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Biomedical subjects

M J Klag

Publications and source records attributed to M J Klag.

At least 37 records · Page 2Linked to original sources
PubMed1999

Body weight patterns from 20 to 49 years of age and subsequent risk for diabetes mellitus: the Johns Hopkins Precursors Study.

BACKGROUND: Obesity in middle age is a well-known risk factor for the development of type 2 diabetes mellitus. However, the importance of weight and weight gain at younger ages is less certain. OBJECTIVE: To determine the relationship of body weight patterns from 20 to 49 years of age with the subsequent risk for type 2 diabetes mellitus. SETTING: An ongoing longitudinal study of former medical students. PARTICIPANTS: Nine hundred sixteen white men without diabetes at 50 years of age. MEASUREMENTS: Weight and height measured in medical school, then assessed by mailed questionnaire to 49 years of age. MAIN OUTCOME: Incident type 2 diabetes mellitus based on physician self-report. RESULTS: During 14 255 person-years of follow-up, there were 35 incident cases of type 2 diabetes mellitus (2.5 per 1000 person-years). After simultaneous adjustment for age, physical activity, lifetime maternal history of diabetes, and smoking, body mass indexes (BMIs; calculated as weight in kilograms divided by the square of height in meters) at 25, 35, and 45 years of age were all strongly associated with diabetes risk (relative risks for overweight [BMI> or =25.0] vs. not overweight, >3.0; all Ps<.05), as were maximum and average BMI to 49 years of age. The relationship of BMI at 25 years of age to diabetes risk was substantially attenuated by adjustment for BMI at 45 years of age and average BMI, but was independent of weight change, weight variability, or maximum BMI. CONCLUSION: In men, overweight at 25 years of age strongly predicts diabetes risk in middle age, largely through its association with overweight at 45 years of age and high average BMI to 49 years of age.

Adult↗
PubMed1999

Plasma insulin levels and incidence of hypertension in African Americans and whites.

BACKGROUND: Hyperinsulinemia may play an important role in the pathogenesis of hypertension in whites but the role of hyperinsulinemia in hypertension in African Americans is controversial. SUBJECTS AND METHODS: We studied the relationship between insulin levels and subsequent incidence of hypertension in 140 African Americans and 237 whites who were initially screened for possible participation in the Trials of Hypertension Prevention, phase 1. Plasma insulin and serum glucose were measured at baseline and at a follow-up examination 7 years later. Blood pressure was measured by trained observers using a random-zero sphygmomanometer. Incident hypertension was defined as an average systolic pressure of 160 mm Hg or higher and/or diastolic pressure of 95 mm Hg or higher at a single visit and/or use of antihypertensive medication during follow-up. RESULTS: Over the 7 years of follow-up, the incidence of hypertension was 25.7% in the African Americans and 25.3% in the whites. Baseline plasma insulin and insulin-to-glucose ratio were associated with an increased risk of hypertension in both the African Americans and the whites. After adjustment for age, sex, race, body mass, heart rate, and alcohol consumption at baseline as well as intervention assignment in the Trials of Hypertension Prevention, phase 1, a 1-SD (21 pmol/mmol) difference in baseline insulin-to-glucose ratio was associated with a 2.77 (95% confidence interval, 1.48-5.19) odds ratio of hypertension in the African Americans and a 1.69 (95% confidence interval, 1.08-2.64) odds ratio in the whites. CONCLUSION: These results suggest that higher plasma insulin levels are associated with an increased risk of hypertension in both African Americans and whites.

Adult↗
PubMed1999

Body mass index in young men and the risk of subsequent knee and hip osteoarthritis.

PURPOSE: Obesity in middle age is associated with an increased risk of osteoarthritis of the knees in later life. We sought to determine whether body mass index in young men was a risk factor for the subsequent development of osteoarthritis of the knee and hip. SUBJECTS AND METHODS: Body mass index was assessed in 1,180 male medical students at age 23 +/- 2 (mean +/- SD) years and at several times during follow-up. The incidence of knee and hip osteoarthritis was ascertained by self-report and corroborated with information on symptoms and radiographic findings. RESULTS: During a median follow-up of 36 years, 62 participants developed knee osteoarthritis and 27 developed hip osteoarthritis. The incidence of knee, but not hip, osteoarthritis was strongly associated with body mass index assessed at ages 20 to 29 years and 30 to 39 years (both P <0.001). For body mass index assessed at ages 20 to 29 years, the incidence of knee osteoarthritis at age 65 years was 12.8% among the heaviest subjects (range 24.7 to 37.6 kg/m2), threefold greater than the incidence of 4.0% in the leanest (15.6 to 22.8 kg/m2) category of body mass index (P = 0.0001). Thus, for a man who was 180 cm (5'11") tall, each 8 kg (18 lb) greater weight at ages 20 to 29 years was associated with an increased risk of subsequent knee osteoarthritis (relative risk = 1.7, 95% confidence interval 1.3 to 2.1), after adjustment for year of birth, physical activity, and knee injury. Body mass index at ages 20 to 29 years was more predictive of future osteoarthritis than at ages 30 to 39 or 40 to 49 years. CONCLUSION: Greater body mass index in young men ages 20 to 29 years is associated with an increased risk of subsequent knee, but not hip, osteoarthritis, suggesting that cumulative exposure to greater weight during young adult life is an important cause of osteoarthritis.

Adult↗
PubMed1999

The renin-angiotensin system and blood pressure: differences between blacks and whites.

Although blacks have lower plasma renin activity compared to whites, the corresponding differences in serum angiotensin converting enzyme (ACE) levels have not been well studied. Furthermore, few studies have examined the relationship of renin activity and ACE levels to blood pressure (BP) in blacks. We addressed these questions in a cross-sectional study conducted in 110 blacks and 183 whites who were not on antihypertensive medications. Three BP readings were obtained during a clinic visit. Plasma renin activity was assayed by radioimmunoassay and serum ACE levels were measured by spectrophotometry. Mean systolic and diastolic BP were 122.6 and 77.9 mm Hg in the blacks, and 123.4 and 77.9 mm Hg in the whites, respectively. Plasma renin activity was significantly lower in the blacks compared to the whites (0.92 v 1.26 ng/mL/h, respectively, P < .05), but ACE levels were similar in both groups (28.8 v 29.6 U/L, respectively). Renin activity was significantly and inversely associated with systolic and diastolic BP in both the blacks and the whites. ACE levels, however, were inversely associated with BP in the blacks but positively associated with BP in the whites (P = .02 for interaction on diastolic BP), even after adjustment for age, gender, body mass index (BMI), alcohol consumption, and heart rate. The corresponding interaction between ACE level and race on systolic BP was of borderline significance (P = .06). These results suggest that levels of ACE are similar in blacks and whites but their association with BP is possibly reflecting underlying ethnic differences in regulation of BP.

Adult↗
PubMed1999

The effect of chronic coffee drinking on blood pressure: a meta-analysis of controlled clinical trials.

We sought to assess the effect of coffee consumption on blood pressure in humans. Our data sources included a MEDLINE search of the literature published before December 1997, bibliography review, and expert consultation. We selected controlled trials in which coffee consumption was the only difference between the intervention and control groups, mean blood pressure change was reported for each group or period, and treatment lasted for >24 hours. Of 36 studies initially identified, 11 (522 participants) met these inclusion criteria. Information on sample size, study design, participant characteristics (gender, race, age, baseline blood pressure, and antihypertensive medications), and treatment results were abstracted by 3 reviewers using a standardized protocol. Treatment effect of coffee consumption on blood pressure was estimated with the use of a random-effects model. In the 11 trials, median duration was 56 days (range, 14 to 79 days), and median dose of coffee was 5 cups/d. Systolic and diastolic blood pressure increased by 2.4 (range, 1.0 to 3.7) mm Hg and 1.2 (range, 0.4 to 2.1) mm Hg, respectively, with coffee treatment compared with control. Multiple linear regression analysis identified an independent, positive relationship between cups of coffee consumed and subsequent change in systolic blood pressure, independent of age of study participants and study design characteristics. The effect of coffee drinking on systolic and diastolic blood pressure was greater in trials with younger participants. Our findings provide support for a relationship between coffee consumption and higher blood pressure. Trials of coffee cessation of longer duration and in persons with hypertension should be performed.

Adolescent↗
PubMed1998

Aspirin and risk of hemorrhagic stroke: a meta-analysis of randomized controlled trials.

CONTEXT: Aspirin has been widely used to prevent myocardial infarction and ischemic stroke but some studies have suggested it increases risk of hemorrhagic stroke. OBJECTIVE: To estimate the risk of hemorrhagic stroke associated with aspirin treatment. DATA SOURCES: Studies were retrieved using MEDLINE (search terms, aspirin, cerebrovascular disorders, and stroke), bibliographies of the articles retrieved, and the authors' reference files. STUDY SELECTION: All trials published in English-language journals before July 1997 in which participants were randomized to aspirin or a control treatment for at least 1 month and in which the incidence of stroke subtype was reported. DATA EXTRACTION: Information on country of origin, sample size, duration, study design, aspirin dosage, participant characteristics, and outcomes was abstracted independently by 2 authors who used a standardized protocol. DATA SYNTHESIS: Data from 16 trials with 55462 participants and 108 hemorrhagic stroke cases were analyzed. The mean dosage of aspirin was 273 mg/d and mean duration of treatment was 37 months. Aspirin use was associated with an absolute risk reduction in myocardial infarction of 137 events per 10000 persons (95% confidence interval [CI], 107-167; P<.001) and in ischemic stroke, a reduction of 39 events per 10000 persons (95% CI, 17-61; P<.001). However, aspirin treatment was also associated with an absolute risk increase in hemorrhagic stroke of 12 events per 10000 persons (95% CI, 5-20; P<.001). This risk did not differ by participant or study design characteristics. CONCLUSIONS: These results indicate that aspirin therapy increases the risk of hemorrhagic stroke. However, the overall benefit of aspirin use on myocardial infarction and ischemic stroke may outweigh its adverse effects on risk of hemorrhagic stroke in most populations.

Aspirin↗
PubMed1998

Depression is a risk factor for coronary artery disease in men: the precursors study.

BACKGROUND: Several studies have found that depression is an independent predictor of poor outcome after the onset of clinical coronary artery disease. There are few data concerning depression as a risk factor for the development of coronary artery disease. OBJECTIVE: To determine if clinical depression is an independent risk factor for incident coronary artery disease. PATIENTS AND METHODS: The Johns Hopkins Precursors Study is a prospective, observational study of 1190 male medical students who were enrolled between 1948 and 1964 and who continued to be followed up. In medical school and through the follow-up period, information was collected on family history, health behaviors, and clinical depression. Cardiovascular disease end points have been assessed with reviews of annual questionnaires, National Death Index searches, medical records, death certificates, and autopsy reports. RESULTS: The cumulative incidence of clinical depression in the medical students at 40 years of follow-up was 12%. Men who developed clinical depression drank more coffee than those who did not but did not differ in terms of baseline blood pressure, serum cholesterol levels, smoking status, physical activity, obesity, or family history of coronary artery disease. In multivariate analysis, the men who reported clinical depression were at significantly greater risk for subsequent coronary heart disease (relative risk [RR], 2.12; 95% confidence interval [CI], 1.24-3.63) and myocardial infarction (RR, 2.12; 95% CI, 1.11-4.06). The increased risk associated with clinical depression was present even for myocardial infarctions occurring 10 years after the onset of the first depressive episode (RR, 2.1; 95% CI, 1.1-4.0). CONCLUSION: Clinical depression appears to be an independent risk factor for incident coronary artery disease for several decades after the onset of the clinical depression.

Aged↗
PubMed1998

Agreement among indicators of vitamin C status.

Agreement among three indicators of vitamin C status--serum ascorbate level, a 24-hour recall, and the frequency of fruit and vegetable consumption--was examined using data from the Second National Health and Nutrition Examination Survey conducted between 1976 and 1980. Agreement between pairs of these indicators was good when assessed at the group level but inconsistent at the individual level. These indicators, when classified as continuous measures, had moderately good agreement (r = 0.45-0.54), whereas agreement was poor when classified as quartiles (kappa = 0.17-0.23). Agreement between clinically based categories of serum ascorbate and total intake levels was poorer than expected (kappa = 0.25) as was agreement between low or deficient levels of both of these indicators (kappa = 0.3). Disagreement between low or deficient serum and intake levels was greater in participants who were younger, African American compared with white and other races, less educated, current smokers, nonsupplement users, and examined in the winter compared with in the summer or fall. These findings suggest that the indicators cannot be used interchangeably to assess vitamin C status because they distinguish between different aspects of status, intake level versus serum level, an indicator of available pool. Moreover, depending upon how these indicators are used in statistical analyses, they may classify individuals differently.

Adult↗
PubMed1998

Youthful precursors of midlife social support.

Measures of family stability, sociocultural background, and emotional ties to parents in medical students (N = 589, mean age = 22 years) predicted their social support measures, assessed 23 to 39 years later (mean age = 56 years). Father's education and family's involvement in church were positively associated with group participation (number of group memberships), whereas parental loss between the ages of 11 and 20 was negatively associated with group participation; perceived emotional closeness to parents was positively associated with social closeness (number of close contacts providing emotional and instrumental support). Thus, group participation and social closeness were influenced by distinctly different childhood factors.

Adult↗
PubMed1998

"U" curve association of blood pressure and mortality in hemodialysis patients. Medical Directors of Dialysis Clinic, Inc.

BACKGROUND: Hypertension may play an important role in the pathogenesis of the excess cardiovascular and cerebrovascular (CV) morbidity observed in hemodialysis patients (HD). However, the optimal blood pressure (BP) range for HD patients has not been defined. We postulated that there is a "U" curve relationship between BP and CV mortality. To explore this hypothesis we studied 5,433 HD patients in Dialysis Clinic Inc., a large not-for-profit chain, over a five year period. METHODS: Cox regression, with fixed and time-varying covariates, was used to assess the effect of systolic blood pressure (SBP) and diastolic blood pressure (DBP), pre- and post-dialysis, on CV mortality, while adjusting for age, gender, ethnicity, primary cause of end-stage renal disease, Kt/V, serum albumin, and antihypertensive medications. RESULTS: The overall impact of BP on CV mortality was modest. Pre-dialysis, neither systolic nor diastolic hypertension were associated with an increase in CV mortality. Post-dialysis, SBP > or = 180 mm Hg (RR = 1.96, P < 0.015) and DBP > or = 90 mm Hg (RR = 1.73, P < 0.05) were associated with increased CV mortality. Low SBP (SBP < 110 mm Hg) was associated with increased CV mortality, pre- and post-dialysis. CONCLUSIONS: The results suggest the presence of a "U" curve relationship between SBP post-dialysis and CV mortality in HD patients.

Adult↗
PubMed1998

Lack of familial clustering of hepatitis C virus infection.

BACKGROUND: Although transmission of hepatitis C virus (HCV) through parental exposure is well documented, it is still controversial whether familial clustering of HCV occurs. METHODS: To investigate risk factors for HCV infection, 109 cases and 84 non-infected controls were studied. In addition, 250 family members (104 men, 146 women) of cases and 170 family members of controls (64 men, 106 women) were tested for HCV infection using an anti-HCV antibody, alanine aminotransferase (ALT), and reverse transcribed polymerase chain reaction (RT-PCR). RESULTS: In the case-control analysis, people aged > or =60 were almost three times more likely to be infected by HCV than those aged <40. Risk of HCV infection was most strongly related to a history of blood transfusion (OR = 12.6, 95% CI: 4.3-36.5) followed by a history of jaundice (OR = 4.1, 95% CI: 1.3-12.6). Only one family member of cases and no-one related to the controls had HCV infection. CONCLUSIONS: These results suggest that, in Korea, age and parenteral exposure, such as a blood transfusion, are risk factors for HCV infection and familial clustering of HCV infection, if it occurs, is rare.

Adult↗
PubMed1998

Seven-year incidence of hypertension in a cohort of middle-aged African Americans and whites.

Many studies have suggested that African Americans have a higher prevalence of hypertension than whites. The authors conducted a prospective study of hypertension incidence from 1987-1988 to 1994-1995 in 140 African American and 237 white adults aged 30 to 54 years at baseline. The study participants were screened for participation in the Trials of Hypertension Prevention, phase 1, an 18-month lifestyle modification intervention trial aimed at lowering blood pressure, at the Baltimore Clinical Center. Baseline age, blood pressure, body mass index, and heart rate were similar in the two groups. Compared with whites, however, African Americans had a lower percentage of men, college graduates, and households with an income > or = $40,000 per year. African Americans also had lower mean urinary sodium to creatinine ratio and potassium to creatinine ratio, but a similar sodium to potassium ratio. The incidence of hypertension (blood pressure > or = 160/95 mm Hg and/or taking antihypertensive medication) over 7 years of follow-up was nearly identical: 25.7% in African Americans and 25.3% in whites. Baseline age, gender, blood pressure, and heart rate were all associated with the incidence of hypertension. Even after adjustment for these covariables, the risk of hypertension was not higher in African Americans compared with whites. These results indicate that middle-aged African Americans and whites have a similar risk of developing hypertension given the same age, initial blood pressure, and body mass index at baseline.

Adult↗
PubMed1998

Familial aggregation of renal disease in a population-based case-control study.

Family history of renal disease has been associated with an increased risk of end-stage renal disease (ESRD). It is uncertain whether this risk is mediated by familial aggregation of risk factors for ESRD, such as diabetes and hypertension. The association of ESRD with familial aggregation of renal disease was examined in a large, population-based case-control study conducted in Maryland, Virginia, West Virginia, and Washington, DC. The number of first-degree relatives who were affected with any type of renal disease was compared between 689 newly treated ESRD patients registered in the Medicare ESRD program (92% of all eligible incident cases presenting between January and July of 1991) and 361 control subjects without ESRD who were selected by random-digit dialing (90% response rate). Patients and control subjects were frequency matched by age; patients with ESRD caused by polycystic kidney disease and other known hereditary kidney diseases were excluded. Analysis was conducted using multiple logistic regression. After controlling for the proband's age, gender, race, family size, socioeconomic status, and personal and family histories of diabetes and hypertension, having one first-degree relative with renal disease increased the odds of ESRD by 1.3 (95% confidence interval, 0.7 to 2.6) and having two or more affected first-degree relatives increased the odds of ESRD by 10.4 (95% confidence interval, 2.7 to 40.2). These data support familial aggregation of renal disease in excess of that predicted by clustering of diabetes and hypertension within families, suggesting that either genetic susceptibility or environmental exposures shared within families increase the risk of developing ESRD. This risk is also much higher when two or more first-degree relatives have renal disease. Unraveling the molecular basis of this increase in risk may provide new avenues for treatment and prevention of ESRD.

Adult↗
PubMed1998

Epidemiology of cardiovascular risk factors in chronic renal disease.

Treatment and prevention of cardiovascular disease in the general population has benefited greatly from the identification of cardiovascular disease risk factors. Given the particularly high risk of cardiovascular disease and total mortality among patients with chronic renal insufficiency (CRI) and end-stage renal disease (ESRD), it is important to assess the role of traditional and nontraditional risk factors for cardiovascular disease. This review discusses the foundations of risk factor epidemiology and briefly summarizes the evidence regarding cardiovascular risk factors in renal disease. Diabetes and hypertension have a very high prevalence in patients with CRI. Patients with CRI and ESRD also have a higher frequency of cardiac dysfunction and left ventricular hypertrophy, which further increase the risk of cardiovascular disease. Finally, patients with renal disease have a higher prevalence of less established risk factors, including low HDL, and high triglycerides, lipoprotein(a), and homocysteine, where prospective studies and clinical trials are needed to provide a scientific basis for reduction of cardiovascular risk among patients with renal disease.

Cardiovascular Diseases↗
PubMed1997

Risk of end-stage renal disease in diabetes mellitus: a prospective cohort study of men screened for MRFIT. Multiple Risk Factor Intervention Trial.

CONTEXT: Diabetes is a frequent cause of end-stage renal disease (ESRD). However, the degree of risk is uncertain. OBJECTIVE: To determine the relative risk (RR) of ESRD related to diabetes in the United States. DESIGN: Nonconcurrent prospective cohort study. PARTICIPANTS: A total of 332544 men aged 35 to 57 years from 18 US cities screened in 1973 to 1975 for participation in the Multiple Risk Factor Intervention Trial (MRFIT). MAIN EXPOSURE: Diabetes mellitus defined by self-reported use of medication for diabetes at baseline. MAIN OUTCOME: Incident ESRD through 1990 assessed from a national ESRD registry and by surveillance for death from renal disease. RESULTS: Over an average follow-up of 16 years, there were 136 cases of ESRD in 5147 diabetic men and 678 cases in 327397 nondiabetic men. Age-adjusted incidence of all-cause ESRD in the diabetic men was 199.8 per 100000 person-years compared with 13.7 per 100000 person years in their nondiabetic counterparts (RR, 12.7; 95% confidence interval [CI], 10.5-15.4). Diabetic men were also at higher risk for ESRD ascribed to causes other than diabetes (RR=4.3; 95% CI, 3.2-5.9). With simultaneous adjustment for age, ethnicity, income, blood pressure, serum cholesterol level, and history of myocardial infarction, diabetic men remained at higher risk for all-cause ESRD (RR, 9.0; 95% CI, 7.4-11.0), ESRD ascribed to diabetes (RR, 92.3; 95% CI, 64.6-131.9), and ESRD ascribed to nondiabetic causes (RR, 3.0; 95% CI, 2.2-4.1). CONCLUSIONS: Diabetes mellitus is a strong independent risk factor for ESRD, even for ESRD ascribed to causes other than diabetes. Improvements in the prevention and control of diabetes should produce substantial reductions in ESRD incidence.

Adult↗
PubMed1997

Insomnia in young men and subsequent depression. The Johns Hopkins Precursors Study.

The Johns Hopkins Precursors Study, a long-term prospective study, was used to study the relation between self-reported sleep disturbances and subsequent clinical depression and psychiatric distress. A total of 1,053 men provided information on sleep habits during medical school at The Johns Hopkins University (classes of 1948-1964) and have been followed since graduation. During a median follow-up period of 34 years (range 1-45), 101 men developed clinical depression (cumulative incidence at 40 years, 12.2%), including 13 suicides. In Cox proportional hazards analysis adjusted for age at graduation, class year, parental history of clinical depression, coffee drinking, and measures of temperament, the relative risk of clinical depression was greater in those who reported insomnia in medical school (relative risk (RR) 2.0, 95% confidence interval (CI) 1.2-3.3) compared with those who did not and greater in those with difficulty sleeping under stress in medical school (RR 1.8, 95% CI 1.2-2.7) compared with those who did not report difficulty. There were weaker associations for those who reported poor quality of sleep (RR 1.6, 95% CI 0.9-2.9) and sleep duration of 7 hours or less (RR 1.5, 95% CI 0.9-2.3) with development of clinical depression. Similar associations were observed between reports of sleep disturbances in medical school and psychiatric distress assessed in 1988 by the General Health Questionnaire. These findings suggest that insomnia in young men is indicative of a greater risk for subsequent clinical depression and psychiatric distress that persists for at least 30 years.

Adult↗