Biomedical subjects

Ronald Klein

Publications and source records attributed to Ronald Klein.

208 records · Page 12Linked to original sources

PubMed2002

ACE-I and ARBs in early diabetic nephropathy.

INTRODUCTION: Antihypertensive treatment of patients with clinical manifestations of diabetic nephropathy, and especially, renin-angiotensin system (RAS) inhibition, slows, but may not fully arrest progression towards end-stage renal disease. Studies using hard endpoints such as doubling of serum creatinine, dialysis, or death that are initiated before emergence of any renal functional abnormalities in diabetes, would be of impractical length and size. We therefore undertook a primary prevention study (The Renin-Angiotensin System Study or RASS) to determine if inhibition of the RAS could slow the development of a key diabetic glomerulopathy structural endpoint, increase in mesangial fractional volume (Vv[Mes/glom]). METHODS: This is a parallel group, double-blind, placebo-controlled trial with 285 patients with Type 1 diabetes mellitus (95 per group) randomised to receive the angiotensin-converting enzyme inhibitor, enalapril, the angiotensin II receptor blocker, losartan, or placebo. All patients are normotensive, normoalbuminuric and have normal or increased glomerular filtration rates at study entry. The study is based on primary endpoint of change in Vv(Mes/glom) from baseline to the five-year renal biopsy, with baseline and interval measures of albumin excretion rate, glomerular filtration rate, blood pressure, and glycaemia. Baseline, mid-point, and five-year retinal fundus photography are also performed. RESULTS: One thousand and sixty-five patients were interviewed, 707 refused participation and 73 were excluded. The target of 285 subjects were randomised and their clinical and demographic characteristics are described. Biopsy complications occurred in 17 (6%), only one of which required hospitalisation. There were no permanent biopsy-related sequelae. CONCLUSIONS: Renal structural variables are reasonable surrogate endpoints for studies of progression of early diabetic nephropathy. Although requiring substantial recruitment effort, diabetic nephropathy primary prevention trials based on change in renal structure are feasible.

Adult↗

PubMed2002

Blindness, visual impairment and the problem of uncorrected refractive error in a Mexican-American population: Proyecto VER.

PURPOSE: To report the prevalence of blindness and visual impairment and the contribution of uncorrected refractive error to visual loss, in a population-based sample of Mexican Americans aged 40 and older. METHODS: Proyecto VER is a population-based study of blindness and visual impairment in Mexican Americans in Arizona. Block groups in Tucson and Nogales were randomly selected with probability proportional to the size of the Mexican-American population aged 40 and older. Participants had a complete ophthalmic evaluation, including assessment of presenting and best corrected visual acuity using standardized procedures. Those with presenting visual acuity worse than 20/30 had refraction to determine best corrected vision. A home questionnaire and a clinic examination provided data on education, perception of visual impairment, income, and acculturation. RESULTS: The prevalence of presenting visual acuity worse than 20/40 was 8.2%, with uncorrected refractive error accounting for 73% of the impaired acuity. In multivariate models comparing those who improved two or more lines on the acuity chart with proper refraction with those who had adequate optical correction, uncorrected refractive error showed a strong association with age, less than 13 years of education (odds ratio [OR] 1.6, 95% confidence interval [CI] 1.5-2.0), low acculturation index (OR 1.3, CI 1.1-1.3), lack of insurance coverage (OR 1.4, CI 1.1-1.7), and not having seen an eye-care provider in the past 2 years (OR 2.5, CI 2.1-3.0). Prevalence of best corrected acuity worse than 20/40 increased from 0.3% in those aged 40 to 49 years to 18% in those aged 80 years or more. CONCLUSIONS: Visual loss in this Mexican-American population is higher than has been reported in whites and is comparable to that in African Americans. Almost three quarters of those with visual acuity impairment would improve with optical correction. Socioeconomic factors that are probable markers of limited access to health care services were associated with uncorrected refractive error. These data suggest that education programs and interventions to improve access to eye care could significantly decrease the burden of visual loss among Mexican Americans.

Adult↗

PubMed2002

Prevalence and 5-year incidence of tinnitus among older adults: the epidemiology of hearing loss study.

Tinnitus (ringing or buzzing in the ear or head) can range from barely noticeable to debilitating. Although a few studies have estimated the prevalence of this condition in adult populations, we know of no population-based estimates of incidence. As part of a population-based study of hearing loss in adults aged 48 to 92 years at baseline in Beaver Dam, Wisconsin, self-reported data on tinnitus were obtained at the baseline examination (1993-1995; N = 3753) and again 5 years later (1998-2000; N = 2800). A person was classified as having tinnitus if their tinnitus was at least moderate in severity or caused difficulty in falling asleep. The prevalence of tinnitus at baseline was 8.2 percent. The 5-year incidence of tinnitus among the 2513 participants at risk was 5.7 percent. Risk factors for prevalent and incident tinnitus were evaluated. The results suggest that tinnitus is a common problem for older adults and is associated with some modifiable risk factors.

Aged↗

PubMed2002

Changes in refraction over 10 years in an adult population: the Beaver Dam Eye study.

PURPOSE: To quantify the 10-year change in refraction in persons more than 40 years of age. METHODS: All people 43 to 84 years of age and living in Beaver Dam, Wisconsin, in 1988 were invited for a baseline examination (1988-1990), a 5-year follow-up examination (1993-1995), and a 10-year follow-up examination (1998-2000). Refractions were determined according to the same protocol at all examinations. Aphakic and pseudophakic eyes and eyes with best corrected visual acuity of 20/200 or worse were excluded. After exclusions, refraction data were available on 2362 right eyes of the 2937 people examined at baseline and 10-year follow-up. RESULTS: Age was related to the direction and amount of change in refraction. Spherical equivalent became more positive in the youngest subjects and more negative in the oldest. After adjustment for the severity of nuclear sclerosis and other factors, the 10-year change in refraction was +0.48, +0.03, and -0.19 D for persons 43 to 59, 60 to 69 and 70+ years of age at the baseline examination, respectively. Severity of nuclear sclerosis was also strongly related to amount of change. Those with mild nuclear sclerosis at baseline had a change of +0.35 D, whereas those with severe nuclear sclerosis had a change of -0.53 D. The amount of change was also related to diabetes and weakly related to baseline refractive error, but was unrelated to gender and education. In addition to the longitudinal changes observed, there was a birth cohort effect. In comparing people of the same age across examinations, those born in more recent years had more myopia than those born in earlier years. CONCLUSIONS: Significant changes in spherical equivalent in adults occur over a 10-year period. Younger people became more hyperopic, whereas older people became more myopic. These data provide evidence of a longitudinal change in refraction in adults, which may explain the refractive patterns observed in cross-sectional studies.

Adult↗

PubMed2002

Refractive errors and 10-year incidence of age-related maculopathy.

PURPOSE: To describe the relationship of refractive errors to the 10-year incidence of age-related maculopathy (ARM) in a defined white population. METHODS: Persons aged 43 to 86 years of age in Beaver Dam, Wisconsin, were invited for a baseline examination from 1988 through 1990, and follow-up examinations 5 and 10 years later (n = 3684). Refraction was measured at baseline, with myopia defined as a spherical equivalent of -1.00 D or less, emmetropia as -0.75 to +0.75 D and hyperopia as +1.00 D or more. At each examination, signs of ARM were ascertained from grading stereoscopic color fundus photographs based on a standard protocol. The association between baseline refractive status and the 10-year incidence and progression of ARM was analyzed. RESULTS: The 10-year cumulative incidence for early ARM was 7.1%, 7.7%, and 11.7%, in eyes with myopia, emmetropia, and hyperopia, respectively. The corresponding 10-year cumulative incidence for late ARM was 0.3%, 0.8%, and 2.2%. When age was controlled for, there was no association between myopia and incident early (relative risk [RR] 1.0, 95% confidence interval [CI], 0.7-1.3) and late (RR 0.5, 95% CI, 0.2-1.5) ARM. Similarly, after controlling for age, hyperopia was not associated with incident early (RR 0.9, 95% CI, 0.7-1.1) or late (RR 1.2, 95% CI, 0.6-2.3) ARM. CONCLUSIONS: These prospective population-based data provide no evidence of an association between refractive errors and risk of ARM.

Adult↗

PubMed2002

The impact of visual impairment and eye disease on vision-related quality of life in a Mexican-American population: proyecto VER.

PURPOSE: To describe the relationship of visual acuity impairment and eye disease on vision-related quality of life, as measured by the 25-item National Eye Institute Visual Function Questionnaire (NEI-VFQ-25), in a cross-sectional, population-based study of older Hispanic persons living in Arizona. METHODS: A random sample of block groups with Hispanic residents in Nogales and Tucson, Arizona, were selected for study. Participants were interviewed at home with a questionnaire that included the NEI-VFQ-25, an instrument measuring vision-related quality of life. Acuity was obtained with Early Treatment Diabetic Retinopathy Study (ETDRS) charts and standard protocol. Cataract was determined by clinical examination, diabetic retinopathy was diagnosed on stereo fundus photographs, and glaucoma was diagnosed on the basis of clinical examination and visual field results. Analyses were done to determine the degree of association between subscale scores and acuity in the better-seeing eye, monocular visual impairment, and specific eye diseases, with adjustment for acuity. RESULTS: Of the 4774 participants in the study, 99.7% had completed questionnaires that were not completed by proxy. Participants with visual impairment had associated decrements in scores on all subscales, with a decrease in presenting acuity associated with a worse score (P < 0.05), after adjustment for demographic variables. Monocular impairment was also associated with lower scores in several subscales. In those with cataract, low acuity explained most of the low scores, but those with glaucoma or diabetic retinopathy had low scores independent of acuity. CONCLUSIONS: In this study of Mexican-American persons aged 40 or more, monocular impairment and better-eye acuity was associated with a decrease in most domains representing quality of life. Subjects with uncorrected refractive error, cataract, diabetic retinopathy, and glaucoma had associated decrements in quality of life, many not explained by loss of acuity. Further work on the specific measures of vision associated with reported decreases in quality of life, such as visual field or contrast sensitivity, is warranted.

Adult↗

PubMed2002

Prevalence of sleep problems and quality of life in an older population.

STUDY OBJECTIVES: To determine the prevalence of insomnia traits in a population and the effect of these traits on health-related quality of life. DESIGN: The Epidemiology of Hearing Loss Study is a population-based study in Beaver Dam, Wisconsin. SETTING: Participants were interviewed as part of the 5-year follow-up examination (1998-2000) of the Epidemiology of Hearing Loss Study. Participants were interviewed at the study office in Beaver Dam, WI, by telephone, or at their residence. PARTICIPANTS: 2800 adults aged 53-97 years. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Participants were asked to what extent they experienced difficulty getting to sleep, waking up at night and having a hard time getting back to sleep, and waking up repeatedly during the night for any reason. A response of "often" or "almost always" was coded as positive for an insomnia trait. The SF-36 was administered to assess mental and physical function. Twenty-six percent of the population reported one insomnia trait, 13% reported two, and 10% reported three. All eight domains and the Mental and Physical Component Summary scores of the SF-36 decreased significantly (F-test for linear trend statistically significant at p<0.0001) as the number of reported insomnia traits increased. CONCLUSIONS: These results indicate that symptoms of insomnia are common among older adults and are associated with a decrease in health related quality of life.

Adult↗

PubMedDate not supplied

Ten-year incidence of self-reported erectile dysfunction in people with long-term type 1 diabetes.

OBJECTIVE: The purpose of this report is to examine the overall 10-year incidence of erectile dysfunction and its relationships to other characteristics in men with younger onset diabetes. METHODS: In a population-based cohort study in southern Wisconsin, a 10-year cumulative incidence of reported erectile dysfunction was obtained in men who were 21 years of age or older, were less than 30 years of age at diagnosis of diabetes, had 10 or more years of diabetes, and were taking insulin (n=264). RESULTS: Twenty-five percent developed erectile dysfunction. The incidence of erectile dysfunction increased with age (from 10.2% in those 21-29 years of age to 48.6% in those 40 years of age or older, P<.0001) and with increasing duration of diabetes (from 16.0% in those with 11-14 years of diabetes at baseline to 38.2% in those with 25 or more years of diabetes, P=.01). In multivariate analyses, incidence of erectile dysfunction was associated with age [odds ratio (OR) 1.10, 95% confidence interval (CI), 1.06, 1.14], untreated hypertension (OR 5.01, 95% CI, 2.05, 12.27), and a history of smoking (OR 2.41, 95% CI, 1.09, 5.30) at baseline. CONCLUSIONS: These data suggest that cessation of cigarette smoking and tighter control of blood pressure might prevent or delay the onset of erectile dysfunction in persons with type 1 diabetes.

Adult↗

PubMedDate not supplied

Medical records as sources of data on cardiovascular disease events in persons with diabetes.

PURPOSE: The aim of this study is to evaluate medical records as a source of data on cardiovascular disease over a 20-year interval. METHODS: Participants in a population-based cohort of persons with Type 1 diabetes were asked whether they had been told by a doctor that they had several specific cardiovascular events. In addition, they were asked when and where they were hospitalized for myocardial infarction, stroke, surgical procedures, and for other conditions and procedures. The medical care institution was contacted to obtain copies of the relevant hospitalization. RESULTS: Overall, the confirmation of the self-reported events was 86.0% when medical records were obtained. Percent confirmed varied with the diagnosis. Reports of poor circulation in the lower extremities were confirmed in 42.6%, stroke was confirmed in 70%, and coronary bypass surgery was confirmed in 100% of cases. The success of obtaining medical records was greater for those events that were reported to have occurred more recently than those reported further in the past, especially when 10 or more years had elapsed. CONCLUSION: Medical record confirmation of reported cardiovascular events in persons with Type 1 diabetes was high for some events when medical records could be obtained but was lower for "poor circulation" to the legs and stroke possibly related to the lack of specificity of our questions, to incorrect attribution of symptoms by the respondent, or to inaccurate recall of a physician's examination. Medical record confirmation was better for more recent than past events. Therefore, when hard copy documentation is needed, it should be sought within 10 years of the event.

Cardiovascular Diseases↗

PubMedDate not supplied

The relationship between albuminuria and hypercholesterolemia.

BACKGROUND: To test the hypothesis that the albuminuria is an independent risk factor for hypercholesterolemia. METHODS: Cross-sectional study (The Third National Health and Nutrition Examination Survey (NHANES III), 1988-1994) of the civilian, noninstitutionalized US population. Of the total 33,994 NHANES III participants, those aged 17 years or more and those who had complete urinary albumin-to-creatinine (UAC) ratio information formed our primary study population (n=17,702). The main outcomes of interest were: high serum TC level, defined as levels more than 6.2 mmol/L (240 mg/dL); high serum LDL cholesterol level, defined as levels more that 4.1 mmol/L (160 mg/dL); and low serum HDL cholesterol level, defined as levels less that 0.9 mmol/L (35 mg/dL). RESULTS: Compared to individuals with normoalbuminuria, the odds ratio (OR) of high serum TC level and high LDL cholesterol level were respectively 1.04 and 1.32 for those with microalbuminuria, and 1.96 and 1.69 for those with macroalbuminuria. Increasing quintiles of UAC ratio was associated with graded increase in the odds of high serum TC (OR, 1,1.23,1.25,1.33,1.46; p trend=0.02) and LDL cholesterol (OR, 1, 0.99, 1.09, 1.46, 1.59; p trend=0.02) levels. In our analyses, the fourth quintile of UAC ratio was associated with significant OR of hypercholesterolemia, despite it being in the currently accepted normal range. However, albuminuria was not associated with low HDL cholesterol in our analysis. CONCLUSIONS: Increasing albuminuria is associated with continuous, and graded increase in the odds of high serum TC and LDL cholesterol levels. Our results call for future follow-up studies to confirm if albuminuria precedes the development of hypercholesterolemia.

Adolescent↗