Cardiorespiratory fitness and coronary artery calcification in young adults: The CARDIA Study

Whether cardiorespiratory fitness relates to early subclinical atherosclerotic vascular disease remains unknown. We investigated the relation of cardiorespiratory fitness to coronary artery calcification (CAC) in 2373 African-American and White young adults from the Coronary Artery Risk Development in Young Adults (CARDIA) Study. We measured cardiorespiratory fitness in 1985-1986 (baseline) using a symptom-limited exercise test on a treadmill. Coronary calcium scores were measured in 2001-2002 (year 15) using electron-beam or multi-detector computed tomography. CAC was classified as present or absent, while cardiorespiratory fitness was classified as sex-specific low, moderate, and high fitness categories. After adjustment for age, sex, race, clinical center, education, cigarette smoking, waist girth, alcohol intake, physical activity, systolic blood pressure, antihypertensive medication use, diabetes mellitus, and fasting insulin, baseline cardiorespiratory fitness was inversely associated with prevalence of CAC in young adults (P for trend=0.03). The odds ratios of having CAC for persons in the moderately and highly fit individuals were 0.80 (95% confidence interval (CI), 0.55-1.15) and 0.59 (95% CI, 0.36-0.97), respectively, as compared with the low-fit individuals. High levels of cardiorespiratory fitness were associated with a lower risk of having coronary calcification 15 years later in African-American and White young adults.     

Early adult risk factor levels and subsequent coronary artery calcification: the CARDIA Study.

OBJECTIVES: We sought to determine whether early adult levels of cardiovascular risk factors predict subsequent coronary artery calcium (CAC) better than concurrent or average 15-year levels and independent of a 15-year change in levels. BACKGROUND: Few studies have used multiple measures over the course of time to predict subclinical atherosclerosis. METHODS: African American and white adults, ages 18 to 30 years, in 4 U.S. cities were enrolled in the prospective CARDIA (Coronary Artery Risk Development in Young Adults) study from 1985 to 1986. Risk factors were measured at years 0, 2, 5, 7, 10, and 15, and CAC was assessed at year 15 (n = 3,043). RESULTS: Overall, 9.6% adults had any CAC, with a greater prevalence among men than women (15.0% vs. 5.1%), white than African American men (17.6% vs. 11.3%), and ages 40 to 45 years than 33 to 39 years (13.3% vs. 5.5%). Baseline levels predicted CAC presence (C = 0.79) equally as well as average 15-year levels (C = 0.79; p = 0.8262) and better than concurrent levels (C = 0.77; p = 0.019), despite a 15-year change in risk factor levels. Multivariate-adjusted odds ratios of having CAC by ages 33 to 45 years were 1.5 (95% confidence interval [CI] 1.3 to 1.7) per 10 cigarettes, 1.5 (95% CI 1.3 to 1.8) per 30 mg/dl low-density lipoprotein cholesterol, 1.3 (95% CI 1.1 to 1.5) per 10 mm Hg systolic blood pressure, and 1.2 (95% CI 1.1 to 1.4) per 15 mg/dl glucose at baseline. Young adults with above optimal risk factor levels at baseline were 2 to 3 times as likely to have CAC. CONCLUSIONS: Early adult levels of modifiable risk factors, albeit low, were equally or more informative about odds of CAC in middle age than subsequent levels. Earlier risk assessment and efforts to achieve and maintain optimal risk factor levels may be needed.     

Prevalence and correlates of coronary calcification in black and white young adults: the Coronary Artery Risk Development in Young Adults (CARDIA) Study

Whereas cardiovascular risk factor levels are substantially different in black and white Americans, the relative rates of cardiovascular disease in the 2 groups are not always consistent with these differences. To compare the prevalence of coronary calcification, an indicator of coronary atherosclerosis, in young adult blacks and whites, we performed electron-beam computed tomography of the heart in 443 men and women aged 28 to 40 years recruited from a population-based cohort. The presence of calcium, defined as at least 1 focus of at least 2.05 mm(2) in area and >130 Hounsfield units in density within the coronary arteries, was identified in 16.1% of black men, 11.8% of black women, 17.1% of white men, and 4.6% of white women (P=0.04 for comparison across groups). Coronary calcium was associated with age and male sex, and after adjustment for age, race, and sex, coronary calcium was positively associated with body mass index, weight, systolic blood pressure, total cholesterol, low density lipoprotein cholesterol, triglycerides, and fasting insulin and negatively associated with education (all P<0.05). Independent risk factors included male sex, body mass index, and low density lipoprotein cholesterol. Race was not significantly associated with coronary calcium in men or women, before or after adjustment for risk factors. Coronary calcification is associated with increased levels of cardiovascular risk factors in young adults, and its prevalence is not significantly different in blacks and whites.     

Fluoroscopic coronary artery calcification and associated coronary disease in asymptomatic young men.

Little is known about the diagnostic significance of coronary artery calcification detected fluoroscopically in apparently healthy young men. This study compared the presence of fluoroscopically detected coronary artery calcification with angiographic coronary artery disease in asymptomatic male military aircrew undergoing noninvasive cardiac screening tests and coronary arteriography for occupational indications. Of 1,466 men screened with coronary fluoroscopy, 613 underwent coronary arteriography because of one or more abnormal noninvasive test results. The mean age (+/- SD) of all subjects screened was 40.2 +/- 5 years (range 26 to 65). Significant coronary artery disease (greater than or equal to 50% diameter stenosis) was found in 104 of the 613 subjects with arteriograms (16.9% disease prevalence). Overall sensitivity and specificity for coronary artery calcification detection of significant disease, based only on those subjects undergoing arteriography, were 66.3% and 77.6%, respectively. For measurable disease (mild plus significant), sensitivity was 60.6% and specificity 85.9%. Positive and negative predictive values were 37.7% and 91.9%, respectively, for significant disease. For measurable disease, positive and negative predictive values were 68.9% and 80.9%, respectively. In these asymptomatic young men, a fluoroscopic examination negative for coronary artery calcification indicated a low risk of significant coronary artery disease, whereas a positive test result (calcification present) substantially increased the likelihood of angiographically significant coronary artery disease.     

青中年冠心病患者代谢综合征危险因素的分布与聚集状况分析

目的分析青中年冠心病患者中代谢综合征(MS)危险因素的分布与聚集状况,为早期防治干预提供依据。方法对103例青中年男性[年龄30～50(43.3±5.7)岁]冠心病患者及64例男性[年龄28～50(42.8±6.3)岁]冠状动脉造影正常的对照组的临床特征和生化特点进行比较。按照中华医学会糖尿病学分会标准诊断MS。结果两组在年龄上无差异。冠心病组的吸烟率显著高于对照组,但在冠心病家族史方面两组无差异。冠心病组的总胆固醇(TC)、餐后2h血糖(2hPBG)、空腹胰岛素(FINS)、胰岛素抵抗指数(HOMAIR)均显著高于对照组,而HDLC显著低于后者。冠心病组MS的发生率显著高于对照组(P<0.01)。Logistic回归分析显示,吸烟、低HDLC、HOMAIR、MS使青中年人冠心病患病的相对危险度增加。结论青中年冠心病患者多种代谢异常更加严重,对于青中年男性应重视MS的预防,以减少心血管事件的发生。     

Racial differences in coronary artery calcification in older adults

Reports on race-related differences in coronary artery calcium (CAC) are just beginning to emerge and have not been well studied in the elderly. This study was undertaken to assess whether such differences exist and the relationship between CAC and cardiovascular risk factors in a cohort of elderly community-dwelling adults. CAC was measured by using electron-beam tomography in 614 adults (aged 67 to 99 years), of whom 59% were women and 23% were black. The median CAC score was lower in blacks than in whites for men (159 versus 787, respectively; P<0.001) and for women (134 versus 233, respectively; P=0.02) after adjustment for age, cardiovascular disease, and risk factors for cardiovascular disease, although this difference was stronger and remained significant among men only. Lower CAC scores were also observed in the subgroup of blacks with a history of myocardial infarction. The lower CAC scores in blacks compared with whites observed in this study is consistent with either a lower prevalence of coronary artery disease or a lower extent of calcification of coronary artery disease.     

Plasma leptin levels and coronary artery calcification in older adults

CONTEXT: Leptin is associated with adiposity and insulin resistance and may play a direct role in vascular calcification. It is unclear, however, whether leptin is an independent predictor of atherosclerotic burden. OBJECTIVE: The aim of this study was to examine the association between plasma leptin and coronary artery calcification (CAC) in an ethnically diverse cohort of older adult men and women free of clinical cardiovascular disease. DESIGN: This was a cross-sectional study with data collection between January 2002 and February 2004 as part of the ADVANCE Study. SETTING: The study was conducted at an integrated health care delivery system in Northern California. PARTICIPANTS: Participants included 949 men and women aged 60-69 yr old. INTERVENTIONS: There were no interventions. MAIN OUTCOME MEASURE: The main outcome measure was CAC by multidetector row computed tomography. RESULTS: In ordinal logistic regression, plasma leptin levels were positively associated with extent of CAC independently of age, race/ethnicity, and smoking status in women (odds ratio of higher CAC for the sex-specific upper tertile vs. lower tertile = 1.81; 95% confidence interval, 1.10-3.00) but not in men (odds ratio = 1.29; 95% confidence interval = 0.89-1.86). However, this association was explained by metabolic risk factors and adiposity measures. CONCLUSIONS: Our findings support a role of leptin on vascular calcification in women but, in our sample of older adults, the association between leptin and CAC was not independent of other cardiac risk factors.     

Association between endothelial biomarkers and arterial elasticity in young adults: the CARDIA Study

Reduced arterial elasticity and endothelial dysfunction both may indicate early cardiovascular (CV) disease in young adults. Pulse waveform analysis estimates large (LAE) and small (SAE) artery elasticity noninvasively. We assessed the associations between LAE and SAE and markers of endothelial dysfunction and CV risk factors. The Coronary Artery Risk Development in Young Adults (CARDIA) assessed arterial elasticity and other characteristics cross-sectionally in 389 men and 381 women age 27 to 42 years in 1995 (CARDIA year 10) and circulating levels of P-selectin and soluble intercellular adhesion molecule 1 (sICAM1) in 2000. We adjusted for variables included in the estimation of arterial elasticity (year 10 height, body mass index, age, heart rate, and blood pressure) and other year 10 characteristics. Mean adjusted SAE was 8.5 vs. 7.6 mL/mm Hg × 100 in those with urine albumin/creatinine ratio ≤4 vs. microalbuminuria (ratio >25; P_trend = .008). Mean LAE was 25.6 vs. 24.2 mL/mm Hg × 10 in the lowest vs. highest quintile of P-selectin (P_trend = .004). sICAM1 was unrelated to either LAE or SAE. Plasma triglycerides were inversely related to LAE (P_trend = .029). Cigarette smokers had lower SAE than nonsmokers (P_trend = .009). In addition to smoking and triglycerides, biomarkers for endothelial dysfunction were associated with impaired LAE and SAE in young adults.     

Nighttime blood pressure dipping in young adults and coronary artery calcium 10-15 years later: the coronary artery risk development in young adults study

Nighttime blood pressure (BP) dipping can be quantified as the ratio of mean nighttime (sleep) BP to mean daytime (awake) BP. People whose dipping ratio is ≥ 0.90 have been referred to as nondippers, and nondipping is associated with cardiovascular disease events. We examined the relationship between systolic nighttime BP dipping in young adults and the presence of coronary artery calcium (CAC) 10 to 15 years later using data from the ambulatory BP monitoring substudy of the Coronary Artery Risk Development in Young Adults Study. Among 239 participants with adequate measures of both nighttime and daytime readings and coronary artery calcium, the systolic BP dipping ratio ranged from 0.72 to 1.24 (mean, 0.88; SD, 0.06), and CAC was present 10 to 15 years later in 54 participants (22.6%). Compared with those whose systolic BP dipping ratio ranged from 0.88 to 0.92 (quartile 3), the 57 participants (23.9%) with less pronounced or absent dipping (ratio, 0.92-1.24; quartile 4) had an unadjusted odds ratio of 4.08 (95% CI, 1.48-11.2) for the presence of CAC. The 60 participants (25.1%) with a more pronounced dipping (ratio, 0.72-0.85; quartile 1) also had greater odds for presence of CAC (odds ratio, 4.76 [95% CI, 1.76-12.9]). When modeled as a continuous predictor, a U-shaped relationship between systolic BP dipping ratio and future CAC was apparent and persisted after adjustment for multiple potential confounders (P<0.001 for quadratic term). Both failure of systolic BP to dip sufficiently and "overdipping" during nighttime may be associated with future subclinical coronary atherosclerosis.     

Prediction of coronary artery calcium in young adults using the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) risk score: the CARDIA study

BACKGROUND: Using data from autopsied young people aged 15 to 34 years, the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) study developed a risk score based on age, sex, smoking status, high-density lipoprotein and non-high-density lipoprotein cholesterol levels, and the presence of obesity, hyperglycemia, and hypertension to predict advanced coronary artery atherosclerosis. METHODS: The Coronary Artery Risk Development in Young Adults (CARDIA) study assessed coronary artery calcium (CAC) by computed tomography in young adults participating in the 15-year examination. The PDAY risk score was calculated from risk factors measured at the CARDIA examinations at years 0, 5, 10, and 15. RESULTS: Odds ratios for amount of CAC (6 ordinal categories) for a 1-point increase in risk score computed from the modifiable risk factors ranged from 1.10 to 1.16 (all statistically significant). Odds ratios for presence of any amount of CAC ranged from 1.09 to 1.15 (all statistically significant), with the highest odds ratio for the risk score at year 0. An increase in risk score between years 0 and 15 increased the odds of CAC, and a decrease in risk score decreased the odds of CAC. A positive family history of cardiovascular disease increased the odds of CAC. The c statistics ranged from 0.752 to 0.770, with the highest discrimination based on the year 0 revised PDAY risk score that included family history and increased the points for the sex differential. CONCLUSION: The PDAY risk score predicts CAC up to 15 years before its assessment, and risk score change during 15 years affects the risk of CAC.     

Ambulatory blood pressure and coronary artery calcification in middle-aged and younger adults

BACKGROUND: The objective of this study was to investigate relationships between blood pressure (BP) determined by ambulatory monitoring and coronary artery calcification (CAC) determined by electron beam computed tomography (EBCT) in middle-aged and younger adults without symptoms of coronary artery disease. METHODS: Measures of office and ambulatory BP were analyzed in 298 asymptomatic adults (134 women and 164 men) from the white population of Rochester, MN, who were 20 to 60 years old (mean +/- SD, 40 +/- 9 years). For the ambulatory BP measurements, the active period of the day was defined as the daytime, out-of-bed hours and the inactive period as the nighttime, in-bed hours. Logistic regression was used to assess whether ambulatory measures of BP influenced the probability of having CAC detected by EBCT. RESULTS: After adjusting for sex, age, and office measures of BP, ambulatory diastolic BP during the active and inactive periods were each statistically significant additional predictors of the probability of having CAC. Similarly, after adjusting for sex, age, and ambulatory systolic BP, ambulatory diastolic BPs during each period were also statistically significant additional predictors of the probability of having CAC. In contrast, measures of ambulatory systolic BP, pulse pressure, and diurnal dipping of BP levels from the active to the inactive period did not make statistically significant additional contributions to the probability of having CAC. CONCLUSION: These findings emphasize the role that the hemodynamic stress of diastolic BP may play in the early development of atherosclerotic coronary artery disease.     

Age-dependent associations between blood pressure and coronary artery calcification in asymptomatic adults

OBJECTIVE: The age-dependent roles of the components of blood pressure (BP) in the development of coronary artery calcification (CAC) are poorly understood. DESIGN: We examined systolic (SBP), diastolic (DBP), mean arterial pressure (MAP) and pulse pressure (PP) as predictors of CAC in 830 asymptomatic, non-diabetic participants in a community-based study who were aged > or = 30 years and free of antihypertensive therapy or known cardiovascular disease. METHODS: CAC was measured with electron beam computed tomography. Tobit regression was used in two age groups (< 50 years and > or = 50 years) to evaluate the relationship of BP components with presence and quantity of CAC, adjusting for traditional coronary artery disease (CAD) risk factors. RESULTS: Among those aged < 50 years, CAC was positively associated with SBP, DBP and MAP, considering each pressure individually and DBP was the strongest predictor (P = 0.0088). Among those aged > or = 50 years, CAC was positively associated with SBP (P = 0.0257) and PP (P = 0.0028), considered individually. When SBP and DBP were in the same model, presence and CAC quantity were positively associated with SBP (P = 0.0024) and negatively with DBP (P = 0.0401), favoring PP as the best predictor of CAC. CONCLUSIONS: SBP, DBP and PP have age-dependent roles in the prediction of CAC similar to their roles in prediction of future CAD events. These observations provide new evidence supporting the measurement of CAC as a surrogate of target organ disease and subsequently, as a predictor of increased risk of future CAD events.     

C-reactive protein concentration and incident hypertension in young adults: the CARDIA study

BACKGROUND: There is increasing evidence that C-reactive protein (CRP) concentration, a measure of inflammation, is an independent risk factor for the development of hypertension in older adults. However, it is unknown whether a similar relationship exists in younger individuals. METHODS: The Coronary Artery Risk Development in Young Adults (CARDIA) study was initiated in 1985-1986 to determine the factors that are associated with coronary risk development in young adults. C-reactive protein concentrations were measured in 3919 African American and white men and women enrolled in CARDIA using blood specimens from the year 7 examination (1992-1993), when the age of the cohort was 25 to 37 years, and the year 15 examination (2000-2001). RESULTS: In unadjusted analyses, CRP concentrations greater than 3 mg/L, compared with those less than 1 mg/L, was associated with a 79% greater risk of incident hypertension (odds ratio [OR], 1.79; 95% confidence interval [CI], 1.40-2.28). However, CRP concentration did not predict risk of incident hypertension after adjusting for year 7 body mass index (BMI) (OR, 1.14; 95% CI, 0.86-1.53) or year 7 BMI and other potential confounders (OR, 1.13; 95% CI, 0.83-1.52). In addition, year 7 CRP concentration was not associated with change in systolic or diastolic blood pressure after adjusting for BMI (P = .10 and P = .70, respectively). These findings were similar within each of the race- and sex-specific groups. CONCLUSION: C-reactive protein is associated with hypertension in young adults, but in contrast to the finding in older populations, the association is no longer present after adjusting for BMI.     

Heart rate and subsequent blood pressure in young adults: the CARDIA study

The objective of the present study was to examine the hypothesis that baseline heart rate (HR) predicts subsequent blood pressure (BP) independently of baseline BP. In the multicenter longitudinal Coronary Artery Risk Development in Young Adults study of black and white men and women initially aged 18 to 30 years, we studied 4762 participants who were not current users of antihypertensive drugs and had no history of heart problems at the baseline examination (1985-1986). In each race-sex subgroup, we estimated the effect of baseline HR on BP 2, 5, 7, and 10 years later by use of repeated measures regression analysis, adjusting for baseline BP, age, education, body fatness, physical fitness, fasting insulin, parental hypertension, cigarette smoking, alcohol consumption, oral contraceptive use, and change of body mass index from baseline. The association between baseline HR and subsequent systolic BP (SBP) was explained by multivariable adjustment. However, HR was an independent predictor of subsequent diastolic BP (DBP) regardless of initial BP and other confounders in white men, white women, and black men (0.7 mm Hg increase per 10 bpm). We incorporated the part of the association that was already present at baseline by not adjusting for baseline DBP: the mean increase in subsequent DBP was 1.3 mm Hg per 10 bpm in white men, white women, and black men. A high HR may be considered a risk factor for subsequent high DBP in young persons.     

冠状动脉钙化与冠状动脉狭窄的相关性研究

目的探究冠心病患者冠状动脉钙化积分与冠状动脉狭窄的相关性。方法入选54例冠心病住院患者,年龄52～84岁,（平均68.47±9.35）岁;其中男性36例,女性18例,行16层螺旋计算机断层扫描,计算冠状动脉钙化积分,并与冠状动脉造影进行比较,分析冠状动脉总钙化积分及各冠状动脉节段（共分16个节段）钙化积分与冠状动脉造影所示冠脉狭窄程度的相关性,同时分析冠状动脉总钙化积分与年龄的相关性。结果冠状动脉总钙化积分与年龄呈正相关（r=0.372,P=0.009）、冠状动脉总钙化积分仅与部分冠状动脉节段狭窄程度呈正相关：RA（1#）、LAD（7#）、D1（9#）、LCX（11#）,（相关系数、P值分别为：r=0.499,P〈0.01;r=0.431,P〈0.01;r=0.440,P〈0.01;r=0.469,P〈0.01）。冠状动脉各节段钙化积分与对应血管节段狭窄程度相关分析结果提示：RA（1#）、LM（5#）、LCX（11#）节段钙化积分与对应节段狭窄程度呈正相关。结论总冠状动脉钙化积分与年龄呈正相关,提示随年龄增长冠状动脉钙化发生率增加,但冠状动脉钙化积分仅在部分冠状动脉节段与狭窄程度呈正相关,且限于三支冠状动脉近段。