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Biomedical subjects

Tobias Kurth

Publications and source records attributed to Tobias Kurth.

28 records · Page 2Linked to original sources

Smoking and risk of hemorrhagic stroke in women.

BACKGROUND AND PURPOSE: Several studies established smoking as a risk factor for ischemic stroke and subarachnoid hemorrhage (SAH) in men and women. A recent study added smoking as a risk factor for intracerebral hemorrhage (ICH) in men. In contrast, the impact of smoking on ICH in women is less clear. METHODS: Prospective cohort study among 39 783 US women participating in the Women's Health Study. Smoking habits and stroke occurrence were self-reported. Stroke cases were confirmed by medical record review. We used Cox proportional hazards model to evaluate the association of smoking with risk of total hemorrhagic stroke, ICH, and SAH. We categorized smoking into never, past, and current smokers of <15 and >or=15 cigarettes per day. RESULTS: During 9 years of follow up, a total of 70 hemorrhagic strokes occurred, of which 40 were ICH and 29 were SAH. Never smokers and past smokers had equal rates of ICH and SAH. Current smokers of <15 cigarettes per day had a multivariable-adjusted relative risk (RR) of 1.93 (95% CI, 0.75 to 5.02) for total hemorrhagic stroke, 2.15 (95% CI, 0.62 to 7.43) for ICH, and 1.70 (95% CI, 0.38 to 7.60) for SAH. Women who smoked >or=15 cigarettes per day had RR of 3.29 (95% CI, 1.72 to 6.29) for total hemorrhagic stroke, 2.67 (95% CI, 1.04 to 6.90) for ICH, and 4.02 (95% CI, 1.63 to 9.89) for SAH compared with never smokers. CONCLUSIONS: This prospective study indicates an increased risk of total hemorrhagic stroke, ICH, and SAH in women who are current cigarette smokers. The risk increases with the amount of cigarettes smoked.

Cerebral Hemorrhage↗

Cholesterol and the risk of ischemic stroke.

BACKGROUND AND PURPOSE: Large epidemiological studies have not established cholesterol levels as a risk factor for ischemic stroke, but recent clinical trials have demonstrated a reduction in the ischemic stroke rate for patients taking HMG-CoA reductase inhibitors ("statins"). The goal of this study was to evaluate whether total cholesterol (TC), high-density lipoprotein (HDL), triglycerides, and the TC:HDL ratio are risk factors for ischemic stroke in apparently healthy men enrolled in the Physicians' Health Study. METHODS: We used a nested case-control study design and matched 296 ischemic stroke cases with an equal number of controls on age, tobacco use, and follow-up time. At baseline, TC, HDL, and triglyceride levels were measured. We calculated odds ratios (ORs) and their 95% confidence intervals (CIs) using conditional logistic regression, adjusting for major risk factors for ischemic stroke. RESULTS: Compared with the reference lowest quartile, the highest quartile for TC had an adjusted OR of 1.56 (95% CI, 0.84 to 2.92), the highest quartile of HDL had an adjusted OR of 0.75 (95% CI, 0.43 to 1.30), and the highest quartile of triglycerides had an adjusted OR of 1.07 (95% CI, 0.63 to 1.82). Although the highest quartile of the TC:HDL ratio had an adjusted OR of 1.62 (95% CI, 0.93 to 2.82), the risk of ischemic stroke was not a linear relationship. CONCLUSIONS: After adjustment, TC, HDL, and triglycerides were not significantly associated with ischemic stroke risk, and for the TC:HDL ratio, a suggestion of increased risk of ischemic stroke was limited to those with the highest levels.

Brain Ischemia↗

Inhibition of clinical benefits of aspirin on first myocardial infarction by nonsteroidal antiinflammatory drugs.

BACKGROUND: There is clear evidence from numerous randomized trials and their meta-analyses that aspirin reduces risks of first myocardial infarction (MI). Recent data also suggest that other nonsteroidal anti-inflammatory drugs (NSAIDs) may interfere with this benefit of aspirin. METHODS AND RESULTS: We performed subgroup analysis from a 5-year randomized, double-blind, placebo-controlled trial of 325 mg aspirin on alternate days among 22 071 apparently healthy US male physicians with prospective observational data on use of NSAIDs. A total of 378 MIs were confirmed, 139 in the aspirin group and 239 in the placebo group. Aspirin conferred a statistical extreme (P<0.00001) 44% reduction in risk of first MI. Among participants randomized to aspirin, use of NSAIDs on 1 to 59 d/y was not associated with MI (multivariable adjusted relative risk [RR], 1.21; 95% confidence interval [CI], 0.78 to 1.87), whereas the use of NSAIDs on > or =60 d/y was associated with MI (RR, 2.86; 95% CI, 1.25 to 6.56) compared with no use of NSAIDs. In the placebo group, the RRs for MI across the same categories of NSAID use were 1.14 (95% CI, 0.81 to 1.60) and 0.21 (95% CI, 0.03 to 1.48). CONCLUSIONS: These data suggest that regular but not intermittent use of NSAIDs inhibits the clinical benefits of aspirin. Chance, bias, and confounding remain plausible alternative explanations, despite the prospective design and adjustment for covariates. Nonetheless, we believe the most plausible interpretation of the data to be that regular but not intermittent use of NSAIDs inhibits the clinical benefit of aspirin on first MI.

Adult↗

Smoking and the risk of hemorrhagic stroke in men.

BACKGROUND AND PURPOSE: Smoking is an established risk factor for ischemic stroke and subarachnoid hemorrhage (SAH), but the impact of smoking on intracerebral hemorrhage (ICH) is less clear. METHODS: Prospective cohort study among 22,022 US male physicians participating in the Physicians' Health Study. Incidence of stroke was measured by self-report and confirmed by medical record review. We used Cox proportional-hazards models to evaluate the association of smoking with risk of total hemorrhagic stroke, ICH, and SAH. We categorized smoking into 4 groups: never, past, or current smokers of <20 or of >or=20 cigarettes per day. RESULTS: During 17.8 years of follow-up, 108 ICHs and 31 SAHs occurred. Never smokers and past smokers had equal rates of ICH and SAH. Current smokers of <20 cigarettes per day had multivariable-adjusted relative risks of 1.65 (95% CI, 0.61 to 4.50) for total hemorrhagic stroke, 1.60 (95% CI, 0.50 to 5.07) for ICH, and 1.75 (95% CI, 0.24 to 13.09) for SAH when compared with never smokers. Current smokers of >or=20 cigarettes had relative risks of 2.36 (95% CI, 1.38 to 4.02) for total hemorrhagic stroke, 2.06 (95% CI, 1.08 to 3.96) for ICH, and 3.22 (95% CI, 1.26 to 8.18) for SAH when compared with never smokers. CONCLUSIONS: This prospective study suggests an increased risk of total hemorrhagic stroke, ICH, and SAH in current cigarette smokers with a graded increase in risk that depended on how many cigarettes were smoked. The effect of smoking on ICH is of about the same magnitude as the effect of smoking on ischemic stroke. Our results add to the multiple health benefits that can be accrued by abstaining from cigarette smoking.

Adult↗

Analgesic use and change in kidney function in apparently healthy men.

BACKGROUND: Studies using a single creatinine measurement have yielded inconsistent results regarding analgesic use and kidney function. METHODS: This is a prospective cohort study of 4,494 US male physicians who provided blood samples in both 1982 and 1996. Outcomes measured were increase in plasma creatinine level of 0.3 mg/dL or greater (> or =26.5 micromol/L) and decline in glomerular filtration rate (GFR) of 29.0 mL/min/1.73 m2 or greater during this 14-year period. Self-reported use of aspirin, acetaminophen, and other nonsteroidal anti-inflammatory drugs (NSAIDs) was classified as never (<12 pills during the study period), 12 to 1,499 pills, 1,500 to 2,499 pills, and 2,500 or greater pills during the study period. RESULTS: Blood measurements made 14 years apart showed increased creatinine levels in 242 participants and decreased GFRs in 224 participants. Compared with never use, multivariable-adjusted odds ratios (ORs) of increased creatinine levels were 0.98 (95% confidence interval [CI], 0.43 to 2.23) for 2,500 or greater pills of aspirin, 1.02 (95% CI, 0.55 to 1.90) for 2,500 or greater pills of acetaminophen, and 1.12 (95% CI, 0.67 to 1.87) for 2,500 or greater pills of other NSAIDs. For decreased GFRs, ORs for intake of 2,500 or greater pills were 0.75 (95% CI, 0.35 to 1.57) for aspirin, 1.22 (95% CI, 0.66 to 2.26) for acetaminophen, and 1.11 (95% CI, 0.65 to 1.90) for other NSAIDs. Use of aspirin, but not acetaminophen or other NSAIDs, was associated with a reduced risk for change in kidney function in participants without cardiovascular risk factors and a possible but nonsignificant increase in those with cardiovascular risk factors. CONCLUSION: Occasional to moderate analgesic intake of aspirin, acetaminophen, or NSAIDs does not appear to increase the risk for decline in kidney function during a period of 14 years.

Acetaminophen↗

Interobserver agreement in the classification of stroke in the Women's Health Study.

BACKGROUND AND PURPOSE: Accurate classification of stroke events is essential in large cohort studies of risk factor assessment and in treatment trials such as the Women's Health Study (WHS). METHODS: Based on medical record review, we assessed interrater reliability in stroke classification and disability status in the WHS using the kappa statistic. RESULTS: During 7.0 years of follow-up, 271 incident strokes occurred, of which 133 were reclassified. There was excellent interrater agreement in the diagnosis of major stroke types, hemorrhagic subtypes, and degree of disability, as well as substantial agreement in the definition of the vascular territory involved. Only moderate agreement was reached in the classification of ischemic subtypes. CONCLUSIONS: Major stroke types, degree of disability, and vascular territory involved can be reliably classified on the basis of a review of medical records in the WHS, whereas classification of ischemic stroke subtypes needs further refinement of diagnostic criteria.

Cohort Studies↗

Cholesterol and the risk of renal dysfunction in apparently healthy men.

Despite extensive knowledge about abnormal lipid patterns in patients with end-stage renal disease, the association between cholesterol and the development of renal dysfunction is unclear. We evaluated this association in a prospective cohort study among 4,483 initially healthy men participating in the Physicians' Health Study who provided blood samples in 1982 and 1996. Main outcome measures were elevated creatinine, defined as >/= 1.5 mg/dl (133 micromol/L), and reduced estimated creatinine clearance, defined as </=55 ml/min. Cholesterol parameters included total cholesterol (<200, 200 to 239, and >/= 240 mg/dl), HDL (<40 or >/= 40 mg/dl), total non-HDL cholesterol, and the ratio of total cholesterol to HDL. We used logistic regression to calculate age- and multivariable adjusted odds ratios as a measure for the relative risk. After 14 yr, 134 men (3.0%) had elevated creatinine and 244 (5.4%) had reduced creatinine clearance. The multivariable relative risk for elevated creatinine was 1.77 (95% confidence interval [CI], 1.10 to 2.86) for total cholesterol >/= 240 mg/dl, 2.16 (95% CI, 1.42 to 3.27) for HDL <40 mg/dl, 2.34 (95% CI, 1.34 to 4.07) for the highest quartile of total cholesterol/HDL ratio (>/= >6.8), and 2.16 (95% CI, 1.22 to 3.80) for the highest quartile of non-HDL cholesterol (>/= 196.1). Similar although smaller associations were observed between cholesterol parameters and reduced creatinine clearance. Elevated total cholesterol, high non-HDL cholesterol, a high ratio of total cholesterol/HDL, and low HDL in particular were significantly associated with an increased risk of developing renal dysfunction in men with an initial creatinine <1.5 mg/dl.

Cholesterol↗

Assessment of functioning and disability after ischemic stroke.

BACKGROUND AND PURPOSE: Functioning and disability after ischemic stroke are clinically meaningful and of major relevance to patients. Despite many instruments available to assess these outcomes, little is known about their interrelation and predictive factors. METHODS: We prospectively identified 4264 patients with acute ischemic stroke from 30 hospitals in Germany during a 1-year period between 1998 and 1999 and registered them in a common data bank. The patients were centrally followed up via telephone interview after 100 days and 1 year to assess various scales such as the Barthel Index (BI), modified Rankin Scale (MRS), extended Barthel Index (EBI), Short Form-36 Physical Functioning (SF-36 PF), and Center for Epidemiologic Studies-Depression short form (CES-D). RESULTS: Outcome status could be assessed in 67.2% of patients 100 days after hospital admission. Of these, 13.9% had died, 53.7% had regained functional independence (BI <95), 46.3% had no or mild residual symptoms (MRS < or =1), and 44.6% had no higher cognitive deficits on the EBI. Of the patients who personally answered the follow-up questions, 67% had no major physical disability (SF-36 PF <60), and 32.9% reported symptoms classified as depression (CES-D > or =10). The high percentage of patients reaching the maximum score (ceiling effect) in the BI was less pronounced in the MRS and SF-36 PF. The predictive factors for dichotomized outcomes on each scale were similar for adverse functioning and disability but varied considerably for depression. CONCLUSIONS: To avoid ceiling effects in outcome distribution of patients treated in specialized stroke centers, the MRS and SF-36 PF instruments are preferable to the BI. Parametric use of the SF-36 PF could further improve outcome measurement by considering individual treatment effects.

Aged↗

Body mass index and the risk of stroke in men.

BACKGROUND: Although obesity is an established risk factor for coronary heart disease, its role as a risk factor for stroke remains controversial. METHODS: Prospective cohort study among 21 414 US male physicians participating in the Physicians' Health Study. Incidence of total, ischemic, and hemorrhagic stroke was measured by self-report and confirmed by medical record review. We used Cox proportional hazards models to evaluate the association of body mass index (BMI), calculated as self-reported weight in kilograms divided by the square of the height in meters, with risk of total, ischemic, and hemorrhagic stroke. RESULTS: During 12.5 years of follow-up, 747 strokes (631 ischemic, 104 hemorrhagic, and 12 undefined) occurred. Compared with participants with BMIs less than 23, those with BMIs of 30 or greater had an adjusted relative risk of 2.00 (95% confidence interval [CI], 1.48-2.71) for total stroke, 1.95 (95% CI, 1.39-2.72) for ischemic stroke, and 2.25 (95% CI, 1.01-5.01) for hemorrhagic stroke. When BMI was evaluated as a continuous variable, each unit increase of BMI was associated with a significant 6% increase in the adjusted relative risks of total (95% CI, 4%-8%), ischemic (95% CI, 3%-8%), and hemorrhagic stroke (95% CI, 1%-12%). Additional adjustment for hypertension, diabetes mellitus, and hypercholesterolemia slightly attenuated the risks for total and ischemic (relative risk, 4%; 95% CI, 2%-7%), but not hemorrhagic, stroke. CONCLUSIONS: These prospective data indicate a significant increase in the relative risk of total stroke and its 2 major subtypes with each unit increase of BMI that is independent of the effects of hypertension, diabetes, and cholesterol. Because BMI is a modifiable risk factor, the prevention of stroke may be another benefit associated with preventing obesity in adults.

Age Factors↗