title: Intentional weight loss in young adults: sex-specific genetic and environmental effects.
abstract: OBJECTIVE
  To explore eating styles associated with intentional weight loss (IWL) and to determine whether the genetic liability in IWL is entirely shared with genetic liability affecting BMI.
  
  
  METHODS
  As part of a longitudinal assessment of various health-related behaviors in a large population-based sample of twins, eating styles, BMI, and the number of times the study participants had intentionally lost > or = 5 kg were assessed by questionnaire from 4667 male and female twins (22 to 27 years of age). Associations of eating styles and IWL were explored using polytomous logistic regression models adjusted for BMI. Sex-specific bivariate structural equation modeling was used to explore genetic and environmental correlations of BMI and IWL.
  
  
  RESULTS
  Individuals who had engaged in IWL exhibited markedly more restricting, overeating, and alternating restricting/overeating than those in the no-IWL group. Snacking and eating in the evening were characteristic of women with at least two IWL attempts. Eating in response to visual and emotional cues was very pronounced in women who had engaged in IWL but much less so in men. IWL was estimated to have a heritability of 38% [95% confidence interval (CI), 19% to 55%] in men and 66% (95% CI, 55% to 75%) in women. The genetic covariance of BMI and IWL was 0.38 (95% CI, 0.28 to 0.47) for men and 0.45 (95% CI, 0.41 to 0.52) for women.
  
  
  CONCLUSIONS
  Distinct sex differences exist in eating styles associated with IWL and in the heritability of IWL. Most genetic factors affecting BMI are different from those affecting IWL.
authors.affiliation: Department of Public Health, university of Helsinki, Finland. anna.keski-rahkonen@helsinki.fi
authors.forename: Anna
authors.initials: A
authors.lastname: Keski-Rahkonen
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Neale
authors.forename: Cynthia M
authors.initials: CM
authors.lastname: Bulik
authors.forename: Kirsi H
authors.initials: KH
authors.lastname: Pietiläinen
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Rose
authors.forename: Jaakko
authors.initials: J
authors.lastname: Kaprio
authors.forename: Aila
authors.initials: A
authors.lastname: Rissanen
mesh_terms: D000293:Adolescent; D000328:Adult; D015992:Body Mass Index; D004435:Eating / Q000502:physiology / Q000523:psychology; D004777:Environment; D005260:Female; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D011247:Pregnancy; D012727:Sex Characteristics; D011795:Surveys and Questionnaires; D018433:Twin Studies as Topic; D015431:Weight Loss / Q000235:genetics*