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Ronald Klein

Publications and source records attributed to Ronald Klein.

At least 181 records · Page 10Linked to original sources
PubMed2003

Computer-assisted retinal vessel measurement in an older population: correlation between right and left eyes.

This study assessed the correlation between computer-assisted retinal vessel measurements of right and left eyes, from subjects in a defined, community-based older population. Retinal photographs from participants in the Blue Mountains Eye Study were digitized. All retinal arterioles and venules located 0.5-1.0 disc diameters from the optic disc margin were identified and a computer program measured their diameters. Pearson correlation (R2) statistic was used to assess the correlation in a random subsample of 1546 images. Substantial correlation between right and left eye measurements was found for summary indices of retinal arterioles (R2 = 0.70) and venules (R2 = 0.77). Higher correlation was found for intragrader (R2 0.75-079) than for intergrader assessment (R2 0.67-0.72). Moderate correlation was found in arteriole-to-venule ratio assessed by the same (R2 = 0.57) or different (R2 = 0.52) graders. Measurements from one eye can thus adequately represent the retinal vessel diameters of a person.

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PubMed2003

Correlation between generalized and focal retinal arteriolar narrowing in an older population.

This study aimed to assess the associations between generalized and focal retinal arteriolar narrowing in the Blue Mountains Eye Study population (n = 3654 persons aged 49+ years). Summarized estimates of the average retinal arteriolar diameter, the central retinal arteriolar equivalent (CRAE) and arteriole-to-venule ratio were obtained from right eye photographs of each participant using a computer-assisted method. Focal retinal arteriolar narrowing was graded from retinal photographs of both eyes using a 'light-box' method. The proportion of subjects with focal arteriolar narrowing increased as CRAE decreased from the widest (2.2%) to the narrowest (7.8%) quintile (P for trend = 0.001). A receiver operating characteristic curve was constructed using CRAE to detect focal arteriolar narrowing. With the diagnostic cut point set at the 4th decile of CRAE, the sensitivity and specificity in detecting focal arteriolar narrowing were 64% and 61%,respectively. These data suggest a moderate correlation between generalized (CRAE) and focal arteriolar narrowing. However, no significant association was found between arteriole-to-venule ratio and focal arteriolar narrowing.

Arterioles↗
PubMed2003

Revised formulas for summarizing retinal vessel diameters.

Background/Purpose. Recent findings suggest that an objective assessment of retinal vessel caliber from fundus photographs provide information about the association of microvascular characteristics with macrovascular disease. Current methods used to quantify retinal vessel caliber, introduced by Parr(1,2) and Hubbard,(3) are not independent of scale and are affected by the number of vessels. To improve upon these methods we introduce revised formulas for quantifying vessel caliber. Methods. Revised formulas were estimated using retinal vessel measurements from 44 young adults free of hypertension and diabetes. Comparisons between the two methods were done using digitized photographs from 4926 participants at the baseline examination of the Beaver Dam Eye Study (BDES), an ongoing population-based cohort study initiated in 1987. Individual arterioles and venules were measured using semi-automated computer software from which summary measures were calculated. Results. Correlation coefficients between the Parr-Hubbard and revised formulas were high (Pearson correlation coefficients ranging from 0.94 to 0.98). Both arteriolar and venular caliber significantly increased with an increasing number of vessels measured using the Parr-Hubbard formulas (p < 0.001), which in turn affected the relationship to mean arterial blood pressure. To the contrary, the revised formulas were not affected by the number of measured vessels (p > 0.50). Conclusions. We describe revised formulas for summarizing retinal vessel diameters measured from fundus photographs to be used in future studies and analyses. The revised formulas correlate highly with the previously used Parr-Hubbard formulas, but offer the advantages of being more robust against variability in the number of vessels observed, being independent of image scale, and being easier to implement.

Adult↗
PubMed2003

Do multiple families alter estimates of risk for age-related cataract in a population-based study? The Beaver Dam Eye Study.

We sought to determine the effect of "genetic" load on the strengths of risk factors for age-related cataracts in the population-based Beaver Dam Eye Study. Of the 4,926 participants in the baseline examination in 1988 to 1990, 2,338 were members of 594 family groups. There were no important differences in the risks due to pack-years smoked, systolic and diastolic blood pressures, body mass index, current smoking, hypertension or hormone replacement therapy for either the whole population or subgroups created by omitting siblings or any family relation. There were some differences when the analyses were limited to only a randomly selected family member or a randomly selected sibling. These latter findings may relate to the older average age of those in sibships or in families compared to those not in families. We conclude that for the associations we explored, the relatively large number of families in our population had little effect on the strengths of the risk factors, and that limiting analyses to only those not in families may distort risk factor associations by altering the age structure in this population.

Adult↗
PubMed2003

The impact of hearing loss on quality of life in older adults.

PURPOSE: The authors investigate the impact of hearing loss on quality of life in a large population of older adults. DESIGN AND METHODS: Data are from the 5-year follow-up Epidemiology of Hearing Loss Study, a population-based longitudinal study of age-related hearing impairment conducted in Beaver Dam, WI. Participants (N = 2,688) were 53-97 years old (mean = 69 years) and 42% were male. Difficulties with communication were assessed by using the Hearing Handicap for the Elderly-Screening version (HHIE-S), with additional questions regarding communication difficulties in specific situations. Health-related quality of life was assessed by using measures of activities of daily living (ADLs), instrumental ADLs (IADLs) and the Short Form 36 Health Survey (SF-36). Hearing loss measured by audiometry was categorized on the basis of the pure-tone average of hearing thresholds at 0.5, 1, 2, and 4 kHz. RESULTS: Of participants, 28% had a mild hearing loss and 24% had a moderate to severe hearing loss. Severity of hearing loss was significantly associated with having a hearing handicap and with self-reported communication difficulties. Individuals with moderate to severe hearing loss were more likely than individuals without hearing loss to have impaired ADLs and IADLs. Severity of hearing loss was significantly associated with decreased function in both the Mental Component Summary score and the Physical Component Summary score of the SF-36 as well as with six of the eight individual domain scores. IMPLICATIONS: Severity of hearing loss is associated with reduced quality of life in older adults.

Activities of Daily Living↗
PubMed2003

Relationships between age, blood pressure, and retinal vessel diameters in an older population.

PURPOSE: To describe the cross-sectional relationships between age, blood pressure (BP), and quantitative measures of retinal vessel diameters in an older Australian population. METHODS: Retinal photographs from right eyes of participants (n = 3654, aged 49+ years) in the Blue Mountains Eye study taken during baseline examinations (1992-1994) were digitized. The width of all retinal vessels located 0.5 to 1.0 disc diameters from the disc margin was measured by a computer-assisted method. Summarized estimates for central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) represent average retinal vessel diameters. The arteriole-to-venule ratio (AVR) was calculated. Associations between age and BP and CRAE, CRVE, and AVR were assessed with generalized linear models. RESULTS: Retinal vessel diameters decreased with increasing age in both men and women. CRAE and CRVE decreased by 4.8 microm and 4.1 microm, respectively, per decade increase in age, after adjusting for sex and mean arterial blood pressure. Mean AVR declined by 0.01 for each increasing decade of age, until 79 years. After adjustment for age, sex, smoking, and body mass index, CRAE, CRVE and AVR were all significantly and inversely associated with BP. For every 10-mm Hg increase in mean arterial blood pressure, AVR decreased by 0.012 and CRAE and CRVE decreased by 3.5 microm and 0.96 microm, respectively. CONCLUSIONS: Retinal arteriolar and venular diameters narrow with increasing age, and these parameters are inversely related to BP, independent of age, gender, and smoking. The findings are consistent with those from the Atherosclerosis Risk in Communities Study suggesting that decreased retinal vessel diameters may reflect microvascular damage from elevated blood pressure.

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PubMed2003

Retinal vessel diameters and their associations with age and blood pressure.

PURPOSE: To describe the cross-sectional relationship between retinal arteriolar and venular diameters with age and blood pressure. METHODS: A population-based study was conducted in Beaver Dam, Wisconsin (n=4926, age range, 43-84 years). Retinal photographs of right eyes taken at the baseline examination (1988-90) were digitized. All arterioles and venules located in the area between one-half and one disc diameter from the optic disc margin were measured with a computer-based program. These measurements were combined to provide the average diameters of retinal arterioles and venules of each eye, and the association with age and blood pressure (BP) was analyzed. RESULTS: After controlling for gender, hypertension, diabetes, serum glucose and lipids, cigarette smoking, and body mass index, retinal arteriolar diameters were found to be decreased by 2.1 microm (95% confidence interval [CI], 1.5-2.7) for each decade increase in age, and by 4.4 microm (95% CI, 3.8-5.0) for each 10-mm Hg increase in mean arterial BP. The association of narrowed retinal arterioles and higher BP was stronger in younger persons. For each 10-mm Hg increase in mean arterial BP, arteriolar diameters decreased by 7.0 microm in persons aged 43 to 54 years but by only 2.5 microm in persons aged 75 to 84 years. In contrast, retinal venular diameters narrowed with increasing age but not with increasing BP. CONCLUSIONS: Retinal arteriolar diameters are narrower in older persons and in persons with higher BP, independent of other factors. The weaker association of retinal arteriolar diameters and BP in older people may reflect greater sclerosis of the retinal arterioles, preventing a degree of narrowing with higher BP similar to that seen in younger persons.

Adult↗
PubMed2003

Longitudinal studies of incidence and progression of diabetic retinopathy assessed by retinal photography in pima indians.

OBJECTIVE: To examine incidence and progression of retinopathy using retinal photographs in Pima Indians and to compare the results with those obtained when retinopathy is assessed by direct ophthalmoscopy. RESEARCH DESIGN AND METHODS: We undertook an analysis of examinations conducted between 1 April 1982 and 31 December 1990 in residents of the Gila River Community in central Arizona. Data were taken from 411 people with diabetes who had at least two examinations during this period. Incidence and progression of retinopathy were evaluated by retinal photography and fundoscopy, and hazard rate ratios were calculated for various potential risk factors measured at baseline. RESULTS: Previously diagnosed retinopathy tended to progress, except in individuals with minimal nonproliferative retinopathy, among whom follow-up examinations were more likely to show no retinopathy. Diabetes duration (hazard rate ratio [HRR], 1.06 per year difference [P = 0.007]), hyperglycemia (HbA(1) HRR, 1.27 per 1% difference [P < 0.0001]), the type of treatment for diabetes (insulin use HRR, 3.06 [P = 0.0007], and oral hypoglycemic use HRR, 2.40 [P = 0.0034], compared with individuals on no pharmacotherapy), and macroalbuminuria (HRR, 2.86, compared with individuals without macroalbuminuria [P = 0.0486]) were associated with the development of retinopathy. Although fundoscopy detected fewer cases of retinopathy, HRRs for most risk factors were similar when retinopathy was assessed by fundoscopy rather than retinal photography. CONCLUSIONS: Although retinopathy tends to worsen over time, some eyes show improvement, especially in patients with minimal nonproliferative retinopathy. As in other populations, glycemic control is the major modifiable risk factor for the development and progression of retinopathy.

Adolescent↗
PubMed2003

Retinal emboli and cardiovascular disease: the Beaver Dam Eye Study.

PURPOSE: To describe the 10-year incidence of retinal emboli, the associated risk factors, and the relationship of retinal emboli to stroke and ischemic heart disease mortality. METHODS: The Beaver Dam Eye Study (n = 4,926) is a population-based study of persons 43 to 86 years of age. Retinal emboli were detected at baseline (1988-1990) and at a 5-year (1993-1995) and a 10-year (1998-2000) follow-up by grading of stereoscopic 30 degrees color fundus photographs using standardized protocols. Cause-specific mortality was determined from death certificates. RESULTS: The 10-year cumulative incidence of retinal emboli was 1.5%. While adjusting for age and sex, the incidence of retinal emboli was associated with increased pulse pressure (odds ratio [OR] 4th versus 1st quartile range, 2.42; 95% confidence interval (CI), 0.98-5.97; P test of trend = .03), higher serum total cholesterol (OR, 2.77; 95% CI, 1.06-7.23; P = .03), higher leukocyte count (OR, 2.28; 95% CI, 1.04-4.96; P = .05), smoking status (OR current versus never smoker, 4.60: 95% CI, 2.08-10.16; P < .001), and a history of coronary artery bypass surgery (OR, 7.17; 95% CI, 3.18-16.18; P < .001) at baseline. While controlling for age, sex, and systemic factors, a significantly higher hazard of dying with a mention of stroke on the death certificate was found in people with retinal emboli (hazard ratio, 2.40; 95% CI, 1.16-4.99) compared with those without. CONCLUSIONS: The data show an association of smoking and cardiovascular disease with the incidence of retinal emboli. Also, persons with retinal emboli are at increased risk of stroke-related death.

Adult↗
PubMed2003

Relationship of measures of frailty to visual function: the Beaver Dam Eye Study.

PURPOSE: To investigate the association of standard measures of frailty to visual acuity and contrast sensitivity. METHODS: Time to walk a measured course, handgrip strength, peak expiratory flow rate, ability to stand from a sitting position without using arms, best-corrected visual acuity, and contrast sensitivity were assessed at the third examination (1998-2000) of the Beaver Dam Eye Study. The study is population-based with the initial census in 1988-1990. RESULTS: All measures of frailty and vision were significantly associated with age (poorer function at older ages). In general, women had poorer function than men in each age category. An "index of frailty" consisting of highest quartile (slowest) gait time, lowest quartile of peak expiratory flow rate, lowest quartile of handgrip strength, and inability to stand from sitting in one try (for those not in a wheelchair) was constructed for women and men. A score of 0 was the minimum amount of frailty, while a score of 4 indicated the maximum amount. Controlling for age, those with no evidence of frailty (score = 0) were likely to have the best visual acuity and best contrast sensitivity, while those with maximum evidence of frailty (score = 4) were likely to have poorest visual acuity and contrast sensitivity. CONCLUSION: Greater frailty was associated with poorer visual functions. Including a measure of visual function when assessing frailty may improve upon the usefulness of an index of frailty in predicting incidence of chronic systemic diseases and survival.

Adult↗
PubMed2002

Prevalence of olfactory impairment in older adults.

CONTEXT: Older adults represent the fastest-growing segment of the US population, and prevalences of vision and hearing impairment have been extensively evaluated. However, despite the importance of sense of smell for nutrition and safety, the prevalence of olfactory impairment in older US adults has not been studied. OBJECTIVE: To determine the prevalence of olfactory impairment in older adults. DESIGN, SETTING, AND PARTICIPANTS: A total of 2491 Beaver Dam, Wis, residents aged 53 to 97 years participating in the 5-year follow-up examination (1998-2000) for the Epidemiology of Hearing Loss Study, a population-based, cross-sectional study. MAIN OUTCOME MEASURES: Olfactory impairment, assessed by the San Diego Odor Identification Test and self-report. RESULTS: The mean (SD) prevalence of impaired olfaction was 24.5% (1.7%). The prevalence increased with age; 62.5% (95% confidence interval [CI], 57.4%-67.7%) of 80- to 97-year-olds had olfactory impairment. Olfactory impairment was more prevalent among men (adjusted prevalence ratio, 1.92; 95% CI, 1.65-2.19). Current smoking, stroke, epilepsy, and nasal congestion or upper respiratory tract infection were also associated with increased prevalence of olfactory impairment. Self-reported olfactory impairment was low (9.5%) and this measure became less accurate with age. In the oldest group, aged 80 to 97 years, sensitivity of self-report was 12% for women and 18% for men. CONCLUSIONS: This study demonstrates that prevalence of olfactory impairment among older adults is high and increases with age. Self-report significantly underestimated prevalence rates obtained by olfaction testing. Physicians and caregivers should be particularly alert to the potential for olfactory impairment in the elderly population.

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PubMed2002

Ten-year incidence of age-related maculopathy and smoking and drinking: the Beaver Dam Eye Study.

The authors examined associations between smoking and alcohol consumption and the long-term incidence of age-related maculopathy (ARM) in people in the Beaver Dam Eye Study who were aged 43-86 years (n = 3,684) in 1988-1990 and examined over a 10-year period. ARM status was determined by grading stereoscopic color fundus photographs. After controlling for age, sex, and other factors, the authors found that people who had smoked more were more likely to develop large (> or =250 micro m in diameter) soft drusen (risk ratio (RR) per 10 pack-years smoked = 1.08, 95% confidence interval (CI): 1.02, 1.14) and pigmentary abnormalities (RR = 1.09, 95% CI: 1.04, 1.14) and to have progression of early ARM (RR = 1.05, 95% CI: 1.00, 1.10) than people who had smoked less. Smoking was not associated with the incidence of late ARM. People who reported being heavy drinkers at baseline were more likely to develop late ARM (RR = 6.94, 95% CI: 1.85, 26.1) than people who reported never having been heavy drinkers. Smoking appears to have a modest, positive association with early but not late signs of ARM, and heavy drinking appears to be related to an increased risk of late ARM, although the exposure and outcome were infrequent, and the effect is based on few exposed cases.

Adult↗
PubMed2002

Cerebral white matter lesions, retinopathy, and incident clinical stroke.

CONTEXT: White matter lesions (WMLs) detected on cerebral imaging scans have been hypothesized to have a microvascular etiology and to precede the development of clinical stroke. However, few clinical data are available to support these hypotheses. OBJECTIVE: To examine the relationship of WMLs, retinal microvascular abnormalities, and incident clinical stroke in healthy, middle-aged men and women. DESIGN AND SETTING: The Atherosclerosis Risk in Communities Study (ARIC), a prospective, population-based cohort study conducted in 4 US communities and initiated in 1987-1989. PARTICIPANTS: A total of 1684 persons aged 51 to 72 years who had cerebral magnetic resonance imaging (MRI) and retinal photography at the third examination (1993-1995). MAIN OUTCOME MEASURES: Odds of WMLs, defined by standardized methods from MRI, by presence or absence of specific retinal microvascular abnormality (eg, microaneurysm, retinal hemorrhage) on retinal photograph; incident clinical stroke, ascertained after a median follow-up of 4.7 years, according to presence or absence of WMLs and retinopathy. RESULTS: Persons with retinopathy were more likely to have WMLs than those without retinopathy (22.9% vs 9.9%; odds ratio, 2.5; 95% confidence interval [CI], 1.5-4.0, adjusted for age, sex, race, and vascular risk factors). The 5-year cumulative incidence of clinical stroke was higher in persons with vs without WMLs (6.8% vs 1.4%; adjusted relative risk [RR], 3.4; 95% CI, 1.5-7.7) and in persons with vs without retinopathy (8.0% vs 1.4%; adjusted RR, 4.9; 95% CI, 2.0-11.9). Persons with both WMLs and retinopathy had a significantly higher 5-year cumulative incidence of stroke than those without either WMLs or retinopathy (20.0% vs 1.4%; adjusted RR, 18.1; 95% CI, 5.9-55.4). CONCLUSIONS: In this cohort, middle-aged persons with cerebral WMLs detected on MRI were more likely to have retinal microvascular abnormalities and to have an increased risk of clinical stroke than people without WMLs. The risk of stroke was higher when retinopathy was simultaneously present in persons with WMLs.

Aged↗
PubMed2002

Retinal arteriolar narrowing and risk of diabetes mellitus in middle-aged persons.

CONTEXT: Microvascular processes have been hypothesized to play a role in the pathogenesis of type 2 diabetes mellitus, but prospective clinical data regarding this hypothesis are unavailable. OBJECTIVE: To examine the relation of retinal arteriolar narrowing, a marker of microvascular damage from aging, hypertension, and inflammation, to incident diabetes in healthy middle-aged persons. DESIGN, SETTING, AND PARTICIPANTS: The Atherosclerosis Risk in Communities Study, an ongoing population-based, prospective cohort study in 4 US communities that began in 1987-1989. Included in this analysis were 7993 persons aged 49 to 73 years without diabetes, of whom retinal photographs were taken during the third examination (1993-1995). MAIN OUTCOME MEASURES: Incident diabetes (defined as fasting glucose levels of > or =126 mg/dL [7.0 mmol/L], casual levels of > or =200 mg/dL [11.1 mmol/L], diabetic medications use, or physician diagnosis of diabetes at the fourth examination) by quartile of retinal arteriole-to-venule ratio (AVR). RESULTS: After a median follow-up of 3.5 years, 291 persons (3.6%) had incident diabetes. The incidence of diabetes was higher in persons with lower AVR at baseline (2.4%, 3.1%, 4.0%, and 5.2%, from highest to lowest AVR quartile; P for trend < .001). After controlling for fasting glucose and insulin levels, family history of diabetes, adiposity, physical activity, blood pressure, and other factors, persons in the lowest quartile of AVR were 71% more likely to develop diabetes than those in the highest quartile (odds ratio [OR], 1.71; 95% confidence interval [CI], 1.13-2.57; P for trend =.002). This association persisted with different diagnostic criteria (OR, 1.92; 95% CI, 1.10-3.36; P for trend =.01, using a fasting glucose level of > or =141 mg/dL [7.8 mmol/L] as a cutoff), and was seen even in people at lower risk of diabetes, including those without a family history of diabetes, without impaired fasting glucose, and with lower measures of adiposity. CONCLUSIONS: Retinal arteriolar narrowing is independently associated with risk of diabetes, supporting a microvascular role in the development of clinical diabetes.

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