Differences in food habits and cardiovascular disease risk factors among Native Americans with and without diabetes: the Inter-Tribal Heart Project

OBJECTIVE

To examine differences in food habits among Native Americans with and without diabetes.

DESIGN

A cross-sectional epidemiological study in which participants underwent a physical examination and answered an extensive interviewer-administered questionnaire to assess differences in food servings, preparation and eating habits.

SETTING/PARTICIPANTS

Participants aged >/=25 years were randomly selected from three reservations in Minnesota and Wisconsin. There were 990 persons without diabetes, 294 with a prior diagnosis of diabetes, and 80 with fasting glucose >125 mg dl(-1) but no prior diabetes diagnosis.

RESULTS

Persons with prior diabetes diagnosis were less likely than those without diabetes to report eating fast-food meals two or more times per week, eat visible fat on meat or the skin on poultry, eat fried chicken or fried fish, to add fat to cooked vegetables and drink whole milk. Persons with previously undiagnosed diabetes were more likely than previously diagnosed persons to report eating fast-food meals two or more times per week, eat visible fat on meat and the skin on poultry, drink whole milk and eat fried fish, but were less likely to drink low-fat milk. Previously undiagnosed persons were more likely than either diagnosed persons or persons without diabetes to consume lard from cooked foods and use it when cooking.

CONCLUSION

Persons with diagnosed diabetes showed healthier eating patterns than those without diabetes, while undiagnosed persons showed some less favourable patterns. Because virtually all persons with diabetes in these communities receive nutrition education, the results suggest that nutrition education programmes for diabetics may be associated with healthier eating patterns.

Geographic variation in cardiovascular disease risk factors among American Indians and comparisons with the corresponding state populations

OBJECTIVES

(1) To compare the prevalence of self-reported CVD, diabetes, hypertension, fair/poor perceived health status, and current tobacco use from three surveys of American Indians - two in the Southeast (Catawba Diabetes and Health Survey [CDHS] and Lumbee Diabetes and Health Survey [LDHS]) and one in the upper Midwest (Inter-Tribal Heart Project [ITHP]). (2) To compare the prevalence estimates from the CDHS, LDHS, ITHP with those for the corresponding state populations (South Carolina, North Carolina, Minnesota and Wisconsin, respectively) derived from the Behavioral Risk Factor Surveillance System (BRFSS).

METHODS

Pearson's Chi-square analyses were used to detect statistically significant differences in the age-adjusted prevalence estimates across the study populations.

RESULTS

Among these three populations of American Indians, the ITHP participants had the highest prevalence estimates of diabetes (20.1%) and current cigarette smoking (62.8%). The CDHS participants had the highest prevalence estimate of fair/poor perceived health status (32.0%). The LDHS participants had the highest prevalence estimate of chewing tobacco use (14.0%), and the lowest prevalence of CVD. The prevalence estimates of self-reported diabetes were dramatically higher among American Indian participants in the ITHP (20.1%) and CDHS (14.9%) than among participants in the corresponding state BRFSS (5.8% MN and WI and 6.6% SC), as were the estimates for hypertension.

CONCLUSION

The substantial variations in prevalence of CVD and its risk factors among Tribal Nations suggests that distinct cultural norms, historic conditions, and important health issues of each American Indian community must be recognized and incorporated into all health promotion programs and policies.

Evidence of increasing coronary heart disease mortality among black men of lower social class

PURPOSE

Few data are available to examine coronary heart disease (CHD) mortality trends by social class in the United States, in contrast to ample data and well-documented social class disparities in CHD in Europe. In addition, previous analyses of U.S. national data indicated that the rate of decline in CHD mortality slowed substantially for blacks in the 1980s. Using a recently published method for calculating mortality rates by social class, we examined trends in CHD mortality for black men and white men aged 35-54 in North Carolina from 1984 to 1993.

METHODS

Men were assigned to one of four social classes: primary white collar (I), secondary white collar (II), primary blue collar (III), or secondary blue collar (IV), based on usual occupation as recorded on the death certificate. Population denominators for each social class were constructed using data from census Public Use Microdata Sample files. Average annual percent change in mortality rates for each race-social class group was derived from linear regression of the log-transformed age-adjusted rates.

RESULTS

For black men, CHD mortality increased by 18% in social class II, by 2% in social class III, and by 6% in social class IV over the 10-year study period. In contrast, CHD mortality decreased by 33% for black men in social class I (the highest class). CHD mortality declined for all white men, with the greatest decline in social class I and the least decline in social class IV.

CONCLUSIONS

These results suggest that CHD prevention efforts have not benefited black men of lower social class, and that public health programs need to be targeted to these men.

Physical activity patterns of Chippewa and Menominee Indians: the Inter-Tribal Heart Project

INTRODUCTION

Leisure-time (LTPA), occupational, transportation, and household physical activity were evaluated among participants in the Inter-Tribal Heart Project (ITHP).

METHODS

Age-stratified random samples of persons aged > or =25 years were drawn from three communities of Chippewa and Menominee Indians in Minnesota and Wisconsin. Participants (843 women and 501 men) completed an interviewer-administered questionnaire. Logistic regression analyses were performed to assess age-adjusted associations between no reported LTPA and potential correlates.

RESULTS

During leisure time, 12% of women and 17% of men were active 7-12 months in the past year; 33% of women and 21% of men reported no LTPA. During a typical workday for employed persons, approximately 90% of both genders walked > or =20 minutes, for carrying/lifting moderate to heavy objects the median value for men was 1 hour and women 0 hours. The median value of weekly household activity for men was 3 hours compared to 10 hours for women. Little transportation activity was reported by either gender. Age, household income, smoking, and poor/fair self-perceived health were associated with leisure-time inactivity in women (p < 0.05). Age, poor/fair self-perceived health, and smoking were associated with leisure-time inactivity in men (p < 0.05). Walking was the most prevalent activity in the population.

CONCLUSIONS

Prevalence of leisure-time inactivity is higher than the national health objective of 15%, however, ITHP participants obtain a substantial amount of occupational and household activity that may lower risks of chronic diseases. Health promotion efforts to increase LTPA may lead not only to reduced chronic disease risk, but to additional benefits of enjoyment and improved psychological well-being.

Heart failure survival among older adults in the United States: a poor prognosis for an emerging epidemic in the Medicare population

OBJECTIVE

To describe the 6-year probability of survival for older adults after their first hospitalization for heart failure.

SETTING

National Medicare hospital claims records for 1984 through 1986 and Medicare enrollment records from 1986 through 1992.

DESIGN

We identified a national cohort of 170 239 (9% black patients) Medicare patients, 67 years or older, with no evidence of heart failure in 1984 or 1985, who were hospitalized and discharged for the first time in 1986 with a principal diagnosis of heart failure. For groups defined by race, sex, age, Medicaid eligibility, and comorbid conditions, we compared the probability of survival with Cox proportional hazards regression.

RESULTS

Only 19% of black men, 16% of white men, 25% of black women, and 23% of white women survived 6 years. One third died within the first year. Men had lower median survival and 38% greater risk of mortality than did women (P<.05). White men had 10% greater risk of mortality than did black men (P<.05). Medicaid eligibility (white adults only) and diabetes were associated with increased mortality (P<.05).

CONCLUSIONS

The prognosis for older adults with heart failure underscores the importance of prevention strategies and early detection and treatment modalities that can prevent, improve, or reverse myocardial dysfunction, particularly for the growing number of adults who are at increased risk for developing heart failure because of hypertension, diabetes, or myocardial infarction.

Prevalence and correlates of the insulin resistance syndrome among Native Americans. The Inter-Tribal Heart Project

OBJECTIVE

The clustering of factors characterizing the insulin resistance syndrome has not been assessed among Native Americans, a population at high risk for diabetes and cardiovascular disease. We examined the distribution and correlates of the insulin resistance syndrome among individuals in three Chippewa and Menominee communities in Wisconsin and Minnesota.

RESEARCH DESIGN AND METHODS

Cross-sectional data from 488 men and 822 women ages > or = 25 years in the Inter-Tribal Heart Project (1992-1994) were included. The clustering of each individual trait (hypertension, diabetes, high triglycerides, and low HDL cholesterol) with the other traits and the association of the number of traits with measures of adiposity and insulin levels were examined.

RESULTS

Among the men, 40.4, 32.6, 17.4, and 9.6% had none, one, two, or at least three of the four traits, respectively; among the women, the respective percentages were 53.2, 25.6, 15.3, and 6.0%. The percentage of individuals with each particular trait significantly increased (P < 0.01) among those with none, one, or at least two other syndrome traits. Having more syndrome traits was significantly related (P < 0.001) to higher BMI, conicity index, waist circumference, and waist-to-hip and waist-to-thigh ratios. Among individuals with normal glucose levels, having more syndrome traits was significantly related (P < or = 0.05) to higher fasting insulin levels after adjusting for age and measures of adiposity, although associations were attenuated with adjustment for either BMI or waist circumference.

CONCLUSIONS

Traits characterizing the insulin resistance syndrome were found to be clustered to a significant degree among Native Americans in this study. Comprehensive public health efforts are needed to reduce adverse levels of these risk factors in this high-risk population.

Prevalence of multiple cardiovascular disease risk factors among women in the United States, 1992 and 1995: the Behavioral Risk Factor Surveillance System

We sought to examine the prevalence of self-reported multiple cardiovascular disease (CVD) risk factors (hypertension, high blood cholesterol, diabetes, overweight, and current smoking) among women in 1992 and 1995 in the United States using data from the Behavioral Risk Factor Surveillance System. In 1992, 37.5%, 34.4%, and 28.1% of women had zero, one, and two or more of the five risk factors, respectively. In 1995, the respective estimates were 35.5%, 34.3%, and 30%. In both years, the prevalence of two or more risk factors increased with age, decreased with educational level, was higher among black women (lowest among Hispanic women and women of other ethnic groups), and higher among women reporting cost as a barrier to healthcare. The percentage of women with two or more risk factors was higher in 1995 than in 1992 for 35 of 48 states, being statistically significant for 7 states. The percentage of women with at least two risk factors was not significantly lower in 1995 than in 1992 for any state. A higher percentage of women reported having multiple CVD risk factors in 1995 compared with 1992. A multifactorial approach to primary prevention and risk factor reduction should be encouraged to help reduce the prevalence and burden of CVD among women.

Serum folate and risk for coronary heart disease: results from a cohort of US adults

PURPOSE

To assess the role of serum folate in the risk for coronary heart disease in a national cohort of US adults.

METHODS

Data from the First National Health and Nutrition Examination Survey Epidemiologic Follow-up Study (N = 1921) were used to determine whether a low serum folate concentration was associated with an increased risk for incident coronary heart disease (N = 284). The Cox proportional hazards model adjusted for age, sex, race, education, serum cholesterol, systolic blood pressure, body mass index, cigarette smoking, and alcohol consumption.

RESULTS

The association between folate and risk for coronary heart disease differed by age group (p = 0.03). Among persons aged 35-55 years, the relative risk for heart disease was 2.4 (95% confidence interval (CI), 1.1-5.2) for persons in the lowest quartile (< or = 9.9 nmol/L) when compared with those in the highest quartile (> or = 21.8 nmol/L). However, among persons > or = 55 years the relative risk was 0.5 (95% CI, 0.3-0.8) for comparisons of the lowest versus highest quartiles.

CONCLUSIONS

If the age differences in the risk for heart disease are confirmed, randomized clinical trials assessing the role of folic acid for the prevention of heart disease may need to include young adults in order to demonstrate benefits related to folate supplementation.

American Indian heritage and risk factors for renal injury

BACKGROUND

Little is known about the causes and consequences of renal disease among American Indians in the Great Lakes region of the United States.

METHODS

We examined clinical correlates of albumin/creatinine ratios among 1368 participants in the three tribal communities of the Inter-Tribal Heart Project using univariate and multivariate analysis.

RESULTS

Compared to 1086 participants without albuminuria, the 240 with microalbuminuria (30 to 299 mg/g) and the 42 with macroalbuminuria (>300 mg/g) were more likely to report a history of a myocardial infarction (6.4%, 16.0%, and 23.8%, respectively, P < 0.001). Similarly, compared to patients without albuminuria, those with microalbuminuria and macroalbuminuria were more likely to report a history of stroke (2.3%, 8.4% and 26.2%, respectively, P < 0.001). In a multiple linear regression model, independent correlates of albumin excretion (P < 0.05) included: fasting blood sugar, treated diabetes, treated hypertension, higher systolic blood pressure, lower diastolic blood pressure, abnormal electrocardiogram, a history of stroke, the degree of American Indian heritage, and lower household income.

CONCLUSIONS

Urinary albumin excretion is associated with cardiovascular disease outcomes and risk factors among American Indians of the Great Lakes region. Both heredity and socioeconomic status appear to play a role in the pathogenesis of renal injury in this population.

Ischemic heart disease and stroke mortality in African-American, Hispanic, and non-Hispanic white men and women, 1985 to 1991

We compare recent trends in ischemic heart disease (IHD) and stroke mortality in California among the 6 major sex-racial or -ethnic groups. Rates of age-specific and -adjusted mortality were calculated for persons aged 35 and older during the years 1985 to 1991. Log-linear regression modeling was performed to estimate the average annual percentage change in mortality. During 1985 through 1991, the mortality for IHD and stroke was generally highest for African Americans, intermediate for non-Hispanic whites, and lowest for Hispanics. Age-adjusted mortality for IHD declined significantly in all sex-racial or -ethnic groups except African-American women, and stroke rates declined significantly in all groups except African-American and Hispanic men. African Americans had excess IHD mortality relative to non-Hispanic whites until late in life, after which mortality of non-Hispanic whites was higher. Similarly, African Americans and Hispanics had excess stroke mortality relative to non-Hispanic whites early in life, whereas stroke mortality in non-Hispanic whites was higher at older ages. The lower IHD and stroke mortality among Hispanics was paradoxical, given the generally adverse risk profile and socioeconomic status observed among Hispanics. An alarmingly high prevalence of self-reported cardiovascular disease risk factors in 1994 to 1996, particularly hypertension, leisure-time sedentary lifestyle, and obesity, is a serious public health concern, with implications for future trends in cardiovascular disease mortality. Of particular concern was the growing disparities in stroke and IHD mortality among younger-aged African Americans relative to Hispanics and non-Hispanic whites.

Impact of multiple risk factor profiles on determining cardiovascular disease risk

BACKGROUND

We examined the association between clustering of risk factors and the risk for coronary heart disease, stroke, and all-cause mortality.

METHODS

Data from the First National Health and Nutrition Examination Survey Epidemiologic Follow-Up Study (N = 12,932) were used to estimate the relative risk for coronary heart disease (N = 2,255), stroke (N = 929), and death from any cause (N = 4,506) by the number of cardiovascular disease risk factors present. Risk factors included current smoking, overweight, hypertension, high blood cholesterol, and diabetes.

RESULTS

The proportions of respondents with 0, 1, 2, 3, or > or = 4 risk factors were 25.0, 32.8, 27.8, 12.3, and 2.1%, respectively. Relative risks for coronary heart disease associated with having 1, 2, 3, and > or = 4 risk factors were 1.6 (95% confidence interval [CI] 1.4, 1.9), 2.2 (95% CI 1.9, 2.6), 3.1 (95% CI 2.6, 3.6), and 5.0 (95% CI 3.9, 6.3), respectively. Relative risks for stroke associated with the same risk levels were 1.4 (95% CI 1.1, 1.8), 1.9 (95% CI 1.5, 2.4), 2.3 (95% CI 1.7, 3.0), and 4.3 (95% CI 3.0, 6.3), respectively. Similar results were observed for all-cause mortality.

CONCLUSIONS

Risk for cardiovascular disease and all-cause mortality increased substantially with each additional risk factor. This supports the continued need for primary prevention of cardiovascular disease risk factors.

Social class and premature mortality among men: a method for state-based surveillance

OBJECTIVES

This study examined trends in mortality by social class for Black and White men aged 35 through 54 years in North Carolina, for 1984 through 1993, using an inexpensive, newly developed state-based surveillance method.

METHODS

Data from death certificates and census files permitted examination of four social classes, defined on the basis of occupation.

RESULTS

Premature mortality was inversely associated with social class for both Blacks and Whites. Blacks were at least twice as likely to die as Whites within each social class.

CONCLUSIONS

Adoption of state-specific surveillance of social class and premature mortality would provide data crucial for developing and evaluating public health programs to reduce social inequalities in health.

Pharmacologic management of heart failure among older adults by office-based physicians in the United States

BACKGROUND

Despite the recent availability of new classes of heart failure medications, little is known about national patterns in the actual physician utilization of these drugs.

METHODS

In the National Ambulatory Medical Care Survey, 2912 US physicians reported on 16,968 office visits in 1991-1992 with patients aged > or = 65 years. National estimates were obtained from weighted results that accounted for the complex sampling design.

RESULTS

An estimated 8.3 million (2.6%) office visits with older adults involved heart failure. This included 9.3% of visits to cardiologists, 4.3% to internists, 3.5% to general and family physicians, and 0.6% to other physicians. The most frequently prescribed medications during visits with these patients were diuretics (69%), digitalis compounds (46%), angiotensin-converting enzyme inhibitors (30%), and nitrates (19%). Internists and general and family physicians prescribed angiotensin-converting enzyme inhibitors, digitalis compounds, and loop diuretics for patients with heart failure less often than did cardiologists.

CONCLUSIONS

These are the first national surveillance estimates of physician practices in the management of heart failure. These data were collected during the same period in which heart failure clinical trial results were initially published, and they provide a baseline for monitoring the influence of recent clinical practice guidelines and professional education on changes in the management of heart failure by primary care physicians.

National trends in the initial hospitalization for heart failure

OBJECTIVES

Heart failure is a major health care burden among older adults, but information on recent trends has not been available. We compare rates, sociodemographic characteristics, and discharge outcomes of the initial hospitalization for heart failure in the Medicare populations of 1986 and 1993.

DESIGN

Information reported on the Medicare hospital claims record during initial hospitalization for heart failure was compared for patients aged 65 and older hospitalized in 1986 (N = 631,306) and those aged 65 and older hospitalized in 1993 (N = 803,506).

RESULTS

Age-standardized hospitalization rates (per 1000 person-years) for any diagnosis of heart failure were higher in 1993 than in 1986 (white: 24.6 vs 22.4, black: 26.1 vs 22.4, respectively). Age-specific results suggested an earlier onset of heart failure in black adults. In 1993, compared with 1986, higher proportions of heart failure patients were discharged to another care facility (white: 23.9% vs 16.8%, black: 17.6% vs 10.5%, respectively) or to health service care at home (white: 11.3% vs 6.0%, black: 12.4% vs 6.5%, respectively). In contrast, in-hospital mortality was lower in 1993 than in 1986 (white: 10.4% vs 13.3%, black: 8.9% vs 11.1%, respectively).

CONCLUSION

The increased numbers of hospitalizations for heart failure and the likelihood that these patients will require advanced nursing care after discharge have important implications for future national health care expenditures and resources.

Secular trends in ischemic heart disease mortality in California versus the United States, 1980 to 1991

We compare the recent trends in ischemic heart disease mortality in California and the United States. Because California was among the first states to have declines in ischemic heart disease mortality, an examination of these recent trends may provide important clues for upcoming national trends. Age-adjusted and -specific ischemic heart disease mortality rates were calculated by sex for persons aged 35 and older during the years 1980 to 1991. Log-linear regression modeling was used to estimate the average annual percentage change in mortality. Between 1980 and 1991, the annual age-adjusted ischemic heart disease mortality declined less in California than in the United States for both women (1.9% versus 3.1%) and men (3.1% versus 3.5%). In California, it increased slightly between 1986 and 1990 for the oldest women and men. The slower rates of decline in mortality of this disease in California compared with the United States and the rising rates among the most elderly Californians suggest that careful attention should be paid to these trends in death rates of and risk factors for this disease in California.

Social class and race disparities in premature stroke mortality among men in North Carolina

The purpose of this work was to examine the association between social class and premature stroke mortality among blacks and whites. For black men and white men in North Carolina, aged 35-54 years, mortality data from vital statistics files and population data from Census Public Use Microdata Sample files were matched according to social class for the years 1984-1993. Four categories of social class were defined based upon a two-dimensional classification scheme of occupations. For each category of social class, race-specific age-adjusted stroke mortality rates were calculated, and race-specific prevalences of income, wealth, education, unemployment, and disability were estimated. Women were excluded because comparable information on social class was not available from the mortality and population data sources. For both black men and white men, the highest rates of premature stroke mortality were observed among the lowest social classes. The rate ratios (RR) between the lowest and highest social class were 2.8 for black men and 2.3 for white men. Within each social class, black men had substantially higher rates of premature stroke mortality than white men (black-to-white RR ranged from 4.0 to 4.9). Among both black men and white men, the highest social class consistently had the most favorable levels of income, wealth, education, and employment. The inverse association between social class and stroke mortality for both black men and white men supports the need for stroke prevention efforts that address the structural inequalities in economic and social conditions.

Leisure-time physical activity among older adults. United States, 1990

OBJECTIVE

To investigate the prevalence and selected correlates of leisure-time physical activity in a nationally representative sample of persons aged 65 years or older.

METHODS

Data from 2783 older male and 5018 older female respondents to the 1990 National Health Interview Survey were used. Regular physical activity was defined as participation in leisure-time physical activities 3 times or more per week for 30 minutes or more during the previous 2 weeks. Odds ratios (ORs) were estimated from multivariate logistic regression analysis.

RESULTS

Prevalence of regular physical activity was 37% among older men and 24% among older women. Correlates of regular physical activity included the perception of excellent to good health (men: OR, 1.5; 95% confidence interval [CI], 1.1-1.9; women: OR, 1.6; 95% CI, 1.3-1.9), correct exercise knowledge (men: OR, 2.4; 95% CI, 1.9-3.1; women: OR, 2.7; 95% CI, 2.2-3.4), no activity limitations (men: OR, 1.3; 95% CI, 1.0-1.6; women: OR, 1.7; 95% CI, 1.4-2.0) and not perceiving "a lot" of stress during the previous 2 weeks (men: OR, 1.7; 95% CI, 1.2-2.4; women: OR, 1.3; 95% CI, 1.0-1.6). Among those who had been told at least twice that they had high blood pressure, physician's advice to exercise was associated with regular physical activity (men: OR, 1.6; 95% CI, 1.2-2.3; women: OR, 1.5; 95% CI, 1.2-1.9). The 2 major activities among active older adults were walking (men, 69%; women, 75%) and gardening (men, 45%; women, 35%).

CONCLUSIONS

Prevalence of regular physical activity is low among older Americans. Identifying the correlates of physical activity will help to formulate strategies to increase physical activity in this age group.

Serum folate and risk for ischemic stroke. First National Health and Nutrition Examination Survey epidemiologic follow-up study

BACKGROUND AND PURPOSE

A serum folate concentration < or = 9.2 nmol/L has been associated with elevated levels of plasma homocyst(e)ine. Elevated homocyst(e)ine levels have been associated with ischemic stroke in case-control studies; however, the results from prospective studies have been equivocal. We investigated whether a folate concentration < or = 9.2 nmol/L was associated with ischemic stroke in a national cohort.

METHODS

We used data from the First National Health and Nutrition Examination Survey Epidemiologic Follow-up Study (n = 2006). Cox proportional hazards analyses were used to adjust for differences in follow-up time and covariates. During the 13-year follow-up, 98 ischemic strokes occurred.

RESULTS

After adjusting for age, race, sex, education, diabetes, history of heart disease, systolic blood pressure, body mass index, hemoglobin level, cigarette smoking, and alcohol intake, participants with a folate concentration < or = 9.2 nmol/L were at slightly increased risk for ischemic stroke (relative risk [RR], 1.37; 95% confidence interval [CI], 0.82 to 2.29). There was a folate-race interaction (P = .11 for interaction term). Whites with a folate concentration < or = 9.2 nmol/L had a relative risk of 1.18 (95% CI, 0.67 to 2.08), whereas blacks had a relative risk of 3.60 (95% CI, 1.02 to 12.71).

CONCLUSIONS

These findings suggest that a folate concentration < or = 9.2 nmol/L may be a risk factor for ischemic stroke, especially in blacks. However, given the small number of stroke events, additional studies are needed to assess the role of folate in the epidemiology of ischemic stroke.

The shifting stroke belt. Changes in the geographic pattern of stroke mortality in the United States, 1962 to 1988

BACKGROUND AND PURPOSE

The factors that contribute to the Stroke Belt--a concentration of high stroke mortality rates in the southeastern United States--remain unidentified. Previous hypotheses that focused on physical properties of the area have not been confirmed. This study describes changes in the locations of areas with the highest rates of stroke mortality and the implications for new hypotheses regarding the Stroke Belt.

METHODS

We calculated annual, age-adjusted stroke mortality rates for black women, black men, white women, and white men for the years 1962 to 1988 using a three-piece log-linear regression model. Maps were produced with the state economic area (SEA) as the unit of analysis. The baseline Stroke Belt was defined as the area with the largest concentration of high-quintile SEAs in 1962.

RESULTS

The concentration of high-rate SEAs tended to shift away from the Piedmont region of the Southeast and toward the Mississippi River valley. For example, whereas among black women in 1962, 72% of SEAs in the baseline Stroke Belt were in the highest quintile, by 1988 this percentage had dropped to 48%. Similar patterns were observed for the other race/sex groups.

CONCLUSIONS

Temporal changes in the location of areas with the highest stroke mortality rates suggest that new hypotheses for understanding the geographic pattern of stroke mortality should consider temporal trends in a variety of medical, socioeconomic, and behavioral factors.

Race and sex differences in rates of invasive cardiac procedures in US hospitals. Data from the National Hospital Discharge Survey

BACKGROUND

Lower rates of invasive cardiac procedures have been reported for blacks and women than for white men. However, few studies have adjusted for differences in the type of hospital of admission, insurance status, and disease severity. SETTING, DESIGN, AND PARTICIPANTS: Data from the National Hospital Discharge Survey were used to investigate race and sex differences in rates of cardiac catheterization, percutaneous transluminal coronary angioplasty, and coronary artery bypass surgery among 10,348 persons hospitalized for acute myocardial infarction.

RESULTS

White men consistently had the highest procedure rates, followed by white women, black men, and black women. After matching for the hospital of admission and adjusting for age, in-hospital mortality, health insurance, and hospital transfer rates (with white men as the referent), the odds ratios for cardiac catheterization were 0.67 (95% confidence interval [CI], 0.51 to 0.87) for black men, 0.72 (95% CI, 0.63 to 0.83) for white women, and 0.50 (95% CI, 0.37 to 0.68) for black women. Similar race-sex differences were noted for percutaneous transluminal coronary angioplasty and coronary artery bypass surgery.

CONCLUSIONS

Race and sex differentials in the rates of invasive cardiac procedures remained despite matching for the hospital of admission and controlling for other factors that influence procedure rates, suggesting that the race and sex of the patient influence the use of these procedures.

Trends in survival after stroke among Medicare beneficiaries

BACKGROUND AND PURPOSE

Most strokes occur among people aged 65 years and older. The increasing proportion of persons who are in this age group underlines the importance for health-care providers to be aware of trends in poststroke survival. We investigated poststroke survival trends from 1985 to 1989 among Medicare beneficiaries.

METHODS

Medicare hospital claim records and enrollment data were obtained on 1 901 439 Medicare patients with a principal diagnosis of stroke occurring during the years 1985 through 1989. Cox proportional hazard techniques were used to compare the 2-year poststroke survival for strokes occurring in 1986, 1987, 1988, and 1989 relative to strokes occurring in 1985. Poststroke survival trends were examined among groups defined by age, race, region, type of stroke, and, for a 20% subset, history of stroke.

RESULTS

We observed a modest improvement in poststroke survival from 1985 to 1989 (1989:1985 hazard ratio, 0.96; P < .05). Trends for persons with hemorrhagic stroke showed more improvement (hazard ratio, 0.88; P < .05) than those for persons with ischemic stroke (hazard ratio, 0.98; P < .05). Improvement was also greater among persons without known prior hospitalization for stroke (hazard ratio, 0.94; P < .05) and during periods of follow-up shorter than 2 years.

CONCLUSIONS

The variations in poststroke survival among subgroups of the population have important implications for the quality of life of stroke survivors and for the future medical and nursing needs of these populations.

Trends in nonfatal coronary heart disease in the United States, 1980 through 1989

BACKGROUND

Although coronary heart disease mortality has been decreasing, little is known about trends in morbidity from coronary heart disease. We evaluated trends in nonfatal coronary heart disease in the United States during 1980 through 1989.

METHODS

We analyzed data from the National Health Interview Survey, an ongoing survey of representative samples of the civilian, noninstitutionalized population of the United States. Survey respondents were determined to have coronary heart disease if they reported ever having a myocardial infarction or heart attack, angina pectoris, or coronary heart disease. Incidence was defined as initial onset of a coronary heart disease condition during the year preceding the interview date.

RESULTS

About 6 million people were estimated to be living with coronary heart disease. The age-standardized prevalence was relatively constant at about 25 per 1000. Among white men, however, prevalence increased significantly over the 10-year period. Among 75- to 84-year-old men, prevalence increased from 100 per 1000 in 1980 to 179 per 1000 in 1989. Among men and women 45 to 54 years old, prevalence decreased. Overall, the incidence rate of nonfatal coronary heart disease was relatively flat (at about 3 per 1000 per year after 1983). Among white women, the incidence rate increased from 1.4 to 2.8 per 1000, and by the end of the decade it nearly equaled the incidence rate among white men.

CONCLUSIONS

Overall, the burden of nonfatal coronary heart disease remained fairly constant during the 1980s. The trends, however, were not uniform in all population groups. The apparent increasing incidence among women deserves continued monitoring. An encouraging trend is the decreasing prevalence in the younger age groups.

Saturation mutagenesis of a DNA region of bend. Base steps other than ApA influence the bend

A 60 base-pair region of a simian virus 40 DNA fragment was mutagenized to determine base-pairs that are critical for the fragment to bend. The site-directed mutagenesis saturated this region with all possible single base-pair substitutions. The mobility of each mutated fragment was measured by polyacrylamide electrophoresis at 4 degrees C and at 65 degrees C to assess the degree of bend. Four conclusions can be drawn. First, interruptions within the A tracts and changes in the phasing of the A tracts alter the degree of bend. Second, G tracts phased at a half-helical turn from an A tract are additive to the bend. Third, guanine residues in a nearest-neighbor contact with the A tracts modify the bend. Fourth, some mutations that do not obviously relate to the A tracts also alter the DNA bend and suggest clearly that base steps other than ApA are involved in sequence-directed DNA bends.

Guanine tracts enhance sequence directed DNA bends

Synthetic DNA fragments were constructed to determine the effect of G tracts, in conjunction with periodically spaced A tracts, on DNA bends. Relative length measurements showed that the G tracts spaced at the half helical turn enhanced the DNA bend. When the G tract was interrupted with a thymine or shortened to one or two guanines, the relative lengths decreased. If the G tract was replaced with either an A tract or a T tract, the bend was cancelled. Replacement with a C tract decreased the relative length to that of a thymine interruption suggesting that bend enhancement due to G tracts requires A tracts on the same strand.