Risk Factors for Developing Cardiac Disease in Late Middle‐Aged and Older Men and Women: A Prospective Study

To the Editor: Previous studies have identified several risk factors for developing cardiac disease (CD), particularly in younger samples. Hypertension and coronary heart disease were found to be predictive for the development of congestive heart failure (CHF).1,2 However, neither Seeman et al.3 nor Penninx et al.4 found, in older persons, any significant association between blood pressure and cardiac events. Diabetes mellitus also emerged as an important risk factor for CD, with greater risk for older women than for older men.2,3 Other independent risk factors for the development of CHF were (past) smoking behavior, obesity, and (psychological) stress.5 Depressive symptomatology was found to be related to CD, particularly myocardial infarction and ischemic heart disease.4,6–10 However, Mendes de Leon et al. reported a significant association between depressive symptoms and myocardial infarction only in older women,9 whereas Penninx et al. found that depressed mood was related to cardiovascular events only in older men.10 Although most of these studies suggested that subjects with a history of hypertension, diabetes mellitus, obesity, and smoking are at risk for developing CD, these main, well-known risk factors have mostly been studied in samples of middle-aged men.3 Studies on risk factors for older men and women produced inconsistent findings regarding the risks associated with smoking, high blood pressure, depressive symptoms, and obesity.3 In addition, several of the studies mentioned above did not differentiate between men and women, did not use large population-based samples, and focused on only a few risk factors, and several studies also used samples including only younger or younger and older subjects. Furthermore, most research included only cardiac mortality or hospitalization as endpoint of observation. Cardiac events may then have induced risk factors for mortality or hospitalization (such as depression and nonadherence with medical regimen).11 In the present prospective study of older people, we included hypertension, heart disease, diabetes mellitus, depressive symptomatology, obesity, and past smoking behavior as potential risk factors for developing subsequent CD in a large sample of late middle-aged and older persons. Endpoint of measurement included CD irrespective of mortality or hospitalization The analyses were conducted separately for men and women. The investigation was part of the Groningen Longitudinal Aging Study.12 In 1993, 5,279 persons age 57 and older from the patient panels of 27 family physicians who register every doctor-patient encounter in a computerized health information system were interviewed. The interviews collected data on six risk factors: body mass index, life-time smoking exposure, depressive symptoms, heart disease, hypertension, and diabetes mellitus, plus age, level of education, and number of chronic medical conditions. Patients who had a new postbaseline cardiac event were recruited through the 27 family physicians. Two cardiac events were included: CHF and acute myocardial infarction (AMI). Each fortnight, from the baseline wave in 1993 until January 1, 1998, these physicians passed on the names of all patients with a new episode of CHF or AMI according to the criteria of the International Classification of Primary Care (ICPC).13 Between the baseline wave in 1993 and January 1, 1998, the family physicians identified 253 men (mean age ± standard deviation, 71.7 ± 8.0 years) and 219 women (75.4 ± 7.8 years) with a new postbaseline cardiac event according to the ICPC classification. Table 1 shows the outcomes of the multivariate Cox regression analyses. Lifetime smoking exposure, depressive symptomatology, and (nonspecified) heart disease were predictive for the development of CD in both men and women. In addition, female diabetes mellitus patients had an 87% higher risk of developing CD than did those without diabetes mellitus at baseline. The results were similar when the participants who suffered from either heart disease or hypertension at baseline were excluded. The results from our study are largely consistent with previous research findings concerning the impact of lifetime smoking exposure, heart disease, and diabetes mellitus on cardiac events. However, the results with respect to the role of hypertension and depressive symptomatology in the occurrence of cardiac events in older persons from previous studies were inconsistent. Our study showed that depressive symptoms seem to play a role in the occurrence of new episodes of CD in both older men and women. Various biological and behavioral mechanisms may be responsible for the association of depressive symptomatology with the development of CD.4 For instance, previous research suggested that depressed patients exhibit exaggerated platelet reactivity, which may be a mechanism by which depression is a risk factor for CD.14 Alternatively, depressive patients may adopt unhealthy life styles and may be less likely to follow health recommendations.11,15 In any case, preventive efforts concerning cardiac events should not only target smoking, heart disease, and diabetes mellitus but also depressive symptomatology.