Archival ReportAssociation of Major Depressive Disorder with Serum Myeloperoxidase and Other Markers of Inflammation: A Twin Study
Section snippets
Subjects
The Twins Heart Study (THS) is an investigation of psychological, behavioral, and biological risk factors for subclinical cardiovascular disease using twins. Twins were selected from the Vietnam Era Twin (VET) Registry (26), which includes 7369 middle-aged male-male twin pairs both of whom served in the United States military during the time of the Vietnam War.
The Twins Heart Study included 93 monozygotic and 87 dizygotic twin pairs who were born between 1946 and 1956. Zygosity information was
Results
Of the 180 THS twin pairs, we excluded 1 pair because of missing MPO data and another pair because of implausible TNF-α values. Of the remaining 178 pairs, 67 pairs were discordant for lifetime history of MDD and 111 were not. The majority of twins with MDD were in remission, with only eight subjects meeting DMS-IV criteria for a current major depressive episode and 77% having had the last depressive episode >1 year before examination.
Both in the entire population of twins and within the
Discussion
We found that MDD is associated with higher levels of inflammation and that this association is particularly robust for MPO, an inflammatory biomarker that was never studied before in relation to depression. However, we also found evidence for genetic confounding in this association. Our results are consistent with the hypothesis that there is a common genetic substrate linking MDD and inflammation, suggesting that these two phenotypes share a common pathophysiological mechanism.
Limitations
Our study is cross-sectional, thus limited in the ability to discern the temporal order between MDD and inflammation. However, based on our results, the covariation of these two phenotypes may mostly be due to a common genetic precursor rather than a cause-effect relationship. Another limitation is that few twins met the criteria for a current major depressive episode, preventing us from examining the data in relation to current versus past depression. However, there was no relationship between
References (56)
- et al.
Serum myeloperoxidase levels are associated with the future risk of coronary artery disease in apparently healthy individuals: The EPIC-Norfolk Prospective Population Study
J Am Coll Cardiol
(2007) The macrophage theory of depression
Med Hypotheses
(1991)- et al.
Sustained low-grade pro-inflammatory state in unmedicated, remitted women with major depressive disorder as evidenced by elevated serum levels of the acute phase proteins C-reactive protein and serum amyloid A
Biol Psychiatry
(2007) - et al.
Clinical depression and inflammatory risk markers for coronary heart disease
Am J Cardiol
(2002) - et al.
Inflammatory markers and depressed mood in older persons: Results from the health, aging and body composition study
Biol Psychiatry
(2003) - et al.
Inflammation and coagulation factors in persons >65 years of age with symptoms of depression but without evidence of myocardial ischemia
Am J Cardiol
(2002) - et al.
Depression and inflammation in patients with coronary heart disease: Findings from the Heart and Soul Study
Biol Psychiatry
(2007) - et al.
Where there is depression, there is inflammation . . . sometimes!
Biol Psychiatry
(2007) - et al.
Depression as a risk factor for cardiac mortality and morbidity: A review of potential mechanisms
J Psychosom Res
(2002) - et al.
Cytokines sing the blues: Inflammation and the pathogenesis of depression
Trends Immunol
(2006)