Coronary artery calcium score, risk factors, and incident coronary heart disease events.

BACKGROUND: Whether the absence of coronary artery calcium, or conversely the presence of high volumes of coronary artery calcium, may alter assessment of coronary heart disease risk based on traditional risk factors is uncertain. We sought to identify a potential threshold of coronary artery calcium for clinical use and examine the predictive power of coronary artery calcium in individuals categorized using conventional coronary heart disease risk assessment. METHODS: The study included 10,746 men and women (36.3%) with a mean age of 53.8+/-9.9 years who were either physician- or self-referred for electron beam tomography scanning to a preventive medical clinic. Coronary heart disease risk factors were elicited by use of a questionnaire. RESULTS: During a mean follow-up of 3.5 years, 81 primary events (coronary heart disease death or nonfatal myocardial infarction) occurred. Among individuals with a coronary artery calcium score of zero, the primary event rate was very low (0.4 events per 1000 person-years of observation). When participants were stratified by self-reported coronary heart disease risk factors (0-2, or 3-4), a coronary artery calcium score >or=100 was associated with substantially increased risk of coronary heart disease events within each level of stratification. In a subgroup of participants with available clinical data, similar results were found when participants were categorized by Framingham risk scores. CONCLUSIONS: Coronary artery calcium score can identify individuals at increased risk for coronary heart disease events who otherwise would be considered low-risk based on clinical assessment. A coronary artery calcium score of zero is associated with very low risk for coronary heart disease in the short to intermediate term ( approximately 3.5 years) regardless of the number of risk factors present.

Coronary artery calcium, exercise tolerance, and CHD events in asymptomatic men.

Coronary artery calcium (CAC) scores >/=100 are predictive of CHD events in asymptomatic men. Exercise tolerance of >/=10METs predicts lower event rates in CHD patients; however, its relationship with events in individuals with subclinical atherosclerosis is less known. Participants were 710 asymptomatic men from the Aerobics Center Longitudinal Study whose exercise tolerance (ET) was quantified (<10 or >/=10METs) and whose CAC score was >/=100 as measured by electron beam tomography. During 3.5 years of follow-up 59 CHD events occurred. The age-adjusted hazard ratio (HR) of CHD events was 0.26 (95% CI=0.15-0.45) in men whose ET was >/=10METs compared with men whose ET was <10METs. Adjustment for CHD risk factors and abnormal exercise ECG did not change the association between ET and CHD. The extent of underlying atherosclerosis did not influence the association between ET and CHD; for example, the HR for CHD events in the >/=10MET group among men with CAC scores <400 and >/=400 was 0.16 (95% CI=0.05-0.56) and 0.23 (95% CI=0.11-0.46), respectively. In asymptomatic men with subclinical coronary atherosclerosis, an ET of >/=10METs identifies patients at lower risk for manifest CHD.

Cardiorespiratory fitness, macronutrient intake, and the metabolic syndrome: the Aerobics Center Longitudinal Study.

OBJECTIVE: This study examines the cross-sectional associations between cardiorespiratory fitness and the metabolic syndrome with adjustment for macronutrient intake from 3-day dietary records. DESIGN: Cross-sectional study. SUBJECTS/SETTING: Women and men who had a comprehensive medical examination, including a symptom-limited maximal treadmill exercise test, and completed 3-day dietary records at the Cooper Clinic, Dallas, TX. MAIN OUTCOME MEASURES: Metabolic syndrome as defined by the National Cholesterol Education Program Adult Treatment Panel III criteria. STATISTICAL ANALYSES PERFORMED: Analysis of variance was used to examine differences in continuous data. General linear analysis was used to examine linear trends. Mantel-Haenszel chi(2) analyses were used to examine differences in categorical data. Logistic regression was used to estimate odds ratios and 95% confidence intervals. RESULTS: After adjusting for sex and age, cardiorespiratory fitness was inversely associated with the prevalence of metabolic syndrome (P<0.001). Adjustment for macronutrient intake and other potential confounding variables did not alter the association between cardiorespiratory fitness and prevalent metabolic syndrome. CONCLUSIONS: Cardiorespiratory fitness is inversely associated with the prevalence of metabolic syndrome. Patients should be encouraged to increase their physical activity to decrease their risk for metabolic syndrome and coronary heart disease.

The evolution of physical activity recommendations: how much is enough?

Physical inactivity is a major public health problem, and compelling evidence suggests that it is a contributing factor in several chronic diseases and conditions. Recognition of the health and functional hazards of a sedentary way of life has led numerous groups to promulgate public health recommendations for physical activity. In this report, we review the evolution of physical activity recommendations, discuss reasons for differences in the recommendations, and provide a summary recommendation in an attempt to harmonize existing differences. Current public health recommendations for physical activity are for 30 min of moderate-intensity activity each day, which provides substantial benefits across a broad range of health outcomes for sedentary adults. This dose of exercise may be insufficient to prevent unhealthful weight gain for some persons who may need additional exercise or caloric restriction to minimize the likelihood of further weight gain. Persons who get 30 min of moderate-intensity exercise per day are likely to achieve additional health benefits if they exercise more. In addition to aerobic exercise, people should engage in resistance training and flexibility exercises at least twice a week, which will promote the maintenance of lean body mass, improvements in muscular strength and endurance, and preservation of function, all of which enable long-term participation in regular physical activity and promote quality of life.

Comparison of coronary artery calcium detected by electron beam tomography in patients with to those without symptomatic coronary heart disease.

Although the presence of coronary artery calcium (CAC) has been associated with the prevalence and incidence of coronary heart disease (CHD), it is unclear if this association has a threshold or a continuous relation. The aim of this research was to explore the relation between CAC, as detected by electron beam tomography (EBT), and CHD in a cross-sectional study of women and men who presented to a single center for elective screening with EBT from 1995 to 1998. Of 17,967 participants, patients with CHD had higher CAC levels than those without CHD. Using subjects without CAC as the referent group, the odds ratios for prevalent CHD increased significantly across increasing quartiles of CAC in the overall population and in both genders. In a subset of the population, after adjusting for CHD risk factors, CAC scores in the fourth quartile were associated with an odds ratio of 33.8 (p <0.001) for prevalent CHD. Among patients with and without CHD, men were more likely than women to have detectable CAC (58.1% vs 28.3% and 96.1% vs 68.9% respectively, p <0.001 for each); the prevalence of detectable CAC increased with age and was higher in men than in women. There was an increased risk for prevalent CHD at all levels of CAC >0, with the greatest increase in risk occurring in patients with CAC scores >95. These observations support the potential of EBT as a sensitive test for detection of CHD.

Patterns of change in hostility from college to midlife in the UNC Alumni Heart Study predict high-risk status.

OBJECTIVE: To examine hostility measured in college and patterns of change in hostility from college to midlife as predictors of high health-related risk later in midlife. METHODS: Logistic regression models were used to test hostility/risk associations. RESULTS: College hostility predicted being a current smoker, consuming more than two drinks of alcohol, low social support, achieving less than expected in career and in relationships, risk for depression, and appraisal of life changing for the worse in terms of family events at midlife. Change in hostility did not predict smoking and drinking; however, it did significantly predict social isolation, lower income (only for women), obesity, avoidance of exercise, high-fat diet, and negative changes in economic life, work life, and physical health events-all risk indicators measured during the next decade. Appraisals of social support, lowered expectations, risk for depression, and reports of family life changing for the worse were predicted at both time periods. When change in hostility was modeled with college hostility, all risk indicators were significantly predicted by college hostility. CONCLUSIONS: High hostility in college and change in hostility from college to midlife predicts a full range of health risk indicators. When compared with the average population decline in hostility, gains in hostility at midlife are related to increased risk while declines in hostility are related to reduced risk. Higher midlife hostility is associated with increased odds of being in the higher risk group. Future research should focus on developing interventions to reduce hostility.

Liver fat is not a marker of metabolic risk in lean premenopausal women.

We examined the independent associations among abdominal adipose tissue (AT) depots, liver fat, cardiorespiratory fitness (CRF), and metabolic risk factors in 86 lean premenopausal women. We measured abdominal AT and liver fat by computed tomography (CT), and CRF by a maximal treadmill exercise test. Liver fat was not related to any abdominal AT depot, metabolic risk factor, or CRF (P > .10). Visceral AT mass (kilograms) remained a significant (P < .05) predictor of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), TC/high-density lipoprotein cholesterol (HDL-C), and LDL-C/HDL-C after statistical adjustment for CRF. Abdominal subcutaneous AT mass was also a significant (P < .05) correlate of TC/HDL-C and LDL-C/HDL-C after control for CRF. Visceral AT remained a significant predictor (P < .05) of TC and LDL-C after control for abdominal subcutaneous AT. Conversely, subcutaneous AT did not remain a significant correlate after control for visceral AT. However, the deep subcutaneous AT depot remained significantly associated with LDL-C, TC/HDL-C, and LDL-C/HDL-C after control for visceral AT. In contrast, visceral AT remained correlated with triglycerides (TG) alone, after control for the deep subcutaneous AT. These observations suggest that liver fat is not a determinant of metabolic risk in lean women. Conversely, both visceral and the deep subcutaneous depot are determinants of metabolic risk in premenopausal woman despite the absence of obesity.

Cardiorespiratory fitness is associated with lower abdominal fat independent of body mass index.

PURPOSE: To determine whether, for a given body mass index (BMI), men with high cardiorespiratory fitness (CRF) have lower waist circumference (WC) and less total abdominal, abdominal subcutaneous, and visceral adipose tissue (AT) compared with men with low CRF. METHODS: Subjects were categorized into HIGH CRF (N = 169) and LOW CRF (N = 124) groups based on age and CRF measured using a maximal treadmill test. Total abdominal, abdominal subcutaneous and visceral AT were measured by computerized tomography. RESULTS: For a given BMI, men in the HIGH CRF group had significantly lower WC (P < 0.001), total abdominal (P < 0.001), visceral AT (P < 0.001), and abdominal subcutaneous AT (P < 0.001) compared with men in the LOW CRF group. CONCLUSION: These findings suggest that the ability of CRF to attenuate the health risks associated with BMI may be partially mediated through a reduction in abdominal AT. Accordingly, our observations reinforce the importance of regular physical activity in the prevention and reduction of obesity-related health risk independent of a corresponding reduction in body weight.

Visceral fat is an independent predictor of all-cause mortality in men.

OBJECTIVE: To examine the independent associations of abdominal fat (visceral and subcutaneous) and liver fat with all-cause mortality. RESEARCH METHODS AND PROCEDURES: Participants included 291 men [97 decedents and 194 controls; mean age, 56.4 +/- 12.0 (SD) years] who received a computed tomography (CT) examination at the preventive medicine clinic in Dallas, TX, between 1995 and 1999, with a mean mortality follow-up of 2.2 +/- 1.3 years. Abdominal fat was determined using contiguous CT images from the L3-L4 to L4-L5 intervertebral space. Liver fat was assessed using the CT-determined liver attenuation value, which is inversely related to liver fat. Logistic regression was used to determine the independent association between the fat depots and all-cause mortality. RESULTS: During the study, there were 97 deaths. Visceral fat [odds ratio (OR) per SD: 1.83; 95% CI: 1.23 to 2.73], abdominal subcutaneous fat (1.44; 1.02 to 2.03), liver fat (0.64; 0.46 to 0.87), and waist circumference (1.41; 1.01 to 1.98) were significant individual predictors of mortality after controlling for age and length of follow-up. In a model including all three fat measures (subcutaneous, visceral, and liver fat), age, and length of follow-up, only visceral fat (1.93; 1.15 to 3.23) was a significant predictor of mortality. DISCUSSION: Visceral fat is a strong, independent predictor of all-cause mortality in men.

Coronary artery calcium score and coronary heart disease events in a large cohort of asymptomatic men and women.

Coronary artery calcium (CAC), a measure of subclinical coronary heart disease (CHD), may be useful in identifying asymptomatic persons at risk of CHD events. The current study included 10,746 adults who were 22-96 years of age, were free of known CHD, and had their CAC quantified by electron-beam tomography at baseline as part of a preventive medical examination at the Cooper Clinic (Dallas, Texas) during 1995-2000. During a mean follow-up of 3.5 years, 81 hard events (CHD death, nonfatal myocardial infarction) and 287 total events (hard events plus coronary revascularization) occurred. Age-adjusted rates (per 1,000 person-years) of hard events were computed according to four CAC categories: no detectable CAC and incremental sex-specific thirds of detectable CAC; these rates were, respectively, 0.4, 1.5, 4.8, and 8.7 (trend p<0.0001) for men and 0.7, 2.3, 3.1, and 6.3 (trend p=0.02) for women. CAC levels also were positively associated with rates of total CHD events for women and men (trend p<0.0001 each). The association between CAC and CHD events remained significant after adjustment for CHD risk factors. CAC was associated with CHD events in persons with no baseline CHD risk factors and in younger (aged <40 years) and older (aged >65 years) study participants. These findings show that CAC is associated with an increased risk of CHD events in asymptomatic women and men.

Visceral fat and liver fat are independent predictors of metabolic risk factors in men.

We examined the independent associations among abdominal adipose tissue (AT), liver fat, cardiorespiratory fitness (CRF), and lipid variables in 161 Caucasian men who had a wide variation in adiposity. We measured AT and liver fat by computed tomography and CRF by a maximal exercise test on a treadmill. Visceral AT remained a significant (P or= 0.05) correlate of any lipid variable after control for visceral AT and CRF. Furthermore, subdivision of subcutaneous AT into deep and superficial depots did not alter these observations. Visceral AT was the strongest correlate of liver fat and remained so after control for abdominal subcutaneous AT, CRF, and alcohol consumption (r = -0.34, P < 0.01). In contrast, abdominal subcutaneous AT and CRF were not significant (P > 0.10) correlates of liver fat after control for visceral AT. Visceral AT remained a significant (P < 0.01) correlate of TG, HDL-C, and TC/HDL-C independent of liver fat. However, liver fat was also a significant correlate (P