title: Depressive symptoms, insulin resistance, and risk of diabetes in women at midlife.
abstract: OBJECTIVE
  To examine depression and 3-year change in insulin resistance and risk of diabetes and whether associations vary by race.
  
  
  METHODS
  We analyzed data from 2,662 Caucasian, African-American, Hispanic, Japanese-American, and Chinese-American women without a history of diabetes from the Study of Women's Health Across the Nation. We estimated regression coefficients and odds ratios to determine whether depression (Center for Epidemiological Studies Depression Scale score > or =16) predicted increases in homeostasis model assessment of insulin resistance (HOMA-IR) and greater risk of incident diabetes, respectively, over 3 years.
  
  
  RESULTS
  Mean baseline HOMA-IR was 1.31 (SD 0.86) and increased 0.05 units per year for all women (P <0.0001). A total of 97 incident cases of diabetes occurred. Depression was associated with absolute levels of HOMA-IR (P <0.04) but was unrelated to changes in HOMA-IR; associations did not vary by race. The association between depression and HOMA-IR was eliminated after adjustment for central adiposity (P=0.85). Depression predicted a 1.66-fold greater risk of diabetes (P <0.03), which became nonsignificant after adjustment for central adiposity (P=0.12). We also observed a depression-by-race interaction (P <0.05) in analyses limited to Caucasians and African Americans, the only groups with enough diabetes cases to reliably test this interaction. Race-stratified models showed that depression predicted 2.56-fold greater risk of diabetes in African Americans only, after risk factor adjustment (P=0.008).
  
  
  CONCLUSIONS
  Depression is associated with higher HOMA-IR values and incident diabetes in middle-aged women. These associations are mediated largely through central adiposity. However, African-American women with depression experience increased risk of diabetes independent of central adiposity and other risk factors.
authors.affiliation: Department of Preventive Medicine, Rush University Medical Center, 1700 W. Van Buren St., Suite 470, Chicago, IL 60612, USA. susan_everson@rush.edu
authors.forename: Susan A
authors.initials: SA
authors.lastname: Everson-Rose
authors.forename: Peter M
authors.initials: PM
authors.lastname: Meyer
authors.forename: Lynda H
authors.initials: LH
authors.lastname: Powell
authors.forename: Dilip
authors.initials: D
authors.lastname: Pandey
authors.forename: Javier I
authors.initials: JI
authors.lastname: Torréns
authors.forename: Howard M
authors.initials: HM
authors.lastname: Kravitz
authors.forename: Joyce T
authors.initials: JT
authors.lastname: Bromberger
authors.forename: Karen A
authors.initials: KA
authors.lastname: Matthews
mesh_terms: D001786:Blood Glucose / Q000378:metabolism; D003863:Depression / Q000453:epidemiology*; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology*; D005006:Ethnicity; D005260:Female; D006801:Humans; D015994:Incidence; D007333:Insulin Resistance / Q000502:physiology*; D008137:Longitudinal Studies; D008875:Middle Aged; D044469:Racial Groups; D012307:Risk Factors; D014481:United States / Q000453:epidemiology
chemical_list: D001786:Blood Glucose