Gregory L. Burke

Cardiovascular risk factors in young adults: The CARDIA baseline monograph

Gary R. Cutter, PhD*(1), Gregory L. Burke, MD (2), Alan R. Dyer, PhD (3), Gary D. Friedman, MD (4), Joan E. Hilner, MPH, MA, RD (5), Glenn H. Hughes, PhD (6), Stephen B. Hulley, MD (7), David R. Jacobs Jr., PhD (2), Kiang Liu, PhD (3), Teri A. Manolio, MD, MHS (8), Albert Oberman, MD (9), Laura L. Perkins, PhD (5), Peter J. Savage, MD (8), Joyce R. Serwitz, MEd (5), Stephen Sidney, MD (4), Lynne E. Wagenknecht, Dr PH (5)

Association of fasting insulin with blood pressure and lipids in young adults. The CARDIA study.

The association of insulin with cardiovascular disease (CVD) may be mediated in part by the associations of insulin with CVD risk factors, particularly blood pressure and serum lipids. These associations were examined in 4576 black and white young adults in the CARDIA Study. Fasting insulin level was correlated in univariate analysis with systolic blood pressure (r = 0.16), diastolic blood pressure (r = 0.13), triglycerides (r = 0.27), total cholesterol (r = 0.10), high density lipoprotein (HDL) cholesterol (r = -0.25), and low density lipoprotein (LDL) cholesterol (r = 0.14), and with age, sex, race, glucose, body mass index, alcohol intake, cigarette use, physical activity, and treadmill duration (all p less than 0.0001). After adjustment for these covariates, insulin remained positively associated with blood pressure, triglycerides, total and LDL cholesterol, and apolipoprotein B and was negatively associated with HDL, HDL2 and HDL3 cholesterol, and apolipoprotein A-I in all four race-sex groups. Higher levels of fasting insulin are associated with unfavorable levels of CVD risk factors in young adults; these associations, though relatively small, can be expected to increase the risk of atherosclerosis. Demonstration of these relationships in a large, racially diverse, healthy population suggests that insulin may be an important intermediate risk factor for CVD in a broad segment of the U.S. population.

Trends in prevalence of diabetes mellitus in patients with myocardial infarction and effect of diabetes on survival. The Minnesota Heart Survey.

Objective The purpose of this study was to document trends in the prevalence of diabetes among men and women hospitalized for myocardial infarction (MI) and to determine the effect of diabetes on in-hospital case fatality rates and long-term survival. Research Design and Methods: The Minnesota Heart Survey is a population-based surveillance system that has monitored trends in coronary heart disease morbidity since 1970. As part of this effort, a 50% random sample of acute Ml discharge records in Minneapolis-St. Paul metropolitan area hospitals was abstracted in 1970,1980, and 1985. Research Design and Methods The Minnesota Heart Survey is a population-based surveillance system that has monitored trends in coronary heart disease morbidity since 1970. As part of this effort, a 50% random sample of acute MI discharge records in Minneapolis-St. Paul metropolitan area hospitals was abstracted in 1970, 1980, and 1985. Results The prevalence of diabetes among MI patients was compared over time, and the data indicated a significant increase between 1970 and 1985 in both men (8.2 vs. 16.8%, P = 0.001) and women (16.0 vs. 25.8%, P = 0.01). Diabetic individuals had an odds ratio of in-hospital death after an MI 1.5 times that of nondiabetic individuals (P < 0.01) after controlling for the effects of sex, age, and year of MI. Among discharged MI survivors, the risk of death was 40% higher (P < 0.01) in diabetic individuals than nondiabetic individuals after 6 yr of follow-up. Compared with nondiabetic individuals, diabetic individuals appeared more likely to have cardiac (pump) failure with acute MI. Conclusions Our findings suggest that the risk of coronary heart disease morbidity and mortality attributable to diabetes may be increasing over time. Therefore, clinicians need to take extra care in the management of MIs in diabetic individuals, and public health efforts to reduce diabetes prevalence are warranted.

Cigarette smoking behavior is strongly related to educational status: The cardia study☆

The prevalence and correlates of cigarette smoking were examined in 5,116 men and women ages 18-30 years including both blacks and whites of varied educational levels. Prevalence of smoking was approximately 30% in each race by gender subgroup after adjusting for age and education. The prevalence decreased with increasing education, from 54% among participants with less than a high school education to 12% among those with graduate degrees (P less than 0.001). Cessation rates followed a similar pattern, with former smokers twice as common among those with more education. Differences in smoking prevalence across occupational groups were largely explained by differences in educational achievement. More educated individuals smoked fewer cigarettes per day and chose brands with lower nicotine yield. Race and gender were not strongly related to smoking prevalence. However, among smokers, whites reported smoking 50% more cigarettes per day than blacks but the average nicotine and tar content of the cigarette was nearly three times higher among blacks than whites. The strong inverse relationship between education and cigarette smoking patterns has important implications for public health efforts directed at the prevention of cigarette smoking.

Implications of obesity for cardiovascular disease in blacks: the CARDIA and ARIC studies.

To examine the relation of obesity to cardiovascular disease in blacks, we analyzed data from two population studies, including young and middle-aged adults. Obesity, defined by using the sum of subscapular and triceps skinfold measurements, was positively associated with atherogenic plasma lipids, systolic blood pressure, serum glucose and insulin, and prevalence of diabetes mellitus. The strength of these associations, for the most part, was similar in blacks and whites. However, with each unit increase in sum of skinfold thicknesses, plasma triglyceride concentrations in blacks appeared to increase only one-third to one-half as much as in whites. Prevalence of cardiovascular disease in 45- to 65-y-old blacks was associated with obesity; the odds ratio (95% confidence interval), adjusted for age and cigarette smoking, was 1.3 (0.9, 1.8) in both black men and black women. Additional analyses showed that abdominal adiposity conferred increased risk. These findings suggest that both blacks and whites should avoid excess adiposity.

Obesity and overweight in young adults: the CARDIA study.

The associations of body size with age, race, sex, and education in young adults were examined in 5,115 black and white, men and women ages 18-30 years. Black women were more obese than white women with greater mean levels of body mass index (25.8 vs 23.1 kg/m2), subscapular skinfold thickness (19.9 vs 15.2 mm), and waist girth (76.7 vs 72.0 cm), all P less than 0.0001. Black women were more likely to exceed 20% of ideal body weights (black women 23.7%, white women 9.1%, P less than 0.0001). No similar differences were found in men. Associations of measures of body size with age and education differed among race/sex groups. Body mass index and skinfolds increased with age among white and black men and black women, but not among white women. The association of education with obesity was negative among white women and positive among black men with no significant association noted among white men and black women. These data show a complex relationship between age, sex, race, education, and obesity in young adulthood.

Prevalence of cardiovascular disease risk factors in blacks and whites: the Minnesota Heart Survey.

Two cross-sectional surveys were conducted in 1985 and 1986 to measure the prevalence of coronary heart disease (CHD) risk factors in Blacks and Whites. A home interview was followed by a survey center visit. Participation rates were 78 per cent and 90 per cent for the home interview and 65 per cent and 68 per cent for the survey center visit. Adjusted for age and education, systolic and diastolic blood pressure was 3 to 4 mmHg higher in Blacks. Hypertension was more prevalent in Blacks than Whites (44 per cent vs 28 per cent); serum total cholesterol was approximately 0.4 mmol/l lower in Black than White men and 0.08 mmol/l lower in Black than White women. Among men, more Blacks than Whites were current cigarette smokers (44 per cent vs 30 per cent); however, White smokers smoked more cigarettes per day (26 vs 17). Similar differences were noted for women, although the prevalence and quantity of cigarette consumption was less than men. The excess prevalence of these CHD risk factors in Blacks, especially among women, may explain their elevated CHD and stroke mortality rates in the Twin Cities.

Correlates of fasting insulin levels in young adults: The cardia study

Elevated fasting insulin is an independent risk factor for hyperlipidemia, hypertension, and cardiovascular disease, but determinants of insulin other than age and body mass remain poorly described. Potentially modifiable factors associated with insulin were identified by correlating anthropometric, dietary and physical activity data in the CARDIA cohort of 2643 black and 2472 white men and women aged 18-30 years. Insulin was positively correlated with serum glucose, body mass index (BMI), skinfold thickness, waist/hip ratio and sucrose intake, and negatively correlated with heavy physical activity score, treadmill exercise duration, and magnesium intake (each p less than 0.01). After adjustment for other covariates, the positive association of insulin with waist/hip ratio, skinfold thickness, and sucrose intake remained in the group as a whole, as did the negative associations with magnesium and treadmill duration. These relationships provide insight into potentially modifiable factors affecting insulin levels, and should be considered in interpreting associations between insulin levels and cardiovascular disease.

Hospitalization and case fatality for pulmonary embolism in the twin cities: 1979–1984

To better characterize the morbidity from pulmonary embolism, we examined hospital discharge data for all acute care facilities (except for the Veterans Administration Medical Center) in the Minneapolis-St. Paul metropolitan area in each year from 1979 to 1984 for persons aged 30 to 74 years. For each person in whom the discharge diagnoses included pulmonary embolism, the age, sex, year of admission, and vital status at discharge were recorded. Annual age-sex-specific and age-adjusted sex-specific hospitalization rates were calculated. Similar analyses were undertaken for case fatality. With the exception of men younger than 55 years of age, all groups experienced significant decline in the pulmonary embolism discharge rate. No significant temporal changes were observed in any of the case fatality rates. These data suggest that changes in pulmonary embolism mortality in the United States from 1979 to 1984 may reflect declining occurrence of the disease and are likely not the result of changes in case fatality. Further studies in this area are needed.

Secular trends in Q wave and non-Q wave acute myocardial infarction. The Minnesota Heart Survey.

The Minnesota Heart Survey examined trends of Q wave and non-Q wave acute myocardial infarction (AMI) using a 50% random sample of all hospital discharges of patients with AMI or another acute coronary disease from 35 of 36 hospitals in 1970 and 30 of 31 hospitals in 1980 in the Minneapolis-St. Paul metropolitan area. A total of 1,901 and 1,864 potential AMI cases were abstracted in 1970 and 1980, respectively. Electrocardiograms were coded according to the Minnesota code. AMIs were validated by computerized algorithm based on chest pain, enzymes, electrocardiograms, and autopsy. This study shows that with the use of a consistent, standard diagnostic algorithm, attack rates for Q wave AMI did not change significantly between 1970 and 1980 and that attack rates for non-Q wave AMI decreased significantly during the same decade. However, when the more sensitive cardiac enzymes creatine phosphokinase and creatine phosphokinase-MB were considered, attack rates of both Q wave and non-Q wave AMIs increased. This research documents four important trends for community AMI rates that are at variance with those reported by others. There was a decline in non-Q wave AMI attack rates from 1970 to 1980; women had outcomes equal to or worse than those for men for both case-fatality and 7-year survival rates; patients with non-Q wave AMIs had worse in-hospital prognoses than those with Q wave AMIs; and 7-year survival rates were worse for Q wave AMI in 1980. These findings demonstrate the need for standard diagnostic criteria for Q wave and non-Q wave AMI if trends are to be monitored. In the future, as new trials of operative and nonoperative therapies of AMI are undertaken, these considerations will increase in importance.