Purified transcription factor AP-1 interacts with TPA-inducible enhancer elements

The enhancer-binding protein AP-1 has been purified to greater than 95% homogeneity from HeLa cells by sequence-specific DNA affinity chromatography and identified as a 47 kd polypeptide. Purified AP-1 activates transcription in vitro of the wild-type human metallothionein IIA (hMT IIA) gene but not mutant hMT IIA promoters lacking AP-1 recognition sites. DNAase I protection analysis indicates that genetically defined enhancer elements in hMT IIA, SV40, and the human collagenase gene contain high-affinity AP-1-binding sites, each with a conserved recognition motif, TGACTCA. These three genes are transcriptionally induced by treatment of cells with the tumor promoter TPA. Here we demonstrate that multiple synthetic copies of the consensus AP-1-binding site can act as TPA-inducible enhancers in various plasmid constructs after transfection into HeLa cells. These findings suggest that AP-1 is a transcription factor that functions by interacting with a specific enhancer element, and that its activities may be modulated by treatment of cells with TPA, known to stimulate protein kinase C.

Cognitive deficits in depression: possible implications for functional neuropathology

BACKGROUND

While depression is known to involve a disturbance of mood, movement and cognition, its associated cognitive deficits are frequently viewed as simple epiphenomena of the disorder.

AIMS

To review the status of cognitive deficits in depression and their putative neurobiological underpinnings.

METHOD

Selective computerised review of the literature examining cognitive deficits in depression and their brain correlates.

RESULTS

Recent studies report both mnemonic deficits and the presence of executive impairment--possibly selective for set-shifting tasks--in depression. Many studies suggest that these occur independent of age, depression severity and subtype, task 'difficulty', motivation and response bias: some persist upon clinical 'recovery'.

CONCLUSIONS

Mnemonic and executive deficits do no appear to be epiphenomena of depressive disorder. A focus on the interactions between motivation, affect and cognitive function may allow greater understanding of the interplay between key aspects of the dorsal and ventral aspects of the prefrontal cortex in depression.

Enhanced cleavage of type II collagen by collagenases in osteoarthritic articular cartilage

We demonstrate the direct involvement of increased collagenase activity in the cleavage of type II collagen in osteoarthritic human femoral condylar cartilage by developing and using antibodies reactive to carboxy-terminal (COL2-3/4C(short)) and amino-terminal (COL2-1/4N1) neoepitopes generated by cleavage of native human type II collagen by collagenase matrix metalloproteinase (MMP)-1 (collagenase-1), MMP-8 (collagenase-2), and MMP-13 (collagenase-3). A secondary cleavage followed the initial cleavage produced by these recombinant collagenases. This generated neoepitope COL2-1/4N2. There was significantly more COL2-3/4C(short) neoepitope in osteoarthritis (OA) compared to adult nonarthritic cartilages as determined by immunoassay of cartilage extracts. A synthetic preferential inhibitor of MMP-13 significantly reduced the unstimulated release in culture of neoepitope COL2-3/4C(short) from human osteoarthritic cartilage explants. These data suggest that collagenase(s) produced by chondrocytes is (are) involved in the cleavage and denaturation of type II collagen in articular cartilage, that this is increased in OA, and that MMP-13 may play a significant role in this process.

The exosome: a conserved eukaryotic RNA processing complex containing multiple 3'-->5' exoribonucleases

We identified a complex in S. cerevisiae, the "exosome," consisting of the five essential proteins Rrp4p, Rrp41p, Rrp42p, Rrp43p, and Rrp44p (Dis3p). Remarkably, four of these proteins are homologous to characterized bacterial 3'-->5' exoribonucleases; Rrp44p is homologous to RNase II, while Rrp41p, Rrp42p, and Rrp43p are related to RNase PH. Recombinant Rrp4p, Rrp44p, and Rrp41p are 3'-->5' exoribonucleases in vitro that have distributive, processive, and phosphorolytic activities, respectively. All components of the exosome are required for 3' processing of the 5.8S rRNA. Human Rrp4p is found in a comparably sized complex, and expression of the hRRP4 gene in yeast complements the rrp4-1 mutation. We conclude that the exosome constitutes a highly conserved eukaryotic RNA processing complex.

Effect of fenofibrate on the need for laser treatment for diabetic retinopathy (FIELD study): a randomised controlled trial

BACKGROUND

Laser treatment for diabetic retinopathy is often associated with visual field reduction and other ocular side-effects. Our aim was to assess whether long-term lipid-lowering therapy with fenofibrate could reduce the progression of retinopathy and the need for laser treatment in patients with type 2 diabetes mellitus.

METHODS

The Fenofibrate Intervention and Event Lowering in Diabetes (FIELD) study was a multinational randomised trial of 9795 patients aged 50-75 years with type 2 diabetes mellitus. Eligible patients were randomly assigned to receive fenofibrate 200 mg/day (n=4895) or matching placebo (n=4900). At each clinic visit, information concerning laser treatment for diabetic retinopathy-a prespecified tertiary endpoint of the main study-was gathered. Adjudication by ophthalmologists masked to treatment allocation defined instances of laser treatment for macular oedema, proliferative retinopathy, or other eye conditions. In a substudy of 1012 patients, standardised retinal photography was done and photographs graded with Early Treatment Diabetic Retinopathy Study (ETDRS) criteria to determine the cumulative incidence of diabetic retinopathy and its component lesions. Analyses were by intention to treat. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN64783481.

FINDINGS

Laser treatment was needed more frequently in participants with poorer glycaemic or blood pressure control than in those with good control of these factors, and in those with a greater burden of clinical microvascular disease, but the need for such treatment was not affected by plasma lipid concentrations. The requirement for first laser treatment for all retinopathy was significantly lower in the fenofibrate group than in the placebo group (164 [3.4%] patients on fenofibrate vs 238 [4.9%] on placebo; hazard ratio [HR] 0.69, 95% CI 0.56-0.84; p=0.0002; absolute risk reduction 1.5% [0.7-2.3]). In the ophthalmology substudy, the primary endpoint of 2-step progression of retinopathy grade did not differ significantly between the two groups overall (46 [9.6%] patients on fenofibrate vs 57 [12.3%] on placebo; p=0.19) or in the subset of patients without pre-existing retinopathy (43 [11.4%] vs 43 [11.7%]; p=0.87). By contrast, in patients with pre-existing retinopathy, significantly fewer patients on fenofibrate had a 2-step progression than did those on placebo (three [3.1%] patients vs 14 [14.6%]; p=0.004). An exploratory composite endpoint of 2-step progression of retinopathy grade, macular oedema, or laser treatments was significantly lower in the fenofibrate group than in the placebo group (HR 0.66, 95% CI 0.47-0.94; p=0.022).

INTERPRETATION

Treatment with fenofibrate in individuals with type 2 diabetes mellitus reduces the need for laser treatment for diabetic retinopathy, although the mechanism of this effect does not seem to be related to plasma concentrations of lipids.

Prevalence of age-related maculopathy in Australia. The Blue Mountains Eye Study

PURPOSE

To examine the prevalence of age-related maculopathy (drusen and retinal pigmentary abnormalities) and end-stage age-related macular degeneration lesions (neovascular maculopathy or geographic atrophy) in a defined older Australian urban population.

SUBJECTS

All noninstitutionalized residents 49 years of age or older who were identified in a door-to-door census of two postcode areas west of Sydney, Australia.

METHODS

All participants received a detailed eye examination, including stereoscopic photographs of each macula. Two trained graders used the Wisconsin Age-related Maculopathy Grading System to assess the presence and severity of typical lesions.

RESULTS

A marked age-related increase in all typical lesions of age-related maculopathy and macular degeneration was observed. End-stage age-related macular degeneration was present in 1.9% of the population, rising from 0% among people younger than 55 years of age to 18.5% among those 85 years of age or older. Soft drusen were found in 13.3% of people, with distinct drusen more frequent than indistinct soft drusen. Retinal pigmentary abnormalities were found in 12.6% of people. For end-stage lesions and soft drusen, females had higher age-specific prevalence rates than males, whereas retinal pigmentary abnormalities were more frequent in males, although most of these differences were not significant. Prevalence rates for all lesions were lower (statistically significant for retinal pigmentary abnormalities and soft drusen) than for the United States Beaver Dam Eye Study which examined a similar population.

CONCLUSIONS

These data provide detailed prevalence rates for most components of ARM in an Australian population and reinforce the Beaver Dam Eye Study findings for the relative age-specific frequency of age-related macular degeneration components.

Risk factors for age-related macular degeneration: Pooled findings from three continents

OBJECTIVE

To assess the prevalence and potential risk factors for late age-related macular degeneration (AMD) in three racially similar populations from North America, Europe, and AUSTRALIA:

DESIGN

Combined analysis of population-based eye disease prevalence data.

PARTICIPANTS

There were 14,752 participants with gradable photographs from the Beaver Dam Eye Study (n = 4756), Rotterdam Study (n = 6411), and Blue Mountains Eye Study (n = 3585).

MAIN OUTCOME MEASURES

AMD diagnosis was made from masked grading of stereo macular photographs. Final classification of AMD cases was agreed by consensus between study investigators.

RESULTS

AMD prevalence was strongly age related. Overall, AMD was present in 0.2% of the combined population aged 55 to 64 years, rising to 13% of the population older than 85 years. Prevalence of neovascular AMD (NV) increased from 0.17% among subjects aged 55 to 64 years to 5.8% for those older than 85 years. Prevalence of pure geographic atrophy (GA) increased from 0.04% to 4.2% for these age groups. There were no significant gender differences in the prevalence of NV or GA. Subjects in the Rotterdam population had a significantly lower age-adjusted and smoking-adjusted risk of NV than subjects in the Beaver Dam and Blue Mountains populations. Apart from age, tobacco smoking was the only risk factor consistently associated with any form of AMD in all sites separately and in pooled analyses over the three sites.

CONCLUSIONS

These combined data from racially similar communities across three continents provide strong and consistent evidence that tobacco smoking is the principal known preventable exposure associated with any form of AMD.

The relationship between glaucoma and myopia: the Blue Mountains Eye Study

OBJECTIVE

To quantify the relationship between myopia and open-angle glaucoma, ocular hypertension (OH), and intraocular pressure (IOP) in a representative older population.

DESIGN

Cross-sectional population-based study of 3654 Australians 49 to 97 years of age.

METHODS

Subjects with any myopia (> or =-1.0 diopter [D]) were identified by a standardized subjective refraction and categorized into low myopia (> or =-1.0 D to <-3.0 D) or moderate-to-high myopia (> or =-3.0 D). Glaucoma was diagnosed from characteristic visual field loss, combined with optic disc cupping and rim thinning, without reference to IOP. Ocular hypertension was diagnosed when applanation IOP was greater than 21 mmHg in either eye in the absence of glaucomatous visual field and optic disc changes.

MAIN OUTCOME MEASURE

General estimating equation models were used to assess associations between eyes with myopia and either glaucoma or OH.

RESULTS

Glaucoma was present in 4.2% of eyes with low myopia and 4.4% of eyes with moderate-to-high myopia compared to 1.5% of eyes without myopia. The relationship between glaucoma and myopia was maintained after adjusting for known glaucoma risk factors, odds ratio (OR) of 2.3, and 95% confidence intervals (CI) of 1.3 to 4.1 for low myopia. It was stronger for eyes with moderate-to-high myopia (OR, 3.3; CI, 1.7-6.4). Only a borderline relationship was found with OH, OR of 1.8 (CI, 1.2-2.9) for low myopia, and OR of 0.9 (CI, 0.4-2.0) for moderate-to-high myopia. Mean IOP was approximately 0.5 mmHg higher in myopic eyes compared to nonmyopic eyes.

CONCLUSIONS

This study has confirmed a strong relationship between myopia and glaucoma. Myopic subjects had a twofold to threefold increased risk of glaucoma compared with that of nonmyopic subjects. The risk was independent of other glaucoma risk factors and IOP.

Prevalence of open-angle glaucoma in Australia. The Blue Mountains Eye Study

PURPOSE

The purpose of this study was to determine the prevalence of open-angle glaucoma and ocular hypertension in an Australian community whose residents are 49 years of age or older.

SUBJECTS

There were 3654 persons, representing 82.4% of permanent residents from an area west of Sydney, Australia, who were examined. The population was identified by a door-to-door census of all dwellings and by closely matched findings from the national census.

METHODS

All participants received a detailed eye examination, including applanation tonometry, suprathreshold automated perimetry (Humphrey 76-point test), and Zeiss stereoscopic optic disc photography. Glaucoma suspects were asked to return for full threshold fields (Humphrey 30-2 test), gonioscopy, and repeat tonometry.

RESULTS

A 5-point hemifield difference on the 76-point test was found in 616 persons (19% of people tested). Humphrey 30-2 tests were performed on 336 glaucoma suspects (9.2% of population), of whom 125 had typical glaucomatous field defects. Two hundred three persons had enlarged or asymmetric cup-disc ratios (> or = 0.7 in 1 or both eyes or a cup-disc ratio difference of > or = 0.3). Open-angle glaucoma was diagnosed when glaucomatous defects on the 30-2 test matched the optic disc changes, without regard to the intraocular pressure level. This congruence was found in 87 participants (2.4%), whereas an additional 21 persons (0.6%) had clinical signs of open-angle glaucoma but incomplete examination findings. Open-angle glaucoma was thus found in 108 persons, a prevalence of 3.0% (95% confidence interval [CI], 2.5-3.6), of whom 49% were diagnosed previously. An exponential rise in prevalence was observed with increasing age. Ocular hypertension, defined as an intraocular pressure in either eye greater than 21 mmHg, without matching disc and field changes, was present in 3.7% of this population (95% CI, 3.1-4.3), but there was no significant age-related increase in prevalence. The prevalence of glaucoma was higher in women after adjusting for age (odds ratio, 1.5; CI, 1.0-2.2). There was no sex difference in the age-adjusted prevalence of ocular hypertension.

CONCLUSIONS

These data provide detailed age and sex-specific prevalence rates for open-angle glaucoma and ocular hypertension in an older Australian population.

Visual acuity and the causes of visual loss in Australia. The Blue Mountains Eye Study

BACKGROUND

The Blue Mountains Eye Study is a population-based study of vision and the causes of visual impairment and blindness in a well-defined urban, Australian population 49 years of age and older.

METHODS

The logarithm of the minimum angle of resolution (logMAR) visual acuity was measured before and after refraction in 3647 persons, representing an 88% response rate in two postcode areas in the Blue Mountains area, west of Sydney.

RESULTS

Refraction improved visual acuity by one or more lines in 45% of participants and by three or more lines in 13%. Visual impairment (visual acuity 20/40 or worse in the better eye) was found in 170 participants (4.7%). Mild visual impairment (Snellen equivalent 20/40 to 20/60 in the better eye) was found in 3.4% moderate visual impairment (20/80 to 20/160 in the better eye) in 0.6%, and severe visual impairment or blindness (20/200 or worse in the better eye) in 0.7%. Visual impairment increased with age from 0.8% of persons 49 to 54 years of age to 42% of persons 85 years of age or older. Visual impairment was significantly more frequent in females at all ages. Among persons with severe visual impairment, 79% were female. After adjusting for age, females were less likely to achieve 20/20 best-corrected visual acuity than males (odds ratio, 0.57; confidence interval, 0.48-0.66). After adjusting for age and sex, no association was found between visual acuity and socioeconomic status. Age-related macular degeneration was the cause of blindness in 21 of the 24 persons with corrected visual acuity of 20/200 or worse.

CONCLUSION

Increasing age and female sex were independent predictors of visual impairment.

Functions of the exosome in rRNA, snoRNA and snRNA synthesis

The yeast nuclear exosome contains multiple 3'-->5' exoribonucleases, raising the question of why so many activities are present in the complex. All components are required during the 3' processing of the 5.8S rRNA, together with the putative RNA helicase Dob1p/Mtr4p. During this processing three distinct steps can be resolved, and hand-over between different exonucleases appears to occur at least twice. 3' processing of snoRNAs (small nucleolar RNAs) that are excised from polycistronic precursors or from mRNA introns is also a multi-step process that involves the exosome, with final trimming specifically dependent on the Rrp6p component. The spliceosomal U4 snRNA (small nuclear RNA) is synthesized from a 3' extended precursor that is cleaved by Rnt1p at sites 135 and 169 nt downstream of the mature 3' end. This cleavage is followed by 3'-->5' processing of the pre-snRNA involving the exosome complex and Dob1p. The exosome, together with Rnt1p, also participates in the 3' processing of the U1 and U5 snRNAs. We conclude that the exosome is involved in the processing of many RNA substrates and that different components can have distinct functions.

Prevalence and associations of retinal vein occlusion in Australia. The Blue Mountains Eye Study

OBJECTIVE

To determine the prevalence and associations of retinal vein occlusion (RVO) in a defined older Australian population.

DESIGN

Participants (N = 3654; age, > or = 49 years), representing 88% of the permanent residents from an area west of Sydney, Australia, underwent a detailed eye examination, including stereophotography (Zeiss). The diagnosis of RVO was made clinically and from photographic grading.

RESULTS

Signs of RVO were found in 59 participants (1.6%; 95% confidence interval, 1.3-1.9). The prevalence for each age-specific participant was as follows: 0.7%, younger than 60 years; 1.2%, 60 to 69 years; 2.1%, 70 to 79 years; and 4.6%, 80 years or older. There was no significant sex difference in prevalence. Branch RVO was observed in 41 subjects (69.5%); of this number, 10 subjects had branch RVO outside the vascular arcade or in the nasal fundus and 3 subjects developed new vessels. Hemispheric RVO was found in 3 subjects (5.1%), and central RVO was observed in 15 (25%); RVO was bilateral in 3 subjects (5.1%). Visual acuity was affected most in the people with central RVO, with a visual acuity of 20/200 or less in 60% compared with 14% among the people with branch RVO. Retinal vein occlusion was the fifth most frequent cause of unilateral blindness in this population. Significant associations with RVO were found with glaucoma, hypertension, stroke, and angina.

CONCLUSIONS

This study emphasizes RVO as an important cause of unilateral visual loss in an older population. The proportion of the 3 vein occlusion sites shows some differences from those of clinic-based reports and suggests a likely selection bias in previous clinic studies.

Acid-base titration across the membrane system of rat-liver mitochondria. Catalysis by uncouplers

1. Pulsed acid-base titrations of suspensions of rat-liver mitochondria under anaerobic equilibrium conditions show fast and slow titration processes. 2. The fast process is the titration of the outer aqueous phase of the mitochondria, which is continuous with the suspension medium, and the slow process can be identified with the titration of the inner aqueous phase of the mitochondria, which is separated from the outer aqueous phase by the non-aqueous osmotic barrier or M phase of the cristae membrane system. 3. The buffering power of the outer and inner phases have been separately measured over a range of pH values. 4. The rate of titration of the inner aqueous phase under a known protonmotive force across the M phase has been characterized by an effective proton conductance coefficient, which, near pH7 and at 25 degrees , is only 0.45mumho/cm.(2) of the M-phase membrane. 5. The low effective proton conductance of the M phase will account quantitatively for the observed respiratory control in state 4, assuming that oxidoreduction and phosphorylation are coupled by a circulating proton current as required by the chemi-osmotic hypothesis. 6. The addition of 2,4-dinitrophenol (or carbonyl cyanide p-trifluoromethoxyphenylhydrazone) at normal uncoupling concentrations causes a large increase in the effective proton conductance of the M phase of the cristae membrane. 7. The increase of the effective proton conductance of the M phase by 2,4-dinitrophenol (or carbonyl cyanide p-trifluoromethoxyphenylhydrazone) will account quantitatively for the short-circuiting effect of the uncoupling agent on the proton current and for the observed rise of the rate of respiration to that characteristic of state 3 or higher.

The yeast exosome and human PM-Scl are related complexes of 3' --> 5' exonucleases

We previously identified a complex of 3' --> 5' exoribonucleases, designated the exosome, that is expected to play a major role in diverse RNA processing and degradation pathways. Further biochemical and genetic analyses have revealed six novel components of the complex. Therefore, the complex contains 11 components, 10 of which are predicted to be 3' --> 5' exoribonucleases on the basis of sequence homology. Human homologs were identified for 9 of the 11 yeast exosome components, three of which complement mutations in the respective yeast genes. Two of the newly identified exosome components are homologous to known components of the PM-Scl particle, a multisubunit complex recognized by autoimmune sera of patients suffering from polymyositis-scleroderma overlap syndrome. We demonstrate that the homolog of the Rrp4p exosome subunit is also a component of the PM-Scl complex, thereby providing compelling evidence that the yeast exosome and human PM-Scl complexes are functionally equivalent. The two complexes are similar in size, and biochemical fractionation and indirect immunofluorescence experiments show that, in both yeast and humans, nuclear and cytoplasmic forms of the complex exist that differ only by the presence of the Rrp6p/PM-Scl100 subunit exclusively in the nuclear complex.

Respiration-driven proton translocation in rat liver mitochondria

1. Pulses of acidity of the outer aqueous phase of rat liver mitochondrial suspensions induced by pulses of respiration are due to the translocation of H(+) (or OH(-)) ions across the osmotic barrier (M phase) of the cristae membrane and cannot be attributed to the formation (with acid production) of a chemical intermediate that subsequently decomposes. 2. The effective quantity of protons translocated per bivalent reducing equivalent passing through the succinate-oxidizing and beta-hydroxybutyrate-oxidizing spans of the respiratory chain are very close to 4 and 6 respectively. These quotients are constant between pH5.5 and 8.5 and are independent of changes in the ionic composition of the mitochondrial suspension medium provided that the conditions permit the accurate experimental measurement of the proton translocation. 3. Apparent changes in the -->H(+)/O quotients may be induced by conditions preventing the occurrence of the usual backlash; these apparent changes of -->H(+)/O are attributable to a very fast electrically driven component of the decay of the acid pulses that is not included in the experimental extrapolations. 4. Apparent changes in the -->H(+)/O quotients may also be induced by the presence of anions, such as succinate, malonate and phosphate, or by cations such as Na(+). These apparent changes of -->H(+)/O are due to an increase in the rate of the pH-driven decay of the acid pulses. 5. The uncoupling agents, 2,4-dinitrophenol, carbonyl cyanide p-trifluoromethoxyphenylhydrazone and gramicidin increase the effective proton conductance of the M phase and thus increase the rate of decay of the respiration-driven acid pulses, but do not change the initial -->H(+)/O quotients. The increase in effective proton conductance of the M phase caused by these uncouplers accounts quantitatively for their uncoupling action; and the fact that the initial -->H(+)/O quotients are unchanged shows that uncoupler-sensitive chemical intermediates do not exist between the respiratory-chain system and the effective proton-translocating mechanism. 6. Stoicheiometric acid-base changes associated with the activity of the regions of the respiratory chain on the oxygen side of the rotenone- and antimycin A-sensitive sites gives experimental support for a suggested configuration of loop 3.

Prevalence and associations of epiretinal membranes. The Blue Mountains Eye Study, Australia

PURPOSE

The purpose of the study is to determine the prevalence and associations of epiretinal membranes in a defined older Australian population and to assess their influence on visual acuity.

METHODS

Three thousand six hundred fifty-four persons 49 years of age or older, representing 88% of permanent residents from an area west of Sydney, underwent a detailed eye examination, including stereo retinal photography. Epiretinal membranes were diagnosed clinically and from photographic grading.

RESULTS

Signs of epiretinal membranes were found in 243 participants (7%; 95% confidence interval [CI], 6.1, 7.6), bilateral in 31%. The prevalence was 1.9% in persons younger than 60 years of age, 7.2% in persons 60 to 69 years of age, 11.6% in persons 70 to 79 years of age, and 9.3% in persons 80 years of age and older, with slightly higher rates in women. Two stages were identified: an early form without retinal folds, termed "cellophane macular reflex" present in 4.8%, and a later stage with retinal folds, termed "preretinal macular fibrosis" (PMF), found in 2.2% of the population. Preretinal macular fibrosis, but not cellophane macular reflex, had a small, significant effect on visual acuity. Preretinal macular fibrosis was significantly associated with diabetes, after age-gender adjustment, in subjects without signs of diabetic retinopathy (odds ratio, 3.2; 95% CI, 1.4, 7.2). Preretinal macular fibrosis also was associated with increased fasting plasma glucose (odds ratio, 1.2; 95% CI, 1.1, 1.3). Epiretinal membranes were found in 16.8% of persons who had undergone cataract surgery in one or both eyes (including PMF in 3.7%), in 16.1% of retinal vein occlusion cases (PMF in 12.5%), both significantly higher rates than in subjects without these conditions (P < 0.0001), and in 11% of persons with diabetic retinopathy (PMF in 3.6%), not significantly higher (P = 0.17).

CONCLUSIONS

This study has documented the frequency and mild effect on vision of epiretinal membranes in an older population. Diabetes was associated significantly with idiopathic cases, whereas well-known associations with past cataract surgery and retinal disease were confirmed.

Visual impairment and falls in older adults: the Blue Mountains Eye Study

OBJECTIVES

To examine the association between visual impairment and falls in older people.

DESIGN

Cross-sectional survey of eye disease with retrospective collection of falls data.

SETTING

Two postcode areas in the Blue Mountains west of Sydney, Australia.

PARTICIPANTS

All people 49 years of age and older were invited to participate, 3654 (82.4%) of 4433 eligible residents took part, and 3299 answered questions about falls.

MEASUREMENTS

Subjects had a detailed eye examination and answered questions about health and vision status, use of medication, and number of falls in the previous 12 months.

RESULTS

Tests of visual function that had a statistically significant association with two or more falls after adjustment for confounders were visual acuity (prevalence ratio (PR) 1.9 for visual acuity worse than 20/30), contrast sensitivity (PR 1.2 for a 1-unit decrease at 6 cycles per degree), and suprathreshold visual field screening (PR 1.5 for 5 or more points missing). However, only visual acuity and contrast sensitivity were significantly associated with two or more falls per 1 standard deviation decrease. The presence of posterior subcapsular cataract (PR 2.1) and use of nonmiotic glaucoma medication (PR 2.0) had a statistically significant association with two or more falls; presence of age-related macular degeneration, diabetic retinopathy, and cortical or nuclear cataract did not.

CONCLUSION

Visual impairment is strongly associated with two or more falls in older adults. In addition to poor visual acuity, visual factors such as reduced visual field, impaired contrast sensitivity, and the presence of cataract may explain this association.