Temporal Trends in the Population Attributable Risk for Cardiovascular Disease: The Atherosclerosis Risk in Communities Study
What are the relative contributions (and changes in this contribution over time) of traditional cardiovascular (CV) risk factors to incident cardiovascular disease (CVD) events?
A total of 15,792 participants were enrolled in the ARIC (Atherosclerosis Risk in Communities) study at the first examination, of which 13,541 participants (56% women, 26% black) contributed any personal observations for the current analyses. This cohort was ages 52-66 years and free of CVD at exams in 1987 through 1989, 1990 through 1992, 1993 through 1995, or 1996 through 1998. At each examination, the estimated population-attributable risks (PARs) of traditional risk factors (hypertension, diabetes mellitus, obesity, hypercholesterolemia, and smoking) for the 10-year incidence of CVD was calculated.
Of the participants who contributed observations to this analysis (n = 13,541), 56% were women and 26% were black. Mean body mass index slightly but significantly increased from the first to the fourth examination (p < 0.001), and the proportion of individuals with obesity increased from 26% to 33% over this same time period (p < 0.001). The frequencies of hypertension (39% to 45%) and diabetes mellitus (12% to 14%) also increased from the first to the fourth examination, whereas the frequencies of smoking (24% to 16%) and hypercholesterolemia (68% to 55%) decreased (p < 0.001 for all). Overall, the PAR of all risk factors combined appeared to decrease from the late 1980s to the late 1990s (0.58 to 0.53). The combined PAR was higher in women than men in 1987 through 1989 (0.68 vs. 0.51, p < 0.001), but not by the late 1990s (0.58 vs. 0.48, p = 0.08). The combined PAR was higher in blacks than whites in the late 1980s (0.67 vs. 0.57, p = 0.049), and this difference was more pronounced by the late 1990s (0.67 vs. 0.48, p = 0.002). By the late 1990s, the PAR of hypertension had become higher in women than men (p = 0.02) and also appeared higher in blacks than whites (p = 0.08). By the late 1990s, the PAR of diabetes mellitus remained higher in women than men (p < 0.0001) and in blacks than whites (p < 0.0001).
The investigators concluded that the contribution to CVD of all traditional risk factors combined is greater in blacks than whites, and this difference may be increasing. The contributions of hypertension and diabetes mellitus remain especially high, in women as well as in blacks. These findings underscore the continued need for individual as well as population approaches to CVD risk factor modification.
These data suggest that continued risk factor identification and modification is a key component of decreasing CVD burden. Particularly among women and blacks, the burden of CVD risk merits further development of targeted interventions to reduce hypertension and diabetes.
Keywords: Incidence, Atherosclerosis, Body Mass Index, European Continental Ancestry Group, Risk Factors, Obesity, Hypercholesterolemia, Hypertension, Diabetes Mellitus, Smoking
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