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Biomedical subjects

M A McGee

Publications and source records attributed to M A McGee.

At least 19 recordsLinked to original sources
PubMed2006

New postnatal urinary incontinence: obstetric and other risk factors in primiparae.

OBJECTIVE: To identify obstetric and other risk factors for urinary incontinence that occurs during pregnancy or after childbirth. DESIGN: Questionnaire survey of women. SETTING: Maternity units in Aberdeen (Scotland), Birmingham (England) and Dunedin (New Zealand). POPULATION: A total of 3405 primiparous women with singleton births delivered during 1 year. METHODS: Questionnaire responses and obstetric case note data were analysed using multivariate analysis to identify associations with urinary incontinence. MAIN OUTCOME MEASURES: Urinary incontinence at 3 months after delivery first starting in pregnancy or after birth. RESULTS: The prevalence of urinary incontinence was 29%. New incontinence first beginning after delivery was associated with older maternal age (oldest versus youngest group, OR 2.02, 95% CI 1.35-3.02) and method of delivery (caesarean section versus spontaneous vaginal delivery, OR 0.28, 95% CI 0.19-0.41). There were no significant associations with forceps delivery (OR 1.18, 95% CI 0.92-1.51) or vacuum delivery (OR 1.16, 95% CI 0.83-1.63). Incontinence first occurring during pregnancy and still present at 3 months was associated with higher maternal body mass index (BMI>25, OR 1.68, 95% CI 1.16-2.43) and heavier babies (birthweight in top quartile, OR 1.56, 95% CI 1.12-2.19). In these women, caesarean section was associated with less incontinence (OR 0.39, 95% CI 0.27-0.58) but incontinence was not associated with age. CONCLUSIONS: Women have less urinary incontinence after a first delivery by caesarean section whether or not that first starts during pregnancy. Older maternal age was associated with new postnatal incontinence, and higher BMI and heavier babies with incontinence first starting during pregnancy. The effect of further deliveries may modify these findings.

Adult↗
PubMed2004

What interventions should we add to weight reducing diets in adults with obesity? A systematic review of randomized controlled trials of adding drug therapy, exercise, behaviour therapy or combinations of these interventions.

BACKGROUND: Evidence is needed for the effectiveness of interventions given with reducing diets for obese adults: drug therapy, exercise, or behaviour therapy. METHODS: We systematically reviewed randomized controlled trials in any language. We searched 13 databases and handsearched journals. Trials lasted 1 year or more. One investigator extracted data and a second checked data extraction. Trial quality was assessed. RESULTS: Adding orlistat to diet was associated with weight change for up to 24 months (-3.26 kg, 95% CI, -4.15 to -2.37 kg), and statistically significant beneficial changes were found for total and LDL cholesterol, blood pressure and glycaemic control. Adding sibutramine to diet was associated with a 12 month weight change of -4.18 kg (95% CI, -5.14 to -3.21 kg), and statistically significant beneficial effects on high density lipoprotein cholesterol (HDL) and triglycerides (TGs), but an increase in diastolic blood pressure. Adding exercise to diet, or to diet and behaviour therapy, was associated with improved weight loss for up to 36 months and improvements in HDL, TGs and blood pressure. Adding behaviour therapy to diet, or to diet and sibutramine together, was associated with improved weight loss for up to 18 months. Adding drugs, exercise or behaviour therapy to dietary advice was each associated with similar weight change. CONCLUSIONS: Adding orlistat, sibutramine, exercise, or behaviour modification to dietary advice can improve long-term weight loss.

Adult↗
PubMed2004

What are the long-term benefits of weight reducing diets in adults? A systematic review of randomized controlled trials.

BACKGROUND: Evidence is needed for the best long-term diet for weight loss, and improvement in cardiac risk and disease in obese adults. METHODS: We systematically reviewed randomized controlled trials (RCTs) in any language. We searched 13 databases and handsearched journals. Trials lasted 1 year or more. One investigator extracted the data and a second checked data extraction. Trial quality was assessed. RESULTS: Low fat diets (LFDs) produced significant weight losses up to 36 months (-3.55 kg; 95% CI, -4.54 to -2.55 kg). Blood pressure, lipids and fasting plasma glucose improved with these diets after 12 months. Four studies found that LFDs may prevent type 2 diabetes and reduce antihypertensive medication for up to 3 years. A very low calorie diet (VLCD, < 4.2 MJ day(-1)) was associated with the most weight loss after 12 months (-13.40 kg; 95% CI, -18.43 to -8.37 kg) in one small study with beneficial effects on asthma. There was no evidence that low carbohydrate protein sparing modified fasts (PSMFs) were associated with greater long-term weight loss than low calorie diets (LCDs, 4.2-6.7 MJ day(-1)) or VLCDs. PSMFs were, however, associated with greater lowering of fasting plasma glucose and HbA1c than LCDs. CONCLUSIONS: Little evidence supports the use of diets other than LFDs for weight reduction. With the increasing prevalence of morbid obesity, long-term follow-up in RCTs is needed to evaluate the effect of LCDs, VLCDs and PSMFs more fully.

Adult↗
PubMed2004

Death by suicide in Grampian 1991-1999: comparison with a previous study.

OBJECTIVES: To review the changes in suicide and undetermined death rates in Grampian between 1991-1999 and to make comparisons with a previous study on the same population. DESIGN: All suicide and undetermined deaths in Grampian recorded by the General Register Office for Scotland were included and linked with the psychiatric case records from Grampian Health Board. RESULTS: The high suicide and undetermined death rates in Grampian are accounted for by the excess of deaths in males. In males there has been a change in the method used to commit suicide with hanging now being the commonest method used. Firearm deaths have reduced dramatically since legislation was introduced in 1997 (RR = 021,95% CI [0.05,0.91). For those with previous psychiatric contact, a greater proportion were drug users than in 1974-1990 (OR = 3.75,95%CI [2.7, 5.2]). A higher percentage of suicides have a history of more than one previous attempt at suicide than in 1974-990. In Grampian there is a lower percentage of inpatient suicide than the rest of Scotland. CONCLUSION: There have been changes in suicide trends in Grampian and these are similar to elsewhere in Scotland Strategies to address this are discussed.

Cause of Death↗
PubMed2001

Health and ill-health in the older population in England and Wales. The Medical Research Council Cognitive Function and Ageing Study (MRC CFAS).

OBJECTIVE: to provide a profile of disorders and disabilities in the older population. DESIGN: the MRC CFAS drew population samples of people aged 64 years and over from Family Health Service Authority lists at five sites and asked participants about sociodemographic variables, physical and cognitive health and activities of daily living, We calculated the prevalence of co-morbidity from the number of different types of complaint or disability (physical, functional and cognitive), and calculated healthy life expectancies in each of these co-morbid states. SETTING: three urban (Newcastle, Nottingham and Oxford) and two rural sites (Cambridgeshire and Gwynedd). RESULTS: the prevalence of morbidity is low at the youngest ages, as is co-morbidity. Women have consistently greater morbidity than men. Morbidity increases sharply with age, with a more dramatic rise in women. Life expectancy without any morbidity is short at all ages over 64, with the number of years expected with two or more areas affected virtually constant up to 90 years. As a proportion of remaining life expectancy, the period of time spent with two or more areas affected rises by the age of 90 to 30% in men and 60% in women. CONCLUSIONS: preventive programmes for the older population should take into account the large differences between the young old, the middle old and the old old. Our study provides a baseline against which to compare future changes in health in older populations, as well as benchmark expectancies for the UK population.

Activities of Daily Living↗
PubMed2001

Exploring the impact of prevalence and mortality on incidence of dementia in the oldest old: the sensitivity of a deterministic approach.

BACKGROUND: There has been considerable debate about whether dementia is an age-related or an aging-related phenomenon. When the evidence is restricted to prevalence data, the inferences are not sound because incidence, mortality and differential mortality are not taken into account. The aim of the paper is to demonstrate the use and sensitivity of a deterministic model based on the relationship between mortality, incidence and prevalence with the example of the chronic disease dementia. DESIGN: The simple deterministic model used here allows the calculation of one component given the other three. The sensitivity of calculated incidence to individual and combined changes in mortality, differential mortality (as measured by the mortality odds ratio) and prevalence is examined using published data. MAIN RESULTS: Calculated incidence continues to increase with age despite extreme but plausible changes in each of the other components. Calculated incidence declines amongst the oldest old only when the changes are combined. CONCLUSION: The deterministic model is shown to provide robust interrogation of the relationship between prevalence, incidence and survival. The effect incidence and survival have on the age-related and aging-related debate is illustrated. Only with extreme assumptions can the incidence of dementia be lessened. Clearly, more information on the oldest old is needed, but incidence studies of sufficient size at such great ages are problematic, and therefore there is a need to use flexible models for maximising the value of empirical data.

Aged↗
PubMed2000

Population norms for the MMSE in the very old: estimates based on longitudinal data. Mini-Mental State Examination.

OBJECTIVE: To report the percentile distribution of Mini-Mental State Examination (MMSE) scores in older people by age, sex, and education level, estimated from longitudinal data, after correcting for loss due to dropout. METHODS: The Cambridge City over 75 Cohort is a population-based study of a cohort of 2106 subjects age 75 years and older at study entry followed up over 9 years. At each of the four waves, cognitive function was assessed using MMSE. Based on these data, the relationship between age and MMSE score was modeled. Percentile distributions by age, sex, and education level were provided using inverse probability weighting to correct for dropouts. RESULTS: Performance on MMSE was related to age in men and women. In women, at age 75, MMSE score ranged from 21 (10th percentile) to 29 (90th percentile). At age 95, the range was 10 (10th percentile) to 27 (90th percentile). The upper end of MMSE distribution was slightly modified with age, whereas the lower end of the distribution was very sensitive to age effect. A similar pattern was observed in both sexes. CONCLUSION: These findings provide norms for MMSE scores in subjects age 75 years and older from longitudinal population-based data. Such norms can be used as reference values to determine where an individual's score lies in relation to his or her age, sex, and education level.

Aged↗
PubMed2000

Neuropathological findings in the very old. Results from the first 101 brains of a population-based longitudinal study of dementing disorders.

We report a unique longitudinal epidemiological study of cognitive decline in the elderly population of the city of Cambridge, UK. A population sample of people aged 75 and over was surveyed between 1984-1996 (n = 2,616) and followed 2.4, 6, and 9 years later. CAMDEX diagnostic criteria were used for clinical assessment, and the neuropathological protocol (in 101 cases) was based on the CERAD method, with additional features to allow Braak staging of neurofibrillary pathology. The main findings are of the heterogeneity of lesions to be found in very old populations, and the existence of considerable overlap in the pathologies found in the demented and nondemented. It seems that white matter (ischemic) pallor an amyloid angiopathy, as well as neuritic plaques, neurofibrillary tangles and Lewy body formation are all lesions that increase the likelihood of dementia.

Age Factors↗
PubMed1999

Estimating the true extent of cognitive decline in the old old.

OBJECTIVE: To measure cognitive change using a brief measure over a period of 9 years and to adjust for attrition in the sample. DESIGN: The Cambridge City over 75 Cohort (CC75C), a complete sample of the 75 years and older age group from five group general practices in the city of Cambridge with a systematic one-third of a further practice, all followed on four occasions. SETTING: Cambridge city, UK, the respondents' place of residence. PARTICIPANTS: A total of 2106 subjects were included at study entry. MEASUREMENTS: A brief interview, administered by a trained interviewer, containing a short cognitive scale and the Mini-Mental State Examination (MMSE) at baseline, 2.4 years, 6 years, and 9 years. RESULTS: Decline in MMSE scores occurred across the population and was greater in the oldest age groups. Attrition at later stages of the follow-up was associated with greater decline at earlier stages. Adjusting the results for loss to the sample leads to considerably higher estimates of decline, with the older age groups declining faster from lower levels. CONCLUSIONS: To date, cognitive decline in the very old has been considerably underestimated by longitudinal studies. If studies of population samples are to reflect the health and social needs of this frail group accurately, adjustments for the effect of attrition must be included before true decline can be estimated.

Age Factors↗
PubMed1998

Examination of the validity of the hierarchical model of neuropathological staging in normal aging and Alzheimer's disease.

The neuropathological staging model of Alzheimer's disease proposed by Braak and Braak [Acta Neuropathol (1991) 82:259] requires that the evolution of neurofibrillary pathology follows a predictable pattern that can be ordered in a regular regional hierarchy. We have operationalized the neuropathological staging system to permit testing of its validity. Forty-two cases were derived from an epidemiological study of cognitive function in an elderly population for which post-mortem brain tissue was collected. Cases with neuropathological diagnoses other than Alzheimer's disease and normal aging were excluded. Neurofibrillary tangle counts were determined in all cortical laminae and regions used for staging. There was a significant correlation between the overall extent of neurofibrillary pathology and the number of regions affected. There were frequent order violations in the proposed hierarchy: 19 instances (45%) involving entorhinal and transentorhinal cortices, and 16 instances (38%) involving CA1 of hippocampus and entorhinal cortex. Only 6 out of 42 cases conformed in all regions to the expected hierarchy. Nevertheless, 90% of the cases had 2 order violations or less, supporting the approximate validity of the hierarchy.

Aging↗
PubMed1998

The description of activities of daily living in five centres in England and Wales. Medical Research Council Cognitive Function and Ageing Study.

OBJECTIVES: the Medical Research Council Cognitive Function and Ageing Study is a longitudinal study of health and well-being of the ageing UK population. We present the screening interview which assesses how this group copes with activities of daily living (ADL), and characteristic ranges for the total score of these activities by age and DESIGN: random sampling was from Family Health Service Authority lists in three urban and two rural areas, including institutions. Participants (n = 13,009) in their 65th year and over were interviewed between 1991 and 1994. The sample was stratified to provide equal numbers in the 65-74 and 75 years and over age groups. Each participant was asked about socio-demographic variables, cognitive function, physical health, medication and ADL (based on the nine items from the self-reported Townsend's disability scale). RESULTS: the scale shows good reliability and validity in this study. There is a high frequency of disability amongst the oldest old, and relationships between ability and age and between ability and sex and other sociodemographic variables: the risk of having difficulty increases with living away from home, with poorer eyesight and speech, with lower social class and with lack of further education. Projections of the number (and percentage) of severely disabled over-65-year-olds in the UK in 2011 and 2051 are 1.4 million (2.2%) and 2.3 million (3.9%) respectively.

Activities of Daily Living↗
PubMed1998

The impact on prevalence of dementia in the oldest age groups of differential mortality patterns: a deterministic approach.

BACKGROUND: Until recently relatively little data have been available on the prevalence of dementia in the oldest age groups, and yet it is these age groups which are expanding fastest. It is therefore important to understand whether the prevalence of dementia rises inexorably with age ('age-dependent'), or, as some suggest, levels off or even declines in the very oldest age groups ('age-related'). Combined analysis of the many prevalence studies now available has led to modelled curves which do suggest a slowing of rise in prevalence at these great ages, and has been interpreted as meaning that dementia is age-related. This interpretation does not take into account the differential survival of individuals with cognitive impairment compared with normals of the same age. METHOD: Flexible prevalence-incidence-duration models were generated using a deterministic approach applied to published combined analyses of prevalence rates, population death rates and mortality odds ratios. RESULTS: The variation in observed prevalence patterns with age is explained to a great extent by the mortality observed in the cognitively impaired. Simple examination of age patterns in prevalence does not answer the fundamental question surrounding the age-dependence of cognitive impairment. CONCLUSION: Inferring biological meaning from these observed curves is not valid without examining the mathematical phenomena of the relationship of incidence, mortality and prevalence. This approach allows an examination of the impact of varying mortality and incidence on the prevalence of dementia and cognitive impairment and will be useful in determining the potential impact of preventive strategies on the population.

Age Distribution↗
PubMed1998

Lung cancer among Chinese females in Singapore 1968-1992: time trends, dialect group differences and implications for aetiology.

BACKGROUND: Chinese females are distinguished internationally as having relatively high lung cancer incidence rates despite a low prevalence of cigarette smoking. In Singapore, this population comprises several dialect groups which have origins in different regions in China, each with its own traditional cultural practices. METHODS: An analysis of 4029 incident cases of the disease notified to the Singapore Cancer Registry for 1968-1992 was undertaken to provide some insight into important aetiologic factors among these women. RESULTS: The age-standardized incidence rate of lung cancer rose from 17.3 per 100,000 woman-years in 1968-1972 to 23.0 in 1978-1982 before falling off in more recent years. Age-period-cohort analysis indicated significant period and birth cohort effects, with the risk being highest for women born around 1908. Between the major dialect groups, Cantonese women had a significantly high rate compared with Hokkiens (relative risk [RR] = 2.6, 95% CI: 2.4-2.8). Histologically, there appears to be an increase in the proportion of adenocarcinomas diagnosed over this period (25.8% in 1968-1972 to 51.3% in 1988-1992). CONCLUSION: Our results suggest that traditional practices which have decreased over the years, and are more prominent among Southern Chinese, may play a part in the aetiology of lung cancer locally.

Adenocarcinoma↗
PubMed1997

The role of polyethylene wear in joint replacement failure.

Aseptic loosening is the major cause of failure of joint replacement prostheses. Polyethylene implants removed at revision surgery regularly show wear. It is proposed that the polyethylene particles released into the tissues as a consequence of this wear induce a tissue response that precedes aseptic loosening. This paper presents the results of recent in vivo and in vitro studies of the biological response to polyethylene wear particles undertaken in the authors' laboratories. A clinical perspective is provided by the inclusion of the authors' recent observations of retrieval analyses of joint replacement implant wear and the tissue response to polyethylene in humans.

Animals↗
PubMed1996

The relationship between clinical dementia and neuropathological staging (Braak) in a very elderly community sample.

The neuropathological staging model proposed by Braak and Braak (1991) implies that the evolution of neurofibrillary pathology follows a predictable sequence and can be ordered in a regular regional hierarchy. A total of 42 cases of an elderly population sample, which had been prospectively clinically assessed, were examined. Clinical diagnosis was made according to the CAMDEX criteria, and the sample reported here did not include cases were vascular dementia according to the criteria proposed by Chui et al. (1991). The neuropathological staging procedure was applied as originally proposed by Braak and Braak (1991). In addition, in all cortical laminae and regions which are essential for the staging model neurofibrillary tangles were quantified. Demented cases had significantly more areas involved and more advanced neuropathological stages. Cases with stages 1-3 tended to be non-demented, and cases with stages 4-6 tended to be demented. However, there was a considerable degree of overlap and no clear-cut threshold could be established. This brings into question the diagnostic value of the staging model.

Aged↗
PubMed1996

Breast cancer in Singapore: trends in incidence 1968-1992.

BACKGROUND: Breast cancer is the most commonly occurring cancer among women in Singapore, a country which has experienced significant changes in lifestyle over the past three decades. The increase in incidence of the disease is a matter of some concern. METHODS: Data from the population-based Singapore Cancer Registry for 1968-1992 were used to determine time trends, inter-ethnic differences and the contributions of age, period and cohort effects to the incidence of the disease. RESULTS: Our results revealed an average annual increase of 3.6% over the 25-year period for all women, form 20.2 per 100,000 women in the period 1968-1972 to 38.8 per 100,000 in 1988-1992. There was a statistically significant difference between the three major ethnic groups, the rate of increase being highest in Malays (4.4%) and lowest in Indians (1.4%). The overall increase was attributable to a strong cohort effect that remained significant when adjusted for time period for Chinese women and for all ethnic groups combined. The risk was observed to increase in successive birth cohorts from the 1890s to 1960s. CONCLUSIONS: Our results suggest that breast cancer incidence rates are likely to continue to increase more sharply in the future as women born after the mid-20th century reach the high-risk age groups. They also suggest the pattern by which important aetiological factors for the disease in our population have exerted their effects, and provide support for the role of demographic and lifestyle changes as possible risk factors.

Adult↗
PubMed1996

Biologic effects of cobalt chrome in cell and animal models.

The literature on animal and cellular models used to study the response to cobalt chrome alloy implants and wear and corrosion products is reviewed. Animal studies show that in solid form cobalt chrome alloy is relatively well tolerated. Injections of large numbers of particles in a single bolus lead to acute inflammation and necrosis, followed by a chronic inflammatory response. Macrophages are the predominant cell type and may persist in the tissues for years. Long term studies have failed to confirm the induction of tumors. In vitro studies confirm the toxic effects of cobalt chrome alloy corrosion products and wear particles, especially cobalt, and show that intracellular corrosion is an important mechanism for early release of cobalt ions. In vitro studies show that cobalt chrome alloy particles induce the release of inflammatory mediators from macrophages before causing cell death. These mediators have significant effects on osteoblastlike cells, as well as inducing bone resorption. Variations in the cell types, implantation site, and characteristics of the particles used in experimental models make interpretation of the results difficult. Standardized methods to control for size, shape, and number of particles for testing are proposed. It is important that in vitro and in vivo findings not be taken in isolation, but be compared with the results of human studies.

Animals↗