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Biomedical subjects

M J Klag

Publications and source records attributed to M J Klag.

At least 73 records · Page 4Linked to original sources

Lack of blood pressure effect with calcium and magnesium supplementation in adults with high-normal blood pressure. Results from Phase I of the Trials of Hypertension Prevention (TOHP). Trials of Hypertension Prevention (TOHP) Collaborative Research Group.

Phase I of the Trials of Hypertension Prevention (TOHP) was a randomized, multicenter investigation that included double-blind, placebo-controlled testing of calcium and magnesium supplementation among 698 healthy adults (10.5% blacks and 31% women) aged 30 to 54 years with high-normal diastolic blood pressure (DBP) (80 to 89 mm Hg). Very high compliance (94 to 96% by pill counts) with daily doses of 1 g of calcium (carbonate), 360 mg of magnesium (diglycine), or placebos was corroborated for the active supplements by significant net increases in all urine and serum compliance measures in white men and for urine compliance measures in white women. Overall, neither calcium nor magnesium produced significant changes in blood pressure at 3 and 6 months. Analyses stratified by baseline intakes of calcium, magnesium, sodium, or initial blood pressures also showed no effect of supplementation. These analyses suggested that calcium supplementation may have resulted in a DBP decrease in white women and that response modifiers in this subgroup might have included lower initial urinary calcium levels, urinary sodium levels, or lower body mass index. However, overall analyses indicated that calcium and magnesium supplements are unlikely to lower blood pressure in adults with high-normal DBP. The subgroup analyses, useful to formulate hypotheses, raise the possibility of a benefit to white women, which requires testing in future trials.

Administration, Oral↗

Oats and buckwheat intakes and cardiovascular disease risk factors in an ethnic minority of China.

The relationship of oats and buckwheat intake to cardiovascular disease risk factors was studied in 850 Yi people, an ethnic minority in southwest China. Blood pressure was measured on 3 consecutive days. Serum total cholesterol, high-density-lipoprotein (HDL) cholesterol, and triglycerides were measured after a 14-h fast. Oats and buckwheat intakes were assessed by questionnaire. In multiple-regression analysis, oats intake (100 g/d) was associated with lower body mass index (-0.25, in kg/m2; P < 0.05), systolic (-3.1 mm Hg, P < 0.001) and diastolic (-1.3 mm Hg, P < 0.01) blood pressure, and HDL cholesterol (-0.13 mmol/L, P < 0.001). Buckwheat intake (100 g/d) was associated with lower serum total cholesterol (-0.07 mmol/L, P < 0.01) and low-density-lipoprotein cholesterol (-0.06 mmol/L, P < 0.05) and a higher ratio of HDL to total cholesterol (0.01, P < 0.05). These findings suggest a role for oats and buckwheat consumption in the prevention and treatment of both hypertension and hypercholesterolemia.

Adolescent↗

Dietary macronutrients and blood pressure in southwestern China.

OBJECTIVES: To study the relationship between dietary macronutrients and blood pressure. DESIGN: A cross-sectional study. SETTING: Liangshan, southwestern China. PARTICIPANTS: Three hundred and twelve Yi farmers living in a remote mountainous area, and 264 Yi migrants and 251 Han people living in an urban setting. MAIN OUTCOME MEASUREMENTS: Blood pressure and dietary nutrient intake, obtained by asking the subjects to recall their nutrient consumption during the previous 24 h, were measured on three consecutive days. RESULTS: After adjusting for age, body mass index, alcohol use, urinary excretion of sodium, total energy intake and area of residence and after correcting for the effects of regression dilution bias, a 1 SD higher intake of dietary total protein (39 g) was associated with lower systolic (-3.55 mmHg), and diastolic (-2.16 mmHg) blood pressures. Likewise, a 1 SD higher fiber intake (10 g) was significantly associated both with a lower systolic (-2.20 mmHg) and with a lower diastolic (-2.08 mmHg) blood pressure. CONCLUSION: Diets higher in protein and fiber content are associated with a lower blood pressure in the present population sample. The present results indicate that dietary intake of macronutrients might be important in the development and prevention of high blood pressure.

Adult↗

Race and socioeconomic status in hypertension and renal disease.

Publications within the past year have added to our understanding of the relationships between race, socioeconomic status, hypertension, and renal disease. The catalog of racial differences in hypertension and renal disease has been enriched on several accounts. Some of these differences can be explained by specific intervening variables, but others remain attributed to race itself. Unfortunately, what 'race' actually represents is still subject to debate. This debate should be encouraged, because the lack of a clear concept of race hinders research in this area. The main new finding of the year may be a confirmation by several studies that low socioeconomic status is an independent risk factor for end-stage renal disease, regardless of race. Research explaining the mechanisms by which poverty affects the risk of kidney failure is urgently needed, as some of these mechanisms may lend themselves to preventive intervention. Interventions aimed at improving the serious socioeconomic consequences of treated end-stage renal disease are also receiving increasing attention, and have been shown to improve patient outcomes.

Humans↗

Stroke in the People's Republic of China. I. Geographic variations in incidence and risk factors.

BACKGROUND AND PURPOSE: Stroke is a major cause of death in the People's Republic of China (PRC), and the geographic distribution of stroke death varies substantially. We conducted an ecological analysis to investigate the relationship of prevalence of hypertension and other risk factors with stroke incidence and mortality in the PRC. METHODS: The relationship between prevalence of risk factors and stroke incidence and mortality in the PRC was assessed in 29 provinces by examining risk factor data from PRC national surveys and incidence and mortality from the 1986 PRC National Stroke Study. RESULTS: A highly statistically significant correlation between prevalence of hypertension and stroke incidence (r = .838, P < .001) and mortality (r = .841, P < .001) was observed. Prevalence of hypertension explained over 70% of the geographic variability in stroke incidence (partial R2 = .703) and mortality (partial R2 = .707) in the PRC. There was a north-south gradient, with a higher prevalence of hypertension and stroke incidence and mortality in the north compared with the south of the country. In multiple Poisson regression analysis, a 10% increase in the prevalence of hypertension was associated with a 2.80-fold higher incidence and 2.68-fold higher mortality from stroke, whereas a 10% increase in the prevalence of alcohol consumption was associated with a 29% higher incidence and a 16% higher mortality from stroke. A 10% increase in the prevalence of cigarette smoking was associated with a 19% higher mortality from stroke. CONCLUSIONS: In the PRC, the prevalence of hypertension is strongly associated with the risk of stroke, and the geographic variation in stroke incidence and mortality is due mainly to differences in the prevalence of hypertension.

Adolescent↗

Stroke in the People's Republic of China. II. Meta-analysis of hypertension and risk of stroke.

BACKGROUND AND PURPOSE: In the People's Republic of China (PRC), stroke accounts for over 1 million deaths per year, more than three times the number of deaths from ischemic heart disease. To quantify the effect of hypertension on stroke in the PRC, we conducted a meta-analysis and estimated the population attributable risk of stroke due to hypertension. METHODS: We searched the Chinese Medical Literature Index and MEDLINE databases to identify studies on the relationship between hypertension and stroke conducted in the PRC. The overall relative risk of stroke in hypertensive persons and the population attributable risk of stroke due to hypertension were calculated by pooling the risk estimates from individual studies. RESULTS: A total of 12 epidemiological studies with 2379 stroke cases was identified. The overall relative risk of stroke associated with hypertension was 5.43 (95% confidence interval [CI], 4.62 to 6.39). The relative risk was similar for hemorrhagic (5.44; 95% CI, 3.99 to 7.40) and ischemic (5.25; 95% CI, 3.95 to 6.98) stroke. On the basis of data from the 1990 PRC population census, vital statistics, and the 1991 PRC National Hypertension Survey, the excess annual mortality from stroke due to hypertension was estimated to be at least 545,000 deaths, with a population attributable risk of 49.5%. CONCLUSIONS: Our data suggest that hypertension is an important risk factor for stroke in the PRC and that hypertension may account for about half of all deaths from stroke in that country. Treatment and prevention of hypertension should be an important societal goal in the PRC.

Adult↗

The psychosocial work environment of physicians. The impact of demands and resources on job dissatisfaction and psychiatric distress in a longitudinal study of Johns Hopkins Medical School graduates.

This study examines the relationship between the psychosocial work environment and cross-sectional job dissatisfaction and prospective psychiatric distress in a cohort of Hopkins Medical School graduates in midcareer. An instrument was constructed consisting of five scales: psychological job demands, patient demands, work control, physician resources, and coworker support. The results of scale reliability and factor analysis are presented. Higher job demands were found to be associated with increases in job dissatisfaction and psychiatric distress and greater resources were associated with decreased levels of dissatisfaction and distress. In multiple-regression analysis, only work control and social support were found to be independently associated with dissatisfaction and distress. These results suggest that the presence of control and social support at work protects physicians from developing job dissatisfaction and psychiatric distress.

Adult↗

Risk of kidney failure associated with the use of acetaminophen, aspirin, and nonsteroidal antiinflammatory drugs.

BACKGROUND: People who take analgesic drugs frequently may be at increased risk of end-stage renal disease (ESRD), but the extent of this risk remains unclear. METHODS: We studied 716 patients treated for ESRD and 361 control subjects of similar age from Maryland, Virginia, West Virginia, and Washington, D.C. The study participants were interviewed by telephone about their past use of medications containing acetaminophen, aspirin, and other nonsteroidal antiinflammatory drugs (NSAIDs). For each analgesic drug, the average use (in pills per year) and the cumulative intake (in pills) were examined for any association with ESRD. RESULTS: Heavier acetaminophen use was associated with an increased risk of ESRD in a dose-dependent fashion. When persons who took an average of 0 to 104 pills per year were used for reference, the odds ratio of ESRD was 1.4 (95 percent confidence interval, 0.8 to 2.4) for those who took 105 to 365 pills per year and 2.1 (95 percent confidence interval, 1.1 to 3.7) for those who took 366 or more pills per year, after adjustment for race, sex, age, and intake of other analgesic drugs. When persons who had taken fewer than 1000 pills containing acetaminophen in their lifetime were used for reference, the odds ratio was 2.0 (95 percent confidence interval, 1.3 to 3.2) for those who had taken 1000 to 4999 pills and 2.4 (95 percent confidence interval, 1.2 to 4.8) for those who had taken 5000 or more pills. Approximately 8 to 10 percent of the overall incidence of ESRD was attributable to acetaminophen use. A cumulative dose of 5000 or more pills containing NSAIDs was also associated with an increased odds of ESRD (odds ratio, 8.8), but the use of aspirin was not. CONCLUSIONS: People who often take acetaminophen or NSAIDs have an increased risk of ESRD, but not those who often take aspirin.

Acetaminophen↗

End-stage renal disease attributable to diabetes mellitus.

OBJECTIVE: To determine the proportion of end-stage renal disease associated with diabetes mellitus in a biracial population, using population-attributable risk estimates. DESIGN: Case-control study. SETTING: Population-based study in Maryland, Virginia, West Virginia, and Washington, D.C. PARTICIPANTS: 716 newly treated patients with kidney failure aged 20 to 64 years and 361 age-matched controls. MEASUREMENTS: Self-reported history of diabetes mellitus, including type, duration, treatment, and complications. RESULTS: Persons with insulin-dependent diabetes (odds ratio, 33.7) and non-insulin-dependent diabetes (odds ratio, 7.0) were at greater risk for end-stage renal disease than were persons without diabetes. The odds ratio was only slightly increased for diabetes lasting less than 15 years, but the ratio increased more than 20-fold for diabetes lasting 15 years or more. The population-attributable risk for kidney failure was 21% for insulin-dependent diabetes and 21% for non-insulin-dependent diabetes (42% overall). A similar proportion of end-stage renal disease was attributed to diabetes in whites (44%) and in blacks (41%). Insulin-dependent diabetes had a relatively greater effect on the incidence of kidney failure in whites; in contrast, non-insulin-dependent diabetes had a relatively greater effect on kidney failure in blacks. CONCLUSIONS: Diabetes mellitus has a major effect on the incidence of end-stage renal disease in nonelderly adults. In black persons, diabetes may be responsible for a larger proportion of end-stage renal disease than is suggested by the use of clinical diagnoses of underlying renal disease made by patients' nephrologists. Prevention of end-stage renal disease associated with diabetes mellitus (both insulin-dependent and non-insulin-dependent diabetes) requires increased attention from laboratory and clinical researchers.

Adult↗

Short- and long-term prognosis after acute myocardial infarction in Chinese men and women.

Most, but not all, studies in Western countries have indicated that women have a higher mortality than men after an acute myocardial infarction, but this has not been well documented in the developing world. The authors studied 601 male and 294 female myocardial infarction patients, aged 26-94 years, admitted to a city hospital in Beijing, China, between 1974 and 1986. A total of 745 (98.8%) of the cohort of 754 who survived past their initial hospitalization were followed up in 1988. Compared with their male counterparts, female myocardial infarction patients were older (63.4 vs. 58.1 years) and had a higher prevalence of tachycardia (heart rate, > or = 110 beats/minute), rales, New York Heart Association class III or IV, and heart block, but a lower prevalence of smoking and white collar occupation (all p < 0.01). The mortality within 28 days of their myocardial infarction was higher in women than in men, mainly in the group whose age was less than 60 years (20.4% vs. 7.1%, p < 0.001). The greater risk of short-term mortality in women persisted even after adjustment for age, history of stroke and hypertension, tachycardia on admission, anterior infarction, Killip class III or IV, and arrhythmia (relative odds = 1.74, 95% confidence interval 1.17-2.60). The 10-year total cumulative mortality in persons who survived the first 28 days following their myocardial infarction was 51.1% for women and 35.9% for men (log rank p = 0.002). After adjustment for age, this difference was not statistically significant (p = 0.3). Our results suggest that, in Beijing, women have a higher short-term mortality after myocardial infarction compared with men.

Adult↗

Body mass and blood pressure in a lean population in southwestern China.

Body mass has been consistently associated with blood pressure in acculturated populations but not in lean populations with low blood pressures. In southwestern China, in 1989, the authors studied the relation between body mass and blood pressure in three community-based random samples: rural Yi farmers (5,023 men, 3,218 women); Yi migrants (1,656 men, 919 women); and Han Chinese living in an urban setting (2,173 men, 1,516 women). The Yi farmers had virtually no obesity or hypertension and had little rise in blood pressure with age. The Yi migrants and Han had a steeper slope of blood pressure with age and consequently more hypertension. For men and women, respectively, mean body mass index (weight (kg)/height (m)2) was 20.6 and 21.0 in the Yi farmers, 21.3 and 21.4 in the Yi migrants, and 21.0 and 21.4 in the Han. Both systolic and diastolic blood pressure were positively related to body mass index in all six ethnicity-sex groups, and the association remained statistically significant after adjustment for age, heart rate, smoking, alcohol intake, and physical activity. The change in mean blood pressure for each kg/m2 increase in body mass index, after adjustment for community of residence, was 1.47 mmHg for systolic pressure and 1.13 mmHg for diastolic pressure. The association between body mass index and blood pressure was greater in men than in women and greater in Yi migrants and Han than in Yi farmers. The percentages of hypertension attributable to overweight (body mass index > or = 25) among the Yi farmers, Yi migrants, and Han, respectively, were 4.1%, 34.1%, and 24.0% for men and 0%, 26.2%, and 28.9% for women. Thus, even in this lean Chinese population with a low mean blood pressure, body mass was positively and independently associated with increased blood pressure.

Adolescent↗

Temperament as a potential predictor of mortality: evidence from a 41-year prospective study.

Psychological factors were hypothesized to influence mortality, in particular, early versus later mortality. To explore the relationship between temperament, a psychological factor, and mortality in a prospective study of 1337 medical students, we constructed a measure portraying three temperament types, using latent class analysis. Death occurred in 113 subjects over 25-41 years of follow-up. In univariate survival analysis, subjects tending to direct tension "inward" when under stress ("Tension-In") had a higher risk of mortality than "Tension-Out" or "Stable" types. These associations persisted after adjustment for age, smoking, cholesterol level, and Quetelet Index. The relative risk (RR) of mortality for Tension-In was 1.56 (95% confidence interval, 1.00-2.44) compared with the Stable group. The risk was due entirely to the excess risk in persons under 55 years of age (RR, 2.59; 95% confidence interval, 1.46-4.62); the corresponding risk of death in older persons was 0.66 (0.30-1.48). Thus temperament is a significant risk factor for mortality, in particular, premature death.

Adult↗

Coffee intake and coronary heart disease.

We examined the risk of coronary heart disease (CHD) associated with coffee intake in 1040 male medical students followed for 28 to 44 years. During the follow-up, CHD developed in 111 men. The relative risks (95% confidence interval) associated with drinking 5 cups of coffee/d were 2.94 (1.27, 6.81) for baseline, 5.52 (1.31, 23.18) for average, and 1.95 (0.86, 4.40) for most recent intake after adjustment for baseline age, serum cholesterol levels, calendar time, and the time-dependent covariates number of cigarettes, body mass index, and incident hypertension and diabetes. Risks were elevated in both smokers and nonsmokers and were stronger for myocardial infarction. Most of the excess risk was associated with coffee drinking prior to 1975. The diagnosis of hypertension was associated with a subsequent reduction in coffee intake. Negative results in some studies may be due to the assessment of coffee intake later in life or to differences in methods of coffee preparation between study populations or over calendar time.

Adult↗

Serum antioxidants and myocardial infarction. Are low levels of carotenoids and alpha-tocopherol risk factors for myocardial infarction?

BACKGROUND: In vitro, animal and epidemiological studies suggest that lipoprotein oxidation may play an important role in atherosclerosis. Antioxidants may protect against lipoprotein oxidation and in that way inhibit atherosclerosis and its clinical sequelae. To investigate this possibility, we examined the association between levels of several antioxidants and myocardial infarction using serum specimens collected 7 to 14 years before the onset of myocardial infarction. METHODS AND RESULTS: A nested case-control design was used. Cases and control subjects were selected from the 25,802 persons who had donated 15 mL of blood in 1974 for a serum bank. Cases comprised 123 persons with a subsequent first diagnosis of myocardial infarction who ranged from 23 through 58 years of age in 1974 and who had had their first diagnosis of myocardial infarction during 1981 to 1988. Two groups of control subjects matched to the cases for sex and age were selected from donors to the serum bank, one from those with hospital admissions during the same period and the other from the total group of donors. Sera were assayed for four carotenoids (beta-carotene, lycopene, lutein, and zeaxanthin), alpha-tocopherol, and cholesterol. Because associations with these serum nutrients showed similar trends whether based on hospital or community controls, the two control groups were combined. There was a significantly increasing risk for subsequent myocardial infarction with decreasing levels of beta-carotene in 1974 (P value for trend, .02) and a suggestive trend with decreasing levels of lutein (P = .09). When the results were stratified by smoking status, the excess risk of myocardial infarction associated with low serum levels of carotenoids was limited to smokers. A protective association with higher levels of alpha-tocopherol was suggested only among persons with high levels of serum cholesterol. CONCLUSIONS: Low serum levels of carotenoids were associated with an increased risk of subsequent myocardial infarction among smokers.

Adult↗

HDL cholesterol and mortality in Finnish men with special reference to alcohol intake.

BACKGROUND: There is substantial evidence that a low serum level of HDL cholesterol (HDLC) is a risk factor for coronary deaths. However, data on older people are scarce, and previous studies have not examined this association in relation to alcohol intake. METHODS AND RESULTS: Coronary mortality, all-cause mortality, and mortality due to alcohol and violence were related to HDLC levels among 7052 male smokers 50 to 69 years old in south and west Finland enrolled from 1984 to 1988 in the ATBC (AT, alpha-tocopherol; BC, beta-carotene) Study placebo group. During the average follow-up period of 4.7 years, 620 men died; 222 of these deaths were from coronary heart disease and 82 from causes related alcohol and violence. HDLC levels were inversely associated with coronary mortality, irrespective of age, whereas high total cholesterol was positively associated with coronary mortality among the younger men, 50 to 59 years of age, but not among the older men, 60 to 69 years old. Correction for temporal variation in HDLC measurement indicated a 43% stronger inverse association between HDLC and coronary mortality compared with that based only on a single value. The inverse association of HDLC and coronary mortality was less marked at higher levels of alcohol intake. All-cause and alcohol- and violence-related mortality were positively associated with HDLC among the younger men. All-cause mortality showed a U-shaped dose response among men > or = 60 years old. CONCLUSIONS: Previous studies may have underestimated the beneficial effect of high HDLC because of regression-dilution bias and the confounding effect of heavy alcohol intake. This study supports the view that, particularly among older men, lipoprotein fractions may be more appropriate for screening than total cholesterol.

Aged↗

Physician knowledge of the CAGE alcohol screening questions and its impact on practice.

A cross-sectional survey of physicians (n = 301) and patients (n = 321) at a university-based department of medicine was completed to determine physician's ability to list CAGE alcohol screening questions and how this knowledge is associated with practice patterns. Forty-five percent of the physicians had heard of the CAGE, but only 14% could list all four of the questions correctly. Physicians who knew the CAGE were more likely to report counseling and referral of their patients who abuse alcohol. However, as assessed by patient interview and chart review, patients with an alcohol abuse problem were no more likely to have been recognized by or to have received more aggressive care from residents who knew the CAGE than patients cared for by residents who did not know the CAGE. Knowledge of an alcohol screening test is not sufficient to change physician practice related to care of patients with an alcohol abuse problem. More attention must be directed towards the development of effective strategies which integrate into clinical practice screening and initial treatment of patients who abuse alcohol.

Adult↗

Effectiveness of the Waksberg telephone sampling method for the selection of population controls.

The effectiveness of the Waksberg telephone sampling method and practical aspects of its implementation were evaluated during the selection of control subjects for a population-based case-control study conducted in Maryland, Virginia, West Virginia, and Washington, DC, in 1991. The first stage of the two-stage sampling procedure was equivalent to simple random sampling. Each telephone number selected was dialed up to 13 times to establish the type of connection. Residential connections were used to generate additional telephone numbers in the second stage by changing the last two digits. Overall, 3,860 telephone numbers yielded 1,311 residences. The proportion of residences was higher in the second stage (54%) than in the first (11%), while that of numbers "not in service" was lower (12% vs. 67%, respectively). Fewer calls (8,735) were made than would have been required by a simple random sampling procedure (up to 18,522). The geographic distribution of residences was similar at both stages of sampling. At the end of enrollment, each sampling unit had yielded 9.8 residences, but only 64% reached 9-11 residences. Compliance rates were 96% for screening (1,259 of 1,311 residences), 90% for interviewing (362 of 403), and 86% overall. Relative to simple random sampling, the Waksberg method considerably reduced the total number of telephone calls, but the sampling process was more complex to manage. This method is particularly suitable for selecting population controls when the density of residential connections is low and variables of interest are not homogeneous within sampling units. Random digit dialing remains an effective method for selecting population controls.

Data Collection↗

Plasma lipoprotein levels as predictors of cardiovascular death in women.

BACKGROUND: The association of lipoprotein levels with cardiovascular disease (CVD) is less well understood in women than in men. To better characterize any relationships, associations between CVD death and total, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) cholesterol and triglyceride levels in women were explored using data from female participants in the Lipid Research Clinics' Follow-up Study. METHODS: Using a sample of 1405 women aged 50 to 69 years from the Lipid Research Clinics' Follow-up Study, age-adjusted CVD death rates and summary relative risk (RR) estimates by categories of lipid and lipoprotein levels were calculated. Multivariate analysis was performed to provide RR estimates adjusted for other CVD risk factors. RESULTS: Average follow-up was 14 years. High-density lipoprotein and triglyceride levels were strong predictors of CVD death in age-adjusted and multivariate analyses. Low-density lipoprotein and total cholesterol levels were poorer predictors of CVD mortality. After adjustment for other CVD risk factors, HDL levels less than 1.30 mmol/L (50 mg/dL) were strongly associated with cardiovascular mortality (RR = 1.74; 95% confidence interval [CI], 1.10 to 2.75). Triglyceride levels were associated with increased CVD mortality at levels of 2.25 to 4.49 mmol/L (200 to 399 mg/dL) (RR = 1.65; 95% CI, 0.99 to 2.77) and 4.50 mmol/L (400 mg/dL) or greater (RR = 3.44; 95% CI, 1.65 to 7.20). At total cholesterol levels of 5.20 mmol/L (200 mg/dL) or greater and at all levels of LDL and triglycerides, women with HDL levels of less than 1.30 mmol/L (< 50 mg/dL) had CVD death rates that were higher than those of women with HDL levels of 1.30 mmol/L (50 mg/dL) or greater. CONCLUSIONS: High-density lipoprotein and triglyceride levels are independent lipid predictors of CVD death in women. Cholesterol screening guidelines should be re-evaluated to reflect the importance of HDL and triglyceride levels in determining CVD risk in women.

Age Factors↗