Association Between Duration of Overall and Abdominal Obesity Beginning in Young Adulthood and Coronary Artery Calcification in Middle Age
What are the consequences of long-term obesity in terms of presence and 10-year progression of coronary artery calcification (CAC)?
Data from the multicenter, community-based CARDIA (Coronary Artery Risk Development in Young Adults) study were used for this analysis. This is a prospective study of 3,275 white and black adults ages 18-30 years at baseline in 1985-1986. Only participants who were not obese were included. Duration of overall and abdominal obesity was calculated using repeat measurements of body mass index (BMI) and waist circumference, respectively, performed 2, 5, 7, 10, 15, 20, and 25 years after baseline. Presence of CAC was measured by computed tomography at the year 15 (2000-2001), year 20 (2005-2006), or year 25 (2010-2011) follow-up examinations. Ten-year progression of CAC (2000-2001 to 2010-2011) was defined as incident CAC in 2010-2011, or an increase in CAC score of 20 Agatston units or greater.
Those with a longer exposure to obesity were more likely to be younger at baseline, female, black, achieve less education, have a higher waist circumference at baseline and during follow-up, and were less physically active and consumed less alcohol. In addition, a longer duration of obesity was associated with higher levels (averaged during follow-up) of blood pressure, glucose, insulin, C-reactive protein, high-density lipoprotein cholesterol, and triglycerides. Presence of diabetes and medication use for hypertension and dyslipidemia also was more frequent among those with a longer duration of obesity. Smoking and total cholesterol level were unrelated to obesity duration. During follow-up, 40.4% and 41.0% developed overall and abdominal obesity, respectively. Rates of CAC per 1,000 person-years were higher for those who experienced more than 20 years versus 0 years of overall obesity (16.0 vs. 11.0, respectively) and abdominal obesity (16.7 vs. 11.0). Approximately 25.2% and 27.7% of those with more than 20 years of overall and abdominal obesity, respectively, experienced progression of CAC versus 20.2% and 19.5% of those with 0 years. After adjustment for BMI or waist circumference and potential confounders, the hazard ratios for CAC for each additional year of overall or abdominal obesity were 1.02 (95% confidence interval [CI], 1.01-1.03) and 1.03 (95% CI, 1.02-1.05), respectively. The adjusted odds ratios for CAC progression were 1.04 (95% CI, 1.01-1.06) and 1.04 (95% CI, 1.01-1.07), respectively. Associations were attenuated but largely persisted following additional adjustment for potential intermediate metabolic factors during follow-up.
The investigators concluded that longer duration of overall and abdominal obesity was associated with subclinical coronary heart disease and its progression through midlife independent of the degree of adiposity. Preventing or at least delaying the onset of obesity in young adulthood may lower the risk of developing atherosclerosis through middle age.
These data support concern that being obese at younger ages is associated with increases in both cardiovascular risk factors and arterial disease.
Keywords: Obesity, Abdominal, Coronary Artery Disease, Atherosclerosis, Follow-Up Studies, European Continental Ancestry Group, Risk Factors, Glucose, Cholesterol, Dyslipidemias, C-Reactive Protein, Body Mass Index, Cardiovascular Diseases, Triglycerides, African Continental Ancestry Group, Hypertension, Diabetes Mellitus, Disease Progression
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