The influence of psychological stress and socioeconomic status on platelet activation in men.
OBJECTIVE
Circulating monocyte- and neutrophil-platelet aggregates are sensitive markers of in vivo platelet activation. Socioeconomic status is inversely associated with risk of coronary heart disease. We assessed the impact of psychological stress on leukocyte-platelet aggregates in men from higher and lower socioeconomic status groups.


METHODS
Participants were 37 healthy non-smoking men aged 30-59 years, divided by occupation into higher and lower social status groups. Blood was drawn at baseline, immediately following stressful behavioural tasks, and at 30 and 75 min post-stress, and aggregates were analysed using flow cytometry. Cardiovascular and subjective stress responses were also monitored.


RESULTS
There were significant increases following stress in monocyte-, neutrophil-, lymphocyte- and total leukocyte-platelet aggregates (all P<0.05). The largest responses were in monocyte-platelet (21% increase) and neutrophil-platelet (16.7% increase) aggregates. Lower socioeconomic status men had greater numbers of leukocyte-platelet aggregates throughout, but the magnitude of stress responses did not vary with social status. The increase in monocyte- and leukocyte-platelet aggregates was associated with systolic blood pressure stress responsivity.


CONCLUSIONS
Psychological stress induces platelet activation as indexed by leukocyte-platelet aggregates, and correlations with cardiovascular stress reactions suggest that sympathoadrenal responses may be responsible. Platelet activation may be a mechanism through which social position influences cardiovascular disease risk.
Department of Epidemiology and Public Health, Psychobiology Group, University College London, UK. a.steptoe@ucl.ac.uk
Andrew
A
Steptoe
Kesson
K
Magid
Susan
S
Edwards
Lena
L
Brydon
Ying
Y
Hong
Jorge
J
Erusalimsky
D000328:Adult; D001792:Blood Platelets / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D002318:Cardiovascular Diseases / Q000503:physiopathology / Q000523:psychology; D002449:Cell Aggregation / Q000502:physiology; D003971:Diastole / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007962:Leukocytes / Q000502:physiology; D008131:London; D008297:Male; D008875:Middle Aged; D009504:Neutrophils / Q000502:physiology; D015539:Platelet Activation / Q000502:physiology*; D012016:Reference Values; D012146:Rest / Q000502:physiology; D012923:Social Class; D013223:Statistics as Topic; D013315:Stress, Psychological / Q000503:physiopathology*; D013599:Systole / Q000502:physiology