Retinopathy in old persons with and without diabetes mellitus: the Age, Gene/Environment Susceptibility--Reykjavik Study (AGES-R).

AIMS/HYPOTHESIS: We aimed to describe the prevalence of retinopathy in an aged cohort of Icelanders with and without diabetes mellitus. METHODS: The study population consisted of 4,994 persons aged ≥ 67 years, who participated in the Age, Gene/Environment Susceptibility-Reykjavik Study (AGES-R). Type 2 diabetes mellitus was defined as HbA(1c) ≥ 6.5% (>48 mmol/mol). Retinopathy was assessed by grading fundus photographs using the modified Airlie House adaptation of the Early Treatment Diabetic Retinopathy Study protocol. Associations between retinopathy and risk factors were estimated using odds ratios obtained from multivariate analyses. RESULTS: The overall prevalence of retinopathy in AGES-R was 12.4%. Diabetes mellitus was present in 516 persons (10.3%), for 512 of whom gradable fundus photos were available, including 138 persons (27.0%, 95% CI 23.2, 31.0) with any retinopathy. Five persons (1.0%, 95% CI 0.3, 2.3) had proliferative retinopathy. Clinically significant macular oedema was present in five persons (1.0%, 95% CI 0.3, 2.3). Independent risk factors for retinopathy in diabetic patients in a multivariate model included HbA(1c), insulin use and use of oral hypoglycaemic agents, the last two being indicators of longer disease duration. In 4478 participants without diabetes mellitus, gradable fundus photos were available for 4,453 participants, with retinopathy present in 476 (10.7%, 95% CI 9.8, 11.6) and clinically significant macular oedema in three persons. Independent risk factors included increasing age and microalbuminuria. CONCLUSIONS/INTERPRETATION: Over three-quarters (78%) of retinopathy cases were found in persons without diabetes and a strong association between microalbuminuria and non-diabetic retinopathy was found. These results may have implications for patient management of the aged.

Diabetic retinopathy in the SEARCH for Diabetes in Youth Cohort: a pilot study.

AIMS: The aim of this pilot study was to generate an initial estimate of the prevalence and correlates of diabetic retinopathy in a racially and ethnically diverse sample of youth with Type 1 and Type 2 diabetes mellitus. METHODS: A pilot study was conducted among 222 individuals with Type 1 diabetes (79% non-Hispanic white, 21% other) and 43 with Type 2 diabetes (28% non-Hispanic white, 72% other), all of > 5 years duration (mean duration 6.8 years) who participated in the SEARCH for Diabetes in Youth study. Diabetic retinopathy was assessed using non-mydriatic retinal photography of both eyes. RESULTS: The prevalence of diabetic retinopathy was 17% for Type 1 diabetes and 42% for Type 2 diabetes (odds ratio 1.50, 95% CI 0.58-3.88; P = 0.40 adjusted for age, duration, gender, race/ethnicity, parental education and HbA(1c). HbA(1c) was significantly higher among those with any diabetic retinopathy (adjusted mean 79 mmol/mol, 9.4%) vs. no diabetic retinopathy (adjusted mean 70 mmol/mol, 8.6%) (P = 0.015). LDL cholesterol was also significantly higher among those with any diabetic retinopathy (adjusted mean 107.2 mg/dl) compared with those without diabetic retinopathy (adjusted mean 97.9 mg/dl) (P = 0.04). CONCLUSIONS: The prevalence of diabetic retinopathy in contemporary young individuals was substantial, particularly among minority youth and those with Type 2 diabetes. Further long-term study of diabetic retinopathy in youth is needed.

Genome-wide association identifies SKIV2L and MYRIP as protective factors for age-related macular degeneration.

Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly in the developed world. We conducted a genome-wide association study in a series of families enriched for AMD and completed a meta-analysis of this new data with results from reanalysis of an existing study of a late-stage case-control cohort. We tested the top findings for replication in 1896 cases and 1866 controls and identified two novel genetic protective factors for AMD. In addition to the complement factor H (CFH) (P=2.3 × 10⁻64) and age-related maculopathy susceptibility 2 (ARMS2) (P=1.2 × 10⁻6°) loci, we observed a protective effect at rs429608, an intronic SNP in SKIV2L (P=5.3 × 10⁻¹5), a gene near the complement component 2 (C2)/complement factor B (BF) locus, that indicates the protective effect may be mediated by variants other than the C2/BF variants previously studied. Haplotype analysis at this locus identified three protective haplotypes defined by the rs429608 protective allele. We also identified a new potentially protective effect at rs2679798 in MYRIP (P=2.9 × 10⁻4), a gene involved in retinal pigment epithelium melanosome trafficking. Interestingly, MYRIP was initially identified in the family-based scan and was confirmed in the case-control set. From these efforts, we report the identification of two novel protective factors for AMD and confirm the previously known associations at CFH, ARMS2 and C3.

The relationship of retinal vessel diameter to changes in diabetic nephropathy structural variables in patients with type 1 diabetes.

AIMS/HYPOTHESIS: We examined whether retinal vessel diameter in persons with type 1 diabetes mellitus is associated with changes in subclinical anatomical and functional indicators of diabetic nephropathy. METHODS: Persons with type 1 diabetes mellitus had gradable fundus photographs and renal biopsy data at baseline and 5-year follow-up (n = 234). Retinal arteriolar and venular diameters were measured at baseline and follow-up. Central retinal arteriole equivalent (CRAE) and central retinal venule equivalent (CRVE) were computed. Baseline and 5-year follow-up renal structural variables were assessed by masked electron microscopic morphometric analyses from percutaneous renal biopsy specimens. Variables assessed included: mesangial fractional volume, glomerular basement membrane width, mesangial matrix fractional volume and glomerular basement membrane width composite glomerulopathy index. RESULTS: While controlling for other covariates, baseline CRAE was positively associated with change in the glomerulopathy index over the 5-year period. Change in CRAE was inversely related to a change in mesangial matrix fractional volume and abnormal mesangial matrix fractional volume, while change in CRVE was directly related to change in the volume fraction of cortex that was interstitium [Vv((Int/cortex))] over the 5-year period. Baseline CRAE or CRVE or changes in these diameters were not related to changes in other anatomical or functional renal endpoints. CONCLUSIONS/INTERPRETATION: Independently of other factors, baseline CRAE correlated with changes in glomerulopathy index, a composite measure of extracellular matrix accumulation in the mesangium and glomerular basement membrane. A narrowing of the CRAE was related to mesangial matrix accumulation. Changes in CRVE were related to changes in Vv((Int/cortex),) a measure of interstitial expansion in persons with type 1 diabetes mellitus.

Test-retest reliability of the San Diego Odor Identification Test and comparison with the brief smell identification test.

This study described the San Diego Odor Identification Test (SDOIT) reliability and compared the SDOIT and the Brief Smell Identification Test (B-SIT). Ninety participants aged 50-70 years completed this 2-visit olfaction study. During visit 1, the SDOIT and B-SIT were administered according to standard protocols. Three weeks later, participants returned to retake the SDOIT. The SDOIT score was the total number of odorants correctly identified out of 8 odorants presented, and olfactory impairment was defined as correctly identifying less than 6 odorants. The B-SIT score was the total number of odorants correctly identified out of 12 odorants presented, and participants correctly identifying less than 9 odorants were categorized as abnormal. The SDOIT reliability was high (concordance correlation coefficient = 0.85, 95% confidence interval [CI] = 0.79-0.91). The same score was obtained on retest for 73% of participants, whereas 18% improved, and 9% declined. Test-retest agreement was 96% for the SDOIT; 4% improved from impaired at visit 1 to unimpaired at visit 2. Overall, SDOIT impairment classification and B-SIT abnormal classification agreed in 96% of participants (kappa = 0.81, 95% CI = 0.63-0.99). In conclusion, the SDOIT showed good test-retest reliability. Agreement for impaired/abnormal olfaction was demonstrated for the SDOIT and the B-SIT.

Association between glycosylated hemoglobin level and 16-year incidence of chronic kidney disease in type 1 diabetes.

CONTEXT: The incidence of recently defined outcome of chronic kidney disease (CKD) has not been widely reported in type 1 diabetes. OBJECTIVE: To examine the prospective association between baseline glycosylated hemoglobin levels and the 16-year incidence of CKD and end-stage renal disease (ESRD) in type 1 diabetes. DESIGN: Prospective cohort study of type 1 diabetes individuals. SETTING: Community based in southwestern Wisconsin. PARTICIPANTS: 547 younger-onset type 1 diabetes individuals who were free of CKD at baseline (1984-86). MAIN OUTCOME MEASURES: Development of CKD (defined as estimated glomerular filtration rate<60 ml/min/1.73 m(2) or ESRD [history of dialysis or renal transplantation]) over 16-year follow-up period, among individuals free of CKD at baseline. Alternate outcome was 16-year incident ESRD. RESULTS: After 16 years of follow-up, there were 158 cases of CKD and 37 cases of ESRD in our cohort. The 16-year cumulative incidence of CKD was 31.7 percent. Elevated glycosylated hemoglobin levels were associated with incident CKD and ESRD in separate models. Multivariable odds ratio (OR) [95% confidence intervals (CI)] comparing the highest quartile of glycosylated hemoglobin (11-15.3%) to the lowest quartile (6-8.6%) was 6.44 (3.61-11.51), p-trend<0.0001 for incident CKD and 21.87 (2.84-168.39), p-trend<0.0001 for ESRD. CONCLUSIONS: Higher baseline glycosylated hemoglobin levels are independently associated with incident CKD and ESRD, among individuals with type 1 diabetes.

Vitamin D Status and Prevalent Early Age-Related Macular Degeneration in African Americans and Caucasians: The Atherosclerosis Risk in Communities (ARIC) Study.

OBJECTIVES: Vitamin D status has been hypothesized to protect against development of early age-related macular degeneration (AMD) via its anti-inflammatory properties and its possible beneficial influence on blood pressure control. We investigated the association between vitamin D status and prevalent early AMD in a community-based cohort. DESIGN: This was a cross-sectional study. SETTING: This was a secondary data analysis of already existing data from the Atherosclerosis Risk in Communities Study (ARIC) cohort collected from 1990 to 1995. PARTICIPANTS: There were 9,734 (7,779 Caucasians, 1,955 African American) ARIC participants (aged 46 to 70 at visit 2 [1990-1992]) with 25(OH)D data available at visit 2, AMD assessment at visit 3 (1993-1995), and complete covariate data. MEASUREMENTS: Vitamin D status was assessed with serum 25-hydroxyvitamin D (25(OH)D) concentrations from bloods drawn at visit 2. Prevalent, early AMD (n=511) was assessed at visit 3 (1993-95) with nonmydriatic retinal photographs of one randomly chosen eye. Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for early AMD by categories of 25(OH)D in nmol/L (deficient <30, inadequate 30-<50, and two categories of adequate status: 50-<75 and ≥75). Linear trend was estimated using continuous 25(OH)D concentrations. ORs were adjusted for age, race, and smoking status. We further adjusted for hypertension status to examine if vitamin D status influenced early AMD via its effects on blood pressure. Exploratory analyses of effect modification by age, sex, race and high risk genotypes [Y402H complement factor H (CFH) rs1061170 and the A69S age-related maculopathy susceptibility 2 (ARMS2) rs10490924 polymorphisms] were conducted. RESULTS: The prevalence of early AMD was 5%, and 5% of participants were vitamin D deficient. The adjusted OR (95% CIs) for early AMD among those with adequate (≥75 nmol/L) compared to deficient (<30 nmol/L) vitamin D status was 0.94 (0.59-1.50), p-trend=0.86. Further adjustment for hypertension status did not influence results (OR [95% CI]=0.95 [0.59-1.52], p-trend=0.84). Results did not vary significantly by age, race, sex, early AMD subtype (soft drusen or retinal pigment epithelium depigmentation), or ARMS2 genotype. Results did not vary significantly by CFH genotype in African Americans. The p for multiplicative interaction between 25(OH)D and CFH genotype was 0.06 in Caucasians, but OR [95% CIs] for AMD by vitamin D status were similar in each CFH genotype and not statistically significant. CONCLUSIONS: Vitamin D status was not associated with early AMD in this cohort sample.

The association between serum uric acid level and long-term incidence of hypertension: Population-based cohort study.

Increasing experimental evidence, including recently developed animal models support a causal role for uric acid in the development of hypertension. However, it is not clear whether serum uric acid levels are independently associated with the long-term incidence of hypertension. We examined the association between serum uric acid levels and 10-year incidence of hypertension in a population-based cohort study based in Beaver Dam city and township, Wisconsin, US. We studied 2520 hypertension-free individuals (56.3% women, age: 43-84 years, 98% Caucasian) at the baseline examination (1988-1990). The main outcome of interest was hypertension (systolic blood pressure (BP) of 140 mm Hg or higher, diastolic BP 90 mm Hg or higher, or combination of self-reported high BP diagnosis and use of antihypertensive medications) incidence over 10 years among baseline normotensive individuals. Nine hundred and fifty-six individuals developed hypertension over a 10-year follow-up period. The relative risk (RR) (95% confidence intervals (CI)) of incident hypertension increased in a dose-dependent manner (P-trend < 0.05 in all models) with increasing uric acid quartiles. Multivariable RR (95% CI) comparing the highest quartile of serum uric acid (> or =390 micromol/l) to the lowest quartile (< or =260 micromol/l) was 1.65 (1.41-1.93). This association persisted in subgroup analyses by categories of smoking, alcohol intake, body mass index, baseline blood pressure and estimated glomerular filtration rate (GFR). In conclusion, increasing quartiles of serum uric acid was associated with 10-year incidence of hypertension independent of smoking, alcohol intake and baseline kidney function suggesting an independent positive association between serum uric acid levels and hypertension development among community-dwelling older adults.

Physical activity and the 15-year cumulative incidence of age-related macular degeneration: the Beaver Dam Eye Study.

BACKGROUND: Cardiovascular disease and age-related macular degeneration (AMD) may share common risk factors. Physical activity improves the cardiovascular risk profile; however, there have been few studies investigating a relationship between physical activity and the long-term incidence of AMD. METHODS: The 15-year cumulative incidence of AMD was determined through four examination phases at 5-year intervals of a population-based study conducted in Beaver Dam, Wisconsin, USA, initiated in 1988-90 (n = 3874 men and women between ages 43 and 86 years). Early AMD (pigment abnormalities or soft indistinct drusen), exudative AMD and geographic atrophy were determined by grading stereoscopic colour fundus photographs. Measures of physical activity were obtained through a questionnaire administered at the baseline examination. RESULTS: After controlling for age, sex, history of arthritis, systolic blood pressure, body mass index, smoking and education, people with an active lifestyle (defined as regular activity > or =3 times/week) at baseline were less likely to develop exudative AMD (odds ratio (OR) 0.3, 95% confidence interval (CI) 0.1 to 0.7) compared with people without an active lifestyle. After multivariate adjustment, increased categories of number of blocks walked per day decreased the risk of exudative AMD (OR 0.7, 95% CI 0.6 to 0.97). Physical activity was not related to the incidence of early AMD or pure geographic atrophy. CONCLUSIONS: These data show a protective effect of physical activity for incident exudative AMD, independent of body mass index and other confounders. They also suggest a possible modifiable behaviour that might be protective against developing AMD.

The use of hearing protection devices by older adults during recreational noise exposure.

A population-based study to assess the use of hearing protection devices by older adults during noisy recreational activities was performed. The population-based Epidemiology of Hearing Loss Study was designed to measure the prevalence of hearing loss in adults residing in Beaver Dam, Wisconsin. The use of hearing protection devices during noisy recreational activities was assessed by performing three examinations over a period of 10 years (1993-1995, no. of participants (n)=3753, aged 48-92 years; 1998-2000, n=2800, aged 53-97 years; 2003-2005, n=2395, aged 58-100 years). The recreational activities included hunting, target shooting, woodworking/carpentry, metalworking, driving loud recreational vehicles, and performing yard work using either power tools or a chain saw. The prevalence of using hearing protection devices during any of these activities increased with time (9.5%, 15.0%, and 19.9% at baseline, 5 years, and 10 years, respectively). However, the use of hearing protection devices remained low for most activities. Those under the age of 65 were twice as likely to use hearing protection devices during noisy activities than were older adults. Men, those with a hearing handicap, and those with significant tinnitus were more likely to use hearing protection devices. Smokers and the less educated were less likely to use hearing protection devices. The results demonstrated that many adults expose themselves to potentially damaging recreational noise, leaving them at risk for hearing loss.

Incidence of gross proteinuria in older-onset diabetes. A population-based perspective.

A few population-based studies describe the incidence of gross proteinuria in people with diabetes. We performed a population-based study in southern Wisconsin of diabetic individuals diagnosed at > or = 30 yr of age either taking insulin (n = 398) or not taking insulin (n = 441). The presence of gross proteinuria (> or = 0.3 g/L) was determined by means of a reagent strip. The incidence of proteinuria in the 4-yr interval was 17.3% (95% CI 13.6-21.0) in those taking insulin and 10.7% (95% CI 7.8-13.6) in those not taking insulin. The relative risk of developing proteinuria for those in the highest level of total pack-yr smoked compared with those who had never smoked was 2.0 (95% CI 1.2-3.3) for those taking insulin and 2.5 (95% CI 1.3-4.5) for those not taking insulin. After controlling for other risk variables, the incidence of gross proteinuria was also associated with higher GHb. These data suggest that smoking and glycemic control, both potentially modifiable factors, are significant risk factors for the development of gross proteinuria.

The Wisconsin Epidemiologic Study of Diabetic Retinopathy. XVI. The relationship of C-peptide to the incidence and progression of diabetic retinopathy.

The relationship between plasma C-peptide and the 6-year incidence and progression of diabetic retinopathy was examined in a population-based study in Wisconsin. Individuals with younger-onset (n = 548) and older-onset (n = 459) diabetes were included. C-peptide was measured by radioimmunoassay with Heding's M1230 antiserum. Retinopathy was determined from stereoscopic fundus photographs. Younger- and older-onset insulin-using individuals with undetectable or low plasma C-peptide (< 0.3 nmol/l) at baseline had the highest incidence and rates of progression of retinopathy, whereas older-onset individuals with C-peptides > 0.3 nmol/l had the lowest incidence and rates of progression of retinopathy. However, within each group (younger-onset using insulin, older-onset using insulin, and older-onset not using insulin), after we controlled for other characteristics associated with retinopathy, there was no relationship between higher levels of C-peptide at baseline and lower 6-year incidence or progression of retinopathy. These data suggest that glycemic control, and not C-peptide, is related to the incidence and progression of diabetic retinopathy.

Ten-year incidence of gross proteinuria in people with diabetes.

There are few population-based epidemiological data describing the long-term incidence of gross proteinuria in people with diabetes. We performed a population-based study in southern Wisconsin of individuals with diabetes diagnosed at either < 30 years of age and taking insulin (younger-onset, n = 666) or > or = 30 years of age either taking (older-onset taking insulin, n = 376) or not taking insulin (older-onset not taking insulin, n = 418). The presence of gross proteinuria (> or = 0.3 g/l) was determined by means of a reagent strip. The incidence of proteinuria in the 10-year interval was 28% in the younger-onset group, it was 40% in the older-onset group taking insulin, and it was 33% in the older-onset group not taking insulin. After we controlled for other risk factors, the 10-year incidence of proteinuria was significantly related to higher glycosylated hemoglobin level and diastolic blood pressure at baseline and to an increase in glycosylated hemoglobin level and an increase in diastolic blood pressure from baseline to the 4-year follow-up in the younger-onset group and to higher glycosylated hemoglobin level, higher systolic blood pressure, and higher total pack-years of cigarettes smoked at baseline and an increase in systolic blood pressure from baseline to the 4-year follow-up in the older-onset groups. These data suggest that modification of three factors--hyperglycemia, high blood pressure, and smoking--may lead to a reduction in the long-term incidence of proteinuria.

Association of elevated IGF-I levels with increased retinopathy in late-onset diabetes.

Insulinlike growth factor I (IGF-I) has been suggested to play a role in the pathogenesis of proliferative diabetic retinopathy (PDR). We determined IGF-I levels in subjects in a large population-based study of 928 people with diabetes diagnosed at 30 yr of age or older. PDR was found in 15.7% of the insulin-using group (n = 517) and in 2.8% of those not using insulin (n = 397). The mean serum level of IGF-I was 208 micrograms/L in individuals using insulin and 222 micrograms/L in those not using insulin, both significantly lower than in a nondiabetic comparison group (278 micrograms/L, P less than 0.0001). Logistic regression analysis was used to examine the relationship between IGF-I and PDR while controlling for other factors associated with the presence of PDR. After controlling for duration of diabetes, glycosylated hemoglobin, systolic blood pressure, presence of proteinuria, and age at diagnosis, higher levels of IGF-I were significantly associated with an increased frequency of PDR (P = 0.025) in the group using insulin. In individuals not using insulin, higher levels of IGF-I were associated with an increased frequency of PDR or moderate non-PDR (P = 0.08). These data suggest that higher IGF-I levels may be a risk factor for the development of severe retinopathy in people with diabetes diagnosed at 30 yr of age or older.

Does insulin-like growth factor I predict incidence and progression of diabetic retinopathy?

We evaluated the relationship of insulin-like growth factor (IGF)-I to incidence and progression of diabetic retinopathy over a 6-year interval in a large population-based study of diabetes in southern Wisconsin. Participants included people with younger-onset diabetes (n = 66 adolescents, n = 661 adults > or = 18 years of age) and older-onset diabetes (n = 285 for those using insulin, n = 248 for those not using insulin). Fundus photographs were graded in a masked fashion using standardized protocols to determine the severity of retinopathy in each eye. Serum IGF-I levels were measured during 1984-1986 using a double-antibody radioimmunoassay. Mean IGF-I was highest in adolescents (499.1 micrograms/l), lower in younger-onset adult (280.1 micrograms/l), and lowest in the older-onset group (205.7 and 221.2 micrograms/l for older-onset group using insulin and not using insulin, respectively). The incidence of retinopathy was not significantly higher in people with higher IGF-I levels in any group. The odds of developing diabetic retinopathy in 6 years for each 10 micrograms/l increase in IGF-I after controlling for age, glycosylated hemoglobin, and duration of diabetes at baseline was 1.21 (95% confidence interval [CI] 0.95-1.54) for adolescents; 1.00 (95% CI 0.93-1.08) for younger-onset adults; 0.93 (95% CI 0.85-1.02) for the older-onset group using insulin; and 0.99 (95% CI 0.95-1.04) for the older-onset group not using insulin. In summary, IGF-I was not associated with 6-year incidence or progression of diabetic retinopathy in any of the groups.

Is insulinlike growth factor I associated with diabetic retinopathy?

Insulinlike growth factor I (IGF-I) is the mediator of the growth-promoting effects of growth hormone and has been suspected of playing a role in the pathogenesis of proliferative diabetic retinopathy (PDR). However, previous attempts to correlate IGF-I levels with PDR have yielded conflicting results. We determined IGF-I levels in a large population-based study of 682 early-onset (diagnosed before 30 yr of age) adult (greater than or equal to 18 yr old) insulin-taking diabetic subjects. PDR was found in 25% of the population. IGF-I levels were measured by radioimmunoassay. The mean serum level of IGF-I was 277 +/- 108 micrograms/L (mean +/- SD). Spearman rank correlations showed statistically significant negative correlations between IGF-I levels and age (r = -0.51, P less than 0.0001), duration of disease (r = -0.36, P less than 0.0001), and glycosylated hemoglobin (r = -0.09, P less than 0.05). There was a significant trend (P less than 0.001) toward decreasing risk of PDR with increasing IGF-I. However, after controlling for duration of diabetes, glycosylated hemoglobin, diastolic blood pressure, and the presence of proteinuria and/or creatinine greater than or equal to 265 microM in a multiple logistic regression model, IGF-I was not significantly associated with PDR. These data suggest that IGF-I may not be a risk factor for the development of PDR.

Wisconsin Epidemiologic Study of Diabetic Retinopathy. XII. Relationship of C-peptide and diabetic retinopathy.

The relationship between plasma C-peptide and the frequency and severity of diabetic retinopathy was examined in a population-based study in Wisconsin in 1984-1986. Individuals with younger- (n = 835) and older- (n = 940) onset diabetes were included. C-peptide was measured by radioimmunoassay with Heding's M1230 antiserum. Retinopathy was determined from stereoscopic fundus photographs. The highest frequencies and most severe retinopathy were found in insulin-using individuals with undetectable or low plasma C-peptide (less than 0.3 nM), whereas the lowest frequencies of retinopathy were found in older-onset overweight individuals not using insulin. In older-onset individuals using insulin, having no detectable C-peptide was significantly associated with the presence of proliferative retinopathy. Otherwise, within each group (younger onset using insulin, older onset using insulin, and older onset not using insulin), after controlling for other characteristics associated with retinopathy, there was no relationship between higher levels of C-peptide and lower frequency of or less severe retinopathy.

The prevalence of age-related maculopathy by geographic region and ethnicity.

The prevalence of age-related maculopathy (ARM) varies considerably in different locations and racial/ethnic groups around the world. At present there are insufficient data to determine whether it is likely that these differences in prevalence, especially for the early forms of ARM are due to variations in genetic and environmental factors or due to variations in age of the cohorts and methods used to ascertain and define ARM. In three population-based studies of whites living in Beaver Dam, Wisconsin, Blue Mountains, Australia, and Rotterdam, The Netherlands, in which similar methods of ascertainment and classification were used to detect and define ARM, late ARM was present in 1.2%, 1.4%, and 1.2% of the population less than 86 years of age, respectively. While data from clinical studies suggest that late ARM associated with choroidal neovascularization is rare in blacks compared with whites, some epidemiological studies suggest that late ARM may be similar in blacks and whites. There are still too few data from various ethnic/racial groups around the world and too few population-based data in older Hispanic and Asian populations to make meaningful comparisons. There is a need for further research into the distribution of ARM and its possible causes using similar methodologies to ascertain and define the disease. Further insights will be gained when genotypes associated with ARM are discovered.

Intraocular pressure and systemic blood pressure: longitudinal perspective: the Beaver Dam Eye Study.

AIM: To investigate the relation between change in systemic blood pressures and change in intraocular pressure. METHODS: This was a population based study of people 43-86 years old living in Beaver Dam, Wisconsin. Measurements at baseline (1988-90) and 5 year follow up of systemic blood pressures, intraocular pressures, and history of use of blood pressure medications. RESULTS: Intraocular pressures were significantly correlated with systolic and diastolic blood pressures at both baseline and follow up. There were significant direct correlations between changes in systemic blood pressures and changes in intraocular pressure. There was a 0.21 (95% CI: 0.16 to 0.27) mm Hg increase in IOP for a 10 mm Hg increase in systolic and 0.43 (0.35 to 0.52) mm Hg increase in IOP for a 10 mm Hg increase in diastolic blood pressure. Further adjustment for diabetes and medication use did not alter these associations. Decreased systolic or diastolic blood pressures of more than 10 mm Hg over 5 years were significantly associated with decreased IOP. CONCLUSIONS: Reduced systemic blood pressure is associated with reduced intraocular pressure. This finding should be evaluated in other studies, especially with respect to the possibility of resultant decreased risk of open angle glaucoma.

Risk factors for hospitalization in people with diabetes.

OBJECTIVE: To determine factors predicting hospitalization in people with diabetes. METHODS: Two population-based groups with diabetes were examined at baseline (1980-1982), 4 years (1984-1986), and 10 years (1990-1992). The younger-onset group (n = 777) consisted of all persons diagnosed as having diabetes before age 30 years who were taking insulin, and the older-onset group (n = 542) consisted of a sample of persons diagnosed after age 30 years. At the 10-year examination, participants were asked if they had been hospitalized in the previous year. Factors from the 4-year examination were examined for their ability to predict hospitalization at the 10-year examination. RESULTS: In the younger-onset group, 25.5% reported being hospitalized. In logistic models, glycosylated hemoglobin level (odds ratio [OR], 1.27; 95% confidence interval [CI], 1.16-1.39 for a 1% increment) and hypertension (OR, 1.60; 95% CI, 1.08-2.38) predicted hospitalization. Factors that were not significant included age, sex, systolic and diastolic blood pressures, body mass, smoking status, and alcohol consumption. In the older-onset group, 30.8% reported being hospitalized. In logistic models, only glycosylated hemoglobin level (OR, 1.16; 95% CI, 1.06-1.29 for a 1% increment) predicted hospitalization. CONCLUSIONS: Glycemic control is subject to intervention. Better control may decrease hospitalization among people with diabetes. Thus, there is considerable potential for reducing health care costs.