggest moderate genetic influences; 0.61 (P < 0.001), 0.14 (P > 0.05), and 0.71 (P < 0.001), respectively. The insulin/glucose factor appeared to be highly heritable, with estimates of 0.87, 0.92, and 0.57 (all P < 0.001), respectively. The heritability estimates for the lipid factor were moderate and consistent across methods: 0.25 (P < 0.10), 0.32 (P < 0.05), and 0.30 (P < 0.05), respectively. These results are consistent with genetic influences on each of the 3 "factors," and suggest that both genetic and environmental effects are involved in the clustering of IRS risk factors.
authors.affiliation: Department of Epidemiology, School of Public Health and Community Medicine, University of Washington, Seattle 98195, USA.
authors.forename: K L
authors.initials: KL
authors.lastname: Edwards
authors.forename: B
authors.initials: B
authors.lastname: Newman
authors.forename: E
authors.initials: E
authors.lastname: Mayer
authors.forename: J V
authors.initials: JV
authors.lastname: Selby
authors.forename: R M
authors.initials: RM
authors.lastname: Krauss
authors.forename: M A
authors.initials: MA
authors.lastname: Austin
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001786:Blood Glucose / Q000235:genetics; D001824:Body Constitution / Q000235:genetics; D002648:Child; D002675:Child, Preschool; D003327:Coronary Disease / Q000453:epidemiology / Q000235:genetics; D004200:Diseases in Twins / Q000235:genetics*; D005163:Factor Analysis, Statistical; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D007328:Insulin / Q000097:blood / Q000235:genetics; D007333:Insulin Resistance / Q000235:genetics*; D016013:Likelihood Functions; D008055:Lipids / Q000097:blood / Q000235:genetics; D008875:Middle Aged; D012044:Regression Analysis; D012307:Risk Factors; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic
chemical_list: D001786:Blood Glucose; D007328:Insulin; D008055:Lipids