Background:
Although psychosocial stressors such as negative life events predict adverse physical and mental health outcomes, significant gaps remain in the literature regarding whether such associations appear with cardiovascular disease (CVD) in middle-aged and older women, a demographic at higher risk for CVD than younger women. Hence, we investigated the relationship of cumulative negative life events and risk of myocardial infarction in the Women’s Health Study (WHS).
Methods and Results:
We performed a prospective, nested case-control study of apparently healthy post-menopausal women participating in the ongoing follow-up cohort of the Women’s Health Study; 26,763 women were followed for an average of 9 years to ascertain MI risk. Participants answered 12 standardized questions about negative life events within 5 years of survey completion (e.g. death/illness/accidental injury of someone close, fired from job, legal trouble, unemployment, marital infidelity, serious financial problems), and 3 questions about lifetime traumatic events (life-threatening illness, accident involving child or spouse, or victim of serious assault). Our cumulative life events score (CLES) was the count of items endorsed on all 15 questions, whereas our traumatic life events score counted positive responses to the 3 traumatic event questions. Women with a CLES score of zero were compared to women with scores >0 who were divided into tertiles; thus defining 4 categories. Among 267 women with a history of MI and 281 age and smoking matched controls, the median age of participants was 56.0 years old (Interquartile range: 51.3 - 60.6). Logistic regression analyses revealed that while increasing CLES was associated with increasing MI risk [Odds Ratio: OR unadjusted model: 1.00, 1.21, 1.52, 1.87; p-trend 0.16], the trend did not reach statistical significance. In models adjusted for CVD risk factors, there was a significant interaction with household income: CLES was associated with MI only in women with household income < $50,000 yearly (OR = 1.24, 95% CI: 1.05-1.49. The odds of MI was significantly higher in women who reported traumatic life events compared to women who did not (ORtraumatic life event score =1.65: 95% CI: 1.02, 2.68); women with traumatic life event(s) had a 65% increase in odds of MI when compared to women without, after adjusting for CVD risk factors and socio-economic status. In question specific analyses, women reporting serious financial problems as a life event had significantly higher odds of MI than women who did not (OR=2.60, 95% CI: 1.20 - 5.64).
Conclusion:
In this analysis among middle aged and older women, we found supportive evidence that negative cumulative life events were associated with MI risk, especially in low-income women and those suffering major traumatic life events. Further research is warranted particularly in women who also have limited socioeconomic resources.
Disentangling the causal inter-relationship between negative life events and depressive symptoms in women: a longitudinal twin study