Depressive symptoms, insulin resistance, and risk of diabetes in women at midlife.
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.
Everson-Rose
Susan A
SA
Department of Preventive Medicine, Rush University Medical Center, 1700 W. Van Buren St., Suite 470, Chicago, IL 60612, USA. susan_everson@rush.edu
Meyer
Peter M
PM
Powell
Lynda H
LH
Pandey
Dilip
D
Torréns
Javier I
JI
Kravitz
Howard M
HM
Bromberger
Joyce T
JT
Matthews
Karen A
KA
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
D001786:Blood Glucose