Trends in Coronary Atherosclerosis: A Tale of Two Population Subgroups

Abstract

Background: We previously investigated trends in subclinical coronary artery disease and associated risk factors among autopsied non-elderly adults who died from nonnatural causes. Although grade of atherosclerosis declined from 1981 through 2009, the trend was nonlinear, ending in 1995, concurrent with increasing obesity/diabetes in this population. The previous study used linear regression and examined trends for all 4 major epicardial coronary arteries combined. The present investigation of coronary artery disease trends for the period 1995 through 2012 was prompted by a desire for more detailed examination of more recent coronary artery disease trends in light of reports that the epidemics of obesity and diabetes have slowed and are perhaps ending.

Methods: This population-based series of cross-sectional investigations identified all Olmsted County, Minnesota residents aged 16-64 years who died 1995 through 2012 (N = 2931). For decedents with nonnatural manner of death, pathology reports were reviewed for grade of atherosclerosis assigned each major epicardial coronary artery. Using logistic regression, we estimated calendar-year trends in grade (unadjusted and age- and sex-adjusted) for each artery, initially as an ordinal measure (range, 0-4); then, based on evidence of nonproportional odds, as a dichotomous variable (any atherosclerosis, yes/no) and as an ordinal measure for persons with atherosclerosis (range, 1-4).

Results: Of 474 nonnatural deaths, 453 (96%) were autopsied; 426 (90%) had coronary stenosis graded. In the ordinal-logistic model for trends in coronary artery disease grade (range, 0-4), the proportional odds assumption did not hold. In subsequent analysis as a dichotomous outcome (grades 0 vs 1-4), each artery exhibited a significant temporal decline in the proportion with any atherosclerosis. Conversely, for subjects with coronary artery disease grade 1-4, age- and sex-adjusted ordinal regression revealed no change over time in 2 arteries and statistically significant temporal increases in severity in 2 arteries.

Conclusions: Findings suggest that efforts to prevent coronary artery disease onset have been relatively successful. However, statistically significant increases in the grade of atherosclerosis in 2 arteries among persons with coronary artery disease may be indicative of a major public health challenge.

Keywords: Atherosclerosis; Cardiovascular disease; Subclinical coronary artery disease; Time trends.

Figure 1

Age- and sex-adjusted rate of deaths due to heart disease in the United States (1900-2011). Data were obtained from several sources.^-

Figure 2

The distribution of grade of stenosis among autopsied non-elderly adult residents of Olmsted County, MN, who died from non-natural causes during successive 6-year periods 1995 through 2012. Grades assigned each of four major epicardial coronary arteries (left anterior descending [LAD], left circumflex [LCX], right coronary artery [RCA], and left main artery [LMA]) ranged from 0 (no reduction in cross-sectional luminal area) through 4, with 1, 2, 3, and 4 defined as more than 0% to 25%, 26% to 50%, 51% to 75%, and over 75%, respectively.