Diabetic retinopathy in Victoria, Australia: the Visual Impairment Project

AIM: To establish the prevalence, severity, and risk factors for diabetic retinopathy in a representative sample of Victorian residents aged 40 years and older. METHODS: A population based, cluster sampling method was used to recruit 4744 participants (86% participation rate). Nine randomly selected, suburban Melbourne clusters and four randomly selected, rural Victorian clusters were used. Participants provided a detailed medical and personal history and underwent an ocular examination including funduscopy and fundus photography. Rural participants provided a blood sample, from which the glycosylated haemoglobin percentage was measured. The diagnosis of diabetic retinopathy was based on fundus photographs from participants with self reported diabetes. RESULTS: The prevalence of diabetic retinopathy among people with self reported diabetes was 29. 1%. The prevalence of untreated, vision threatening retinopathy was 2.8%. Retinopathy was positively associated with a longer reported duration of diabetes diagnosis (p<0.01) and with higher fractions of glycosylated haemoglobin (p<0.01). Retinopathy was not significantly associated with age, ethnicity, body mass index, glaucoma, myopia or intake of alcohol, tobacco, or aspirin (all p > 0.05). CONCLUSIONS: Most people in Victoria with proliferative diabetic retinopathy or clinically significant macular oedema have received laser treatment. There remains however, a small but important group who have not received treatment and whose vision is threatened. People with diabetes should be encouraged to maintain strict glycaemic control and to undergo regular screening to delay or prevent the development of retinopathy.     

Population based assessment of uveitis in an urban population in southern India

AIM: To assess the prevalence of active and inactive uveitis unrelated to previous surgery or trauma in an urban population in southern India. METHODS: As part of the Andhra Pradesh Eye Disease Study, 2522 subjects (85.4% of those eligible), a sample representative of the population of Hyderabad city in southern India, underwent interview and detailed dilated eye examination. Presence of sequelae of uveitis without current active inflammation was defined as inactive uveitis. RESULTS: Unequivocal evidence of active or inactive uveitis unrelated to previous surgery or trauma was present in 21 subjects, an age-sex adjusted prevalence of 0.73% (95% confidence interval (CI) 0.44-1.14%). Active uveitis was present in eight subjects, an age-sex adjusted prevalence of 0.37% (95% CI 0. 19-0.70), of which 0.06% was anterior, 0.25% intermediate, and 0.06% posterior. The 0.36% (95% CI 0.17-0.68%) prevalence of inactive uveitis included macular chorioretinitis scars (0.26%), anterior (0. 07%) and previous vasculitis involving the whole eye (0.03%). The prevalence of visual impairment due to uveitis of less than 6/18 in at least one eye was 0.27%, less than 6/60 in at least one eye was 0. 16%, and less than 6/60 in both eyes was 0.03%. CONCLUSION: These population based cross sectional data give an estimate of the prevalence of various types of uveitis in this urban population in India. Active or past uveitis that might need treatment at some stage was present in one of every 140 people in this population.     

Five-year incidence of open-angle glaucoma: the visual impairment project

PURPOSE: To determine the incidence of open-angle glaucoma (OAG) in Melbourne, Victoria, Australia. DESIGN: Population-based cohort study. PARTICIPANTS: Total of 3271 participants aged 40 years and older from Melbourne, Victoria, Australia. MAIN OUTCOME MEASURES: Five-year incidence of OAG. METHODS: Participants were recruited through a cluster random sampling from nine urban clusters. Baseline examination was conducted from 1992 through 1994, and the follow-up data were collected from 1997 through 1999. Each participant both at baseline and follow-up underwent a standardized ophthalmic examination including intraocular pressure measurement, visual field assessment, cup-to-disc ratio measurement, and paired stereo photographs of the optic disc. Glaucoma was assessed by a consensus group of six ophthalmologists that included two glaucoma specialists. Glaucoma was diagnosed as possible, probable, or definite. RESULTS: The overall incidence of definite OAG was 0.5% (95% confidence limits [CL], 0.3, 0.7); probable and definite incidence of OAG was 1.1% (95% CL, 0.8,1.4); and possible, probable, and definite OAG incidence was 2.7% (95% CL, 1.8, 3.7). The incidence of possible, probable, and definite OAG increases significantly as age increases (P < 0.001). The incidence of definite OAG increases from 0% of participants aged 40 to 49 years to 4.1% of participants aged 80 years and older. The incidence of probable and definite OAG increases from 0.2% of participants aged 40 to 49 years to 5.4% of participants aged 80 years and older. The incidence of possible, probable, and definite OAG increases from 0.5% of participants aged 40 to 49 years to 11% of participants aged 80 years and older. A nonsignificant but higher incidence of definite OAG among men was observed in this study when compared with women (odds ratio, 2.2; 95% CL, 0.9, 5.9). Fifty percent of the definite OAG participants were undiagnosed. CONCLUSIONS: The incidence of OAG increases significantly with age. The undiagnosed cases suggest the need to develop novel community screening strategies for glaucoma.     

Moderate visual impairment in India: the Andhra Pradesh Eye Disease Study

AIM: To assess the prevalence and demographic associations of moderate visual impairment in the population of the southern Indian state of Andhra Pradesh. METHODS: From 94 clusters in one urban and three rural areas of Andhra Pradesh, 11 786 people of all ages were sampled using a stratified, random, cluster, systematic sampling strategy. The eligible people were invited for interview and detailed dilated eye examination by trained professionals. Moderate visual impairment was defined as presenting distance visual acuity less than 6/18 to 6/60 or equivalent visual field loss in the better eye. RESULTS: Of those sampled, 10,293 (87.3%) people participated in the study. In addition to the previously reported 1.84% prevalence of blindness (presenting distance visual acuity less than 6/60 or central visual field less than 20 degrees in the better eye) in this sample, 1237 people had moderate visual impairment, an adjusted prevalence of 8.09% (95% CI 6.89 to 9.30%). The majority of this moderate visual impairment was caused by refractive error (45.8%) and cataract (39.9%). Increasing age, female sex, decreasing socioeconomic status, and rural area of residence had significantly higher odds of being associated with moderate visual impairment. CONCLUSIONS: These data suggest that there is a significant burden of moderate visual impairment in this population in addition to blindness. Extrapolation of these data to the population of India suggests that there were 82 million people with moderate visual impairment in the year 2000, and this number is likely to be 139 million by the year 2020 if the current trend continues. This impending large burden of moderate visual impairment, the majority of which is due to the relatively easily treatable refractive error and cataract, would have to be taken into account while estimating the eye care needs in India, in addition to dealing with blindness. Specific strategies targeting the elderly population, people with low socioeconomic status, those living in the rural areas, and females would have to be implemented in the long term to reduce moderate visual impairment.     

Delivery of photocoagulation treatment for diabetic retinopathy at a large Australian ophthalmic hospital: comparisons with national clinical practice guidelines

Objective: To determine if the delivery of photocoagulation for diabetic retinopathy at a large Australian ophthalmic hospital conforms with Australian National Health and Medical Research Council clinical practice guidelines.
Methods: A retrospective medical record review was conducted of all patients who had initial laser treatment for diabetic retinopathy at the Royal Victorian Eye and Ear Hospital from January 1997 to December 1998.
Results: The study included 322 eyes from 203 patients. The mean age was 65.8 years (range 18−89 years) and the mean duration of diabetes was 14.7 years (range 1−40 years). Panretinal photocoagulation (PRP) alone was performed in 37 eyes over a mean number of 2.6 sessions. The median waiting time for these procedures was 14 days (range 0−146 days) and the median follow-up time was 7.1 weeks (range 1−25 weeks). Focal treatment was performed (without PRP) in 238 eyes and 55.5% of these cases required repeat focal treatment for persistent clinically significant macular oedema. Median waiting time for focal treatment was 20 days (range 0−302 days) and the median follow-up time after treatment was 12.1 weeks (range 1.7−42.0 weeks). Focal and PRP treatment was used in 47 eyes that had maculopathy concurrently with proliferative retinopathy. Focal treatment was applied before (or at the same session as) the PRP wherever possible.
Conclusions: The study indicates that the application of photocoagulation and follow up for diabetic retinopathy at this tertiary referral institution conforms closely with Australian clinical practice guidelines.     

Comparative efficacy between the glycoprotein IIb/IIIa antagonists roxifiban and orbofiban in inhibiting platelet responses in flow models of thrombosis

This study was undertaken to compare the platelet binding characteristics and anti-platelet efficacy of a nonpeptide glycoprotein IIb/IIIa antagonist roxifiban with orbofiban in static and dynamic adhesion and aggregation assays. The results indicate that roxifiban binds with higher affinity to glycoprotein IIb/IIIa receptors and exhibits slower dissociation rates than orbofiban. Furthermore, the platelet inhibitory effects of roxifiban, but not orbofiban, were unaffected by changes in plasma calcium concentrations. Both agents reduced, in a concentration-dependent manner, the size of platelet thrombi deposited onto collagen I upon perfusion of heparinized blood at a shear rate of 1,500/s. At a clinically achievable concentration of 60 nM, roxifiban abrogated the formation of thrombi containing > 20 platelets per thrombus, thereby displaying comparable in vitro efficacy to that achieved by the theoretical maximal abciximab blood concentration (3.5 microg/ml) produced after standard treatment. In contrast, orbofiban, even at 500 nM, was only effective in inhibiting the formation of larger platelet thrombi (> or =150 platelets per thrombus). Pretreatment of surface-anchored platelets with roxifiban (100 nM), but not orbofiban (500 nM), inhibited monocytic THP-1 cell attachment under flow. However, this heterotypic adhesion process was also suppressed when orbofiban (500 nM) was maintained in the perfusion buffer during the entire course of flow experiment. These findings demonstrate roxifiban (unlike orbofiban) is a potent glycoprotein IIb/IIIa antagonist with a long receptor-bound lifetime and prolonged anti-platelet efficacy and may thus be beneficial for the treatment and prevention of acute ischemic syndromes.     

Association of life events and psychological distress in family caregivers of dementia patients

Relationships between life events and psychological distress were investigated for 197 dementia caregivers and 218 non-caregivers. Participants indicated which events on the Louisville Older Persons Events Scale they had experienced over the past six months. Life events were then classified as associated or unassociated with care-giving using differences in incidence rates between caregivers and non-caregivers. Primary care-giving stressors and associated life events were most predictive of psychological distress among caregivers. Among non-caregivers, unassociated negative life events were the strongest predictors of depression and life satisfaction. Implications for the assessment of life events and caregiver interventions are discussed.     

Adolescent vitamin A intake alters susceptibility to mammary carcinogenesis in the Sprague-Dawley rat

We tested the hypothesis that adolescent dietary vitamin A intake impacts mammary gland development and subsequent sensitivity to carcinogenesis. Sprague-Dawley rats were fed a purified diet that was vitamin A deficient, adequate (2.2 mg retinyl palmitate/kg diet), or supranutritional (16 mg retinyl palmitate/kg diet) from 21 to 63 days of age, the period of adolescent mammary gland development. At 73 days of age, rats were given 1-methyl-1-nitrosourea (25 mg/kg body wt i.p.) and monitored for mammary tumors. Tumors appeared earlier and more frequently in rats fed vitamin A-deficient or -supplemented diets. Vitamin A deficiency during adolescence was associated with alveolar mammary gland development and precocious milk protein expression, while supplementation was associated with ductal gland development and suppression of milk protein expression. Differences in circulating estradiol and mammary gland estrogen receptor-alpha, and estrogen-responsive progesterone receptor mRNA were not observed, suggesting that the effects of vitamin A on mammary gland development and carcinogenesis are estrogen independent. Mammary expression of another hormone receptor that regulates milk protein expression, the glucocorticoid receptor, was also unaffected. These results demonstrate that vitamin A intake during adolescence alters mammary gland differentiation and indicate that a narrow range of vitamin A intake during adolescence protects against carcinogenesis.     

The Australian Diabetes,Obesity and Lifestyle Study (AusDiab)--methods and response rates

The Australian Diabetes, Obesity and Lifestyle Study (AusDiab) addresses the urgent need for data on diabetes prevalence, risk factors and associated conditions in Australia. Here we describe the methods used and the response rates obtained. AusDiab was a population-based cross-sectional survey of national diabetes mellitus prevalence and associated risk factors in people aged > or =25 years, conducted between May 1999 and December 2000 in the six states and the Northern Territory of Australia. The study involved an initial household interview, followed by a biomedical examination that included an oral glucose tolerance test (OGTT), standard anthropometric tests, blood pressure measurements and the administration of questionnaires. Of the 20347 eligible people (aged > or =25 years and resident at the address for > or =6 months) who completed a household interview, 11247 (55.3%) attended for the biomedical examination. Of those who completed the biomedical examination 55.1% were female. Comparisons with the 1998 Australian population estimates showed that younger age responders were under-represented at the biomedical examination, while the middle-aged and older age groups were over-represented. Weighting of the AusDiab data for age and gender have corrected for this bias. AusDiab, which is the largest national diabetes prevalence study undertaken in a developed nation to have used an OGTT, provides a valuable national resource for the study of the prevalence and possible causes of diabetes, as well as identifying possible risk factors that may lead to diabetes. Furthermore, it generates the baseline data for a prospective 5-year cohort study. The data will be important for national and regional public health and lifestyle education and health promotion programs.     

The effects of chronic alcohol consumption and exercise on the skeleton of adult male rats

BACKGROUND: Lifestyle factors are known to affect skeletal development and integrity. Specifically, running has been reported to increase risk of fatigue fractures, whereas chronic alcohol consumption has been shown to reduce bone formation and bone mass. The combined effect of exercise and alcohol on the skeleton has yet to be explored, although alcohol consumption is common among certain physically active populations (e.g., military recruits, college athletes). It was hypothesized that chronic alcohol consumption would accentuate the inherent risk associated with endurance running exercise. METHODS: Six-month-old male Sprague Dawley rats were assigned to one of five groups: baseline, exercise-alcohol diet, exercise-normal diet, sham-alcohol diet, and sham-normal diet. Alcohol-fed rats (35% caloric intake) received a liquid diet ad libitum. Normal animals were pair-fed the identical diet with a maltose dextrin caloric substitute. Exercise was conducted on a motorized treadmill 5 days/wk for 16 weeks. Sham rats were placed on a stationary treadmill for matching time periods. Fluorochrome labels were administered 3 days before baseline and at 10 and 2 days before animals were killed. Heart, soleus, and rectus femoris muscles were wet weighed to assess the effects of training. Tibiae were collected for static and dynamic histomorphometric measurements on cancellous and cortical bone. RESULTS: Muscle weights were larger in the exercised rats versus the sham rats. Alcohol had no significant effect on skeletal muscle weight but did result in larger heart weights in both alcohol-treated groups. Cancellous and periosteal bone formation rates were significantly decreased in the alcohol-fed rats versus rats on the normal diet and were associated with a significant reduction in trabecular thickness in the tibial metaphysis. Cortical and cross-sectional areas were also significantly lower in the alcohol-fed groups compared with the non-alcohol-fed groups. Exercise had no significant effect on cancellous or cortical bone measurements. CONCLUSIONS: Chronic alcohol consumption significantly reduced bone formation. Exercise had no effect on the bone and did not attenuate any of the negative effects of alcohol. The results suggest that alcohol consumption weakens the skeleton and increases the incidence of endurance-exercise-related bone injuries. Thus, individuals who are participating in endurance exercise and consuming alcohol may be at greater risk for exercise-related skeletal injuries. Further investigation of the potential for alcohol to induce detrimental effects on the hearts of individuals participating in endurance exercise is indicated.