Familial resemblance for plasma leptin: Sample homogeneity across adiposity and ethnic groups

Treva Rice, Yvon C. Chagnon, Ingrid B. Borecki, Louis Pérusse, Greg Collier, Jacques Gagnon, Arthur S. Leon, James S. Skinner, Jack H. Wilmore, Claude Bouchard, D. C. Rao

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Objective: Previous studies show a wide range in the percentage of variance in leptin levels attributable to genetic factors. These studies differ markedly with respect to ethnicity, study design, and statistical methodology. Therefore, the purpose of this study was to investigate heterogeneity hypotheses across ethnic groups and by adiposity level, using the same statistical methods. Research Methods and Procedures: Samples included black vs. white (HERITAGE Family Study) and random vs. obese (Québec Family Study) individuals from 432 families (1432 individuals). Heritability for leptin, alternatively adjusted for age and sex and then for age, sex, and adiposity was estimated with the use of familial correlations. Heterogeneity in the magnitude of the familial resemblance between samples and the effect of adjusting for adiposity was explored. Results: Heritability did not vary across samples stratified by adiposity level or ethnic group or across adjustment schemes. Maximal heritability, the percentage of additive phenotypic variability due to all familial sources, was 32%. Discussion: Whereas leptin and adiposity were highly correlated within individuals, removing the effects of adiposity did not significantly alter the magnitude of the familial component for leptin. Moreover, this effect did not vary as a function of ethnicity (black vs. white) or adiposity level. Thus, no evidence for heterogeneity was detected. However, a comparison among previous studies raises questions concerning possible genetic heterogeneity in other ethnic groups in which complex interactions among leptin, adiposity, and diabetes status may be important.

Original languageEnglish (US)
Pages (from-to)351-360
Number of pages10
JournalObesity research
Volume10
Issue number5
DOIs
StatePublished - May 2002

Keywords

  • Heritability
  • Insulin
  • Pleiotropy
  • Sedentary
  • Skinfolds

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