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Biomedical subjects

K McPherson

Publications and source records attributed to K McPherson.

At least 163 records · Page 9Linked to original sources

The prognostic significance of blood pressure in the elderly.

Whilst recruiting for the Randomised Trial of the Treatment of Hypertension in Elderly Patients in Primary Care, 10,732 people aged 60-79 years of age (4,736 males and 5,996 females) were screened for hypertension. This constituted 78% of those eligible on the practice lists in this age range. These patients were followed up for a mean period of 2.6 years (range 0.1-11.2 years). All those leaving the practices were registered with the National Health Service Central Registry to ensure completeness of death ascertainment. 1,009 deaths were analysed and standardised mortality ratios computed for all deaths, stroke, coronary artery disease and all cardiovascular causes. Hypertensive patients included in the control group of the trial were also matched with patients found to be normotensive and their mortalities compared. Both high and low levels of SBP were associated with increased mortality producing a U-shaped curve for all deaths and J-shaped curves for cardiovascular causes. With increasing age the higher mortality associated with lower SBP became more pronounced. Similar effects were evident for DBP but in women high DBP was less dangerous than in men. Although the relative impact of hypertension declines with advancing age, the absolute impact is maintained up to the age of eighty.

Age Factors↗

Plasma lipids and lipoprotein cholesterol concentrations in people with different diets in Britain.

Concentrations of total cholesterol and cholesterol in the various lipoprotein fractions were measured in vegans, vegetarians, fish eaters (who did not eat meat), and meat eaters. Total and low density lipoprotein cholesterol concentrations were higher in meat eaters than vegans, with vegetarians and fish eaters having intermediate and similar values. High density lipoprotein cholesterol concentration was highest in the fish eaters but did not differ among the other groups. There were striking trends with age in total and low density lipoprotein cholesterol concentrations, which differed between men and women: women showed a steady increase in concentration with age, whereas concentrations in men did not increase appreciably after the age of 40, which may partly explain sex differences in the prevalence of coronary heart disease. The differences in total cholesterol concentration suggest that the incidence of coronary heart disease may be 24% lower in lifelong British vegetarians and 57% lower in lifelong vegans than in meat eaters.

Adult↗

Social adversity, low birth weight, and preterm delivery.

A prospective study of 483 pregnant women was undertaken to examine possible associations of social and psychiatric factors with both low birth weight (less than 2500 g) and preterm delivery (less than 37 weeks' gestation). As few babies were born before term (n = 14) or with a low birth weight (n = 14) further analyses were conducted to investigate predictors of absolute birth weight and gestational age. Low income was found to be an independent predictor of birth weight when birth weight was treated both as a dichotomous and as a continuous variable. Unemployment was found to be associated with absolute birth weight. Although this effect was statistically accounted for by low income, a low income was frequently caused by unemployment. Smoking independently predicted absolute birth weight and tended to be associated with preterm delivery. None of the factors investigated was associated with gestational age. In contrast with previous findings, factors such as social class, adverse life events, and psychiatric state were not associated with birth outcome. The mechanism underlying the association between low income and low birth weight requires further investigation.

Female↗

Ovarian neoplasms, functional ovarian cysts, and oral contraceptives.

The incidence of ovarian neoplasms and functional ovarian cysts diagnosed at laparotomy or laparoscopy among the 17,000 women taking part in the Oxford Family Planning Association contraceptive study was investigated. Epithelial cancer of the ovary was only 25% as common among those who had ever taken oral contraceptives as those who had never done so (95% confidence interval 8% to 67%). There was little evidence of any important association between use of oral contraceptives and benign teratoma or cystadenoma. Functional cysts of the ovary occurred much less commonly in women who had recently (in the six months preceding diagnosis) taken combined oral contraceptives (but not in those who had taken progestogen only oral contraceptives) than in those who had never taken oral contraceptives or had taken them in the past. This protective effect was more pronounced for corpus luteum cysts (78% reduction; 95% confidence interval 47% to 93%) than for follicular cysts (49% reduction; 95% confidence interval 20% to 70%). It is estimated that about 28 (95% confidence interval 16 to 35) operations for functional ovarian cysts are avoided among every 100,000 women who take oral contraceptives each year.

Adult↗

Early oral contraceptive use and breast cancer: results of another case-control study.

We report the results of a case-control study of oral contraceptive use and breast cancer conducted in London, Oxford and Edinburgh between 1980 and 1984. One thousand one hundred and twenty-five women aged 16-64 years with newly diagnosed breast cancer and a like number of matched controls were interviewed and asked about their past due use of oral contraceptives (OCs). Among women aged 45 years or more at diagnosis there was no evidence of an association between OC use and breast cancer. Among the 351 pairs of women aged under 45 years at diagnosis there was a significantly elevated risk associated with increasing duration of use before first full term pregnancy (relative risk for 4+ years use versus never use = 2.6, 95% confidence limits, 1.3-5.4). Since this result is at variance with the findings in some other studies we have investigated the nature of this association with particular emphasis on possible bias, pill type and a latent effect.

Adolescent↗

Breast self examination and breast cancer stage at diagnosis.

The relationship between breast self examination (BSE) and breast cancer stage at diagnosis was examined in 616 women aged 15-59 years. Differences in tumour characteristics between those not practising BSE and those practising but not taught were small and inconstant. However, women who had both practised and had been taught BSE had more favourable tumours than the non-practising group. The difference was most marked in terms of tumour size and the involvement of axillary nodes. The proportions of women in the non-BSE and taught-BSE groups with each characteristic were respectively: size less than or equal to 2 cm 33% and 45%, T1 clinical stage 27% and 42%, and N0 pathological stage 37% and 50%. This advantage to taught-BSE women persisted after adjustment for the identified confounding factors of age, social class and oral contraceptive use. The likely impact on breast cancer mortality is difficult to assess, although the potential benefit of the lead time gained must not be ignored when assessing the costs and benefits of BSE.

Adolescent↗

Urinary tract infection in relation to diaphragm use and obesity.

We have examined factors influencing the rate of first referral to hospital for urinary tract infection among the 17,032 women taking part in the Oxford Family Planning Association contraceptive study. The risk of first referral declined with age, was higher in nulliparous women than in parous women, was higher in non-obese than in obese women and was higher in current users of the diaphragm than in current users of other methods or no method of contraception. The main increase in the risk of referral in current diaphragm users occurred during the first 24 months when overall rates were 2-3 times higher in users than in non-users or ex-users of the diaphragm. The negative association between hospital referral for urinary tract infection and obesity was unexpected. It was not explicable in terms of age, parity or diaphragm use. It may be that obese women are less likely to receive trauma to the genital area during sexual intercourse than non-obese women because adipose tissue offers them some protection. Another possibility is that increased oestrogenization in obese women, resulting from peripheral conversion of androstenedione to oestrone, has a beneficial effect on the bladder and urethra, thus reducing the liability to infection.

Adult↗

Long-term surveillance of mortality and cancer incidence in women receiving hormone replacement therapy.

This paper reports the preliminary results of a cohort study of 4544 British women receiving hormone replacement therapy (HRT). These women were recruited at 21 specialist menopause clinics around Britain. Up to the end of June 1983, the mean duration of HRT use per woman was 67 months of which, on average, 43% was 'opposed' use. In general, however, both the amount of progestogen given and the number of days per cycle for which it was given was less than would have been the case if the women had been receiving modern opposed therapy. The major focus of the study was to monitor mortality and cancer incidence in the cohort. The mortality results were broadly reassuring: overall mortality was significantly lower than expected on the basis of national rates (relative risk 0.58) and mortality ratios were below unity for all specific causes of death examined apart from cancer of the ovary (relative risk 1.43, 95% confidence limits 0.62-2.82) and suicide or suspected suicide (relative risk 2.53, 95% confidence limits 1.26-4.54). The most likely explanation for the latter finding is selection bias--thus at least 7 of the 11 women who died from suicide or suspected suicide had a psychiatric history before receiving HRT. The cancer incidence results were less reassuring, although they should be interpreted with some caution because cancer registry rates were used for comparative purposes. With this proviso, endometrial cancer risk was significantly elevated (relative risk 2.84, 95% confidence limits 1.46-4.96); many of the women concerned had taken therapy which was predominantly or entirely opposed although only one woman had received an opposed regimen which would now be considered adequately protective to the endometrium. Breast cancer incidence was also significantly increased (relative risk 1.59, 95% confidence limits 1.18-2.10); detailed analysis suggested that the use of unopposed ethinyl-oestradiol in particular might have undesirable effects on the breast.

Breast Neoplasms↗

Teenagers and their health.

Six hundred and forty three children aged 14 to 16, attending three upper schools in Oxfordshire, filled in a health questionnaire. Although over 90% rated their health as fair or good, three quarters had taken medicine in the previous four weeks, three quarters had complained of headaches, and three quarters had had dental fillings. In addition, a third drank alcohol at least once a week, a third felt depressed at least once a week, and a third had had time off school for illness in the previous four weeks. There were strong associations between smoking tobacco and other forms of drug abuse. On the positive side, most children felt responsible for their own health with three quarters agreeing that good health is mainly due to sensible living. Over 85% turned first to their parents for medical advice.

Adolescent↗

Chronic inflammatory bowel disease, cigarette smoking, and use of oral contraceptives: findings in a large cohort study of women of childbearing age.

Since the start in 1968 of the Oxford Family Planning Association contraceptive study 31 women have developed ulcerative colitis and 18 have developed Crohn's disease, giving incidences of 0.15 and 0.09/1000 woman years respectively. The incidence of ulcerative colitis in women who were non-smokers on entry to the study was 0.17/1000 woman years and the incidence in smokers was 0.11/1000 woman years. The findings for Crohn's disease were entirely different, the corresponding incidences being 0.05 and 0.17/1000 woman years respectively. Both ulcerative colitis and Crohn's disease were more common among women currently using oral contraceptives than among those not doing so. Incidences per 1000 woman years for ulcerative colitis were 0.26 in users and 0.11 in non-users; for Crohn's disease the incidences were 0.13 and 0.07 respectively. Though the association between the use of oral contraceptives and chronic inflammatory bowel disease cannot be regarded as established, the effects of smoking have been shown consistently in many studies. This observation provides an important clue to the aetiology of chronic inflammatory bowel disease.

Adult↗

Evaluation of peer intervention training for high school alcohol safety education.

A program of peer intervention in the drinking and driving of others compared with a conventional alcohol safety program in the high school setting. The peer intervention program led to significant increases in self-reported intervention behavior following completion of the course. The conventional alcohol safety program failed to produce changes in intervention behavior during this period. Both the peer intervention program and the conventional alcohol safety program led to significant knowledge gains. Neither program led to significant measured shifts in attitudes.

Accident Prevention↗