Search PubMed⌕ Search

Biomedical subjects

B Muñoz

Publications and source records attributed to B Muñoz.

At least 19 recordsLinked to original sources
PubMed2004

Template bleeding time and PFA-100 have low sensitivity to screen patients with hereditary mucocutaneous hemorrhages: comparative study in 148 patients.

OBJECTIVES AND PATIENTS: We compared the template bleeding time (BT) and closure time (CT) in the PFA-100 as screening tests in 148 consecutive patients with unequivocal mucocutaneous bleeding and positive family history. EXCLUSION CRITERIA: drug intake, concomitant diseases including minor infections, low platelet count, diseases of secondary hemostasis. RESULTS: Type 1 von Willebrand disease (VWD-1) was diagnosed in 26 patients, primary platelet secretion defect (PSD) in 33, VWD-1 + PSD in nine, whereas 80 patients did not comply with the criteria for known hemostatic disorders (UD, unknown diagnosis). BT and CT were prolonged in 35.8% and 29.7% of all the patients, respectively (P = 0.23). Sensitivity increased to 48% if an abnormality of BT and/or CT was considered. Same comparisons for BT and CT in each diagnostic category were, respectively: 42 vs. 61.5% in VWD-1 (P = 0.18), 42 vs. 24% in platelet secretion defects (P = 0.11), 67 vs. 89% in VWD-1 + PSD (P = 0.50), and 27.5 vs. 15% in UD (P = 0.06). CONCLUSION: Both tests were relatively insensitive and not significantly different in detecting incoming patients with mucocutaneous hemorrhages. In patients with VWD-1, the PFA-100 performed slightly better, whereas the opposite occurred in those patients with platelet secretion defects. In the UD group, both tests lost sensitivity, but the BT detected 1.8 times more patients than the PFA-100. Given the large proportion of undiagnosed bleeders and the overall low sensitivity of these tests, clinical decisions still rely on the medical history and etiological diagnosis of the bleeding disorder.

Bleeding Time↗
PubMed2004

Parasitic mycelial forms of coccidioides species in Mexican patients.

Of 26 cases of coccidioidomycosis reported here, 15 showed hyphae, atypical parasitic structures of Coccidioides spp. in fresh cytologic and/or histologic specimen preparations. The finding of this morphology could have implications which should be considered, especially when the disease affects areas of nonendemicity.

Coccidioides↗
PubMed2004

[Treatment of intracranial hypertension of malign tumour origin].

Brain tumours are a frequent cause of intracraneal hypertension syndrome, clinically manifested by headache, nausea and vomiting, and a decrease in the level of consciousness. The keypoint sign of intracraneal hypertension is papilloedema. Other manifestations depend on the localization of the tumour, appearing as neurological focality and seizures. The causes of intracranial hypertension of tumoural origin are the mass effect of the tumour, brain edema, the possibility of intratumoural haemorrhage and hydrocephalus caused by obstruction in the circulation of cerebrospinal fluid. The treatments employed, medical or surgical, act against these causes.

Brain Neoplasms↗
PubMed2003

Bioactive glasses as accelerators of apatite bioactivity.

Synthetic carbonatehydroxyapatite is the ceramic closest to the mineral component of human bone and seems, therefore, the optimum material to use in osseous implants. However, in vitro assays performed to determine its bioactivity have shown no positive results after 2 months of assay. With the aim of improving this bioactivity, a new biphasic material was synthesized composed mainly of synthetic carbonatehydroxyapatite and only 5% of a sol-gel bioactive glass. In vitro assays were assessed to determine the bioactive behavior of this new material and revealed that the addition of a minimal amount of bioactive glass is enough to induce bioactivity on synthetic carbonatehydroxyapatites.

Apatites↗
PubMed2003

Mediterranean diet, but not red wine, is associated with beneficial changes in primary haemostasis.

OBJECTIVE: (1) To compare the effect of an alcohol-free Mediterranean-type diet (MD) and a high-fat diet (HFD) on variables of primary haemostasis (bleeding time, plasma von Willebrand factor and platelet aggregation/secretion). (2) To test whether red wine supplementation modified these variables, independently of the diet. DESIGN, SUBJECTS AND INTERVENTION: Controlled prospective intervention study. Two groups, each consisting of 21 healthy male university students (22+/-3.4 y), received either MD or HFD during 90 days. Between days 30 and 60, both diets were supplemented with 240 ml/day of red wine. Baseline (T0) and T30, T60 and T90-day samples were drawn. Bleeding time was measured before (day 30) and after (day 60) wine supplementation. No drop out from the study was experienced. SETTING: University campus and outpatient nutrition clinic. RESULTS: All baseline (day 0) variables did not differ significantly between study groups. On day 30, individuals on MD had significantly higher levels of plasma beta-carotene, folate, ascorbate, and eicosapentaenoic acid in plasma lipid fractions, than those on HFD. Total plasma cholesterol, HDL and LDL did not change significantly in either study group at any time point. After 30 days on each diet, individuals on MD had longer bleeding time (BT) than those on HFD (7.6+/-2.8 vs 5.8+/-1.7 min; P=0.017). BT did not change significantly after I month of wine supplementation (7.1+/-2.0 vs 5.5+/-2.0 min, respectively). Plasma von Willebrand factor (vWF : Ag) on day 0 was 89+/-40 and 111+/-70% in MD and HFD groups, respectively (P=0.21). These values did not change significantly at 30, 60 or 90 days. MD intake was associated with an increase in platelet serotonin secretion (P=0.02) and a marginal increase in platelet aggregation after stimulation with epinephrine (P=0.07). Wine intake resulted in a marginal decrease in platelet (14)C-5-HT secretion with 4 micro M ADP (P=0.07). However, both platelet aggregation and secretion were consistently increased when using collagen as agonist (1 and 2 micro g/ml, P=0.01). CONCLUSION: The longer BT in individuals on MD, obtained independently of red wine, denotes less interaction of platelets with the vascular wall, which could be beneficial from the point of view of cardiovascular (CV) risk. This effect is not explained by changes in the measured haemostatic determinants of BT (plasma vWF, ex vivo platelet function), and might be attributed to other as yet unknown vascular factors. Moderate consumption of red wine results in a significant increase in ex vivo platelet aggregation and secretion after stimulation with collagen. This observation contradicts previous reports, although further studies are required to elucidate the influence of this finding on CV risk.

Adult↗
PubMed2002

Blindness and visual impairment in the Americas and the Caribbean.

AIM: To summarise available data on the prevalence and causes of visual impairment and blindness in the Americas and the Caribbean. METHODS: The published literature was searched in Medline and LILACS using the following key words: blindness, visual impairment, prevalence. Articles were reviewed, and the references of the articles were also searched for relevant articles, which were also reviewed. RESULTS: Using the mortality in children under the age of 5 as an indicator, the overall prevalence of childhood blindness (in the under age 15 group) for the region was estimated at 0.45/1000, with the majority (67%) living in countries with mortality of children under age 5 above 30/1000 live births. Corneal opacities were more common in countries where the under 5 year mortality are above 30/1000 live births and retinopathy of prematurity (ROP) was an important cause in countries with intermediate death rates. For adults, overall blindness rates were not estimated because of the social, economic, and ethnic diversity in the region. The primary causes of visual loss in adults in the Americas were age related eye diseases, notably cataract and glaucoma in the African-American and Hispanic populations, and age related macular degeneration in the white population. Uncorrected refractive error was a significant cause of decreased vision across ages, ethnic groups, and countries. CONCLUSION: More data are needed on the magnitude and causes of visual loss for the Caribbean and Latin American countries. Rates of blindness and visual loss from available data within these countries are widely disparate. Prevention and control of avoidable blindness needs to be an ongoing focus in this region.

Adolescent↗
PubMed2001

Complementary effects of Mediterranean diet and moderate red wine intake on haemostatic cardiovascular risk factors.

OBJECTIVES: To compare the effect of alcohol-free Mediterranean-type diet (MD) and high-fat diet (HFD) on plasma concentration of emergent haemostatic cardiovascular risk factors (HCVRF). Also, to test if red wine supplementation modifies HCVRF, independent of diet. DESIGN, SUBJECTS AND INTERVENTION: Controlled prospective intervention study. Two groups, each of 21 healthy male university students (22+/-3.4 y), received either MD or HFD for 90 days. Between days 30 and 60, both diets were supplemented with 240 ml/day of red wine. Baseline and T30, T60 and T90-day samples were drawn. No drop out from the study was observed. SETTING: University campus and outpatient nutrition clinic. RESULTS: Volunteers on HFD at T30 had increases in pro-coagulants fibrinogen (22%), factor VIIc (9%), and factor VIIIc (4%), and decreases in natural anticoagulants antithrombin III (3%), protein C (11%) and protein S (6%) and of 20% in plasminogen activator inhibitor-1. At the same time, individuals on MD had increases in fibrinogen (4%), antithrombin III (5%), protein C (3%), protein S (2.7%), and decreases in factor VIIIc (9%), and plasminogen activator inhibitor-1 (21%). After adjusting by baseline values, MD was associated with lower plasma fibrinogen (P=0.03), factor VIIc (P=0.034) and factor VIIIc (P=0.0057) and with higher levels of protein S (P=0.013). Red wine supplementation, in both diets, resulted in decreased plasma fibrinogen (P=0.001) and factor VIIc (P=0.05), and increased tissue plasminogen activator antigen (P=0.01) and plasminogen activator inhibitor-1 antigen (P=0.0003). Wine consumption was also associated with significantly (P=0.01) divergent effects on antithrombin III: it decreased by 10% in individuals on HFD but increased slightly in those on MD. No effects of diet or wine were detected in plasma protein C and C-reactive protein. CONCLUSION: MD and moderate consumption of red wine have complementary, mostly beneficial effects on HCVRF.

Adult↗
PubMed2001

OmpA genotypic evidence for persistent ocular Chlamydia trachomatis infection in Tanzanian village women.

BACKGROUND: Trachoma is still a significant problem in the developing world. Adult women are at higher risk of developing scarring and trichiasis, the potentially blinding sequelae, compared to men. In part, the higher risk may be due to more frequent infections in women because of their frequent contact with children, the main reservoir of C. trachomatis infection. However, other factors associated with infection, particularly constant infection, in adult women need to be identified. METHODS: A group of 118 women who were infected with C. trachomatis and 118 women who were not infected, but of similar age and trachoma status, were identified in 1996 from a population-based sample of women age 16 and older from eleven villages in Kongwa, Tanzania. This group of 236 was re-contacted three years later to ascertain trachoma status and determine infection status using polymerase chain reaction-enzyme immunoassay (PCR-EIA). Positive samples at both time points were examined for serovar and genotype shift, using ompA sequencing information. RESULTS: Of the original 236 women, 165 (70%) completed exams in 1999. Fifty-eight (35%) of the 165 women were excluded from this analysis because they received antibiotic treatment for trachoma in the six months prior to the second exam. Infection at baseline was the most important predictor of infection three years later (Age-adjusted odds ratio (95% confidence interval) 6.6 (1.8-24.4)). A total of 17 women (16%) were infected at the two examinations, and of the 15 for whom genotyping could be done, 11 (73%) were infected with the same ompA genotype at both time points. Chronically infected women were more likely to have trichiasis, scarring, and active trachoma at baseline than those never infected or infected only once. Only 41% of the chronically infected women were living in houses with infected pre-school children, but 24% were in houses with no children. Four of ten women with trichiasis developed incident corneal opacity over the three years. CONCLUSIONS: The data provide evidence for persistence of infection in a sub-group of women. The strongest predictor of infection at follow-up was baseline infection, and most were infected with the same genotype at both time points. For women with persistent infection, at least half were either not living with children or not living with infected children, suggesting that continual re-exposure from a close family member was less likely. Chronic infection is likely related to both exposure and immunological factors, and these need to be further identified. Inclusion of women in community-based treatment programs, regardless of whether a child is present in the house, is likely to be important in preventing the progression of inflammatory trachoma and scarring to trichiasis.

Adolescent↗
PubMed2001

Progression of active trachoma to scarring in a cohort of Tanzanian children.

Risk factors for the incidence of scarring are needed to inform trachoma control programs in countries hyperendemic for this blinding disease. A cohort of pre-school children with constant, severe trachoma, and an age, sex, and neighborhood matched cohort of children without constant severe trachoma were followed for seven years to determine the incidence of scarring. The incidence of scarring in the children with constant severe trachoma was 29.2% versus 9.6% in the comparison group. In a model adjusting for multiple factors, significant predictors of scarring were increasing age, female, and constant severe trachoma (OR = 4.85, 95% CL = 2.05, 11.40). Infection with C. trachomatis at follow up was also associated with scarring in both groups of children. It is likely that these children have a different host response to infection, and represent a subgroup at high risk for the blinding complications of trachoma. Reducing exposure to infection in the community through antibiotics and changes in hygiene practices is still the most promising control strategy.

Child↗
PubMed2001

Diabetes and diabetic retinopathy in a Mexican-American population: Proyecto VER.

OBJECTIVES: The prevalence rate of diabetes is probably higher in Hispanics than in Caucasians, although there is controversy about differences in the risk of diabetic retinopathy. The purpose of the study is to determine the prevalence rates of diabetes and diabetic retinopathy in a population-based study of Hispanics aged > or = 40 years. RESEARCH DESIGN AND METHODS: Proyecto VER is a random sample of Hispanic populations aged > or = 40 years in Arizona. A total of 4,774 individuals (71.6% of the eligible sample) completed the examinations. Diabetes was defined as self-report of a physician diagnosis or HbA(1c) value of > or = 7.0%. Diabetic retinopathy was assessed on stereo fundus photographs of fields 1, 2, and 4. RESULTS: The prevalence rate of diabetes in the Hispanic community (individuals > or = 40 years of age) was 22%. The prevalence rate of diabetic retinopathy (DR) was 48%; 32% had moderate to severe nonproliferative and proliferative retinopathy. DR increased with increasing duration of diabetes and increasing level of HbA(1c). The prevalence rate of DR-like changes in the sample of individuals without diabetic retinopathy was 15% and was not associated with hypertension, systolic blood pressure, or diastolic blood pressure. CONCLUSIONS: The prevalence rate of diabetes in this population of Hispanics is high, almost twice that of Caucasians. The prevalence rate of DR is high but similar to reports in a Caucasian population. The prevalence rate of 9% moderate to severe retinopathy in the newly diagnosed group suggests that efforts to improve detection and treatment of diabetes in Hispanics may be warranted.

Adult↗
PubMed2001

The association of multiple visual impairments with self-reported visual disability: SEE project.

PURPOSE: This report examines the relationship between psychophysical measures of visual impairment and self-reported difficulty with everyday visual tasks in a population-based sample of individuals 65 years of age and older. METHODS: Community-dwelling residents (n = 2520) of Salisbury, MD, between the ages of 65 and 84 were recruited for the study. Visual acuity under normal and low luminance, contrast and glare sensitivity, stereoacuity, and visual fields were measured. Subjective physical disability was assessed with the Activities of Daily Vision Scale (ADVS). RESULTS: In multiple regression analyses adjusted for demographic factors, cognitive status, depression, and number of comorbid medical conditions, each of the vision tests except low luminance acuity was independently associated with lower ADVS scores. The analyses indicate that a factor of 2 reduction in visual acuity or contrast sensitivity, comparable with that observed in mild to moderate lens opacity, was associated with a three- to fivefold odds of reporting difficulty with daily tasks. Although age alone was a significant risk factor for disability, it was not associated with overall ADVS score, once visual impairment and other chronic medical conditions were taken into account. CONCLUSIONS: Visual acuity, contrast and glare sensitivity, stereoacuity, and visual fields are significant independent risk factors for self-reported visual disability in an older population. Visual impairment defined by acuity alone is not the only dimension of the association with subjective disability. Additional vision measures are required to understand the impact of vision loss on everyday life.

Activities of Daily Living↗
PubMed2001

Prevalence of the different types of age-related cataract in an African population.

PURPOSE: To describe the prevalence of different types of cataract and their association with visual acuity in a Tanzanian population aged 40 years and older. METHODS: A prevalence survey for lens opacity, glaucoma, and visual impairment was carried out on all residents age 40 and older of six villages in Kongwa, Tanzania. One examiner graded the lens for presence of nuclear (NSC), posterior subcapsular (PSC), and cortical cataract (CC), using the new WHO Simplified Cataract Grading System. Visual acuity was measured in each eye, both presenting and best corrected, using an illiterate E chart. RESULTS: The proportion of eligible subjects participating was 90% (3268/3641). The prevalence of cataract was as follows: NSC, 15.6%; CC, 8.8%; and PSC, 1.9%. All types of cataract increased with age, from NSC, 1.7%; CC, 2.4%; and PSC, 0.4% for those aged 40 to 49 years to NSC, 59.2%; CC, 23.5%; and PSC, 5.9% for those aged 70 years and older (P < 0.0001 for all cataract types, chi(2) test for trend). Cataract prevalence was higher among women than men for NSC (P = 0.0001), but not for CC (P = 0.15) or PSC (P = 0.25), after adjusting for age. Prevalence rates of visual impairment (BCVA < 6/12), US blindness (< or = 6/60) and WHO blindness (< 6/120) for this population were 13.3%, 2.1%, and 1.3%, respectively. Older age and each of the major types of pure and mixed cataract were independently associated with worse vision in regression modeling. CONCLUSIONS: Unlike African-derived populations in Salisbury and Barbados, NSC rather than CC was most prevalent in this African population. The seeming lower prevalence of CC may to some extent be explained by different grading schemes, differential availability of cataract surgery, the younger mean age of the Tanzanian subjects, and a higher prevalence of NSC in this population.

Adult↗
PubMed2000

Mixed lens opacities and subsequent mortality.

BACKGROUND: Previous studies have found an association between cataract or lens opacity and increased risk of mortality. Further work on determining explanatory factors for this association is needed. OBJECTIVES: To determine, in a population-based cohort of older persons, the 2-year risk of death associated with different types of lens opacities; whether an association of mortality and lens opacity is explained by confounding risk factors such as smoking, diabetes, age, race, and sex, which are known to be related to opacity and mortality; whether lens opacity is a marker for health status; and whether there are differences in cause-specific mortality for persons with and without lens opacity. MAIN OUTCOME MEASURE: Two-year mortality rate. METHODS: The Salisbury Eye Evaluation Project consists of a random sample of 2520 residents of Salisbury, Md, aged 65 to 84 years. At baseline, lens photographs were taken to document nuclear, cortical, posterior subcapsular cataract, and mixed opacities. Data on education, smoking, alcohol use, hypertension, diabetes and other comorbid conditions, handgrip strength, and body mass index were also collected. Two-year follow-up was conducted for mortality and cause of death. RESULTS: Nuclear opacity, particularly severe nuclear opacity, and mixed opacities with nuclear were significant predictors of mortality independent of body mass index, comorbid conditions, smoking, age, race, and sex (mixed nuclear: odds ratio, 2.23; 95% confidence interval, 1.26-3.95). CONCLUSION: Lens opacity status is an independent predictor of 2-year mortality, an association that could not be explained by potential confounders.

Aged↗
PubMed2000

Causes of blindness and visual impairment in a population of older Americans: The Salisbury Eye Evaluation Study.

OBJECTIVE: To determine the causes of blindness and visual impairment in a population-based sample of older Americans. METHODS: A random sample of 3821 residents of Salisbury, Md, between the ages of 65 and 84 years was identified from Medicare records. Sixty-six percent (2520 persons) agreed to undergo an eye examination; 26% of the participants were African American. The clinical examination included acuity testing with an Early Treatment Diabetic Retinopathy Study chart and standardized refraction testing for those with a visual acuity worse than 20/30, slitlamp and dilated retinal examination by an ophthalmologist, tonometry, lens and fundus photography, and a suprathreshold visual field test. Visual impairment was defined as a best-corrected acuity in the better-seeing eye worse than 20/40 and better than 20/200, while blindness was acuity in the better-seeing eye of 20/200 or worse. For those with a visual acuity worse than 20/40 in either eye, one or more causes were assigned by an ophthalmologist and a final cause for each eye was confirmed by a panel of 3 subspecialty ophthalmologists (O.D.S., H.A.Q., and S.B.B.) based on all available evidence. RESULTS: Bilateral presenting acuity worse than 20/40 increased from 4% in the 65- to 74-year age group to 16% in the 80- to 84-year age group. One third of those with presenting acuity worse than 20/40 improved to 20/40 or better with refraction. Overall, 4.5% had a best-corrected acuity worse than 20/40. African Americans were more likely to remain visually impaired than were whites despite refraction (odds ratio [95% confidence interval], 1.7 [1.1-2.6]). Whites were most often impaired or blind from age-related macular degeneration (1.2% vs 0.5%; P=.09). African Americans had higher rates of impairment and blindness from cataract or posterior capsular opacification (2.7% vs 1.1%; P=.006), glaucoma (0.9% vs 0.1%; P=.006), and diabetic retinopathy (1.2% vs 0.2%; P=. 004). CONCLUSIONS: More than half of those with visual impairment or blindness had conditions that were either surgically treatable or potentially preventable. African Americans had a disproportionate number of blinding diseases, particularly those amenable to eye care intervention. Targeted interventions for specific populations to increase appropriate eye care use would greatly improve vision and function in older Americans. Arch Ophthalmol. 2000;118:819-825

Aged↗
PubMed2000

Monocular versus binocular visual acuity as measures of vision impairment and predictors of visual disability.

PURPOSE: To examine the relationship between monocular and binocular visual acuities as predictors of visual disability in a population-based sample of individuals 65 years of age and older. METHODS: Two thousand five hundred twenty community-dwelling residents of Salisbury, Maryland, between the ages of 65 and 84 years of age were recruited for the study. Corrected visual acuity was measured monocularly and binocularly using ETDRS charts. Reading speed, face discrimination, and self-reported difficulty with visual tasks were also determined. RESULTS: Binocular acuity is predicted with reasonable accuracy by acuity in the better eye alone, but not by the widely used American Medical Association (AMA) weighted-average algorithm. The AMA algorithm significantly underestimates binocular acuity when the interocular acuity difference exceeds one line. Monocular acuity and binocular acuity were significantly better predictors of reading speed than the AMA weighted score or a recently proposed Functional Vision Score (FVS). Monocular acuity in the better eye, binocular acuity, and the AMA and FVS algorithms were equally good predictors of self-reported vision disability. None of the acuity measures were good predictors of face recognition ability. CONCLUSIONS: The binocular acuities of older individuals can be inferred from measures of monocular acuity. There is little evidence for binocular inhibition when the monocular acuities in the two eyes are unequal, as opposed to the widely used AMA algorithm for computing binocular visual impairment. For tasks that are strongly associated with visual acuity, such as reading, this association can be captured from measures of monocular acuity and does not require separate assessment of binocular acuity.

Aged↗
PubMed1999

Dry eye and dry mouth in the elderly: a population-based assessment.

BACKGROUND: Symptoms of dry eye and dry mouth are common in the elderly and are often debilitating. Previous research on small populations has been inconsistent regarding the contribution to sicca symptoms of autoimmune markers, medication use, and other factors. The objective of this study was to determine the population prevalence of symptoms of dry eye and dry mouth and to evaluate possible risk factors. METHODS: This is a population-based study of 2481 individuals, aged 65 to 84 years, residing in Salisbury, Md, and identified by the Health Care Financing Medicare database. The main outcome measures included information on sicca symptoms, medical history, medication use, and joint examination results collected in a standardized manner. Autoimmune status was assessed in 1200 individuals by measuring antinuclear antibody, rheumatoid factor, and autoantibodies to the soluble nuclear antigens Ro/SS-A and La/SS-B by double immunodiffusion. RESULTS: Approximately 27% of the population reported dry eye or dry mouth symptoms to be present often or all the time and 4.4% reported both. The prevalence of dry mouth (but not dry eye) symptoms increased with age, female sex, and white race. No association of sicca symptoms was found with rheumatoid arthritis, smoking, alcohol consumption, reproductive hormonal status, or the presence of autoantibodies. A strong, dose-response relationship was observed between sicca symptoms and the use of certain medication classes. The proportion of the population prevalence of sicca symptoms attributable to the use of drying medications was estimated at 62% for dry eye and dry mouth and 38% for dry eye or dry mouth symptoms. CONCLUSIONS: Sicca symptoms are common in the elderly, and medication side effects appear to be a major underlying factor. Our results do not indicate an association between autoimmune status and sicca symptoms and do not support immunologic testing in persons with sicca symptoms in the absence of other important systemic features.

Age Factors↗
PubMed1999

Who participates in population based studies of visual impairment? The Salisbury Eye Evaluation project experience.

PURPOSE: To describe characteristics of respondents and nonrespondents to a home questionnaire and comprehensive clinical examination in a population of elderly Americans. METHODS: The SEE project is a population-based study of age-related eye diseases, visual impairment, and functional status of individuals aged 65 to 84. Potential participants were identified using the Health Care Financing Administration Medicare data base for Salisbury, MD: After sending out an introductory letter, a trained interviewer visited potential participants in their homes, obtained their consent to participate, administered a short screening interview that included questions about their general health and vision, and administered an extensive questionnaire on their diet, medical history, and difficulty performing activities related to vision. The interviewer then scheduled an appointment for the participants to visit a central site for an exam. Potential participants could fall into one of two refusal groups; refusal to take part in the study before the home questionnaire or prior to the clinic visit. RESULTS: The overall response rate for the clinic visit was 65%. Compared to individuals with complete exams, the two groups of refusals were older, less likely to have any college education, more likely to report poor health status, and more likely to need help with Independent Activities of Daily Living (IADL's). Participants with complete home questionnaires that failed to come to the clinic were more likely to have Mini-Mental scores below 25. There were not significant differences by race, gender, or self reported vision status among the three groups. CONCLUSIONS: Population-based studies requiring an in-clinic examination may selectively under-sample those with health and mental difficulties. These differential responses may introduce bias in the study results and need to be addressed when assessing the burden, type and severity of disease in the community. However, self-report of visual status was similar among refusals and participants in this study on vision.

Activities of Daily Living↗