Major depression as a risk factor for chronic disease incidence: longitudinal analyses in a general population cohort.
OBJECTIVE
Cross-sectional studies have consistently reported associations between major depression (MD) and chronic medical conditions. Such studies cannot clarify whether medical conditions increase the risk for MD or vice versa. The latter possibility has received relatively little attention in the literature. In this study, we evaluate the incidence of several important chronic medical conditions in people with and without MD.


METHODS
The data source was the Canadian National Population Health Survey (NPHS). The NPHS included the Composite International Diagnostic Interview Short Form to assess past-year major depressive episodes. The NPHS also collected self-report data about professionally diagnosed long-term medical conditions. A longitudinal cohort was interviewed every 2 years between 1994 and 2002. Proportional hazards models were used to compare the incidence of chronic conditions in respondents with and without MD and to produce age-, sex- and covariate-adjusted estimates of the hazard ratios.


RESULTS
The adjusted hazard ratios associated with MD at baseline interview were elevated for several long-term medical conditions: heart disease (1.7), arthritis (1.9), asthma (2.1), back pain (1.4), chronic bronchitis or emphysema (2.2), hypertension (1.7) and migraines (1.9). The incidences of cataracts and glaucoma, peptic ulcers and thyroid disease were not higher in respondents with MD.


CONCLUSIONS
A set of conditions characterized particularly by pain, inflammation and/or autonomic reactivity has a higher incidence in people with MD.
Patten
Scott B
SB
Department of Community Health Sciences, Faculty of Medicine, University of Calgary, Calgary, AB, Canada T2N 4N1. patten@ucalgary.ca
Williams
Jeanne V A
JV
Lavorato
Dina H
DH
Modgill
Geeta
G
Jetté
Nathalie
N
Eliasziw
Michael
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D002170:Canada; D002908:Chronic Disease / Q000453:epidemiology* / Q000523:psychology; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology; D005260:Female; D006306:Health Surveys; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D011602:Psychophysiologic Disorders / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D012307:Risk Factors; D055815:Young Adult