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 × 10⁻⁶⁰) 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.

Self- and registry-reported cancer in a population-based longitudinal study

PURPOSE

To evaluate the concordance of cancer diagnosis from self- and registry reports.

METHODS

Self-reported diagnosis information from participants in a cohort study was compared with linkage data from the Wisconsin Cancer Reporting System.

RESULTS

Overall, there was good agreement between self- and registry-reported cancers, with 90% of all matches being considered an exact match. Concordance varied by cancer site; agreement was excellent for breast (85.4%) and prostate (78.9%) cancers.

CONCLUSIONS

While self-reported cancer diagnoses for some cancers such as breast and prostate cancer are important sources of information and may be reliable substitutes when registry data are incomplete or not available, a combination of self and registry reports with mortality information may yield the most accurate information about cancer for purposes of health care planning and conducting epidemiologic studies.

Estimating glomerular filtration rate in a population-based study

BACKGROUND

Glomerular filtration rate (GFR)-estimating equations are used to determine the prevalence of chronic kidney disease (CKD) in population-based studies. However, it has been suggested that since the commonly used GFR equations were originally developed from samples of patients with CKD, they underestimate GFR in healthy populations. Few studies have made side-by-side comparisons of the effect of various estimating equations on the prevalence estimates of CKD in a general population sample.

PATIENTS AND METHODS

We examined a population-based sample comprising adults from Wisconsin (age, 43-86 years; 56% women). We compared the prevalence of CKD, defined as a GFR of <60 mL/min per 1.73 m(2) estimated from serum creatinine, by applying various commonly used equations including the modification of diet in renal disease (MDRD) equation, Cockcroft-Gault (CG) equation, and the Mayo equation. We compared the performance of these equations against the CKD definition of cystatin C >1.23 mg/L.

RESULTS

We found that the prevalence of CKD varied widely among different GFR equations. Although the prevalence of CKD was 17.2% with the MDRD equation and 16.5% with the CG equation, it was only 4.8% with the Mayo equation. Only 24% of those identified to have GFR in the range of 50-59 mL/min per 1.73 m(2) by the MDRD equation had cystatin C levels >1.23 mg/L; their mean cystatin C level was only 1 mg/L (interquartile range, 0.9-1.2 mg/L). This finding was similar for the CG equation. For the Mayo equation, 62.8% of those patients with GFR in the range of 50-59 mL/min per 1.73 m(2) had cystatin C levels >1.23 mg/L; their mean cystatin C level was 1.3 mg/L (interquartile range, 1.2-1.5 mg/L). The MDRD and CG equations showed a false-positive rate of >10%.

DISCUSSION

We found that the MDRD and CG equations, the current standard to estimate GFR, appeared to overestimate the prevalence of CKD in a general population sample.

Chitinase induce the release of IL-8 in human airway epithelial cells, via Ca2+-dependent PKC and ERK pathways

Chitinases are produced in significant quantities by hosts defending against infections with chitin-containing organisms. However, little is known about the immune response of exogenous chitinase in human epithelial cells. IL-8 has been suggested to have a role in the pathogenesis of the allergenic inflammation of bronchial asthma. We examined whether Streptomyces griseus (S. griseus) chitinase-induced IL-8 on airway epithelium and identified the involvement of intracellular signalling pathways. H292 cells were treated with S. griseus chitinase with different concentrations and times. The IL-8 levels were determined by specific human IL-8 enzyme-linked immunosorbent assay (ELISA) and reverse transcriptase polymerase chain reaction. Using a series of pharmacological inhibitors, we examined the upstream signalling pathway responsible for IL-8 expression in response to S. griseus chitinase. Cells exposed to S. griseus chitinase showed higher level of IL-8 protein production and mRNA expression. Cells stimulated by S. griseus chitinase resulted in the activation of protein kinase C (PKC), extracellular signal-regulated kinase (ERK) and nuclear factor kappa-B (NF-kB) pathways. Inhibitors of Ca(2+)-dependent PKC (Ro-31-8220, calphostin C and Go6976) significantly abolished chitinase-induced expression of IL-8. However, Ca(2+)-independent PKC inhibitor (rottlerin) did not inhibit IL-8 expression. Through ERK inhibitor (U0126) and NF-kB inhibitor (caffeine acid phenethyl ester) treatment, it was proven that ERK and NF-kB regulated chitinase-induced IL-8 expression. We concluded that S. griseus chitinase-induced IL-8 expression was regulated by the activation of Ca(2+/-)-dependent PKC, ERK and NF-kB in human airway epithelial cells.

Retrodots in the lens in the Beaver Dam Eye Study cohort

OBJECTIVE

To determine the prevalence of retrodots in the lens and the association of these lesions to age-related cataract, and to assess their association with visual impairment and contrast sensitivity.

DESIGN

Longitudinal epidemiologic study.

PARTICIPANTS

The Beaver Dam Eye Study cohort.

METHODS

Eye examinations including grading of standard photographs of the lens and measures of visual function.

MAIN OUTCOME MEASURES

Statistical associations of retrodots with nuclear, cortical, and posterior subcapsular cataracts and with incident visual impairment and impairment of contrast sensitivity.

RESULTS

The prevalence of retrodots at the baseline examination increased with age from 1.68% in those 43 to 54 years of age to 31.20% in those ≥ 75 years of age. After controlling for age, there was no significant difference in the prevalence of retrodots between men and women. The odds ratio (OR) for visual impairment associated with retrodots was 2.22 (95% confidence interval [CI], 1.80-2.75) after controlling for age-related cataracts and other associated characteristics. The association with impaired contrast sensitivity was not significant. Retrodots were not significantly associated with incidence of any type of age-related cataract. The 15-year cumulative incidence of retrodots in right eyes increased with age from 9.3% in those 43 to 54 years of age to 21.1% in those ≥ 75 years of age. In addition to age, incidence of retrodots was independently associated with smoking (OR, 1.27; 95% CI, 1.04-1.56 for ever vs never smoking).

CONCLUSIONS

Retrodots are frequently occurring age-related lens opacities that are associated with decreased vision independent of the presence of age-related cataract. Their incidence is associated with smoking. Further research to determine the underlying process leading to retrodots is necessary before efforts to develop preventions are undertaken.

Selected sun-sensitizing medications and incident cataract

OBJECTIVE

To examine the relationship between the use of sun-sensitizing medications and cumulative incidence of age-related cataract.

METHODS

Sun exposure was estimated from residential history of adults in the Midwestern community of Beaver Dam, Wisconsin, which permitted calculation of Wisconsin sun-years at the baseline examination. Medication history was reported at each examination. Cataract presence was determined by standardized lens photographs that were taken at each examination and graded according to standard protocols.

RESULTS

No significant effects were noted of Wisconsin sun-year exposure or use of sun-sensitizing medications on the cumulative incidence of any type of age-related cataract when controlling for age and sex. However, an interaction term combining Wisconsin sun-years and use of any sun-sensitizing medication was significant (P = .04) such that risk of cortical cataract is significantly higher for the joint risk group. Further controlling for the presence of diabetes mellitus, history of heavy drinking, and hat or sunglasses use did not alter the relationships.

CONCLUSIONS

Data suggest that the use of sun-sensitizing medications interacts with sun exposure to influence the risk of cortical cataract, a common age-related cataract. If confirmed, this finding may have important implications for medication use.

Inflammatory and endothelial dysfunction markers and proteinuria in persons with type 1 diabetes mellitus

OBJECTIVE

We examined the relationship of inflammatory and endothelial dysfunction markers with the prevalence and incidence of gross proteinuria (GP) in persons with type 1 diabetes mellitus.

DESIGN

A longitudinal population-based cohort of persons with type 1 diabetes mellitus was followed from 1990-1992 through 2005-2007.

METHODS

Prevalence and 15-year cumulative incidence of GP were defined as outcome variables. Serum high-sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-alpha), soluble vascular cell adhesion molecule-1 (VCAM-1), soluble intercellular adhesion molecule-1, and serum total homocysteine were measured. Multivariate logistic and discrete linear logistic regression modeling was used for data analysis.

RESULTS

After controlling for duration of diabetes and other confounding factors, TNF-alpha (odds ratio (OR) 3.64; 95% confidence interval (CI) 2.33, 5.70), IL-6 (OR 1.41; 95% CI 1.06, 1.88), VCAM-1 (OR 13.35; 95% CI 5.39, 33.07), and homocysteine (OR 2.98; 95% CI 1.73, 5.16) were associated with prevalent proteinuria. Only hsCRP (OR 1.47; 95% CI 1.02, 2.11) was associated with incident proteinuria.

CONCLUSIONS

These findings suggest a role of inflammation and endothelial dysfunction as markers and contributors of the development of diabetic nephropathy in persons with type 1 diabetes mellitus.

De novo appearance of primitive neuroectodermal tumor in a patient with systemic lupus erythematosus and moyamoya disease

Primitive neuroectodermal tumor is a rare brain tumor composed of undifferentiated or poorly differentiated neuroepithelial cells with a high malignant potential that usually occurs in children, and which is only occasionally encountered in adults. A 19-year-old female with systemic lupus erythematosus presented with right hemiparesis and a headache of 10 days duration. Brain magnetic resonance imaging showed a large solid mass with necrotic portions in the left frontoparietal lobe. Primitive neuroectodermal tumor was confirmed by a neuronavigator-guided brain biopsy. This is the first case report of primitive neuroectodermal tumor associated with systemic lupus erythematosus and moyamoya disease. This case demonstrates that brain tumors, such as primitive neuroectodermal tumor, should be included in the differential diagnosis of neurological manifestations in children and adolescent patients with systemic lupus erythematosus.

Serum calcium and breast cancer risk in a prospective cohort study

Calcium has anti-proliferative and pro-differentiation effects on mammary cells in vitro and can inhibit the development of mammary tumors in mice. While there is some epidemiologic evidence for an inverse relation between dietary calcium intake and breast cancer risk, only one previous study has examined serum calcium levels in relation to breast cancer risk. We investigated this relation in a prospective cohort study of 2,762 women, aged 43-86, who were enrolled in the Beaver Dam Eye Study in 1988 and followed for up to 19 years. We found no evidence for an association between breast cancer risk and either total (hazard ratio, HR = 0.98; 95% CI: 0.60-1.60; 4(th) vs. 1(st) quartile) or ionized (HR = 0.85; 95% CI: 0.53, 1.38; 4(th) vs. 1(st) quartile) serum calcium levels. Additionally, we found no evidence for an association among subgroups defined by menopausal status and body mass index.

Genome-wide linkage analysis of multiple metabolic factors: evidence of genetic heterogeneity

The metabolic syndrome is a highly complex disease and has become one of the major public-health challenges worldwide. We sought to identify genetic loci with potential influence on multiple metabolic factors in a white population in Beaver Dam, Wisconsin, and to explore the possibility of genetic heterogeneity by family history of diabetes (FHD). Three metabolic factors were generated using principal-component factor analysis, and they represented: (i) glycemia, (ii) blood pressure, and (iii) combined (BMI, high-density lipoprotein (HDL) cholesterol, and serum uric acid) factors. Multipoint model-free linkage analysis of these factors with 385 microsatellite markers was performed on 1,055 sib-pairs, using Haseman-Elston regression. Genome-wide suggestive evidence of linkage was found at 30 cM on chromosome 22q (empirical P (P(e)) = 0.0002) for the glycemia factor, at 188-191 cM on chromosome 1q (P(e) = 0.0007) for the blood pressure factor, and at 82 cM on chromosome 17q (P(e) = 0.0007) for the combined factor. Subset analyses of the families by FHD showed evidence of genetic heterogeneity, with divergent linkage signals in the subsets on at least four chromosomes. We found evidence of genetic heterogeneity by FHD for the three metabolic factors. The results also confirmed findings of previous studies that mapped components of the metabolic syndrome to a chromosome 1q region.

The 25-year incidence of visual impairment in type 1 diabetes mellitus the wisconsin epidemiologic study of diabetic retinopathy

OBJECTIVE

To examine the 25-year cumulative incidence of visual impairment (VI) and its relation to various risk factors.

DESIGN

Population-based study.

PARTICIPANTS

Nine hundred fifty-five insulin-taking persons living in an 11-county area in southern Wisconsin with type 1 diabetes diagnosed before age 30 years who participated in a baseline (1980-1982) and at least 1 of 4 follow-up (4-, 10-, 14-, and 25-year) examinations or who died before the first follow-up examination (n = 64).

METHODS

Best-corrected visual acuity (VA) was measured using a modification of the Early Treatment Diabetic Retinopathy Study protocol. Visual impairment and severe VI were defined as best-corrected VA in the better eye of 20/40 or worse and 20/200 or worse, respectively.

MAIN OUTCOME MEASURES

Incidence of VI.

RESULTS

The 25-year cumulative incidences of any VI and severe VI (accounting for competing risk of death) were 13% and 3%, respectively. Multivariate models showed increased risk of VI was associated (hazard ratio, 95% confidence interval, and P value) with more severe baseline retinopathy (1.14 per 1-step increase in retinopathy level; 1.03-1.27; P = 0.01), presence of cataract (2.49 versus absence; 1.53-4.04; P<0.001), higher glycosylated hemoglobin (1.28 per 1%; 1.16-1.42; P<0.001), presence of hypertension (1.72 versus absence; 1.05-2.83; P = 0.03), and currently smoking (vs. never smoked, 1.63; 1.01-2.61; P = 0.04), but not proteinuria.

CONCLUSIONS

These data show that the 25-year cumulative incidence of VI is related to modifiable risk factors and, therefore, that VI may be reduced by better glycemic and blood pressure control and avoidance of smoking.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

EPHA2 is associated with age-related cortical cataract in mice and humans

Age-related cataract is a major cause of blindness worldwide, and cortical cataract is the second most prevalent type of age-related cataract. Although a significant fraction of age-related cataract is heritable, the genetic basis remains to be elucidated. We report that homozygous deletion of Epha2 in two independent strains of mice developed progressive cortical cataract. Retroillumination revealed development of cortical vacuoles at one month of age; visible cataract appeared around three months, which progressed to mature cataract by six months. EPHA2 protein expression in the lens is spatially and temporally regulated. It is low in anterior epithelial cells, upregulated as the cells enter differentiation at the equator, strongly expressed in the cortical fiber cells, but absent in the nuclei. Deletion of Epha2 caused a significant increase in the expression of HSP25 (murine homologue of human HSP27) before the onset of cataract. The overexpressed HSP25 was in an underphosphorylated form, indicating excessive cellular stress and protein misfolding. The orthologous human EPHA2 gene on chromosome 1p36 was tested in three independent worldwide Caucasian populations for allelic association with cortical cataract. Common variants in EPHA2 were found that showed significant association with cortical cataract, and rs6678616 was the most significant in meta-analyses. In addition, we sequenced exons of EPHA2 in linked families and identified a new missense mutation, Arg721Gln, in the protein kinase domain that significantly alters EPHA2 functions in cellular and biochemical assays. Thus, converging evidence from humans and mice suggests that EPHA2 is important in maintaining lens clarity with age.

Cataract is the leading cause of blindness. Cataract may form at any age, but the peak incidence is bimodal—in the perinatal period or later than 50 years of age. The early onset forms follow Mendelian inheritance patterns and are rare. Age-related cataract accounts for 18 million cases of blindness and 59 million cases of reduced vision worldwide. Among three types of age-related cataract, cortical cataract is known to be highly heritable, although few genes have been linked to its etiology. We report here that EPHA2 is associated with cortical cataract. EPHA2 is expressed in mouse and human cortical lens fiber cells, and homozygous deletion of Epha2 in two independent strains of mice led to development of cataract that progressed with age. Common and rare variants including a missense mutation in the EPHA2 gene were associated for cortical cataract in three different Caucasian populations. Our study identified EPHA2 as a gene for human age-related cataract and established Epha2 knockout mice as a model for progressive cortical cataract.

Changes in visual impairment prevalence by period of diagnosis of diabetes: the Wisconsin Epidemiologic Study of Diabetic Retinopathy

OBJECTIVE

To examine relationships of period of diagnosis of type 1 diabetes mellitus (T1DM) to the prevalence of visual impairment (VI).

DESIGN

Population-based longitudinal study.

PARTICIPANTS

Nine hundred fifty-five persons (3719 participant visits) 4 to 80 years of age at baseline who lived in an 11-county area in southern Wisconsin who were diagnosed with T1DM before 30 years of age contributed to the prevalence of VI.

METHODS

Five eye examination visits occurred in the following periods: 1980 through 1982, 1984 through 1986, 1990 through 1992, 1995 through 1996, and 2005 through 2007. Age of diagnosis of T1DM was grouped as before 1960, 1960 through 1969, 1970 through 1974, and 1975 through 1979. Best-corrected visual acuity (VA) using a modification of the Early Treatment Diabetic Retinopathy protocol was measured.

MAIN OUTCOME MEASURES

Visual impairment was defined as best-corrected VA in the better eye of 20/40 or worse.

RESULTS

While controlling for duration of T1DM, there was a lower prevalence of VI for more recent periods of diagnosis of diabetes (odds ratio per category, 0.91; 95% confidence interval, 0.88-0.93; P<0.001). This remained while controlling for glycosylated hemoglobin, blood pressure, and other related factors.

CONCLUSIONS

More recently diagnosed T1DM was associated with a lower prevalence of VI. This is likely because of the diminishing incidence of proliferative diabetic retinopathy (PDR) and clinically significant macular edema (CSME) resulting from better glycemic control and more timely interventions with photocoagulation for CSME and PDR in those with more recently diagnosed T1DM.

Heritability analysis of spherical equivalent, axial length, corneal curvature, and anterior chamber depth in the Beaver Dam Eye Study

OBJECTIVE

To examine genetic influences for quantitative refraction. Spherical equivalent and its related binary traits of myopia and hyperopia are highly correlated within families. Many linkage regions have been reported for myopia, high myopia, and quantitative refraction. However, the measured phenotype of spherical equivalent is in large part dictated by the relationship between the underlying optical components of axial length, corneal curvature, and anterior chamber depth.

METHODS

Using data from the fourth visit of the Beaver Dam Eye Study, we conducted familial correlation and heritability analysis of quantitative spherical equivalent, axial length, anterior chamber depth, and corneal curvature using data from 715 individuals in 189 pedigrees.

RESULTS

Overall, every trait was highly heritable. Heritability estimates were 0.58 (SE 0.13) for spherical equivalent after adjustment for age, education, and nuclear sclerosis; 0.95 (SE 0.11) for corneal curvature after adjustment for height; 0.67 (SE 0.14) for axial length after adjustment for height and education; and 0.78 (SE 0.14) for anterior chamber depth after adjustment for age, education, height, and nuclear sclerosis.

CONCLUSION

Refraction and the underlying traits of axial length, corneal curvature, and anterior chamber depth are highly heritable. Genetic analysis of these traits may provide greater insight into the development of refractive errors.

Patient self-report of prior laser treatment reliably indicates presence of severe diabetic retinopathy

PURPOSE

To determine whether patient self-report of prior laser treatment can be used as a reliable tool for assessing the presence of severe diabetic retinopathy.

DESIGN

This was a retrospective study on two groups of diabetic subjects.

METHODS

One hundred patients with diabetes were recruited from the general eye and retina clinics at the University of Chicago Hospitals. The patients were asked, "Have you ever received laser treatment for your diabetic eye disease (DED)?" A chart review was then conducted noting if the patient had received either focal laser treatment for diabetic macular edema or panretinal photocoagulation for proliferative diabetic retinopathy. Data from the Wisconsin Epidemiological Study of Diabetic Retinopathy (WESDR) were also analyzed. Participant responses to the question "Have you had laser photocoagulation treatment for your eyes?" were analyzed with documentation of photocoagulation scars determined by grading seven-standard field color fundus photographs.

RESULTS

In the University of Chicago group, 96 of 100 (96%) of patients were accurate in reporting whether they had received previous laser treatment for DED (sensitivity 95.8%, specificity 96.1%, and positive predictive value 88.5%). In the WESDR analysis, 2,329 of 2,348 (99%) of participants were accurate in reporting whether they had prior laser treatment for DED (sensitivity 96.0%, specificity 99.5%, and positive predictive value 95.6%).

CONCLUSIONS

The high sensitivity and specificity of our results validate the use of patient self-report as a useful tool in assessing past laser treatment for severe diabetic retinopathy. Patient self-report may be a useful surrogate to clinical examination or medical record review to determine the presence of severe diabetic retinopathy.

Serum cystatin C level, kidney disease markers, and incidence of age-related macular degeneration: the Beaver Dam Eye Study

OBJECTIVE

To examine the associations of the serum cystatin C level and chronic kidney disease with the incidence of age-related macular degeneration (AMD) over 15 years.

METHODS

In this population-based cohort study of 4926 individuals aged 43 to 86 years at baseline, 3779 participated in 1 or more follow-up examinations. Age-related macular degeneration was determined by grading photographs of the macula. Individuals were defined as having mild or moderate to severe chronic kidney disease based on a value of more than 45 mL/min/1.73 m(2) to 60 mL/min/1.73 m(2) or less and 45 mL/min/1.73 m(2) or less, respectively, according to the Modification of Diet in Renal Disease Study equation.

RESULTS

While controlling for age and other risk factors, the level of serum cystatin C at baseline was associated with the incidence of early AMD (odds ratio per log standard deviation [95% confidence interval], 1.16 [1.01-1.35]) and exudative AMD (1.42 [1.03-1.96]) but not geographic atrophy (0.89 [0.56-1.41]) or progression of AMD (1.02 [0.88-1.18]). Mild chronic kidney disease was associated with the 15-year cumulative incidence of early AMD (odds ratio per log standard deviation, 1.36 [95% confidence interval, 1.00-1.86]) but not the incidence of other AMD end points.

CONCLUSION

There is a relationship between the level of serum cystatin C and chronic kidney disease with the incidence of AMD. The underlying biological processes remain to be determined.

Association of age, stature, and education with ocular dimensions in an older white population

OBJECTIVE

To describe ocular biometry relationships in older white adults.

METHODS

Ocular dimensions were measured with partial coherence laser interferometry in 1968 persons (aged 58-100 years, 59% female) seen at the fourth examination of the Beaver Dam Eye Study. Generalized estimating equations-modeled associations of age, sex, height, and education with ocular dimensions: axial length, corneal curvature radius, and anterior chamber depth.

RESULTS

The mean axial length was 23.69 mm; mean corneal curvature radius was 7.70 mm; and mean anterior chamber depth was 3.11 mm. Participants younger than 65 years had larger eyes (longer axial length, greater corneal curvature radius, and deeper anterior chamber depth) than persons aged 75 years or older. Mean axial length was 23.86 mm, 23.66 mm, and 23.55 mm in people aged 64 years and younger, 65 to 74 years, and 75 years or older, respectively. Generally, larger eyes were observed in men (vs women) and in taller (>178 vs <or=158 cm) and more educated (>16 vs <12 years) persons. Adjustment for height accounted for all sex differences. Age differences in axial length were attenuated (P = .06) after adjustment for both height and education.

CONCLUSION

In this older white population, age and sex variations in ocular dimensions are partially explained by differences in stature and education.

The Wisconsin Epidemiologic Study of Diabetic Retinopathy XXIII: the twenty-five-year incidence of macular edema in persons with type 1 diabetes

OBJECTIVE

To examine the 25-year cumulative incidence of macular edema (ME) and its relation to various risk factors.

DESIGN

Population-based study.

PARTICIPANTS

A total of 955 insulin-taking persons living in an 11-county area in southern Wisconsin with type 1 diabetes diagnosed before age 30 years who participated in baseline examinations (1980-1982) and at least 1 of 4 follow-up (4-, 10-, 14-, and 25-year) examinations (n=891) or died before the first follow-up examination (n=64).

METHODS

Stereoscopic color fundus photographs were graded using the modified Airlie House classification and the Early Treatment Diabetic Retinopathy Study retinopathy severity scheme. Competing risk of death was included in statistical models.

MAIN OUTCOME MEASURES

Incidence of ME and clinically significant ME (CSME).

RESULTS

The 25-year cumulative incidence was 29% for ME and 17% for CSME. Annualized incidences of ME were 2.3%, 2.1%, 2.3%, and 0.9% in the first, second, third, and fourth follow-up periods of the study, respectively. In univariate analyses, the incidence of ME was associated with male sex, more severe diabetic retinopathy, higher glycosylated hemoglobin, proteinuria, higher systolic and diastolic blood pressure, and more pack-years of smoking. Multivariate analyses showed that the incidence of ME was related to higher baseline glycosylated hemoglobin (hazard ratio [HR] per 1% 1.17; 95% confidence interval [CI], 1.10-1.25; P<0.001) and higher systolic blood pressure (HR per 10 mmHg 1.15; 95% CI, 1.04-1.26; P=0.004) and marginally to proteinuria (HR 1.43; 95% CI, 0.99-2.08; P=0.06).

CONCLUSIONS

These data show that relatively high 25-year cumulative rates of incidence of ME were related to glycemia and blood pressure. The lower risk of incident ME in the last period of the study may reflect recent improvement in care.

Parents' attained age and biomarkers of aging in their children

Long-lived parents tend to have children with longer life than their age peers. Long life may be at the cost of increased frailty as measured by specific biomarkers. Determining whether biomarkers of aging in children of long-lived parents are more favorable compared to children of parents with shorter lifespan is important. We investigated this question by classifying participants in a population-based study of adults in Beaver Dam, Wisconsin, by the current age or age at death of their parents as reported in 1988-2000 (baseline examination). Biomarkers of aging (i.e., hand grip strength, chair stand, gait time, peak expiratory flow rate, visual acuity, and contrast sensitivity) were measured in participants 10 and 15 years later. Gait time, peak expiratory flow rate, visual acuity, and contrast sensitivity were significantly better in participants whose parents lived longer. Lower scores on an index combining poor measures of all the biomarkers were highly associated with increased parental age. Greater attained parental age was associated with better functional status of adult children as reflected in levels of aging biomarkers and suggests that persons whose parents are long-lived may enjoy not only a longer life but one relatively spared from frailties associated with older age.

Physical activity, white blood cell count, and lung cancer risk in a prospective cohort study

Previous studies have suggested that physical activity may lower lung cancer risk. The association of physical activity with reduced chronic inflammation provides a potential mechanism, yet few studies have directly related inflammatory markers to cancer incidence. The relation among physical activity, inflammation, and lung cancer risk was evaluated in a prospective cohort of 4,831 subjects, 43 to 86 years of age, in Beaver Dam, Wisconsin. A total physical activity index was created by summing up kilocalories per week from sweat-inducing physical activities, city blocks walked, and flights of stairs climbed. Two inflammatory markers, WBC count and serum albumin, were measured at the baseline examination. During an average of 12.8 years of follow-up, 134 incident cases of lung cancer were diagnosed. After multivariable adjustment, participants in the highest tertile of total physical activity index had a 45% reduction in lung cancer risk compared with those in the lowest tertile (hazard ratio, 0.55; 95% confidence interval, 0.35-0.86). Participants with WBC counts in the upper tertile (>or=8 x 10(3)/microL) were 2.81 (95% confidence interval, 1.58-5.01) times as likely to develop lung cancer as those with counts in the lowest tertile (<6.4 x 10(3)/microL). Serum albumin was not related to lung cancer risk. There was no evidence that inflammation mediated the association between physical activity and lung cancer risk, as the physical activity risk estimates were essentially unchanged after adjustment for WBC count. Although the potential for residual confounding by smoking could not be eliminated, these data suggest that physical activity and WBC count are independent risk factors for lung cancer.

Cystatin C, other markers of kidney disease, and incidence of age-related cataract

OBJECTIVE

To investigate the 15-year incidence of 3 specific types of age-related cataract as related to cystatin C and other measures of kidney function.

METHODS

Examinations of a population-based cohort (n = 4926) occurred at 5-year intervals for 15 years. Assessment of medical history, examination, and photographs of the lens after pupil dilation were performed at each examination. Protocols for photography and grading were used. Laboratory measures were from specimens collected at baseline.

RESULTS

In multivariable analyses, a 1-SD increase in the logarithm of cystatin C was associated with 15-year incidence of cortical (odds ratio [OR], 1.24; 95% confidence interval [CI], 1.09-1.41) and posterior subcapsular (OR, 1.24; 95% CI, 1.02-1.50) cataracts. One SD increase in the logarithm of blood urea nitrogen and creatinine were associated with 15-year incidence of posterior subcapsular cataract (OR, 1.22; 95% CI, 1.04-1.42 and OR, 1.26; 95% CI, 1.03-1.54, respectively).

CONCLUSION

Increased levels of cystatin C are associated with increased risk of specific types of age-related cataract. Whether the associations are due to the metabolic changes associated with decreased renal function, common genes, or both awaits further research.

The Wisconsin Epidemiologic Study of Diabetic Retinopathy: XXII the twenty-five-year progression of retinopathy in persons with type 1 diabetes

OBJECTIVE

To examine the 25-year cumulative progression and regression of diabetic retinopathy (DR) and its relation to various risk factors.

DESIGN

Population-based study.

PARTICIPANTS

A total of 955 insulin-taking persons living in an 11-county area in southern Wisconsin with type 1 diabetes diagnosed before age 30 years who participated in a baseline examination (1980-1982) and at least 1 of 4 follow-up (4-, 10-, 14-, and 25-year) examinations or died before the first follow-up examination (n = 64).

METHODS

Stereoscopic color fundus photographs were graded using the modified Airlie House classification and the Early Treatment Diabetic Retinopathy Study retinopathy severity scheme.

MAIN OUTCOME MEASURES

Progression and regression of DR status.

RESULTS

The 25-year cumulative rate of progression of DR was 83%, progression to proliferative DR (PDR) was 42%, and improvement of DR was 18%. Progression of DR was more likely with less severe DR, male sex, higher glycosylated hemoglobin, an increase in glycosylated hemoglobin level, and an increase in diastolic blood pressure level from the baseline to the 4-year follow-up. Increased risk of incidence of PDR was associated with higher glycosylated hemoglobin, higher systolic blood pressure, proteinuria greater body mass index at baseline, and an increase in the glycosylated hemoglobin between the baseline and 4-year follow-up examinations. Lower glycosylated hemoglobin and male sex, as well as decreases in glycosylated hemoglobin and diastolic blood pressure during the first 4 years of follow-up, were associated with improvement in DR. Persons diagnosed most recently with a similar duration of diabetes had a lower prevalence of PDR independently of glycosylated hemoglobin level, blood pressure level, and presence of proteinuria.

CONCLUSIONS

These data show relatively high 25-year cumulative rates of progression of DR and incidence of PDR. The lower risk of prevalent PDR in more recently diagnosed persons possibly reflects improvement in care over the period of the study.

Management of airway involvement of oesophageal cancer using covered retrievable nitinol stents

AIM

To assess the efficacy and safety of covered retrievable nitinol stents in oesophageal cancer patients with airway involvement.

MATERIALS AND METHODS

Under fluoroscopic guidance, covered retrievable nitinol airway stents were placed in 23 oesophageal cancer patients with airway stricture and/or oesophagorespiratory fistula (ERF) over a long period of 12 years. Six patients only had aspiration by ERF and three patients had both airway stricture and asymptomatic ERF. Technical aspects, dyspnoea improvement, and/or resolution of ERF symptoms, complications, reinterventions, and survival data were evaluated.

RESULTS

A total of 27 airway stents (14 tracheal, 11 bronchial, and two hinged) were placed successfully in 23 patients with airway stricture or ERF. Dyspnoea score decreased significantly after stent placement (p<0.001). ERF were sealed off in all nine patients. Complications included stent migration or expectoration (n=4), haemoptysis (n=2), sputum retention (n=7), and tumour overgrowth (n=1). All three migrated stents were easily removed. Twenty-one patients died, with the median survival period of 76 days (range 2-197 days).

CONCLUSION

Placement of covered retrievable expandable nitinol stents was safe and effective for the palliative treatment of airway strictures and/or ERF, with a reasonable range of complications, in patients with advanced oesophageal cancer.

Syndecan-1 expression in gallbladder cancer and its prognostic significance

AIM

To determine whether the immunohistochemical detection of syndecan-1 could provide useful information as a novel therapeutic or prognostic factor in primary gallbladder (GB) cancer.

MATERIALS AND METHODS

Forty-three GB cancer tissues were evaluated by immunohistochemistry for syndecan-1 expression. The relationship between syndecan-1 expression and clinicopathological characteristics, and the univariate survival analysis for the influence of the syndecan-1 expression on the overall survival were analysed.

RESULTS

Epithelial syndecan-1 immunoreactivity was observed in 25 (58.1%) of the 43 GB cancer cases. The tumors with a positive syndecan-1 expression more frequently showed lymph node metastasis (p = 0.037). Although there was no statistically significant association, the tumors with a positive syndecan-1 expression tended to show a deeper invasion depth (p = 0.087) and more frequent lymphovascular invasion (p = 0.064). The Kaplan-Meier survival curves demonstrated that patients with positive syndecan-1 expression had a significantly shorter survival time than those patients with negative syndecan-1 expression (p = 0.05).

CONCLUSIONS

A subset of GB cancers revealed an epithelial overexpression of syndecan-1, which was associated with a progressive pathological feature and an aggressive clinical course. Therefore, epithelial syndecan-1 expression may be a predictor for a poor prognosis in patients with GB cancer.

Direct observation of dispersive Kondo resonance peaks in a heavy-fermion system

Ce 4d-4f resonant angle-resolved photoemission spectroscopy was carried out to study the electronic structure of strongly correlated Ce 4f electrons in a quasi-two-dimensional nonmagnetic heavy-fermion system CeCoGe1.2Si0.8. For the first time, dispersive coherent peaks of an f state crossing the Fermi level, the so-called Kondo resonance, are directly observed together with the hybridized conduction band. Moreover, the experimental band dispersion is quantitatively in good agreement with a simple hybridization-band picture based on the periodic Anderson model. The obtained physical quantities, i.e., coherent temperature, Kondo temperature, and mass enhancement, are comparable to the results of thermodynamic measurements. These results manifest an itinerant nature of Ce 4f electrons in heavy-fermion systems and clarify their microscopic hybridization mechanism.

Data mining, neural nets, trees--problems 2 and 3 of Genetic Analysis Workshop 15

Genome-wide association studies using thousands to hundreds of thousands of single nucleotide polymorphism (SNP) markers and region-wide association studies using a dense panel of SNPs are already in use to identify disease susceptibility genes and to predict disease risk in individuals. Because these tasks become increasingly important, three different data sets were provided for the Genetic Analysis Workshop 15, thus allowing examination of various novel and existing data mining methods for both classification and identification of disease susceptibility genes, gene by gene or gene by environment interaction. The approach most often applied in this presentation group was random forests because of its simplicity, elegance, and robustness. It was used for prediction and for screening for interesting SNPs in a first step. The logistic tree with unbiased selection approach appeared to be an interesting alternative to efficiently select interesting SNPs. Machine learning, specifically ensemble methods, might be useful as pre-screening tools for large-scale association studies because they can be less prone to overfitting, can be less computer processor time intensive, can easily include pair-wise and higher-order interactions compared with standard statistical approaches and can also have a high capability for classification. However, improved implementations that are able to deal with hundreds of thousands of SNPs at a time are required.

Impairment of the reproductive potential of male fathead minnows by environmentally relevant exposures to 4-nonylphenolf

The synthetic organic compound 4-nonylphenol (NP) has been detected in many human-impacted surface waters in North America. In this study, we examined the ability of NP to alter reproductive competence in male fathead minnows after a 28 day flow-through exposure in a range of environmentally relevant concentrations bracketing the U.S. Environmental Protection Agency toxicity-based NP chronic exposure criterion of 6.1 microg NP/L. Exposure to NP at and above the EPA chronic exposure criterion resulted in an induction of plasma vitellogenin (VTG) within 14 days. However, 7 days after the cessation of exposure, VTG concentrations had dropped more than 50% and few males expressed VTG above the detection threshold. All of the morphological endpoints, including gonadosomatic index, hepatosomatic index, secondary sexual characters, and histopathology, were unaltered by all NP treatments. However, when NP-exposed male fish were allowed to compete with control males for access to nest sites and females, most treatments altered the reproductive competence of exposed males. At lower NP concentrations, exposed males out-competed control males, possibly by being primed through the estrogenic NP exposure in a fashion similar to priming by pheromones released from female fathead minnows. At higher NP exposure concentrations, this priming effect was negated by the adverse effects of the exposure and control males out-competed treated males. Results of this study indicate the complexity of endocrine disrupting effects and the need for multiple analysis levels to assess the effects of these compounds on aquatic organisms.

Incidence of age-related cataract over a 15-year interval the Beaver Dam Eye Study

OBJECTIVE

To describe the long-term incidence of nuclear cataract, cortical cataract, and posterior subcapsular cataract (PSC) and to evaluate age and cohort effects on these rates.

DESIGN

Population-based study.

PARTICIPANTS

Members of the Beaver Dam Eye Study cohort.

METHODS

Subjects were seen in study offices for examinations (slit lamp, checking for occludable angles, dilation of pupils, lens photographs, measurement of blood pressures, and study interview).

MAIN OUTCOME MEASURES

Lens photographs were taken with specially modified cameras that have been maintained over the course of all study examinations. Photographs were graded according to standard protocols that have been continued throughout all the examinations.

RESULTS

Cumulative incidence of nuclear cataract was 29.7% (95% confidence interval [CI], 28.0-31.4); cortical cataract, 22.9% (95% CI, 21.3-24.5); PSC, 8.4% (95% CI, 7.4-9.4); and cataract surgery, 17.7% (95% CI, 16.4-19.0). The cumulative incidence increased with age and was greater for women after accounting for competing events. The relationship between age and incidence of cataracts was quadratic for nuclear cataract, cubic for cortical cataract, and linear for PSC. For persons with similar ages at time of examination, those in more recent birth cohorts were less likely to have any type of prevalent cataract; the effect was significant for nuclear cataract and for cataract surgery, and the effect persisted after controlling for relevant confounders. There were apparent cohort effects on cataract incidence.

CONCLUSIONS

Age-adjusted incidence of all cataract types increased with increasing age, although the age effect was not linear for all 3 types. More recent birth cohorts are relatively protected relative to persons born earlier. Further follow-up is needed to verify the trends we report here and to determine whether cohort effects on 10-year incidence are significant.

Detecting disease-causing genes by LASSO-Patternsearch algorithm

The Genetic Analysis Workshop 15 Problem 3 simulated rheumatoid arthritis data set provided 100 replicates of simulated single-nucleotide polymorphism (SNP) and covariate data sets for 1500 families with an affected sib pair and 2000 controls, modeled after real rheumatoid arthritis data. The data generation model included nine unobserved trait loci, most of which have one or more of the generated SNPs associated with them. These data sets provide an ideal experimental test bed for evaluating new and old algorithms for selecting SNPs and covariates that can separate cases from controls, because the cases and controls are known as well as the identities of the trait loci. LASSO-Patternsearch is a new multi-step algorithm with a LASSO-type penalized likelihood method at its core specifically designed to detect and model interactions between important predictor variables. In this article the original LASSO-Patternsearch algorithm is modified to handle the large number of SNPs plus covariates. We start with a screen step within the framework of parametric logistic regression. The patterns that survived the screen step were further selected by a penalized logistic regression with the LASSO penalty. And finally, a parametric logistic regression model were built on the patterns that survived the LASSO step. In our analysis of Genetic Analysis Workshop 15 Problem 3 data we have identified most of the associated SNPs and relevant covariates. Upon using the model as a classifier, very competitive error rates were obtained.

Supplements and age-related eye conditions the beaver dam eye study

OBJECTIVE

To investigate the association of use of vitamin, mineral, and nonvitamin nonmineral supplements with common age-related eye diseases.

DESIGN

Population-based prospective study with incidence data.

PARTICIPANTS

Subjects were participants in the Beaver Dam Eye Study who contributed data in 1988 to 1990 (n = 4926), 1993 to 1995 (n = 3722), 1998 to 2000 (n = 2962), and 2003 to 2005 (n = 2375).

METHODS

Use of all medications and supplements were collected from study participants at each of 4 examinations. Intraocular pressure (IOP) measurement and fundus and lens photography were done at each visit. Visual field data are available only from baseline. Photographs of the lenses, retina, and discs were graded using standard protocols by trained graders.

MAIN OUTCOME MEASURES

Incidence of age-related cataracts, macular degeneration (AMD), and high IOP for one set of analyses and incidence of supplement use for the second set of analyses.

RESULTS

There was little evidence of any significant associations between supplement use and incident ocular outcomes except for a small protective effect for cortical cataracts by vitamins A and D, zinc, and multivitamins and increased odds of late AMD. Late AMD was associated with incident use of vitamins A, C, and E and zinc.

CONCLUSIONS

Age-related macular degeneration seems to precede use of vitamins A, C, and E and zinc. This may reflect advice by family, friends, and health care providers about the benefits of Age-Related Eye Disease Study-like supplements.

Regulation of German cockroach extract-induced IL-8 expression in human airway epithelial cells

BACKGROUND

Cockroaches have been known as a cause of respiratory allergies such as asthma. IL-8 plays an integral role in the coordination and persistence of the inflammatory process in the chronic inflammation of the airways in asthma.

OBJECTIVE

We investigated the mechanism by which German cockroach extract (GCE) triggers IL-8 release from human airway epithelial cells.

METHODS

Chemical inhibitors were pretreated before addition of GCE for promoter activity and protein synthesis of IL-8. The Transcriptional activity of IL-8 promoter was analysed by mutational, deletional anaylsis and electrophoretic mobility shift assay (EMSA).

RESULTS

Stimulation of H292 cells with GCE resulted in a time- and concentration-dependent induction of IL-8 transcription and protein synthesis. IL-8 promoter deletion analysis indicated that position -132 to +41 was essential for GCE-induced IL-8 transcription, and mutants with substitutions in activator protein (AP)-1, nuclear factor (NF)-IL6 and NF-kappaB-binding sites revealed a requirement for NF-kappaB and NF-IL6, but not AP-1, in GCE-induced activation of the IL-8 promoter. The DNA-binding activities of NF-kappaB and NF-IL6 were induced by GCE, as determined by EMSA. The chemical inhibition of extracellular signal-regulated kinase (ERK) attenuated GCE-induced transcriptional activity and protein synthesis. In addition, through aprotinin treatment and PAR2 small interfering RNA transfection, it was proven that protease of GCE is consistent with the regulation of GCE-induced IL-8.

CONCLUSION

We conclude that GCE with protease activity-induced IL-8 expression is regulated by transcriptional activation of NF-kappaB and NF-IL6 coordinating with the ERK pathway in human airway epithelial cells.

A longitudinal study of nonvitamin, nonmineral supplement use: prevalence, associations, and survival in an aging population

PURPOSE

We sought to describe population and survival characteristics in nonvitamin, nonmineral (NVNM) supplement users in a population-based cohort study.

METHODS

People from 43 to 86 years of age living in Beaver Dam, Wisconsin, participated in a baseline examination from 1988 to 1990 (n = 4,926) and three follow-up examinations at 5-year intervals (n = 3,722, 2,962, 2,375 at each successive examination). Medication and supplement use, medical and lifestyle factors were collected during the examination and survival was monitored through 2002.

RESULTS

NVNM supplement use increased from 5% at baseline, to 6% at the second, to 21% at the third to 30% at the fourth examination. In general, younger age, vitamin or mineral use, and taking more medications was directly related to NVNM supplement use, while current smoking and history of other systemic diseases (e.g., cardiovascular disease, cancer) was inversely related to NVNM supplement use. After adjusting for age, sex, and other medical and lifestyle factors, users of NVNM supplements had lower mortality (hazard ratio, 0.74; 95% confidence interval, 0.57-0.95, p = 0.02) than nonusers.

CONCLUSIONS

NVNM supplement users had a healthier lifestyle and fewer co-morbid medical conditions and were more likely to survive after adjusting for these factors than non-users.

Attained parental age and children's survival at mid-life ages in a large population

OBJECTIVE

Long-lived persons tend to share a survival advantage with their parents and siblings; however, there is limited information on benefit beyond the extremes of longevity. We evaluated a survival benefit associated with age of parents.

METHODS

A population-based study of adults 43-86 years of age in a Midwestern town was performed (n = 4,926). Extensive exam and questionnaire information including current age or age at death of parents of study participants was obtained.

RESULTS

While adjusting for age and gender, those with at least one parent surviving to 100 years of age had the best survival (92% survive to age 70 and 54% to age 90). There appeared to be a survival benefit for each decade of maximal parental age. A trend persists when additional risk factors are included in the model.

DISCUSSION

There is a survival benefit to offspring of increasing parental age that is apparent as early as 80 years of parental age.

Genetics of Pigment Changes and Geographic Atrophy

PURPOSE

Studies of age-related macular degeneration (AMD) often involve persons with both choroidal neovascularization and geographic atrophy (GA), but few genome-wide scans (GWSs) have discriminated between these two outcomes.

METHODS

To comprehend the role of pigmentary abnormalities (PA) and GA in AMD, the authors analyzed the data from a previous GWS on AMD (FARMS [Family Age-Related Maculopathy Study]sample of 34 extended families) looking only at PA. Presented are new GWS data from the full Beaver Dam Eye Study (BDES) family cohort, including longitudinal data at baseline and 5- and 10-year follow-up. A linkage analysis for PA/GA was performed on both samples for 338 markers covering all autosomes. Another linkage analysis using the rate of change along the PA/GA scale was performed with the BDES sample.

RESULTS

Analysis of the FARMS sample provided evidence for linkage with P < 0.01 in the 1q25, 5p13, 6q21-23, and 11q14 regions. The most significant peak was found on chromosome 1, near complement factor H (CFH), with P= 6.20 x 10(-4). Analysis using the rate of change in BDES replicated the peaks in 5p13 and 6q21-23, suggesting that these loci may contribute to the rate of progression of PA/GA. Association analysis of CFH polymorphisms suggest that CFH may play a role in the development of pigmentary abnormalities and may modify the progression along the PA/GA scale.

CONCLUSIONS

These findings suggest a complex, heterogeneous model for PA/GA.

Complement factor H and hemicentin-1 in age-related macular degeneration and renal phenotypes

In this study, we investigated the associations of complement factor H (CFH) and hemicentin-1 (HMCN1) with age-related macular degeneration (AMD) and renal function. Three scales, measuring the course of AMD and drusen development, were examined in two samples: the Family Age-Related Macular degeneration Study (FARMS), consisting of families ascertained through a single individual with severe AMD, and an unascertained population-based family cohort, the Beaver Dam Eye Study (BDES), which was also used to assess longitudinal changes in AMD and associations with renal function. Associations were performed by a regression accounting for known risk factors as well as familial and sibling effects. Strong evidence of the association of rs1061170 (Y402H) variation with AMD was confirmed (P = 9.15 x 10(-5) in BDES, P = 0.016 in FARMS). This association was observed in multiple AMD scales, suggesting that its role is not phenotype-specific. Polymorphisms in both CFH and HMCN1 appeared to influence the longitudinal rate of change of AMD. The rs1061170 polymorphism was also associated with a reduction in estimated glomerular filtration rate (eGFR) (P = 0.046). Another CFH polymorphism, rs800292, was similarly associated with eGFR [beta = -0.90 (P = 0.022)]. Associations between rs743137 (P = 0.05) and rs680638 (P = 0.022) in HMCN1 with calculated creatinine clearance progression were also observed. Both genes appear to play a role in both AMD and renal pathophysiology. These findings support evidence for common pathways influencing ocular and renal function and suggest that further work is required on their common determinants.

Association of retinal vessel caliber to optic disc and cup diameters

PURPOSE

To investigate whether optic disc size is related to retinal venule and arteriole diameters.

METHODS

The population of Beaver Dam, Wisconsin, aged 43 to 86 years were invited to participate in a baseline examination from 1988 to 1990. During this examination, photographs, centered on the optic discs, were taken after pupil dilation. Optic discs and cups were measured from stereoscopic photographs, whereas retinal vessel measurements were taken from a single digitized photograph. Central retinal vein and central retinal arterial equivalents were subsequently calculated. Data for 3887 right eyes are included in the analyses.

RESULTS

Narrower retinal venules and arterioles were found in the smaller optic discs controlling for optic cup diameter as well as age, systolic and diastolic blood pressure, refraction, and sex. Central retinal artery equivalents ranged from 156.04 +/- 16.82 microm in the smallest optic disc category to 165.93 +/- 15.17 microm in the larger disc category (P < 0.001). Central retinal vein equivalents ranged from 228.93 +/- 21.26 microm in the smallest to 243.18 +/- 22.32 microm in the larger disc categories (P < 0.001). The significant reduction in retinal vessel diameters was only apparent for the smallest optic disc sizes. A reduction in retinal vessel diameters was less consistent and not significant for small optic cup sizes.

CONCLUSIONS

Smallest optic discs were associated with smaller central retinal artery and central retinal vein diameters. This anatomic relationship may be useful as an additional associated indicator for nonarteritic anterior ischemic optic neuropathy as well as for retinal vascular events.

Confirmation of linkage to ocular refraction on chromosome 22q and identification of a novel linkage region on 1q

OBJECTIVE

To localize genes influencing ocular refraction in subjects in the Beaver Dam Eye Study. Previous studies establish that myopia clusters within families and linkage to myopia has been demonstrated on 2q, 4q, 12q, 17q, 18q, 22q, and Xq. Few studies have examined genetic effects across the entire range of refraction, though linkages to 1p, 3q, 4q, 8p, and 11p have been reported, and our previous analysis of the Beaver Dam Eye Study demonstrated substantial heritability for refraction (68%).

METHODS

We conducted nonparametric sibling-pair and genome-wide linkage analyses on spherical equivalent adjusting for age, education, and nuclear sclerosis, in 834 sibling pairs in 486 extended pedigrees.

RESULTS

We identified a novel region of suggestive linkage on 1q (multipoint, P<.00019) and replicated the 22q region (multipoint, P = .0033) previously linked to myopia. Additionally, there was some evidence of linkage to 7p (multipoint, P = .0023).

CONCLUSION

Refraction is a complex trait influenced by both genes and environment. Our work confirms a previously reported linkage region on 22q and identifies 2 novel regions of linkage on 1q and 7p.

CLINICAL RELEVANCE

Further, genetic research is needed to finemap this trait to identify the causative gene. Modifying the actions of such a gene might lead to a reduction in the risk of refractive error.

Identification of novel genetic loci for intraocular pressure: a genomewide scan of the Beaver Dam Eye Study

OBJECTIVE

To identify genetic loci that control intraocular pressure (IOP).

METHODS

We performed a genomewide scan of IOP, using 486 pedigrees ascertained through a population-based cohort, the Beaver Dam Eye Study. Linkage analysis was performed using the modified Haseman-Elston regression models and variance components linkage analysis.

RESULTS

Seven regions of interest were identified on chromosomes 2, 5, 6, 7, 12, 15, and 19. The novel linkage region on chromosome 19p had an empirical multipoint P value of 6.1 x 10(-5). Two of the regions (2 and 19) were especially interesting since each has been identified as a potential linkage region for blood pressure.

CONCLUSIONS

The results of this genomewide scan provide evidence that a quantitative trait locus may influence elevated IOP and may colocalize with blood pressure loci. These loci may control systemic pressure reflected in the eye and vascular system.

CLINICAL RELEVANCE

Glaucoma is a leading cause of blindness in the world, and the identification of genes that contribute to this disease is essential. Elevated IOP is a principal risk factor for primary open-angle glaucoma and an intriguing quantitative trait that may strongly influence the development of disease.

Changes in visual acuity in a population over a 15-year period: the Beaver Dam Eye Study

PURPOSE

To describe the change in visual acuity in a 15-year period.

DESIGN

Population-based study.

METHODS

setting: Beaver Dam, Wisconsin. participants: 4068 persons 43 to 86 years of age at the time of a baseline examination in 1988 to 1990, and with follow-up examinations every five years thereafter. observation procedures: Best-corrected visual acuity after refraction, assessed by a modification of the ETDRS protocol. main outcome measure: Doubling of the visual angle; incidence of visual impairment.

RESULTS

Eight percent of the population developed impaired vision (20/40 or worse), 0.8% developed severe visual impairment (20/200 or worse), 7% had doubling of the visual angle, and 2% had improved vision. People 75 years of age or older at baseline were more likely to develop impaired vision (odds ratio [OR] 12.8, 95% confidence interval [CI] 9.6 to 17.1, P < .001), doubling of the visual angle (OR 7.8, 95% CI 5.6 to 10.7, P < .001), and severe visual impairment (OR 20.6, 95% CI 9.5 to 44.8, P<0.001) compared with people younger than 75 years of age.

CONCLUSIONS

These data provide population-based estimates of the cumulative 15-year incidence of loss of vision over a wide spectrum of ages. In people 75 years of age or older the cumulative incidence of visual impairment accounting for the competing risk of death is 25%, of which 4% is severe, indicating a public health problem of considerable proportions as the US population in this age is expected to increase by 55% from 18 million in the year 2005 to 28 million by the year 2025.

Statin use and incident nuclear cataract

CONTEXT

Statins are widely prescribed for their lipid-lowering effects but also have putative antioxidant properties. Oxidative stress is believed to play a role in the development of nuclear cataract, but little is known regarding the relationship of statin use and cataract incidence.

OBJECTIVE

To evaluate the relationship of use of statins and incident cataract in adults in a midwestern community in the United States.

DESIGN, SETTING, AND PARTICIPANTS

The Beaver Dam Eye Study, an observational, longitudinal, population-based study of age-related eye disease in Beaver Dam, Wis. There were 1299 persons who were seen at the third examination in 1998-2000, had gradable photographs in both eyes, and were deemed to be at risk of developing nuclear cataract within 5 years.

MAIN OUTCOME MEASURE

Five-year incidence of cataract with respect to statin use. Cataracts were graded from photographs taken through the participant's dilated pupil.

RESULTS

A total of 210 persons developed incident nuclear cataract in the interval from 1998-2000 to 2003-2005. Five-year incidence of nuclear cataract was 12.2% in statin users compared with 17.2% in nonusers (odds ratio [OR], 0.55; 95% confidence interval [CI], 0.36-0.84), controlling for age. When only never smokers without diabetes were assessed, the age-, lipid level-, and sex-adjusted OR was 0.40 (95% CI, 0.18-0.90). Five-year incidence of cortical cataract was 9.9% in statin users and 7.5% in nonusers (OR, 1.28; 95% CI, 0.79-2.08); posterior subcapsular cataract occurred in 3.0% of statin users and 3.4% of nonusers (OR, 0.82; 95% CI, 0.39-1.71).

CONCLUSION

Statin use in a general population appears to be associated with lower risk of nuclear cataract, the most common type of age-related cataract.

Comparability of cup and disk diameters measured from nonstereoscopic digital and stereoscopic film images

PURPOSE

To compare gradings of optic disk and cup diameters from stereoscopic film and nonstereoscopic digital images.

DESIGN

Comparison of techniques.

METHODS

setting: CLINIC-BASED.

PATIENT POPULATION

Right eyes of 62 adults. observation procedures: Images of the disk were taken through pharmacologically dilated pupils with a 45-degree digital camera (6.3 megapixels) and with a stereoscopic 30-degree film camera. Measurements were taken for vertical diameters of optic disks and cups.

MAIN OUTCOME MEASURES

Agreement of disk and cup measurements and cup to disk ratios.

RESULTS

Optic disks and cups were slightly smaller when graded from the stereoscopic film images. Cup-to-disk ratios were similar. Correlations between film and digital images measurements were high.

CONCLUSIONS

Measurements taken from nonstereoscopic digital images through a dilated pupil were similar to those taken from stereoscopic film images. Lack of stereoscopic effect may lead to small differences in measuring the optic disk and cup diameters. Nonstereoscopic digital imaging may be useful in epidemiologic studies when measures of optic cups and disks are needed.

Genome-Wide Linkage Study of Retinal Vessel Diameters in the Beaver Dam Eye Study

Retinal vessels can be observed noninvasively and provide a window to microvascular systems elsewhere in the body. Generalized retinal arteriolar narrowing can represent structural changes resulting from persistent high blood pressure. However, data from recent studies also suggest that generalized retinal arteriolar narrowing might precede hypertension and contribute to its pathogenesis. To determine whether vessel diameters in the eye are genetically determined, we conducted a genome-wide linkage scan on retinal vessel diameters (central retinal artery equivalent and central retinal vein equivalent) using data from the Beaver Dam Eye Study. There were 7 regions on 5 chromosomes (3q28, 5q35, 7q21, 7q32, 11q14, 11q24, and 17q11) showing linkage signals at the nominal multipoint significance level of 0.01 for either covariate-unadjusted or -adjusted central retinal artery equivalent; there were 7 regions on 6 chromosomes (1p36, 6p25, 6q14, 8q21, 11p15, 13q34, and 14q21) showing linkage signals at the nominal multipoint significance level of 0.01 for either covariate-unadjusted or -adjusted central retinal vein equivalent. The linkage results for retinal vessel diameters indicate genetic contributions that remain significant even after adjusting for hypertension and other covariates. In summary, we provide evidence demonstrating that genetic factors independent of hypertension affect retinal vessel diameters.

Early experiences with diffusion tensor imaging and magnetic resonance tractography in stroke patients

INTRODUCTION

Recent advances in magnetic resonance (MR) diffusion tensor imaging technique enable evaluation of the anisotropy of white matter tracts in-vivo, as well as the integrity of fibre tracts and their orientation. We describe our initial experiences with diffusion tensor imaging and MR tractography techniques to evaluate the structural degeneration of white matter tracts following stroke.

METHODS

Diffusion tensor imaging data were acquired in 11 cases with stroke on a 3T MR imaging scanner, with three-dimensional diffusion tensor imaging-based colour maps and MR tractography performed offline. We evaluated the spatial relationships of the eloquent white matter tracts to the infarcts and areas of haemorrhage, and classified therewith the tracts as either disrupted or displaced. We compared these with the clinical severity of the neurological deficits and prognosis.

RESULTS

A good correlation was found between tractography findings and patient's clinical recovery. All the patients with disruption of white matter tracts had residual deficits on clinical follow-up, whereas the patients with displaced tracts had near complete neurological recovery.

CONCLUSION

Diffusion tensor imaging and MR tractography provide a novel and useful method to directly visualise changes in the white matter tracts in stroke. This can potentially allow clinical-imaging correlation with prognostic potential.

Markers of inflammation, vascular endothelial dysfunction, and age-related cataract

PURPOSE

To examine the associations of systemic markers of inflammatory disease and vascular endothelial dysfunction with three types of age-related cataract.

DESIGN

Cross-sectional analyses of data from a population-based sample of adults.

METHODS

Standardized protocols for blood collection, measurement of markers, administration of a questionnaire, and grading of lens photographs to determine cataract were used. Univariable and multivariable analyses were performed.

SETTINGS

Cohort in Beaver Dam, Wisconsin.

STUDY POPULATION

A random sample of 396 persons who were > or =50 years of age.

MAIN OUTCOME MEASURE

Prevalent age-related nuclear, cortical, and posterior subcapsular cataract.

RESULTS

Interleukin-6 and intracellular adhesion molecule-1 were associated significantly with prevalent nuclear cataract (odds ratio for each quartile, 1.45 and 2.17, respectively). Many of the associations of markers with cataract types were not linear. There were no significant associations between the markers and cortical or posterior subcapsular cataract.

CONCLUSION

Two serum markers of systemic inflammation and vascular endothelial dysfunction were associated with nuclear cataract.

Does the intraocular pressure effect on optic disc cupping differ by age?

PURPOSE

To investigate whether age influences optic disc cupping in addition to the effects of intraocular pressure (IOP).

METHODS

Population-based study (N = 4,926 at baseline). All measures including fundus photography were done according to standard protocols. Stereoscopic images of the optic disc were graded in masked fashion.

RESULTS

Cup-to-disc ratios (C/D) were directly related to IOP at baseline. Age of 75 years or older was associated with increase in cupping at a given level of IOP, but the age association was attenuated when including refraction in multivariable models. Change in C/D between baseline and 15-year follow-up was also influenced by age such that those 75 years of age or older were at increased risk of cupping. When refraction was included in this model, age was still significant.

CONCLUSIONS

People who are at least 75 years of age are at greater risk of developing optic disc cupping, which is associated with greater IOP.

Genome-wide analyses demonstrate novel loci that predispose to drusen formation

PURPOSE

To test whether genes for drusen formation are independent of age-related macular degeneration (AMD) pathogenesis.

METHODS

A genome-wide model-free linkage analysis was performed, using two semiquantitative drusen traits, size and type, on two sets of data: (1) 325 individuals (225 sib pairs) from the Beaver Dam Eye Study (BDES), and (2) 297 individuals (346 sib pairs) from the Family Age Related Maculopathy Study (FARMS). Apolipoprotein E (APOE) genotypes were used as a covariate in a multipoint sibpair analysis.

RESULTS

The authors found evidence of linkage on 19q13.31 (D19S245), with size of drusen in both the BDES (P = 0.0287) and the FARMS (P = 0.0013; P = 0.0005, combined). In the BDES, type showed linkage evidence on 3p24.3 (D3S1768; P = 0.0189) and 3q25.1 (D3S2404; P = 0.0141); the linkage on 3p24.3 was also found with size (D3S1768; P = 0.0264). In the FARMS, size showed evidence of linkage at 5q33.3 (D5S820; P = 0.0021), 14q32.33 (D14S1007; P = 0.0013), and 16p13.13 (D16S2616; P = 0.0015) and type at 21q21.2 (D21S2052; P = 0.0070). For size in the FARMS, there was a small increase in P-value at marker D19S245 from 0.0044 to 0.0111, and from 0.0044 to 0.0064, when the epsilon4-carrier and the epsilon3-carrier genotype were the covariates, respectively.

CONCLUSIONS

The results show that APOE effects may be mediated early in the progression of ARM to AMD and thus may not be detected by standard genome scans for more severe disease.

Frailty, morbidity and survival

Frailty, as a reflection of decreased physical reserve rather than disability, is assessed by various functional tests rather than by specific disease burden. We investigated association of measures of frailty to disease outcomes and survival in a population-based study of Midwestern adults. The markers of frailty we evaluated were: time to walk a measured course (gait-time), handgrip strength, peak respiratory flow rate, ability to stand from a sitting position without using arms, and best corrected visual acuity. A history of cardiovascular disease, cancer, and hypertension were obtained. Data were collected at the third examination (1998--2000) of the Beaver Dam Eye Study cohort (n=2962). Follow-up for mortality occurred up to 412 years after the 1998--2000 examinations. Markers of frailty were significantly associated with age. Values in the highest quartile (slowest) of gait-time, lowest quartile of peak expiratory flow rate, lowest quartile of handgrip strength, inability to stand from sitting in one try (those not in a wheelchair), and visual impairment were combined in an index to denote a general description of frailty. The range of the index was 0 (no frailty) to 5 (maximum frailty). Greater frailty was significantly associated with cardiovascular disease and hypertension. Frailty was associated with poorer survival over an interval of 412 years after adjusting for age, sex, hypertension, diabetes, and cardiovascular disease. Greater frailty was associated with greater likelihood of concurrent medical conditions and with decreased survival.

Meta-analysis of genome scans of age-related macular degeneration

A genetic contribution to the development of age-related macular degeneration (AMD) is well established. Several genome-wide linkage studies have identified a number of putative susceptibility loci for AMD but only a few of these regions have been replicated in independent studies. Here, we perform a meta-analysis of six AMD genome screens using the genome-scan meta-analysis method, which allows linkage results from several studies to be combined, providing greater power to identify regions that show only weak evidence for linkage in individual studies. Results from non-parametric analysis for a broad AMD clinical phenotype (including two studies with quantitative traits) were extracted. For each study, 120 genomic bins of approximately 30 cM were defined and ranked according to maximum evidence for linkage within each bin. Bin ranks were weighted according to study size and summed across all studies; the summed rank (SR) for each bin was assessed empirically for significance using permutation methods. A high SR indicates a region with consistent evidence for linkage across studies. The strongest evidence for an AMD susceptibility locus was found on chromosome 10q26 where genome-wide significant linkage was observed (P=0.00025). Several other regions met the empirical significance criteria for bins likely to contain linked loci including adjacent pairs of bins on chromosomes 1q, 2p, 3p and 16. Several of the regions identified here showed only weak evidence for linkage in the individual studies. These results will help prioritize regions for future positional and functional candidate gene studies in AMD.