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C HAPTER 33 / Psychosocial Risk Factors: Assessment and Management Interventions 771
67
after angioplasty. If hostility is also a prognostic factor for CHD glucose levels than unemployed women. In the same study, em-
is not known. 4,58 ployed women tended to smoke fewer cigarettes and exercised
82
more than unemployed women. This suggests that factors other
Acute Stress and Stressful Life Events than employment explain observed associations. Low levels of
support from coworkers and supervisors have also been associated
Convincing evidence exists that acute stress or stressful life events with elevated blood pressure after accounting for other factors,
can trigger cardiac events. Observational studies on the incidence such as cigarette smoking. 83 Such findings have led to the sugges-
of cardiac events examined exposure to sudden stresses such as tion that workers who endure “job strain” (intense job demands
84
natural disasters. The incidence of fatal and nonfatal MIs in Los An- with little control) would be more likely to develop CHD. Stud-
geles County significantly increased on the day of the Northridge ies using this assessment of job strain, however, have shown both
earthquake compared with rates before and after the earthquake. 68 positive and negative associations with CHD mortality. 85,86 Lead-
In contrast, mortality rates for other types of heart disease, such as ing researchers suggest that other job factors, for example, little
cardiomyopathy or cerebrovascular disease, did not increase. Simi- support from coworkers, job insecurity, and juggling family and
lar increases were observed after major Japanese earthquakes and job demands, likely influence a person’s perception of employ-
the missile attacks on Israel during the 1991 Gulf War. These ment as a stressor. Similarly, what one person experiences as stress,
studies, however, could not exclude the effects of increased physi- another may view as stimulating and exciting. All things consid-
cal stress caused by exertion. Data from both the missile attacks ered, clearly substantiated evidence supporting the causal rela-
against Israel and the Japanese earthquakes suggest that the inci- tionship between job stress and CHD is still absent. 2,87
dence of MI and CHD mortality was greater in women than in
men. Posttraumatic stress scores were also higher in Japanese
women than in men, suggesting that mental stress could trigger PATHOPHYSIOLOGICAL
these coronary events. 69,70 Some evidence suggests that in the MECHANISMS FOR
hour after high levels of negative emotions, the risk for ischemic
episodes doubles. 71 Some including Krieger 72 have suggested that PSYCHOSOCIAL RISK FACTORS
lower socioeconomic groups appear to have increased incidence of AND CHD
CHD because of acute stress and exposure to stressful life events.
It has been argued that they have less control over their environ- The neuroendocrine response theory, the behavioral mechanisms
ment, which leads to stress. Other factors, such as lack of access to theory, or a combination of both offers the most likely explana-
medical care or engaging in unhealthy lifestyle behaviors, may be tion for the link between psychosocial risk factors and CHD. Ac-
alternative explanations. cording to the neuroendocrine response theory, a state of physio-
Acute stress can also lead to arrthymias and sudden cardiac logical arousal occurs when a person is confronted by real or
death in patients with CHD. 73 The effects of mental stress have imagined threats or stressors. 88 “Fight-or-flight” describes these
been evaluated during angiography by asking patients to solve physiologic responses. 89 Neuroendocrine response systems are ac-
arithmetic problems. Investigators found that stenosed coronary tivated, triggering the release of cortisol and catecholamines (epi-
artery segments responded by dilating. 74 Studies using challeng- nephrine [adrenaline] and norepinephrine) that initiate several
ing video games that have a timing aspect have shown similar re- physiologic responses (Fig. 33-1).
sults. Comparisons of mental and physical activity stress tests found Circulating levels of plasma lipids are also increased and
that mental stress produces higher diastolic blood pressure and platelet and macrophage cells are activated to release chemotactic
lower heart rate responses than physical activity. 75 These studies and cytotoxic substances. Cardiovascular responses include in-
suggest that ischemia caused by mental stress might occur because creased heart rate, blood pressure, muscle and myocardial oxygen
of inappropriate vasoconstrictor responses. Because exposure to se- demands, and accelerated blood flow. Increased blood flow trig-
vere stress cannot be ethically evaluated in experimental human gers a cascade of endothelial vascular responses, including release
studies, conclusive statements about its effects cannot be made. of nitric oxide to promote vasodilation, stimulation of platelets to
release chemoattractants and promote thrombosis, and activation
Job Stress of macrophages. Activated macrophages enhance phagocytic ac-
tivity and have been implicated in the development of atheroscle-
Several observational studies have attempted to link chronic job rotic foam cells and the destabilization and rupture of the fibrous
stress with the precipitation of coronary events. Higher numbers cap surrounding atherosclerotic plaque. 90,91
of MIs occur in the early morning hours and are associated with The neuroendocrine response theory has led to speculation
increases in catecholamines. Weekly patterns suggest an approxi- about the connection between affective states and physiological
mately 20% increase in the incidence of MIs on Mondays, with responses. An association has been found between depression and
the lowest rates occurring on Saturdays and Sundays. 76 Some re- increased nervous system activity, 92 which in turn can increase
late this increased incidence with a person’s return to his or her cardiovascular-disease-related death. Depressed cardiac patients
stressful workplace; others have suggested that lifestyle habits at have increased platelet reactivity, 93,94 and depressed patients fol-
work and at leisure account for this difference. Occupational lowing an MI have shown decreased heart rate variability. 95 The
stress has been posited as the explanation for the increase in CHD risk of sudden death after an MI is significantly higher in patients
risk and mortality in blue-collar workers. 77–79 As more women with a decrease in heart rate variability. 96 Lower heart rate vari-
enter the workforce, some have suggested that women will expe- ability and decreased parasympathetic nervous system activity in
rience increased cardiovascular events. 80,81 When CHD risk fac- depressed patients has been associated with ventricular fibrilla-
tors were examined in middle-aged women in Rancho Bernardo, tion. 22 Carney et al. 97 examined a subsample of ENRICHD pa-
California, employed women had significantly lower lipids and tients and showed that low heart rate variability partially mediates