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Lindenstrom, E; Boysen, G; Nyboe, J
doi: 10.1136/bmj.309.6946.11pmid: 8044059
Abstract Objective: To estimate the influence of plasma total cholesterol, high density lipoprotein cholesterol, and triglycerides on risk of cerebrovascular disease. Design: The Copenhagen city heart study is a prospective observational survey with two cardiovascular examinations at five year intervals. Non- fasting plasma lipids were measured in participants once at each examination, along with other variables. The Cox regression model was used to establish the effect of the factors recorded on cerebrovascular events of mostly, but not exclusively, ischaemic origin. Subjects — 19 698 women and men at least 20 years old, randomly selected after age stratification from an area of central Copenhagen. Main outcome measures: Initial cases of stroke and transient ischaemic attack recorded from hospital records and death certificates from 1976 through 1988. Results: 660 non-haemorrhagic and 33 haemorrhagic events were recorded. Total cholesterol was positively associated with risk of non-haemorrhagic events, but only for levels >8 mmol/l, correspaonding to the upper 5% of the distribution in the study population. For lower plasma cholesterol values the relative risk remained nearly constant. Plasma triglyceride concentration was significantly, positively associated with risk of non- haemorrhagic events. The relative risk corresponding to an increase of 1 mmol/l was 1.12 (95% confidence interval 1.07 to 1.16). There was a negative, log linear association between high density lipoprotein cholesterol and risk of non-haemorrhagic events (0.53 (0.34 to 0.83)). There was no indication that the20effects of plasma lipids were different in women and men. Conclusions: The pattern of the association between plasma cholesterol and risk of ischaemic cerebrovascular disease was not log linear, and the increased risk was confined to the upper 5% of the cholesterol distribution. Further studies should concentrate on the association between plasma cholesterol and varified haemorrhagic stroke.
Penney, G C; Glasier, A; Templeton, A
doi: 10.1136/bmj.309.6946.15pmid: 8044060
Abstract Objectives: To assess and improve the quality of care provided to women undergoing induced abortion. Design — Two rounds of prospective, criterion based case note review audit. Setting: Ten NHS gynaecology units throughout Scotland. Subjects: 2004 patient episodes of abortion care identified consecutively during two rounds of audit. The first round comprised 967 cases and the second round 1037. Interventions: Dissemination of results from the first round of audit and recommendations for change20in the form of a written report and at postgraduate meetings in participating hospitals. Main outcome measures: Improvements in quality of care as assessed against 16 previously agreed criteria, both overall across the 10 study hospitals and within individual hospitals. Results: Overall, four significant improvements occurred: increased availability of early medical abortion, decreased utilisation of surgical abortion at very early gestation, increased use of mifepristone priming before second trimester medical abortion, and increased provision of follow up. At the individual hospital level 42 of 150 elements of care studied20were “close to optimal” at the time of the first round of audit, rising to 54 at the second round (NS). A total of 31 significant improvements in individual elements of care occurred, but 11 significant deteriorations also occurred (at the P<0.05 level). Conclusions: The prospective multicentre audit proved feasible aqnd achieved the aims of any form of audit in terms of identifying deficiencies and variations in care. The audit results promoted objective review of local abortion services in participating hospitals. At least for some elements of care in some hospitals significant improvements were detectable.
Bromwich, P; Cohen, J; Steward, I; Walker, A
doi: 10.1136/bmj.309.6946.19pmid: 8044061
Abstract Objective: To investigate a reported fall in sperm counts during 1940–90 in relation to the reduced lower reference value of “normal” during the same period by assuming the null hypothesis that no change had occurred in the probability distribution of the sperm concentration. Design: Analysis by using various mathematical models of the probaility distribution of sperm concentration together with experimental data which supported a model employing a logarithmic distribution. Subjects: 235 men presenting for stimulated in vitro fertilisation at Midland Fertility Services, Aldridge, in 1992 together with samples of 20 ejaculates from each of five men attending the same centre during 1992–3. Results: The effect of the change in lower reference value for the “normal” sperm concentration (from 60x109 to 20x109/l) depended on the probability distribution of the concentration in the population. If that distribution was normal or uniform, then very little of the reported decline was a consequence of the change in lower reference value. If it was heavily skewed, then most or all of the reported decline may have been a consequence of that change. The limited experimental data available indicate that the distribution was heavily skewed. Conclusions: Depending on the actual distribution of sperm concentration in the population, the reported decline in concentration may have been accounted for entirely or in part by the change in lower reference value. The original evidence does not support the hypothesis that the sperm count declined significantly between 1940 and 1990.
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