Young women post-MI have higher plasma concentrations of interleukin-6 before and after stress testing.
OBJECTIVE
Young women have poorer prognosis after myocardial infarction (MI) and a higher rate of mental stress-induced ischemia compared with similarly aged men. A higher inflammatory status may help explain these sex differences.


METHODS
We examined 98 patients (49 women and 49 men) age 18-59years with recent MI (past 6months). Women and men were matched for age, type of MI, and time since MI. Interleukin 6 (IL-6) concentrations were measured at baseline, after mental stress using a speech task, and after exercise/pharmacologic stress (60 and 90min). Depressive symptoms were measured with the Beck Depression Inventory (BDI-II) and angiographic coronary artery disease (CAD) severity was quantified with the Gensini score. Single-photon emission computed tomography (SPECT) was used to obtain a computerized measurement of stress-induced ischemia (summed difference score, or SDS) and determine whether severity of stress-induced ischemia affects the inflammatory response to stress. Analysis was stratified by the median age of 50. Geometric mean concentrations of IL-6 were obtained from general linear regression models.


RESULTS
In both age groups, women had less angiographic CAD and a similar level of conventional risk factors compared with men. Despite this, baseline IL-6 geometric means before both mental and physical stress were twice as high in women ⩽50years of age compared to age-matched men (3.8 vs. 1.8pg/mL, p=0.001, across both conditions), while they were similar in women and men age >50years (2.3 vs. 2.2pg/mL, p=0.83). After mental stress, IL-6 concentrations increased in both women and men in a similar fashion and remained twice as high in women ⩽50years than men at both 60min (5.4 vs. 2.6pg/mL, p=0.002) and 90min (5.9 vs. 3.4pg/mL, p=0.01). No significant difference was found between women and men >50years of age at any time point after mental stress. Results were similar for physical stress. After accounting for SDS, IL-6 concentrations in young women remained higher after both mental and physical stress. Baseline IL-6 concentrations were not significantly related to inducible ischemia.


CONCLUSIONS
After MI, young women aged 50years or younger, compared with age-matched men, have remarkably higher concentrations of inflammation at baseline and after both mental and physical stress, with a similar inflammatory response to both stressors. Sustained concentrations of inflammation in young women, not their response to stress, may contribute to their adverse outcomes post-MI.
Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA, United States. Electronic address: cherie.rooks@emory.edu.
Cherie R
CR
Rooks
Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA, United States.
Ijeoma
I
Ibeanu
Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA, United States; Department of Medicine, Division of Cardiology, Emory University, Atlanta, GA, United States.
Amit
A
Shah
Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA, United States.
Pratik
P
Pimple
Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA, United States.
Nancy
N
Murrah
Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA, United States.
Lucy
L
Shallenberger
Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, United States.
Thaddeus
T
Pace
Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, United States; Atlanta VAMC, Decatur, GA, United States.
J Douglas
JD
Bremner
University of Alberta, Edmonton, Canada.
Paolo
P
Raggi
Department of Epidemiology, Rollins School of Public Health, Emory University, Atlanta, GA, United States; Department of Medicine, Division of Cardiology, Emory University, Atlanta, GA, United States.
Viola
V
Vaccarino
D000293:Adolescent; D000328:Adult; D003863:Depression / Q000097:blood / Q000150:complications; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood* / Q000209:etiology; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000150:complications / Q000473:pathology; D011569:Psychiatric Status Rating Scales; D012737:Sex Factors; D013315:Stress, Psychological / Q000097:blood* / Q000150:complications / Q000473:pathology; D015899:Tomography, Emission-Computed, Single-Photon; D055815:Young Adult
C508600:IL6 protein, human; D015850:Interleukin-6
Inflammation; Interleukin-6; Ischemia; Sex differences; Stress