Vitamin D insufficiency and cognitive impairment in Asians: a multi-ethnic population-based study and meta-analysis.

BACKGROUND: The relationship between vitamin D insufficiency and cognitive impairment remains equivocal in Asians. We examined the association between circulating 25-hydroxyvitamin D (25OHD) concentration and cognitive performance in a large multi-ethnic Singaporean population-based study. We also conducted a meta-analysis of 25OHD concentrations amongst cognitively impaired older adults in Asia. METHODS: Our population-based cross-sectional study included 2273 persons ≥60 years of age from the Singapore Epidemiology of Eye Diseases (SEED) study (mean ± SD age 70.4 ± 6.2 years; 44.7% female), who were categorized according to 25OHD concentration (i.e. ≤10, 10.1-20 and >20 ng mL(-1) ). The 25OHD concentration was measured and adjusted to reflect a deseasonalized value. Cognition was assessed using the total and domain scores of the Abbreviated Mental Test (AMT). Global cognitive impairment was defined as AMT score of ≤6 if 0-6 years of education and AMT score of ≤8 if >7 years of education. Fully adjusted multivariate models were used. We included seven studies in a meta-analysis of 25OHD and cognition in Asia (6068 participants; 1179 cognitively impaired cases). RESULTS: Participants with 25OHD levels >20 ng mL(-1) (n = 1302) had higher AMT total scores (mean ± SD 8.5 ± 1.9) and were less likely to have cognitive impairment (14.1%) than participants with lower 25OHD levels (overall P < 0.001, P-trend < 0.001). Deseasonalized 25OHD concentration was associated with AMT score (ß = 0.10 per 10 ng mL(-1) , P = 0.035). Vitamin D insufficiency (25OHD ≤20 ng mL(-1) ) was associated with global cognitive impairment (OR 1.56, P = 0.028). Specifically, 25OHD concentration correlated with semantic memory (r = 0.08, P = 0.009) and orientation in time (r = 0.09, P = 0.003). In the meta-analysis, the pooled mean 25OHD difference was -6.83 ng mL(-1) (95% confidence interval -11.36; -2.30), indicating lower 25OHD concentrations amongst cognitively impaired compared to cognitively healthy participants in Asia. CONCLUSION: Vitamin D insufficiency is associated with a greater likelihood of and more severe cognitive impairment in Asian populations.

Feedback of personal retinal images appears to have a motivational impact in people with non-proliferative diabetic retinopathy and suboptimal HbA1c: findings of a pilot study.

AIM: To conduct a pilot study to explore the potential impact of visual feedback of personal retinal images on diabetes outcomes. METHODS: Twenty-five participants with non-proliferative diabetic retinopathy and suboptimal HbA(1c) (> 53 mmol/mol; > 7%) were randomized to receive visual feedback of their own retinal images or to a control group. At baseline and 3-month follow-up, HbA(1c), standard measures of beliefs, diabetes-related distress and self-care activities were assessed. RESULTS: In unadjusted models, relative to controls, the intervention group showed significantly greater improvement in HbA(1c) at 3-month follow-up (-0.6% vs. +0.3%, P < 0.01), as well as enhanced motivation to improve blood glucose management (P < 0.05). CONCLUSIONS: This small pilot study provides preliminary evidence that visual feedback of personal retinal images may offer a practical educational strategy for clinicians in eye care services to improve diabetes outcomes in non-target compliant patients. A fully powered randomized controlled trial is required to confirm these findings and determine the optimal use of feedback to produce sustained effects.

Frequency and risk factors of non-retinopathy ocular conditions in people with diabetes: the Singapore Malay Eye Study.

AIM: To investigate the frequency and risk factors of non-retinopathy ocular conditions in persons with diabetes. METHODS: A population-based cross-sectional study of 3176 Malay persons aged between 40 and 79 years in Singapore was conducted. Cataract, glaucoma, refractive errors, age-related macular degeneration, dry eye, epiretinal membrane, ocular hypertension and retinal conditions were assessed based on standardized interviews, clinical examinations and laboratory investigations. RESULTS: A total of 768 participants (24.2%) had diabetes. People with diabetes were more likely to have cortical cataract (52.1 vs. 37.3%, P < 0.001), ocular hypertension (10.9 vs. 7.4%, P = 0.002) and epiretinal membrane (17.2 vs. 10.1%, P < 0.001) compared with those without diabetes. The odds of having cortical cataract (odds ratio 1.63, 95% CI 1.20-2.20) and epiretinal membrane (among those with previous cataract surgery: odds ratio 1.63, 95% CI 1.20-2.20) were significantly higher in people with diabetes compared with those without. The population attributable risks for cortical cataract and epiretinal membrane because of diabetes were 8.7 and 9.0%, respectively. In persons with diabetes, hypertension and high cholesterol were the major risk factors associated with non-retinopathy eye complications such as ocular hypertension (odds ratio 1.18, 95% CI 1.04-1.33) and retinal emboli (odds ratio 1.99, 95% CI 1.05-3.80). CONCLUSION: Our results allow clinicians to better inform patients with diabetes that they are more likely to have cortical cataract and epiretinal membranes (those with previous cataract surgery) in addition to diabetic retinopathy. Two modifiable risk factors-blood pressure and cholesterol associated with ocular hypertension and retinal emboli, respectively-are also risk factors for non-retinopathy ocular conditions in persons with diabetes.

Republished article: The impact of diabetic retinopathy: understanding the patient's perspective.

Understanding the impact of a condition from the patient's perspective is important, and different types of patient-reported outcomes or instruments are available to help with this. This review article summarises the current evidence on the impact of diabetic retinopathy (DR) and its associated vision impairment on patient-reported outcomes. We have included research that has used a range of outcome measures to assess the impact of DR on generic health-related quality of life, utility, vision-functioning and vision-specific quality of life. This review also offers clarification on frequently misused psychometric terminologies to help clinicians and researchers better understand the literature associated with patient-reported outcome research. Overall, the evidence suggests that DR, particularly in its vision-threatening stages, has a substantial, negative impact on the patient. However, our understanding of the impact of DR is currently restricted due to limitations inherent in currently available patient-reported outcome measures. We conclude by discussing potential directions for future research in this area, such as item banking and computer adaptive testing.

The impact of diabetic retinopathy: understanding the patient's perspective.

Understanding the impact of a condition from the patient's perspective is important, and different types of patient-reported outcomes or instruments are available to help with this. This review article summarises the current evidence on the impact of diabetic retinopathy (DR) and its associated vision impairment on patient-reported outcomes. We have included research that has used a range of outcome measures to assess the impact of DR on generic health-related quality of life, utility, vision-functioning and vision-specific quality of life. This review also offers clarification on frequently misused psychometric terminologies to help clinicians and researchers better understand the literature associated with patient-reported outcome research. Overall, the evidence suggests that DR, particularly in its vision-threatening stages, has a substantial, negative impact on the patient. However, our understanding of the impact of DR is currently restricted due to limitations inherent in currently available patient-reported outcome measures. We conclude by discussing potential directions for future research in this area, such as item banking and computer adaptive testing.

Cataract Symptom Scale: clarifying measurement.

AIM: Previous psychometric evaluation of the Cataract Symptom Scale (CSS) focused on classic assessments of reliability and validity. The aim was to investigate the psychometric properties of the CSS using the Rasch measurement model. METHODS: 243 patients drawn from the Flinders Eye Centre cataract surgery waiting-list self-administered the CSS. Rasch analysis was used to investigate the following properties of the CSS: measurement a single construct (unidimensionality), discrimination between strata of patient ability (person separation) and targeting of item difficulty to person ability. RESULTS: The CSS discriminated between four strata of patients. However, some items did not contribute towards measurement of a single construct, indicating a secondary dimension. This comprised three mobility items, which formed a separate valid subscale. Elimination of these items resulted in the CSS being a unidimensional measure. However, further item deletion was required, as symptoms items did not measure the same construct. The resultant nine-item measure was unidimensional. CONCLUSIONS: The CSS consists of two separate unidimensional constructs: mobility and visual disability. The reduced nine-item measure has good psychometric properties and is unidimensional. The CSS is essentially a measure of visual disability, and not cataract symptoms as it is claimed to be.

Predicting the need for low vision rehabilitation services.

AIMS: To determine the independent predictors of rehabilitation needs for people with low vision using the Impact of Vision Impairment questionnaire (IVI) to measure the quality-of-life consequences of vision-specific restrictions on participation in activities of daily living. METHODS: Patients attending low vision clinics completed the IVI and provided personal and clinical information such as co-morbidities and visual acuity. Rasch analysis was used to generate person measures for the IVI total and three domain scores. Rehabilitation needs were based on "mild", "moderate" or "severe" levels of restriction in participation as determined by the lower, moderate and higher tertiles of persons measures. Logistic regression analyses were used to determine independent predictors of rehabilitation needs. RESULTS: 477 patients (56% women) with a mean age 72 years (SD 15.3) were recruited. Most (74%) had moderate or severe vision loss (presenting visual acuity (VA)<6/18), and 43% had age-related macular degeneration (AMD). Females, shorter duration of vision impairment, having AMD, worse VA, a greater impact of co-morbidities on daily living and reliance on family or friends were univariately associated with poorer IVI scores (p<0.05). In all regression models, VA, the impact of comorbidities on daily living and dependence on family/friends emerged as the three strongest independent predictors of rehabilitation needs. CONCLUSION: In addition to vision, clinicians also need to consider issues relating to dependency when assessing rehabilitation needs. A more holistic approach to patient referral and rehabilitation provision is therefore warranted.

Self-management programs for adults with low vision: needs and challenges.

OBJECTIVE: To explore the needs of individuals with low vision in order to inform the contents of a low vision self-management (SM) program and determine potential barriers to participation. METHODS: Semi-structured interviews were conducted with 48 participants with low vision resulting different from eye conditions. Qualitative analysis was conducted in order to identify major themes. RESULTS: All participants described a range of consequences as a result of vision loss including difficulties with functional activities, social interaction and emotional distress. Less than half were interested in attending a SM program. Barriers included practical reasons as well as a perceived lack of need and unclear or negative perceptions of such a program. CONCLUSION: SM programs for low vision are a promising way to help address the range of difficulties experienced by this population if barriers to participation can be overcome. PRACTICE IMPLICATIONS: SM programs should include vision-specific strategies, training in generic problem-solving and goal setting skills and how to cope with emotional reactions to vision impairment. Programs should be delivered and promoted in such a way to enhance access and encourage uptake by those with a range of vision loss in the community.

The reliability of data collection periods of personal costs associated with vision impairment.

PURPOSE: To determine the reliability of vision-related personal costs collected over 1, 3 and 6 months (extrapolated to 12 months) compared to one-year data. METHODS: Participants of any age, with a presenting visual acuity of < 20/40 in the better eye and an ability to converse in English, were recruited. Monthly cost diaries, in large print and electronic copies with instructions available in audio and Braille, were used prospectively to collect personal costs. The personal expenses were grouped under four categories, namely: (a) medicines, products and equipment, (b) health and community services, (c) informal care and support and (d) other expenses. Sociodemographic and clinical data were also collected. RESULTS: 104 participants (59 females) with a mean age of 64 years completed the 12-months diaries. Almost 40% of the participants had severe visual impairment (< 20/200) in the better eye and the most common cause of vision loss was AMD (n=40; 38%). The mean total personal costs collected from the 12-months diaries were 3,330+/-2,887 AUS dollars. There were no significant differences between the 12-months data and extrapolated 1, 3 and 6-months diaries (t-tests; p=0.17, 0.89 and 0.73, respectively). However, the 1-month variation was substantially larger (SD+/-5,860) compared to the 3-month and 6-month variances (SD+/-3,037 and 3,030, respectively) for total costs. Also, compared to the 12-months diaries, the 1-month data consistently recorded the weakest correlation coefficients for all cost categories compared to the other time intervals. CONCLUSIONS: Given that diary completion can be particularly challenging for individuals with impaired vision, a minimum 3-months data collection period can provide reliable estimates of annual costs associated with vision impairment.

Impact of age related macular degeneration on quality of life.

AIMS: To describe the impact of age related macular degeneration (AMD) on quality of life and explore the association with vision, health, and demographic variables. METHODS: Adult participants diagnosed with AMD and with impaired vision (visual acuity <6/12) were assessed with the Impact of Vision Impairment (IVI) questionnaire. Participants rated the extent that vision restricted participation in activities affecting quality of life and completed the Short Form General Health Survey (SF-12) and a sociodemographic questionnaire. RESULTS: The mean age of the 106 participants (66% female) was 83.6 years (range 64-98). One quarter had mild vision impairment, (VA<6/12-6/18) and 75% had moderate or severely impaired vision. Participants reported from at least "a little" concern on 23 of the 32 IVI items including reading, emotional health, mobility, and participation in relevant activities. Those with mild and moderate vision impairment were similarly affected but significantly different from those with severe vision loss (p<0.05). Distance vision was associated with IVI scores but not age, sex, or duration of vision loss. CONCLUSION: AMD affects many quality of life related activities and not just those related to reading. Referral to low vision care services should be considered for people with mild vision loss and worse.

Differences in the neuromuscular capacity and lean muscle tissue in old and older community-dwelling adults.

BACKGROUND: This study investigated whether there was a worsening of the neuromuscular capacity of older adults after the seventh decade of life. METHODS: Fifteen healthy community-dwelling old (< 70 years of age) and 15 older adults (> or = 70 years of age) were assessed for maximal isometric strength (MVC) and force production characteristics, a one-repetition maximum (1-RM) performance, electromyographic (EMG) activity, and bone-free lean tissue (BFLT) mass of the lower extremity. RESULTS: The isometric MVC, 1-RM, and BFLT mass values in the old group were significantly greater than in the older group. In addition, the individual BFLT mass values correlated significantly with the isometric MVC values (r = .85) and the 1-RM scores of the thigh muscle groups (r = .54-.80). The old group generated significantly greater isometric maximal rate of torque development than the older group and performed significantly better at all intervals of the absolute and relative force-time curves. The voluntary muscle activation of the knee extensors of the old group produced significantly higher integrated EMG (iEMG) activity at each epoch in the early iEMG-time curve compared with the old group. CONCLUSIONS: The results suggest that the age-related deterioration in maximal strength measures and rapid force production characteristics in older adults could be related to a reduction in the mass and neural activation of the thigh muscles. The deterioration of the neuromuscular system of community-dwelling older adults may contribute to an increased difficulty in performing daily activities and may increase their risks of tripping and falling.