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Biomedical subjects

K McPherson

Publications and source records attributed to K McPherson.

At least 145 records · Page 8Linked to original sources
PubMed1990

Epidemiology of pelvic inflammatory disease in parous women with special reference to intrauterine device use.

Up to the end of 1989, 206 parous women in the Oxford Family Planning Association contraceptive study had been referred to hospital with a first episode of pelvic inflammatory disease. Of these, 65 suffered from definite disease described as acute, 81 from definite disease not described as acute and 60 from 'other disease'. Considering all forms of disease together, referral was less common in those aged 25-29 and in those aged 45 or more than in those aged 30-44. Referral was more common in those of low social class, in those who smoked and in those who married young. All these factors were taken into account in analyses considering the effects of contraceptive methods. In these analyses, women currently using the contraceptive pill, the diaphragm, the sheath, female sterilization or an intrauterine device (IUCD) were compared with those currently using other methods or no method of contraception. IUCD ex-users were, however, placed in a separate category, irrespective of their current method of contraception. The relative risks obtained in these analyses, with 95% CI, were as follows: contraceptive pill 0.5 (0.2-0.9), diaphragm 0.6 (0.3-1.2), sheath 1.2 (0.6-2.4), female sterilization 0.7 (0.3-1.5), non-medicated IUCD 3.3 (2.3-5.0), medicated IUCD 1.8 (0.8-4.0), IUCD ex-users 1.3 (0.7-2.3). These data suggest that oral contraceptives, the diaphragm and female sterilization protect against pelvic inflammatory disease and that IUCDs increase the risk. Medicated devices, however, appear to carry only about half the risk of non-medicated devices, and the elevation of risks in IUCD ex-users appears to be small. Special analyses examined the risk associated with use of a Dalkon Shield. Among women currently using an IUCD (of any kind), those who had used a Dalkon Shield (at any time) had nearly five times as great a risk of hospital referral for pelvic inflammatory disease as those who had never used a Dalkon Shield (relative risk 4.7, 95% CI 2.1-9.0).

Acute Disease↗
PubMed1990

Are measurements of height made by health visitors sufficiently accurate for routine screening of growth?

To find out whether measurements of height made by health visitors are sufficiently accurate for use in routine screening of children we carried out an interobserver and intraobserver reliability study. Height measurements were made on a group of 10 children aged 3 years old and 10 aged 4.5 years old by two sets of four health visitors. They used a Microtoise or wall chart and the measurements were compared with those made by a trained auxologist with a Harpenden stadiometer. For a single assessment of height both pieces of equipment gave reasonably accurate results. In a child aged 3 years, with height measured on the Microtoise as 100 cm, the true height could be expected--with 95% probability--to lie between 99.2 cm-101.8 cm. At the age of 4.5 years, if the measurement was 110 cm, the child's true height could be expected to lie between 108.9 cm and 111.9 cm. The narrowest confidence interval for the growth rate from 3 to 4.5 years was achieved with the Microtoise, taking the mean of three measurements. We conclude that measurements made by health visitors are sufficiently accurate for routine screening of height, and the use of such measurements for the calculation of height velocity could be improved by more structured training.

Anthropometry↗
PubMed1989

Mortality among oral contraceptive users: 20 year follow up of women in a cohort study.

OBJECTIVE: To see whether the use of oral contraceptives influences mortality. DESIGN: Non-randomised cohort study of 17,032 women followed up on an annual basis for an average of nearly 16 years. SETTING: 17 Family planning clinics in England and Scotland. SUBJECTS: Women recruited during 1968-74. At the time of recruitment each woman was aged 25-39, married, a white British subject, willing to participate, and either a current user of oral contraceptives or a current user of a diaphragm or intrauterine device (without previous exposure to the pill). MAIN OUTCOME MEASURES: Overall mortality and cause specific mortality. RESULTS: 238 Deaths occurred during the follow up period. The main analyses concerned women entering the study while using either oral contraceptives or a diaphragm or intrauterine device. The overall relative risk of death in the oral contraceptive users was 0.9 (95% confidence interval 0.7 to 1.2). Though the numbers of deaths were small in most individual disease categories, the trends observed were generally consistent with findings in other reports. Thus the relative risk of death in the oral contraceptive users was 4.9 (95% confidence interval 0.7 to 230) for cancer of the cervix, 3.3 (95% confidence interval 0.9 to 17.9) for ischaemic heart disease, and 0.4 (95% confidence interval 0.1 to 1.2) for ovarian cancer. There was a linear trend in the death rates from cervical cancer and ovarian cancer (in opposite directions) with total duration of oral contraceptive use. Death rates from breast cancer (relative risk 0.9; 95% confidence interval 0.5 to 1.4) and suicide and probable suicide (relative risk 1.1; 95% confidence interval 0.3 to 3.6) were much the same in the two contraceptive groups. In 1981 the relative risk of death in oral contraceptive users from circulatory diseases as a group was reported to be 4.2 (95% confidence interval 2.3 to 7.7) in the Royal College of General Practitioners oral contraception study. The corresponding relative risk in this study was only 1.5 (95% confidence interval 0.7 to 3.0). CONCLUSIONS: These findings contain no significant evidence of any overall effect of oral contraceptive use on mortality. None the less, only small numbers of deaths occurred during the study period and a significant adverse (or beneficial) overall effect might emerge in the future. Interestingly, the mortality from circulatory disease associated with oral contraceptive use was substantially less than that found in the Royal College of General Practitioners study.

Adult↗
PubMed1989

Mortality and reoperation after open and transurethral resection of the prostate for benign prostatic hyperplasia.

As part of an ongoing effort to evaluate alternative treatments for benign prostatic hyperplasia, we compared the outcomes of transurethral resection of the prostate with those of open prostatectomy. Men undergoing prostatectomy in Denmark (n = 36,703), Oxfordshire, England (n = 5284), and Manitoba, Canada (n = 12,090), were identified retrospectively through administrative data and followed for up to eight years. The cumulative percentage of patients undergoing a second prostatectomy was substantially higher after transurethral than after open prostatectomy (12.0 vs. 4.5 percent in Denmark, 12.0 vs. 1.8 percent in Oxfordshire, and 15.5 vs. 4.2 percent in Manitoba). The long-term age-specific mortality rates associated with transurethral prostatectomy as compared with open prostatectomy were also elevated in each country. The data on 1650 Canadian patients were used to investigate the contribution of coexisting morbid conditions to the elevated risk of death. The relative risk was 1.45 (95 percent confidence interval, 1.15 to 1.83) before risk adjustment and 1.45 (95 percent confidence interval, 1.15 to 1.84) after adjustment; the higher mortality was seen among low-risk as well as high-risk patients. These findings suggest that transurethral prostatectomy is less effective in overcoming urinary obstruction than the open operation. Our data also raise the possibility that transurethral prostatectomy may result in higher long-term mortality, although we cannot rule out potential confounding effects of unmeasured characteristics of patients.

Aged↗
PubMed1989

Oral contraceptive use influences resting breast proliferation.

The controversy that surrounds oral contraceptive use and breast cancer risk has arisen from epidemiologic studies, yet the direct effect of such use on breast tissue remains undefined. Breast epithelial proliferation was assessed by 3H-thymidine labeling of normal lobular units dissected from benign biopsies of 347 females aged 14 to 48 years. Factors shown to influence this response included cycle phase, time since menarche (breast age), and parity status. Multivariate analysis allowing for these influences was used to compare activity of natural cycles and those artificially regulated by oral contraceptives (OC). The increased activity in nulliparous OC users was highly significant (P less than .005). Comparing the effect of differences in OC type, whether combined, triphasic, progestin only, or according to estrogen or progestin content, showed a heterogeneity in response that was significant (P less than .01). Examined specifically, the formulation of OC according to progestin content did not have a significant influence, although progestin-only OC was most active, while the influence of increasing estrogen content was significant (P less than .05). However, emphasis is given to acknowledging the multiple factors and interactive processes responsible for breast epithelial stimulation when considering strategies of intervention.

Adolescent↗
PubMed1989

Oral contraceptives and breast cancer: latest findings in a large cohort study.

During the interval 1968-74, 17,032 women aged 25-39 years were recruited to the Oxford-Family Planning Association contraceptive study, more than half of whom were using oral contraceptives. These women have been followed up over the years and breast cancer has been diagnosed in 189 of them. We have analysed the available data in two ways. First, we have calculated standardised breast cancer incidence rates in non-users and users of oral contraceptives according to total duration of use, interval since first use, interval since last use, duration of use before first term pregnancy and duration of use before age 25. Secondly, we have conducted case-control within cohort analyses to examine the possible effects of different types of pill and to search for evidence of a latent effect of oral contraceptive use before first term pregnancy on breast cancer risk. We have found no evidence of any adverse effect of oral contraceptive use on the risk of breast cancer in this study. There was, however, little exposure to the pill before first term pregnancy among the participants and virtually no such exposure at a very young age (i.e. below 20 years). Accordingly, the results of this study strengthen the evidence that oral contraceptive use by mature women does not increase breast cancer risk, but add little to the uncertainty about the effects of early use.

Adult↗
PubMed1989

Alcohol, cigarette smoking and breast cancer.

The results of two case-control studies of breast cancer which included questions on exposure to tobacco and alcohol are reported. One study included 998 hospital cases and a like number of matched hospital controls while the other included 118 cases identified during mammographic screening and a like number of matched normal screenees. Both studies used the same questionnaires and the same methods to obtain information. The results with regard to cigarette smoking differed between the two studies. The hospital-based study showed a decreased risk of breast cancer with increasing amounts smoked (relative risk for 15 or more cigarettes per day was 0.82, 95% confidence interval 0.60-1.13) while the screening study showed an increased risk (relative risk for 15 or more cigarettes per day was 2.90, 95% confidence interval 1.16-7.25). Evidence is presented that both results may be attributable to bias in the selection of cases and controls. It is concluded that reliable results on the relationship between smoking and breast cancer are only likely to come from population-based studies. These studies, in general, have found no relationship. Neither study produced any hint of an association between alcohol consumption and breast cancer. From this, it appears that bias in subject selection may not be such a significant factor in interpretation of studies of alcohol and breast cancer as it is in studies of smoking and the disease. A number of other difficulties in the interpretation of studies of alcohol and breast cancer are considered, including the great variation in the amount of alcohol consumed. It is concluded that the assertion that alcohol is a risk factor for breast cancer remains unproven.

Adult↗
PubMed1989

Relationship of body mass index, weight and height to plasma lipid levels in people with different diets in Britain.

Blood samples and self-reported heights and weights have been collected from 114 vegans, 1550 vegetarians, 415 fish eaters who did not eat meat, and 1198 meat eaters. We have previously reported that mean total and LDL cholesterol were lower in the vegetarians and fish eaters than in the meat eaters, while the mean levels in vegans were lower still. We have examined the possibility that this relationship could be explained by differences in the mean body mass index of the four groups. While there was a small positive relationship between body mass index and plasma lipid levels this did not explain the previously reported difference between diet groups. After adjusting for the effect of body mass index there remained a small negative association between height and plasma lipid levels, which has not previously been reported. Height is known to be influenced by childhood ill health and has also been shown to be related to social class, and it may be that the relationship between plasma lipid levels and height can be explained by these factors.

Body Height↗
PubMed1989

Histopathology of breast cancer in young women in relation to use of oral contraceptives.

A detailed review was made of the histopathology of 227 tumours taken from 261 women under 45 years of age with breast cancer. The tumours were classified as follows: whether oral contraceptives had been used at any time; and whether oral contraceptives had been used before first term pregnancy. All analyses were adjusted for the effects of age. Overall, 201 (88.5%) of tumours were infiltrating ductal in type, 19 (8.4%) were infiltrating lobular, and seven (3.1%) were in situ ductal. Of the infiltrating ductal tumours, 28 (14%) were grade I 88 (44%) grade II, and 84 (42%) grade III. Various other tumour characteristics were also examined (per cent of carcinoma in situ, lymphatic permeation, necrosis, lymphoplasmocytic reaction and tumour edge). None of the histopathological features assessed showed any significant association with oral contraceptive use. Some characteristics of the areas of breast tissue adjacent to the tumours were also studied. The degree of cyst formation was considerably less pronounced in those using oral contraceptives before first term pregnancy than in those not doing so.

Breast↗
PubMed1989

International differences in medical care practices.

An overview of several aspects of international comparisons of medical care utilization is presented with a discussion of the usefulness of such comparisons in identifying geographic variations in utilization and in elucidating the nature of clinical decisionmaking regarding various procedures. The discussion includes the purposes of conducting international studies as well as the methodological and policy issues involved. Brief descriptions of some of the studies that have been conducted are also provided.

Cross-Cultural Comparison↗
PubMed1988

Positive correlation of corneal thickness and endothelial cell loss. Serial measurements after cataract surgery.

A significant linear correlation was found between increase in corneal thickness (delta CT) in the immediate postoperative period and percentage of cell loss one and six months after surgery in a prospective study on cataract surgery. Eyes were grouped according to delta CT, and the groups were compared according to the percentage of cell loss. Eyes with delta CT of 0.1 mm or more at five days lost significantly more cells at one and six months than eyes with delta CT of less than 0.025 mm. Eyes were then regrouped according to the percentage of cell loss. Those with cell loss of 30% or more were found to have significantly greater delta CT at 48 hours and five days than eyes with cell loss of less than 30%. The derived probability of cell loss of 30% or more increases the greater the value of delta CT. For delta CT of 100 micron or more at five days, the probability of high cell loss is 30%; this is nearly three times the likelihood that high cell loss had occurred when delta CT is less than 100 micron. Our results suggest that delta CT could be a useful clinical indicator of endothelial cell loss.

Cataract Extraction↗
PubMed1988

Do British women undergo too many or too few hysterectomies?

Hysterectomy is performed much less frequently in Britain than in North America, Australia and some European countries. Various theories have been advanced to explain this lower rate of surgery. These include: fewer health care resources (hospital beds, surgeons); much less fee-for-service medicine; differences in the attitudes of surgeons; differences in health care organisation, in particular the gatekeeping role of general practitioners; and differences in patients' expectations. This paper reviews the evidence on sources of variation and examines the extent to which hysterectomy rates vary between countries, and between small areas and social groups within Britain. Following an examination of national trends, evidence is presented from studies carried out in the Oxford region to illustrate the extent of variation in the rate at which hysterectomy is carried out and to explore the possible reasons for the differences. The article considers the health policy implications of an apparent increase in demand for hysterectomy and argues the case for a thorough evaluation of the impact of this operation on quality of life.

Adult↗
PubMed1988

A prospective study of acute cerebrovascular disease in the community: the Oxfordshire Community Stroke Project 1981-86. 1. Methodology, demography and incident cases of first-ever stroke.

A prospective study of acute cerebrovascular disease in a community of about 105,000 people is reported. The study protocol combined rapid clinical assessment of patients with accurate diagnosis of the pathological type of stroke by CT or necropsy, whether or not they were admitted to hospital. The study population was defined as those people who were registered with one of 50 collaborating general practitioners (GPs). Referrals to the study were primarily from the GPs though, to ensure complete case ascertainment, hospital casualty and admission registers, death certificates and special data from the Oxford Record Linkage Study were also scrutinized. Six hundred and seventy five cases of clinically definite first-ever in a lifetime stroke were registered in four years yielding a crude annual incidence of 1.60/1,000 or 2.00/1,000 when adjusted to the 1981 population of England and Wales. The age and sex specific incidence rates for first stroke showed a steep rise with age for both sexes. The odds of a male sustaining a first stroke were 26% greater than those of a female. Ninety one per cent of patients were examined in a median time of four days after the event by a study neurologist and 88% had cerebral CT or necropsy.

Adolescent↗
PubMed1988

Using diagnosis-related groups for studying variations in hospital admissions.

The diagnosis-related groups (DRG's) have classically focused on resources consumed during a hospital stay. DRG's can also be considered categories for describing cases admitted to a hospital. In this article, we illustrate how consistent patterns of variations in admission rates can be used to classify DRG categories according to the Index of Discretionary Admissions. The consistency of variation in admission rates for modified DRG categories across hospital service areas in Iowa, California, Massachusetts, and Maine was high. The proportion of hospital admissions in the DRG's judged to be most discretionary ranged from 22 percent in Iowa to 14 percent in California.

California↗