title: Sex and Ethnic Differences in the Association of Obesity With Risk of Hepatocellular Carcinoma.
abstract: OBJECTIVE
  Obesity is associated with increased risk for hepatocellular carcinoma (HCC), but the risk associated with obesity may vary by sex or ethnicity. We examined whether the association of body mass index (BMI) with HCC incidence, as well as correlations of BMI with total, visceral, and hepatic adiposity, differs among ethnic groups.
  
  
  METHODS
  We collected data from the Multiethnic Cohort Study, a population-based prospective cohort study of more than 215,000 men and women from Hawaii and California that was assembled from 1993 through 1996. After a median follow-up of 16.6 years, 482 incident HCC cases were identified among 168,476 participants. BMI and risk factor data were obtained from a baseline questionnaire. Cox regression analyses were used to calculate hazard ratios (HRs) and confidence intervals (CIs) for HCC associated with BMI. The black subjects in the Southern Community Cohort Study were included as a replication cohort.
  
  
  RESULTS
  BMI was associated with HCC in men (HR per 5 kg/m(2) increase, 1.26; 95% CI, 1.12-1.42) but not in women (HR, 1.06; 95% CI, 0.90-1.25) (P(interaction) = .009). Although BMI was strongly associated with HCC in Japanese, white, and Latino men, there was no association in black men (P(interaction) = .002). Similarly, no association was found in the blacks who participated in the Southern Community Cohort Study. BMI correlated with total fat mass, measured by dual-energy x-ray absorptiometry, in men and women and in all ethnic groups (R ≥ 0.9). However, there was a lower correlation value for BMI and visceral or liver fat measured by abdominal magnetic resonance imaging in black men (R < 0.5) and in women (R < 0.8).
  
  
  CONCLUSIONS
  On the basis of an analysis of data from the Multiethnic Cohort Study, the association between BMI and HCC differs between sexes and among ethnicities. The lack of association in black men warrants further investigation. Rather than studying markers of total adiposity, studies of obesity and HCC should move beyond BMI and use a better measure for fat-specific depots.
authors.affiliation: Department of Preventive Medicine, University of Southern California, Los Angeles, California; Norris Comprehensive Cancer Center, Los Angeles, California. Electronic address: vsetiawa@usc.edu.
authors.forename: Veronica Wendy
authors.initials: VW
authors.lastname: Setiawan
authors.affiliation: Epidemiology Program, University of Hawaii Cancer Center, Honolulu, Hawaii.
authors.forename: Unhee
authors.initials: U
authors.lastname: Lim
authors.affiliation: Division of Epidemiology, Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee.
authors.forename: Loren
authors.initials: L
authors.lastname: Lipworth
authors.affiliation: Division of Gastroenterology, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California.
authors.forename: Shelly C
authors.initials: SC
authors.lastname: Lu
authors.affiliation: Department of Radiology, University of California San Francisco, San Francisco, California.
authors.forename: John
authors.initials: J
authors.lastname: Shepherd
authors.affiliation: Department of Medicine, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii.
authors.forename: Thomas
authors.initials: T
authors.lastname: Ernst
authors.affiliation: Epidemiology Program, University of Hawaii Cancer Center, Honolulu, Hawaii.
authors.forename: Lynne R
authors.initials: LR
authors.lastname: Wilkens
authors.affiliation: Department of Preventive Medicine, University of Southern California, Los Angeles, California; Norris Comprehensive Cancer Center, Los Angeles, California.
authors.forename: Brian E
authors.initials: BE
authors.lastname: Henderson
authors.affiliation: Epidemiology Program, University of Hawaii Cancer Center, Honolulu, Hawaii.
authors.forename: Loïc
authors.initials: L
authors.lastname: Le Marchand
mesh_terms: D000368:Aged; D015992:Body Mass Index; D002140:California / Q000453:epidemiology; D006528:Carcinoma, Hepatocellular / Q000453:epidemiology*; D016022:Case-Control Studies; D005006:Ethnicity; D005260:Female; D006254:Hawaii / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications*; D011446:Prospective Studies; D012307:Risk Factors; D012737:Sex Factors
keywords: Epidemiology; Liver Cancer; MEC Study; Visceral Adiposity