Plasma fibrinogen levels, other cardiovascular risk factors, and age-related maculopathy: the Blue Mountains Eye Study

OBJECTIVE

To assess the relationship between stages of age-related maculopathy (ARM) and cardiovascular disease and cardiovascular disease risk factors, including serum lipid and plasma fibrinogen levels, smoking, cardiovascular events, systemic hypertension, diabetes mellitus, and obesity.

DESIGN

A cross-sectional study of 3654 subjects from a defined geographic area identified subjects with late age-related macular degeneration (ARMD) and early ARM from the masked grading of retinal photographs. The history, physical examination findings, and fasting blood samples provided data on possible risk factors. Logistic regression, adjusting for age, sex, and possible confounders, and 2-way analysis of variance were used to assess associations.

RESULTS

The only factors significantly associated with ARM included the 2 established risk factors, smoking and family history of ARMD (odds ratios, 4.1 and 4.2, for late ARMD, respectively), and the 2 variables, body mass index (odds ratio, 1.78 for obese compared with normal body mass index for early ARM) and plasma fibrinogen level (odds ratio, 6.7 for a fibrinogen level of >4.5 g/L [highest quartile] compared with a fibrinogen level of <3.4 g/L [lowest quartile] for late ARMD).

CONCLUSIONS

These findings support the concepts that associations exist between plasma fibrinogen levels and late ARMD, a body mass index outside the normal range, and early ARM, and between the family history and smoking and any ARM. We found no other significant associations with any history of cardiovascular disease or other risk factors for cardiovascular disease.

Influence of long-term, low-dose, diuretic-based, antihypertensive therapy on glucose, lipid, uric acid, and potassium levels in older men and women with isolated systolic hypertension: The Systolic Hypertension in the Elderly Program. SHEP Cooperative Research Group

BACKGROUND

Previous studies often of short duration have raised concerns that antihypertensive therapy with diuretics and beta-blockers adversely alters levels of other cardiovascular disease risk factors.

METHODS

The Systolic Hypertension in the Elderly Program was a community-based, multicenter, randomized, double-blind, placebo-controlled clinical trial of treatment of isolated systolic hypertension in men and women aged 60 years and older. This retrospective analysis evaluated development of diabetes mellitus in all 4736 participants in the Systolic Hypertension in the Elderly Program, including changes in serum chemistry test results in a subgroup for 3 years. Patients were randomized to receive placebo or treatment with active drugs, with the dose increased in stepwise fashion if blood pressure control goals were not attained: step 1, 12.5 mg of chlorthalidone or 25.0 mg of chlorthalidone; and step 2, the addition of 25 mg of atenolol or 50 mg of atenolol or reserpine or matching placebo.

RESULTS

After 3 years, the active treatment group had a 13/4 mm Hg greater reduction in systolic and diastolic blood pressure than the placebo group (both groups, P<.001). New cases of diabetes were reported by 8.6% of the participants in the active treatment group and 7.5% of the participants in the placebo group (P=.25). Small effects of active treatment compared with placebo were observed with fasting levels of glucose (+0.20 mmol/L [+3.6 mg/dL]; P<.01), total cholesterol (+0.09 mmol/L [+3.5 mg/dL]; P<.01), high-density lipoprotein cholesterol (-0.02 mmol/L [-0.77 mg/dL]; P<.01) and creatinine (+2.8 micromol/L [+0.03 mg/dL]; P<.001). Larger effects were seen with fasting levels of triglycerides (+0.9 mmol/L [+17 mg/dL]; P<.001), uric acid (+35 micromol/L [+.06 mg/dL]; P<.001), and potassium (-0.3 mmol/L; P<.001). No evidence was found for a subgroup at higher risk of risk factor changes with active treatment.

CONCLUSIONS

Antihypertensive therapy with low-dose chlorthalidone (supplemented if necessary) for isolated systolic hypertension lowers blood pressure and its cardiovascular disease complications and has relatively mild effects on other cardiovascular disease risk factor levels.

Prevalence of diabetic retinopathy in an older community. The Blue Mountains Eye Study

OBJECTIVE

This study aimed to determine the prevalence and characteristics of diabetic retinopathy (DR) in a defined older Australian population.

DESIGN

A total of 3654 persons 49 years of age or older, 88% of permanent residents from an urban area west of Sydney, underwent a detailed eye examination. This included detailed medical history, Zeiss stereo retinal photography, fasting blood glucose, and other blood factors. The diagnosis of DR was made clinically and from photographic grading in persons with a history or biochemical evidence of diabetes.

RESULTS

Diabetes was present in 7% (95% confidence interval, 6.2-7.8) of the population. Signs of DR were found in 82 participants (2.3%; 95% confidence interval, 1.9-2.8). The prevalence was 1.7% in persons younger than 60 years of age, 2.4% in persons 60 to 69 years of age, 2.7% in persons 70 to 79 years of age, and 2.3% in persons 80 years of age or older. There was no significant gender difference in prevalence. After adjusting for age, gender, and the duration since diagnosis of diabetes, higher blood glucose was related to the finding of moderate-to-severe retinopathy (Wisconsin levels 4-7) compared to milder retinopathy (Wisconsin levels 1.5-3). No association was found between the presence of any retinopathy and blood glucose, a history of hypertension or elevated blood pressure, body-mass index, blood lipids, creatinine, or coagulation factors.

CONCLUSIONS

This Australian study has found similar prevalence rates for DR to a recent U.S. population-based study but lower rates for vision-threatening retinopathy than from clinic-based reports. Previous reports of a relationship between advanced retinopathy and blood glucose were supported. Other than diabetes duration and insulin treatment, no other associations with retinopathy were found.

Optic disc hemorrhages in a population with and without signs of glaucoma

OBJECTIVE

This study aimed to determine the prevalence and associations of optic disc hemorrhage in a well-defined older Australian population.

DESIGN

The study design was a population-based, cross-sectional study.

PARTICIPANTS

A total of 3654 persons 49 years of age or older, representing 88% of permanent residents from an area west of Sydney, participated in the study.

MAIN OUTCOME MEASURES

Participants underwent a detailed eye examination. The diagnosis of optic disc hemorrhage was made from masked photographic grading; disc hemorrhages were subclassified as flame or blot in shape. Open-angle glaucoma was diagnosed from matching visual field loss and optic disc rim thinning.

RESULTS

The overall prevalence of disc hemorrhage in either or both eyes was 1.4%. Disc hemorrhage prevalence was higher in women (odds radios [OR], 1.9; confidence interval [CI], 1.0-3.5) and increased with age (OR, 2.2 per decade; CI, 1.7-2.8 per decade). The overall prevalence in subjects with open-angle glaucoma was 13.8% (8% in high-pressure glaucoma and 25% in low-pressure glaucoma) and 1.5% in subjects with ocular hypertension. Disc hemorrhages were associated with increasing intraocular pressure (OR, 1.7 per 5 mmHg; CI, 1.3-2.3 per 5 mmHg), pseudoexfoliation (OR, 3.5; CI, 1.1-11.8), diabetes (OR, 2.9; CI, 1.4-6.3), and increasing systolic blood pressure (OR, 1.1 per 10 mmHg; CI, 1.0-1.3) after adjusting for age and gender. Among subjects without open-angle glaucoma, disc hemorrhages were more frequent in eyes with larger vertical cup-disc ratios and in subjects with a history of typical migraine headache (OR, 2.2; CI, 1.1-4.6). No associations were found among subjects with a history of vascular events, smoking, regular aspirin use, or myopia.

CONCLUSIONS

Disc hemorrhage prevalence in this population is higher than that in the two previous population-based reports. Although the strong association of disc hemorrhage with open-angle glaucoma was confirmed (particularly low-pressure glaucoma), most disc hemorrhages (70%) were found in participants without definite signs of glaucoma.

Associations between leaf structure, orientation, and sunlight exposure in five Western Australian communities

Five plant communities in Western Australia, as well as selected desert and Rocky Mountain species of the western USA, were surveyed to evaluate associations among leaf structure, orientational properties, and the sunlight exposure and precipitation characteristic of each community. Selected leaf structural features have been associated previously with photosynthetic function and included shape, thickness, the ratio of thickness to width, stomatal distribution, leaf surface coloration, and the number and distribution of palisade cell layers. Decreases in annual precipitation (<4 to over 15 cm/yr) and increases in total daily sunlight (4.2 to 29.2 mol photons/m1) corresponded strongly to an increase in the percentage of species in a given community with more inclined (more inclined than +/- 45 degrees from horizontal) or thicker leaf mesophyll (>0.4 mm) leaves. Also, the percentage of species with a leaf thickness to width ratio >0.1, which were amphistomatous, or which had palisade cell layers beneath both leaf surfaces, increased from >20% in the highest rainfall and lowest sunlight community to >80% in the community with least rainfall but greatest sunlight exposure. Over 70% of the species in the most mesic, shaded community had lighter abaxial than adaxial leaf surfaces (leaf bicoloration). All of the above structural features were positively associated with a more inclined leaf orientation (r1 = 0.79), except for leaf bicoloration, which was negatively associated (r1 = 0.75). The ratio of adaxial to abaxial light was more strongly associated with leaf bicoloration (r1 = 0.83) and the presence of multiple adaxial and isobilateral palisade cell layers(r1 = 0.80) than with total incident sunlight on just the adaxial leaf surface (r1 = 0.69 and 0.73, respectively). These results provide field evidence that leaf orientation and structure may have evolved in concert to produce a photosynthetic symmetry in leaf structure in response to the amount of sunlight and other limiting factors of the community. This structural symmetry may serve fundamentally to regulate the distribution of both light and CO2 levels inside the leaf and, thus, increase photosynthetic CO2 uptake per unit leaf biomass.

House dust mite allergen characterisation: implications for T-cell responses and immunotherapy

T cells are central regulators and mediators of allergic sensitisation and disease. The house dust mite allergens are a biochemically diverse group of proteins which are present in extracts and the environment in a wide range of concentrations. Here the importance of ascertaining the contribution of the different allergens to Th2 lymphokine production and the development of allergy is discussed as well as the effect of allelic polymorphisms and inter-species sequence diversity on T-cell activation. The imbalances in allergen concentrations in commercial extracts, the sequence variations from allergens in the environment and the poor discrimination of allergy due to different mite species points to areas of improvement and the development of novel immunotherapeutic strategies and reagents.

Spinal cord injury with a narrow spinal canal: utilizing Torg's ratio method of analyzing cervical spine radiographs

A 65-year-old inebriated man crashed his car and presented with spinal shock and neurogenic shock from a cervical spinal cord injury without cervical spine fracture or dislocation. The lateral cervical spine radiography was initially read as normal, except for degenerative disk disease; however, Torg's ratio method of analyzing cervical spinal canal sagittal width indicated the spinal canal was congenitally narrow. Magnetic resonance imaging confirmed this and showed bulging and herniation of multiple invertebral disks between C2 and C7. This case illustrates the value of using Torg's ratio method of analyzing lateral cervical spine radiographs. Although Torg's method has not been prospectively validated, it may be useful to identify patients at risk for cervical spinal cord injuries without fractures or dislocations. An abnormal Torg's ratio may be the only clue to the fact that the patient is at higher risk of spinal cord injury when the patient's history or examination is questionable because of head injury, drug intoxication, or therapeutic sedation and paralysis.

Hematological indices in an older population sample: derivation of healthy reference values

Factors affecting hematological values were explored, and healthy reference values were estimated from a cross-sectional survey of a population (n = 4433), ages 49 years or more, residing permanently in a defined geographic region. Nursing home residents were excluded. Details of medication use and medical history were obtained by interview, and participants were asked to return after an overnight fast for blood sampling. The participation rate was 82.4%, of whom 88.4% provided a fasting blood sample. Hemoglobin, hematocrit, and erythrocyte counts were higher in men, whereas platelet counts were higher in women. Statistical associations between each hematological index and smoking, alcohol intake, use of certain drugs, chronic disease, and high creatinine values were tested by unpaired t-tests. Separate reference groups were defined for each hematological index by excluding subjects with any of the factors found to be of importance. The resulting reference values are particularly appropriate for evaluating hematological test results in older individuals.

Prevalence and causes of amblyopia in an adult population

OBJECTIVE

The study aimed to determine the prevalence, causes, and associations with amblyopia in a defined older population.

DESIGN

In a population-based study, 3654 persons 49 years of age or older from an area west of Sydney, Australia, underwent a detailed eye examination and history, including objective and subjective refraction, cover testing, and retinal and lens photography. Amblyopia was diagnosed in eyes with reduced best-corrected visual acuity in the absence of any other cause.

RESULTS

Amblyopia was diagnosed in 118 participants, or 3.2% of the population using a visual acuity criterion of 20/30 or less and 2.9% using a visual acuity criterion of 20/40 or less. Using a two-line visual acuity difference between the eyes, the amblyopia prevalence was 2.6% and 2.5%, respectively, for the above criteria. The underlying amblyogenic causes assessed were anisometropia (50%), strabismus (19%), mixed strabismus and anisometropia (27%), and visual deprivation (4%). The visual acuity of the amblyopic eye was 20/200 or worse (19%), 20/80 to 20/160 (19%), 20/40 to 20/63 (52%), and 20/30 (11%). No statistically significant associations were found between amblyopia and gender or eye affected. The most frequent pattern of strabismus was esotropia, whereas hypermetropia was the most frequent refractive error in amblyopic eyes. The mean age at diagnosis was earlier for strabismic and mixed amblyopia (7.4 years) than for anisometropic amblyopia (12.7 years).

CONCLUSION

This study has provided prevalence and cases of amblyopia in an older population. Amblyopia is a frequent cause of lifelong unilateral visual impairment.

Antimicrobial properties of human lysozyme transgenic mouse milk

The antimicrobial properties of standard human lysozyme and the milk of transgenic mice expressing human lysozyme were investigated using bacterial strains important to the dairy industry. Standard human lysozyme was found to be effective at significantly slowing the growth of the milk cold-spoilage organism Pseudomonas fragi (P < 0.001), of a clinical isolate of the mastitis-causing organism Staphylococcus aureus (P < 0.005), and a nonpathogenic strain of E. coli (P < 0.05). Milk from transgenic mice secreting human lysozyme in their milk at an average concentration of 0.3 mg/ml was found to be bacteriostatic against the cold-spoilage organisms Pseudomonas fragi and Lactobacillus viscous and a mastitis-causing strain of Staphylococcus aureus, but not against a pathogenic strain of E. coli. These results demonstrate that transgenic animals producing human lysozyme in their milk can affect the microbial nature of milk.

Reversible renal failure in a patient with the hypereosinophilia syndrome during therapy with alpha interferon

Human recombinant interferon (IFN)-alpha (alpha)-2b was given to a 57-year-old man with hypereosinophilia syndrome refractory to prednisone and hydroxyurea. One year later, he developed progressive renal failure and nephrotic-range proteinuria. Percutaneous kidney biopsy showed focal and segmental glomerular and mesangial sclerosis, chronic interstitial nephritis, and focal tubular necrosis. Discontinuation of cytokine therapy led to marked improvement in renal function and significant reduction in proteinuria. The potential role of IFN-alpha as the cause of renal failure and nephrotic-range proteinuria is discussed. The spectrum of renal disease attributed to IFN-alpha and the proposed pathogenic mechanisms are reviewed.

Serum beta carotene, alpha tocopherol, and age-related maculopathy: the Blue Mountains Eye Study

PURPOSE

To assess associations between serum beta carotene, alpha tocopherol, and age-related maculopathy.

METHODS

We studied 156 subjects with age-related maculopathy matched for age, sex, and month of blood collection to 156 control subjects without age-related maculopathy. Subjects were identified from the Blue Mountains Eye Study: those with late age-related macular degeneration and early age-related maculopathy using examination and grading of retinal photographs, and control subjects without age-related maculopathy randomly sampled from the study population.

RESULT

Neither serum alpha tocopherol nor beta carotene was significantly associated with age-related maculopathy.

CONCLUSION

These findings provide no evidence of a protective association between serum alpha tocopherol or beta carotene and age-related maculopathy.

Social comparison and task prediction: ability similarity and the use of a proxy

It is argued that an important aspect of the self-appraisal of ability involves a person's prediction of his or her own performance level on untried tasks through acquisition of knowledge about how other people have fared at the task. These others are treated as substitutes for a person's own participation in the task--as proxies. It is further argued that social comparison plays a significant role in both the selection of proxies and the impact of proxy information on task prediction. The first experiment, following earlier research on comparison preference in the context of performance prediction, showed that participants interested in performance prediction chose a proxy who had performed at about the same level as they had on a reference task, while those interested in improving their performances chose to see the performances of someone who had done far better than they on the reference task. The second study indicated that participants made more confident predictions for themselves from a similar proxy's task outcome than from that of a proxy whose ability was unknown to them. Participants predicted they would do worse than a more able proxy and better than a less able proxy, but were less confident in their predictions than were those with a similar proxy. Ratings of usefulness of the proxy followed the patterns of confidence ratings closely.

Intravascular stent and endovascular coil placement for a ruptured fusiform aneurysm of the basilar artery. Case report and review of the literature

The authors demonstrate the technical feasibility of using intravascular stents in conjunction with electrolytically detachable coils (Guglielmi detachable coils [GDCs]) for treatment of fusiform, broad-based, acutely ruptured intracranial aneurysms and review the literature on endovascular approaches to ruptured aneurysms and cerebral stent placement. A 77-year-old man presented with an acute subarachnoid hemorrhage of the posterior fossa. A fusiform aneurysm with a broad-based neck measuring 12 mm and involving the distal vertebral artery (VA) and proximal third of the basilar artery (BA) was demonstrated on cerebral angiography. The aneurysm was judged to be inoperable. Six days later a repeated hemorrhage occurred. A 15-mm-long intravascular stent was placed across the base of the aneurysm in the BA and expanded to 4 mm to act as a bridging scaffold to create a neck. A microcatheter was then guided through the interstices of the stent into the body and dome of the aneurysm, and GDCs were deposited for occlusion. The arteriogram obtained after stent placement demonstrated occlusion of the main dome and body of the aneurysm. The coils were stably positioned and held in place by the stent across the distal VA and BA fusiform aneurysm. Excellent blood flow to the distal BA and posterior cerebral artery was maintained through the stent. There were no new brainstem ischemic events attributable to the procedure. No rebleeding from the aneurysm had occurred by the 10.5-month follow-up evaluation, and the patient has experienced significant neurological improvement. Certain types of intracranial fusiform aneurysms may now be treated by combining intravascular stent and GDC placement for aneurysm occlusion via an endovascular approach. This is the first known clinical application of this novel approach in a ruptured cerebral aneurysm.

Association of pseudoexfoliation syndrome with increased vascular risk

PURPOSE

To examine vascular associations with pseudoexfoliation syndrome in view of the wide-spread elastosis now demonstrated in this disorder that affects many tissues, including vessel walls.

METHODS

The Blue Mountains Eye Study is a population-based study of eye disease in an area west of Sydney, Australia. Of 4433 eligible persons aged 49 years or older, 3,654 (82.4%) participated. Signs of pseudoexfoliation were graded clinically, after excluding 108 people who had bilateral cataract surgery.

RESULTS

Pseudoexfoliation was present in 81 (2.3%) of 3546 participants aged 49 years or older. The prevalence of pseudoexfoliation increased with age and was higher in women and in people with glaucoma. Pseudoexfoliation was statistically significantly associated with a history of angina or hypertension or a combined history of angina, acute myocardial infarction, or stroke.

CONCLUSION

Slit-lamp signs of pseudoexfoliation may identify individuals with an increased vascular risk.

Knowledge and beliefs about common eye diseases

PURPOSE

To ascertain the level of knowledge of common causes of blindness in an adult Australian population and to relate this to use of eye care services.

METHODS

A population-based study of common eye diseases in an urban population aged 49 years or older was conducted. The questions were concerned with the awareness and knowledge of and the ability to describe three common eye diseases, namely cataract, glaucoma and age-related macular degeneration (AMD).

RESULTS

Awareness of cataract (98%) and glaucoma (93%) were high in this population, but awareness of AMD was low (20%). Among people who were aware of the target eye disease, only 29% showed some knowledge of glaucoma, 26% showed some knowledge of AMD and 20% showed some knowledge of cataract; this was also low in people who had previous eye treatment, such as cataract surgery. Knowledge was related to education level, occupational prestige and knowledge of other eye diseases. After excluding people with a previous eye disease diagnosis, those people who were aware and had some knowledge of eye disease accessed eyecare services more frequently.

CONCLUSIONS

Knowledge of common eye diseases is generally lacking. Age-related macular degeneration is the leading cause of blindness in Australia, yet only 20% of the present study population had heard of it. As there are often no early symptoms for glaucoma, community awareness of this disease and the need for screening of people at risk may allow timely diagnosis and more effective therapy before advanced visual field loss has occurred. An informed public is more likely to present earlier with visual symptoms before irreversible visual loss has occurred and is more likely to comply better with recommended therapy.

Behavioural and cardiovascular responses of rats to euthanasia using carbon dioxide gas

Our results showed more rapid falls in pulse rate and blood pressure in rats euthanized in a chamber precharged with carbon dioxide (CO2), when compared with rats euthanized more slowly, but death still took over 5 min in the former group. There was no behavioural evidence of pain or distress in either group during euthanasia. Initial ataxia and dyspnoea was punctuated by a lag before death, thus separating euthanasia into three clearly defined phases. All visual signs of death preceded complete vascular collapse by about 1 min in both groups, so we recommend that gas flow be maintained for at least 1 min after apparent death.

Is there an association between migraine headache and open-angle glaucoma? Findings from the Blue Mountains Eye Study

OBJECTIVE

To determine whether an association exists between migraine headache history and open-angle glaucoma (OAG).

DESIGN

Population-based, cross-sectional study.

PARTICIPANTS

Subjects were 3654 people aged 49 or older; 82% of permanent residents from an area west of Sydney participated.

INTERVENTION

All participants underwent an interview and a detailed eye examination, including automated perimetry and stereo optic disc photography.

MAIN OUTCOME MEASURES

Open-angle glaucoma was diagnosed in subjects with matching typical glaucomatous visual field defects and pathologic optic disc cupping, independent of intraocular pressure level. The diagnosis of migraine history (typical or nontypical) was based on participant responses to specific questions, consistent with International Headache Society criteria.

RESULTS

Open-angle glaucoma prevalence increased exponentially with age, with rates of 0.4%, 1.3%, 4.7%, and 11.4% among persons aged less than 60 years, between 60 and 69 years, between 70 and 79 years, and 80 years or older, respectively. The frequency of reporting a past history of typical migraine headache declined with increasing age, with rates of 23.1%, 16.2%, 12.8%, and 10.4% for corresponding age groups. For all age groups combined, there was no significant association between typical migraine headache and OAG (odds ratio [OR], 1.3; 95% confidence interval [CI], 0.8-2.2), after multivariate adjustment. However, after stratifying into 10-year age groups, increased odds for OAG were found for people giving a history of typical migraine headache and aged 70-79 years (OR, 2.5; 95% CI 1.2-5.2), after adjusting for variables found associated with glaucoma. This association was marginally stronger for high-pressure OAG cases (OR, 2.7; 95% CI, 1.1-5.6).

CONCLUSIONS

These data suggest the possibility of an association between history of typical migraine headache and OAG, which could be modified by age.

The influence of age and intraocular pressure on the optic cup in a normal population

PURPOSE

To determine the effects of age and intraocular pressure (IOP) on optic cup and neural rim size, and cup-disc ratio in a well defined population free from apparent glaucoma and other optic nerve disease.

METHODS

Data were collected on 3654 people, 49 years or older, living in the Blue Mountains, west of Sydney. Examination included subjective refraction and Zeiss colour stereo (Carl Zeiss, Oberkochen, Germany) optic disc photographs. Magnification effects of the eye and camera were corrected. After excluding subjects with optic nerve diseases, data from 6579 normal phakic eyes of 3358 subject (91.9% of those examined) were used.

RESULTS

Adjusted for optic disc size and IOP, cup diameter increased 0.01 mm, cup-disc ratio increased 0.01, and neural rim width decreased 0.01 mm for every decade of age increase. Adjusted for age and optic disc size, cup diameter increased 0.01 mm, cup-disc ratio increased 0.04, and neural rim width decreased 0.07 mm for every 10 mmHg increase in IOP. The IOP-related increase in cup-disc ratio amounted to 9.5% of the mean per 10 mmHg, while the age related increase was 1.9% of the mean.

CONCLUSIONS

These data support the hypothesis that there is an age-related loss of tissue from the neuroretinal rim. However the mean change between the ages of 50 and 90 years is very small. The association between increasing IOP and smaller neural rim width could suggest a causal relationship. However, it is also plausible that IOP and optic cup size are both determined by other unmeasured factors.