Biomedical subjects

P Mitchell

Publications and source records attributed to P Mitchell.

At least 253 records · Page 14Linked to original sources

PubMed1998

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

OBJECTIVE: This study aimed to determine the prevalence and characteristics of diabetic retinopathy (DR) in a defined older Australian population. DESIGN: A total of 3654 persons 49 years of age or older, 88% of permanent residents from an urban area west of Sydney, underwent a detailed eye examination. This included detailed medical history, Zeiss stereo retinal photography, fasting blood glucose, and other blood factors. The diagnosis of DR was made clinically and from photographic grading in persons with a history or biochemical evidence of diabetes. RESULTS: Diabetes was present in 7% (95% confidence interval, 6.2-7.8) of the population. Signs of DR were found in 82 participants (2.3%; 95% confidence interval, 1.9-2.8). The prevalence was 1.7% in persons younger than 60 years of age, 2.4% in persons 60 to 69 years of age, 2.7% in persons 70 to 79 years of age, and 2.3% in persons 80 years of age or older. There was no significant gender difference in prevalence. After adjusting for age, gender, and the duration since diagnosis of diabetes, higher blood glucose was related to the finding of moderate-to-severe retinopathy (Wisconsin levels 4-7) compared to milder retinopathy (Wisconsin levels 1.5-3). No association was found between the presence of any retinopathy and blood glucose, a history of hypertension or elevated blood pressure, body-mass index, blood lipids, creatinine, or coagulation factors. CONCLUSIONS: This Australian study has found similar prevalence rates for DR to a recent U.S. population-based study but lower rates for vision-threatening retinopathy than from clinic-based reports. Previous reports of a relationship between advanced retinopathy and blood glucose were supported. Other than diabetes duration and insulin treatment, no other associations with retinopathy were found.

Aged↗

PubMed1998

Iris color, skin sun sensitivity, and age-related maculopathy. The Blue Mountains Eye Study.

OBJECTIVE: The purpose of the study was to assess relationships between age-related maculopathy (ARM) and iris color, skin sun sensitivity, and other sunlight-related factors. DESIGN: Cross-sectional population-based study. PARTICIPANTS: The Blue Mountains Eye Study performed a detailed eye examination of 3654 residents living in the Blue Mountains area, west of Sydney, Australia. MAIN OUTCOME MEASURES: Subjects with late age-related macular degeneration (late AMD), early ARM, and large drusen (> or = 125 microns diameter) were identified using masked grading of retinal photographs. Iris color was graded using standard photographs, and interviewers collected questionnaire data on sunlight-related factors. Logistic regression, adjusting for age, sex, AMD family history, and current smoking, was used to assess associations. RESULTS: Blue iris color was significantly associated with an increased risk of both late AMD (odds ratio [OR], 1.69) and early ARM (OR, 1.45). An increased risk of late AMD, but not early ARM, was associated with both high (OR, 2.54) and low (OR, 2.18) skin sun sensitivity, as assessed using the Fitzpatrick sun-sensitivity scale. These associations remained after adjusting for the presence of sun-related skin damage. Neither history (or treatment) of skin cancer lesions, signs of sun-induced skin damage, or number of severe sunburns was associated with either late AMD or early ARM. CONCLUSIONS: Blue iris color was associated with an increased risk of both late AMD and early ARM in this population. Abnormal skin sensitivity to sunlight was also associated with an increased risk of late AMD.

Cross-Sectional Studies↗

PubMed1998

Medications and cataract. The Blue Mountains Eye Study.

PURPOSE: Corticosteroids are known to cause cataracts, but the effects of other medications on the lens are unclear. The aim of this study was to investigate the relationships between cataracts and a range of medications, including allopurinol, aspirin, chloroquine, diuretics, phenothiazines, and simvastatin. DESIGN: Population-based cross-sectional study. PARTICIPANTS: 3654 individuals 49 to 97 years of age (response rate, 82%) from an urban community near Sydney, Australia, were included. TESTING: Lens photography. PRIMARY OUTCOME MEASURE: Lens photographs were graded for the presence and severity of cortical, nuclear, and posterior subcapsular cataract. RESULTS: After adjusting for numerous potential confounders in ordinal regression models, use of phenothiazines was associated with nuclear cataract (adjusted odds ratio [OR], 2.18; 95% confidence interval [CI], 1.01-4.74); long-term aspirin users (> or = 10 years) had higher prevalence of posterior subcapsular cataract than did nonusers and short-term users (test for trend, P = 0.02); and the antimalarial drug mepacrine was associated with posterior subcapsular cataract (adjusted OR, 3.56; 95% CI, 1.56-8.13). There was a suggestion that use of chloroquine-like drugs for more than 1 year (test for trend, P = 0.12) might also be associated with posterior subcapsular cataract. Antihypertensive medications, cholesterol-lowering drugs, and allopurinol were not associated with any type of cataract. Potassium-sparing diuretics were the only diuretic to show any evidence of an association with cataract (test for trend for posterior subcapsular cataract, P = 0.14). Amiodarone was associated with cortical cataract (age- and gender-adjusted OR, 3.84; 95% CI, 1.01-14.81), but there were too few users to do analyses adjusted for multiple confounders. CONCLUSIONS: Most drugs commonly used in the community do not appear to be associated with cataract. The findings of this study do not support the hypothesis that aspirin protects against cataract.

Age Distribution↗

PubMed1998

Disordered personality style: higher rates in non-melancholic compared to melancholic depression.

OBJECTIVE: We test whether there is differential representation of disordered personality function across melancholic and non-melancholic depressive sub-types, with levels of differentiation examined against differing sub-typing measures. METHOD: In a sample of 245 subjects meeting criteria for a non-psychotic major depressive episode lasting less than 2 years, we examine for differential rates of disordered personality style across melancholic and non-melancholic depression, using four differing sub-typing measures (i.e., DSM-III-R and DSM-IV criteria, Newcastle Index, and the CORE measure). Disordered personality was assessed by psychiatrist ratings of 15 differing personality styles underpinning disorder classes, and several parameters and domains that reflect the arenas whereby disordered personality may be manifested. RESULTS: However defined, those with non-melancholic depression were distinctly more likely to rate as showing disordered personality function, with over-representation to an avoidant personality disorder style being the most consistently and strongly identified personality disorder class. Because of limitations to several of the sub-typing measures, we focus on the DSM-IV system. Discriminant function analyses indicated that those so identified as having non-melancholic depression were significantly more likely to rate as having avoidant and schizoid personality styles. A principal components analysis of our 15 differing personality disorder classes identified three molar classes corresponding to the three-cluster DSM system. Again, non-melancholic (compared to melancholic) subjects were more likely to return higher scores: in order, an 'anxious and fearful' (Cluster C) personality style, then an 'eccentric' Cluster A, and somewhat less clearly, a 'dramatic' Cluster B personality disorder style. Specificity to the non-melancholic depressive class was again suggested in relation to a large number of the parameters and domains measuring disordered personality function. CONCLUSIONS: Disordered personality function appears distinctly more likely in non-melancholic, compared to melancholic depression.

Adolescent↗

PubMed1998

Diabetes in an older Australian population.

PURPOSE: To describe the prevalence of self-reported diabetes and undiagnosed diabetes using new fasting plasma glucose (FPG) criteria, and vascular associations with diabetes history in a representative sample of older Australians attending the population-based Blue Mountains Eye Study. METHODS: 3654 people aged 49 years or older, representing 88% of permanent residents in two postcode areas west of Sydney, underwent a detailed medical and eye examination. This included history of diabetes, vascular events and vascular risk factors. Fasting pathology tests, including glucose, were obtained for 88% of these subjects. RESULTS: A diabetes history was given by 217 people (5.9%), including 7.0% of men and 5.2% of women. Elevated FPG (> or = 7.0 mmol/l) was found in a further 66 people (2.2% of persons who had FPG performed) and Impaired Fasting Glucose (FPG > or = 6.1 mmol/l and < 7.0 mmol/l) was found in a further 127 people (4.2%). History of diabetes was associated with an increased prevalence of obesity, elevated mean blood pressure and serum triglycerides, and lower mean serum cholesterol and HDL-cholesterol. Statistically significant associations were found between diabetes history and history of angina, acute myocardial infarction, stroke, gout and thyroid disease, after adjusting for age and sex using logistic regression. The vascular relationships with diabetes were stronger among people who currently smoked. CONCLUSIONS: This study has found similar diabetes prevalence to recently published Australian National Health Survey findings. Strong cross-sectional associations between diabetes history and vascular events and increased prevalence of vascular risk factors among older subjects with diabetes emphasise the need to address vascular risk factors in this group.

Aged↗

PubMed1998

Non-melancholic depression: the contribution of personality, anxiety and life events to subclassification.

BACKGROUND: We sought to develop a clinically useful subtyping system for the non-melancholic depressive disorders, and here we assess one weighted to central aetiological factors. METHODS: We studied 185 patients meeting DSM-III-R and/or clinical criteria for non-melancholic depression. Data were obtained by self-report, interview of patients and from corroborative witnesses. We developed a set of variables for class definition, assessing: (i) 'P', disordered personality as a vulnerability factor; (ii) 'A', meeting criteria for a lifetime anxiety disorder or positive on probe questions about trait anxiety characteristics, so assessing anxiety as a vulnerability factor; and (iii) 'L', psychiatrist and consensually-rated life event stress prior to depression onset. RESULTS: A latent class analysis generated a four-class solution for the P-A-L variables. Life event stressors had similar item probabilities across all four classes, and did not influence the four-class 'P-A' solution when deleted from the analysis, suggesting that life event stress may act more as a general provoking agent, rather than constituting any distinct 'reactive' or 'situational' depression class. Three classes generated clinically meaningful groupings, reflecting varying contributions of anxiety and disordered personality functioning, and with evidence of differential outcome over the following 12 months. CONCLUSIONS: We suggest that a refined aetiologically-weighted model may assist definition of the non-melancholic depressive disorders, and provide the logic for exploring the comparative utility of differing treatments to identified vulnerability-based classes.

Adult↗

PubMed1998

Qualitative and quantitative analyses of a 'lock and key' hypothesis of depression.

BACKGROUND: We examine a 'lock and key' ('L-K') hypothesis to depression which posits that early adverse experiences establish locks that are activated by keys mirroring the earlier adverse experience to induce depression. METHODS: Two-hundred and seventy clinically depressed patients were examined with open-ended and pre-coded interview questions to ascertain both early adverse experiences and precipitating life events. Qualitative and quantitative data analyses examined for any associations between developmental 'locks' and precipitating 'keys'. RESULTS: Qualitative assessment suggested 'L-K' links in almost one-third of the sample, and examples are provided. While quantitative analyses indicated significant associations between several identical 'lock' and 'key' constructs, evidence of specificity was rare. When individual 'locks' and 'keys' were consolidated into three higher-order constructs, variable models were suggested, including a non-specific link, a specific link and absence of any link. 'L-K' links appeared more likely in those with 'non-melancholic' (versus 'melancholic') depression, with the seemingly greater relevance to 'reactive' (versus 'neurotic') depression in the quantitative analyses inviting speculation that that 'disorder' may be more a reaction to a salient rather than a severe stressor. CONCLUSIONS: This exploratory study suggests that early adverse experiences may variably establish specific and non-specific patterns of vulnerability to having depression triggered by exposure to salient mirroring life event stressors.

Adjustment Disorders↗

PubMed1998

Craniopharyngioma invading the nasal and paranasal spaces, and presenting as nasal obstruction.

A case of craniopharyngioma invading the nasal and paranasal sinuses and presenting as nasal obstruction is reported. Imaging showed a destructive mass of the skull base with involvement of the nose and paranasal sinuses. In the excised mass mitoses were frequent and the proliferation index was high. Invasion of the nasopharynx and presentation as a nasopharyngeal mass is uncommon for a craniopharyngioma.

Biopsy↗

PubMed1998

Client preferences for HIV inpatient care delivery.

This study was concerned with preferences for inpatient models of care by the HIV/AIDS client group, in particular the difference between gay white men (European) and black heterosexuals of African/Caribbean origin. Satisfaction with the care currently provided was also an area of interest. Thirteen per cent (n = 79) of the were surveyed. Seventy per cent (n = 56) of the HIV/AIDS client group indicated a preference for a dedicated care model. Significant results were obtained demonstrating differences in the care model preferred by gay white men and black heterosexuals (p < 0.01). Gay white men were much more likely to state they would leave the trust to receive dedicated care (p < 0.01). Black heterosexuals were more likely to state that they would change treatment areas to avoid dedicated care (p < 0.01) Differences in concern about confidentiality were noted between the two groups. Confidentiality may be one of a number of factors influencing preference of care for African/Caribbeans and this needs to be studied further. The clients surveyed were not universally satisfied with the care they had been receiving. Following the results of the survey radical changes in the management of HIV inpatient care were made.

Africa↗

PubMed1998

Fatal pancarditis associated with human granulocytic Ehrlichiosis in a 44-year-old man.

Human cases of infection with a granulocytotropic Ehrlichia species closely related to Ehrlichia equi are now being described with increasing frequency in the United States, especially in areas where Lyme disease is already endemic. We describe a case of fatal pancarditis during the course of human granulocytic ehrlichiosis (HGE) in a 44-year-old outdoor worker who was previously treated for presumptive Lyme disease. Serological and molecular diagnostic tests for Borrelia burgdorferi and Babesia microti infections were negative. Postmortem serum specimens were seroreactive for HGE, and molecular evidence of infection with the HGE agent was obtained. These findings suggest that carditis may be a manifestation of HGE, further complicating the differential diagnosis of tick-borne illness.

Adult↗

PubMed1998

On modelling personality disorders: are personality style and disordered functioning independent or interdependent constructs?

Current descriptors of personality disorder (PD) are an amalgam of two constructs, personality style and/or disorder. We seek to determine whether their intrinsic personality style descriptors are proxy measures of, or independent of, disordered personality functioning. In a sample of depressed patients, psychiatrists rated 16 differing PD personality style vignettes and assessed eight differing manifestations of disordered functioning. When "personality" vignettes and identified personality clusters were intercorrelated with "disorder" variables, interdependence was generally evident, suggesting that the personality descriptors underpinning current definition of the PDs actually act as proxy criteria for assessing disorder because they are, in and of themselves, descriptors of pathological functioning. The obsessional personality vignette provided an exception, seeming to be independent of disordered function. Such results assist consideration of how best to model, define and measure the personality disorders.

Adolescent↗

PubMed1998

Family history and age-related maculopathy: the Blue Mountains Eye Study.

PURPOSE: To assess the associations between stages of age-related maculopathy (ARM) and reported family history of this eye disease. METHODS: A cross-sectional study of 3654 subjects from a defined geographical area west of Sydney (NSW, Australia) identified subjects with late age-related macular degeneration (AMD) and early ARM from masked detailed grading of retinal photographs. Interviewer-administered questionnaires provided data on family history of ARM. Logistic regression was used to assess associations, adjusting for other known risk factors. RESULTS: A family history of ARM was significantly associated with both late AMD (odds ratio (OR) 3.92; 95% confidence interval (CI) 1.34-11.46) and early ARM (OR 2.17; 95% CI 1.04-4.55). The association was highest for neovascular AMD. CONCLUSIONS: These findings provide persuasive evidence that a stated family history of ARM is an important risk factor for ARM.

Aged↗

PubMed1998

Prevalence of pterygium and pinguecula: the Blue Mountains Eye Study.

PURPOSE: The present study aimed to describe the prevalence of pterygium and pinguecula in an older population and to examine associations with skin, hair and eye colour, skin sun sensitivity, sun-related skin damage and skin cancer METHODS: The Blue Mountains Eye Study examined 3564 people aged 49 years or older Slit-lamp examination recorded pterygium and pinguecula and a questionnaire was used to collect information on physical variables. RESULTS: Two hundred and sixty-six subjects (7.3%) had pterygium (or had a history of pterygium surgery) and 2521 (69.5%) had pinguecula present in either eye. Significantly more men (11%) than women (4.5%) had pterygium (odds ratio (OR) 2.63; 95% confidence interval (CI) 2.03-3.42). This sex difference was aso found for pinguecula, present in 73.6 and 66.3% of men and women, respectively (OR 1.5; 95% CI 1.3-1.7). A s ight age-related increase in prevalence was found for both pterygium and pinguecula. CONCLUSIONS: The study found significant associations between pterygium and increased pigmentation (skin and hair colour), decreased skin sun sensitivity and sun-related skin damage. The age- and sex-specific pterygium prevalence rates in the present study are simi ar to rates found in non-Aboriginals examined in the 1980 Australian Trachoma Programme.

Age Factors↗

PubMed1998

Prevalence and vascular associations with migraine in older Australians.

BACKGROUND: Migraine is a common disorder with recently described vascular associations, yet there are few Australian population-based data describing migraine prevalence. AIMS: To assess the prevalence and vascular associations with lifetime past history of typical migraine headache in a representative sample of older Australians. METHODS: The Blue Mountains Eye Study examined 3654 permanent residents aged 49 or older living in two postcode areas, west of Sydney (82.4% participation) during 1992-4. A structured interview was administered, including questions about past or present history of typical migraine. The diagnosis was consistent with International Headache Society criteria. RESULTS: A lifetime past history of typical migraine was given by 17% of participants, including 22% of women and 10% of men, a female:male ratio of 2.3:1. A marked trend for declining lifetime migraine frequency with increasing age was found for both sexes. Modest statistically significant associations were found with vascular disease history, after multivariate adjustment, which included vascular risk factors. These associations were stronger in men than in women. Among men, typical migraine was significantly associated with history of angina, odds ratio (OR) 2.0, acute myocardial infarction (OR 1.9) and stroke (OR 2.2). Among women, statistically significant associations were present only with history of myocardial infarct (OR 1.8). CONCLUSIONS: These data indicate similar prevalence rates for lifetime typical migraine history in a representative sample of older Australians, compared to recent US and Canadian populations. Modest, statistically significant associations between typical migraine and past history of vascular disease were found, with the strongest associations found in men.

Aged↗

PubMed1998

Validity and reproducibility of a self-administered food frequency questionnaire in older people.

This study assesses the validity and reproducibility of a 145-item self-administered food frequency questionnaire (FFQ) in a representative older population aged 63 to 80. Semi-quantitative FFQs were completed by 89% of 3,654 residents attending a community-based eye study in Sydney, Australia. The FFQ's validity was assessed against three, four-day weighed food records (WFRs) completed four months apart by 79 people. A further 152 subjects completed a repeat FFQ about a year after the baseline FFQ, of whom 131 completed a second repeat FFQ about six weeks later. Both short and long-term reproducibility of the FFQ were assessed using data from these subjects. Comparison of the FFQ with the average of the three, four-day weighed food records resulted in energy-adjusted Spearman correlations above 0.5 for most of the nutrients. The proportion of subjects correctly classified to within one quintile category for each nutrient intake ranged from 57% for zinc to 82% for vitamin C. with most nutrients correctly classified within one quintile for about 70% of subjects. Quadratic weighted kappas were reasonable, between 0.3 and 0.5 for most nutrients. The FFQ was highly reproducible in the short term, with correlations for most nutrients about 0.70 to 0.80 and acceptably reproducible in the longer term, with correlations mostly 0.60 to 0.70. The results verify that it is possible to use relatively simple, but comprehensive, self-administered FFQs to study nutrient exposures in large-scale epidemiological studies of the elderly and to expect reasonably high FFQ response rates.

Aged↗

PubMed1998

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.

Accidental Falls↗

PubMed1998

Bilateral involvement by age related maculopathy lesions in a population.

AIMS: To describe the influences of age and sex on the frequency of bilateral age related macular degeneration (AMD) and age related maculopathy (ARM) lesions. METHODS: The Blue Mountains Eye Study examined 3654 older Australians, 82% of permanent residents living in an area west of Sydney. Stereo macular photographs were graded for AMD (neovascular maculopathy and geographic atrophy) and early ARM lesions (soft drusen, reticular drusen, hyperpigmentation, and hypopigmentation). RESULTS: Among 230 gradable cases of AMD or early ARM, 183 (80%) were bilateral. For AMD, 39/69 cases (57%) were bilateral, while for early ARM, 123/161 cases (77%) had signs in both eyes. Of the individual lesions, reticular drusen (91%) and indistinct soft drusen (79%) were most frequently present in both eyes. Geographic atrophy was bilateral in 56%, neovascular AMD in 40%, and distinct soft drusen in 47%, while hyperpigmentation was bilateral in 38% and hypopigmentation in only 28% of cases. A consistent age related increase in bilateral distribution was observed for most lesions. After adjusting for effects of age, current smoking, and AMD family history AMD and ARM component lesions, except for soft drusen, were more frequently bilateral in women. This sex difference was significant only for neovascular AMD, odds ratio 7.7 (95% confidence intervals 1.3-46.7). An AMD family history was more frequently reported in cases with bilateral involvement. CONCLUSIONS: This study has documented differences in the age related bilaterality of individual ARM components with higher bilateral rates for reticular or indistinct soft drusen compared with other lesions. The increased bilaterality of most ARM lesions among women is likely to contribute to the increased age adjusted risk of AMD blindness found in women.

Age Factors↗

PubMed1998

"Acting out" and "acting in" as behavioral responses to stress: a qualitative and quantitative study.

In a sample of 270 depressed patients, we describe some behaviors in response to stress. One third acknowledged "acting out" behaviors--angry, destructive acts and "out of control" behaviors. Four fifths acknowledged "acting in" behaviors--most commonly withdrawal. As a percentage of subjects acknowledged both response styles (with alternate expression influenced by situation), we developed a dimensional self-report measure within a subsample of 177 who attended a follow-up reassessment. Assignment to four groups with contrasting expressions of "acting out" and "acting in" scores demonstrated differences in age, diagnostic status, age of onset of depression, and self-injurious behaviors.

Acting Out↗