J.M. French

The incidence of thyroid disorders in the community: a twenty-year follow-up of the Whickham Survey

BACKGROUND AND OBJECTIVE The original Whlckham Survey documented the prevalence of thyroid disorders in a randomly selected sample of 2779 adults which matched the population of Great Britain in age, sex and social class. The aim of the twenty‐year follow‐up survey was to determine the Incidence and natural history of thyroid disease in this cohort.

Neurologic and neuropsychological morbidity following major surgery: comparison of coronary artery bypass and peripheral vascular surgery.

As part of a prospective study of the neurologic and neuropsychological complications of coronary artery bypass graft surgery, 312 patients were compared with a control group of 50 patients undergoing major surgery for peripheral vascular disease. The purpose of comparing the 2 groups was to determine to what extent neurologic complications after heart surgery can be attributed to cardiopulmonary bypass. The 2 groups were similar with respect to age, preoperative neurologic and intellectual status, anesthetic methods, duration of operation, perioperative complications, and time spent in the intensive therapy unit. Certain potential risk factors for cerebrovascular disease were more common in the control than the coronary bypass patients. The important difference between the 2 groups was that only the latter group underwent cardiopulmonary bypass. In this group 191 of 312 (61%) and 235 of 298 (79%), respectively, developed early neurologic and neuropsychological complications. By the time of hospital discharge 17% had neurologic disability and 38% had significant neuropsychological symptoms. In the control group 9 of 50 (18%) developed neurologic complications resulting largely from trauma to lower limb sensory nerves. Two patients developed primitive reflexes. Fifteen of 48 (31%) showed neuropsychological impairment on 1 or 2 subtest scores. Moderate or severe intellectual dysfunction was not seen in the control patients in contrast to the 24% thus affected in the coronary bypass group. The difference in frequency and severity of central nervous system complications between the 2 groups is likely to reflect cerebral injury resulting from cardiopulmonary bypass.

A double-blind controlled trial of long chain n-3 polyunsaturated fatty acids in the treatment of multiple sclerosis.

A trial of n-3 polyunsaturated fatty acids in the treatment of multiple sclerosis has been conducted over a 5 year period. Ambulant patients (312) with acute remitting disease were randomly allocated to treatment or placebo. Both groups were given dietary advice to increase the intake of n-6 polyunsaturated fatty acids and the treatment group in addition received capsules containing n-3 polyunsaturated fatty acids. Analysis of clinical outcome at the end of 2 years of treatment was made in terms of the duration, frequency and severity of relapses and the number of patients who had improved or remained unchanged. The results showed no significant difference at the usual 95% confidence limits but there was a trend in favour of the group treated with n-3 polyunsaturated fatty acids in all parameters examined.

Ignoring a Covariate: An Example of Simpson's Paradox

Abstract The possibility that the apparent direction of an association will be reversed when covariates are taken into account is well known, but many examples of this effect are rather contrived. A real example from an epidemiological survey is presented.

Increasing age, diabetes mellitus and recovery from stroke.

In a prospective study of 200 patients with acute stroke, blood glucose and glycated haemoglobin (HbA1) were measured within 72 hours of onset. Unrecognized hyperglycaemia as defined by a raised stable HbA1 more than two s.d. above the mean reference value and no previous history of diabetes was present in 27%. No correlation existed between patient age and admission blood glucose or HbA1 levels (r = 0.1). Cumulative mortality and recovery of limb function was assessed in the first 136 patients with carotid distribution events. Admission blood glucose greater than or equal to 8 mmol/l was shown to be associated with a significantly greater mortality at 4 and 12 weeks (P less than 0.05). Multivariate analysis with age, glucose, HbA1 as independent variables demonstrated that age was the only significant predictor for death at 4 weeks (P less than 0.05) but at 12 weeks both age and blood glucose were significant (P less than 0.05). In patients less than 65 years blood glucose was a significant predictor for death (P less than 0.05) but in patients less than or equal to 65 years HbA1 and not glucose was significantly (P less than 0.05). Patients greater than or equal to 65 years with HbA1 greater than or equal to 7.5% were significantly more likely to have a raised admission blood glucose. Hyperglycaemia on admission was not shown to influence recovery of limb function. Increasing age is of greatest importance in predicting mortality although blood glucose is of prognostic value especially in the young stroke patient.

Is bed rest useful after diagnostic lumbar puncture

A randomized study of 110 patients undergoing their first diagnostic lumbar puncture was performed to compare the effect of immediate mobilization with 4 hours bed rest on the incidence of post lumbar puncture headache. There was no difference between the mobile (n = 54) and bed rest (n = 56) groups in the incidence of post lumbar puncture headache (32% versus 31%, respectively). We conclude that bed rest following lumbar puncture may be an unnecessary imposition on the patient, as well as on nursing staff.

Hyperbaric oxygen and multiple sclerosis: final results of a placebo-controlled, double-blind trial.

The long term results are reported of a trial involving 120 patients with chronic multiple sclerosis who were randomised to receive either 100% oxygen at 2 atmospheres absolute (ATA) for 90 minutes daily for 20 sessions or placebo therapy with air using a simulated compression procedure. The previous finding of subjective improvement in bowel/bladder function at the end of treatment was not confirmed by objective urodynamic assessment. The treatment did not alter disease progression as measured by the Kurtzke disability status scale nor did it alter the rate of acute relapse. There was less deterioration in cerebellar function at one year in the treated patients as measured by the Kurtzke functional systems scale. No other differences were found between the two groups. Psychometric tests and measurements of lymphocyte sub-populations showed no treatment related effects. Evoked potential studies showed no improvements but there was a significant reduction in amplitude of the visual evoked potential in the treated patients at the end of therapy. This might indicate a reversible degree of retinal damage induced by oxygen toxicity.

The Incidence of Diabetes Mellitus in an English Community: A 20‐year Follow‐up of the Whickham Survey

The original Whickham Survey documented the prevalence of diabetes and lipid disorders in a sample of 2779 adults aged 18 years and over, which matched the British population structure. The aim of the 20‐year follow‐up study was to determine the incidence and natural history of diabetes. Outcomes in terms of morbidity and mortality at follow‐up were determined in over 97 % of the original population. Ninety‐four subjects had been identified and treated for diabetes since the first survey, including 17 subjects identified as having a fasting plasma glucose ≥7.8 mmol l−1 at follow‐up. The incidence of diabetes for the total population was 2.2 1000−1 year−1 (95 % confidence interval 1.8, 2.6). The risk factors identified at first survey were corrected for age, cut‐off at the 95 centile and entered into a log linear model. Those which strongly predicted development of diabetes in the total population were fasting blood glucose (odds ratio (OR) (with 95 % confidence intervals) =2.3 (1.5, 3.5)) and body mass index (OR = 2.2 (1.5, 3.3)) in men, and fasting blood glucose (OR = 2.6 (1.7, 4.1)) and fasting serum triglyceride (OR = 2.8 (1.8, 4.4)) in women. A logit model has enabled the calculation of the probability of developing diabetes 20 years later. It was the characteristics of becoming older such as obesity, hypertriglyceridaemia, and raised fasting blood glucose, rather than age itself, which were associated with the development of diabetes.

Description and validation of a Markov model of survival for individuals free of cardiovascular disease that uses Framingham risk factors

BackgroundEstimation of cardiovascular disease risk is increasingly used to inform decisions on interventions, such as the use of antihypertensives and statins, or to communicate the risks of smoking. Crude 10-year cardiovascular disease risk risks may not give a realistic view of the likely impact of an intervention over a lifetime and will underestimate of the risks of smoking. A validated model of survival to act as a decision aid in the consultation may help to address these problems. This study aims to describe the development of such a model for use with people free of cardiovascular disease and evaluates its accuracy against data from a United Kingdom cohort.MethodsA Markov cycle tree evaluated using cohort simulation was developed utilizing Framingham estimates of cardiovascular risk, 1998 United Kingdom mortality data, the relative risk for smoking related non-cardiovascular disease risk and changes in systolic blood pressure and serum total cholesterol total cholesterol with age. The models estimates of survival at 20 years for 1391 members of the Whickham survey cohort between the ages of 35 and 65 were compared with the observed survival at 20-year follow-up.ResultsThe model estimate for survival was 75% and the observed survival was 75.4%. The correlation between estimated and observed survival was 0.933 over 39 subgroups of the cohort stratified by estimated survival, 0.992 for the seven 5-year age bands from 35 to 64, 0.936 for the ten 10 mmHg systolic blood pressure bands between 100 mmHg and 200 mmHg, and 0.693 for the fifteen 0.5 mmol/l total cholesterol bands between 3.0 and 10.0 mmol/l. The model significantly underestimated mortality in those people with a systolic blood pressure greater than or equal to 180 mmHg (p = 0.006).The average gain in life expectancy from the elimination of cardiovascular disease risk as a cause of death was 4.0 years for all the 35 year-old men in the sample (n = 24), and 1.8 years for all the 35 year-old women in the sample (n = 32).ConclusionsThis model accurately estimates 20-year survival in subjects from the Whickham cohort with a systolic blood pressure below 180 mmHg.

Diabetes mellitus and early mortality from stroke

3 Panush RS, Delafuente JC. Vitamins and immunocompetence. World Rev NutrDiet 1985;45:96-132. 4 Goodwin JS, Garrv PJ. Relationship between megadose vitamin supplementation and immunological function in a healthy elderly population. Clin ExpImmunol 1983;51:647-53. 5 Buzina R. The impact of marginal malntitrition on health and behaviour. In: Aebi HE, ed. Problems int nzutrition research todav. Orlando, Fla: Academic Press, 1981:57-74 6 McMurray DN, Loomis SA, Casazza LJ, Rev H. Miranda R. Development of impaired cell-mediated immunuts in mild and moderate malnutrition. Am7 Clin.Niar 198134:68-77. 7 Micksche M? Cerni C, Kokron 0, iitscher R, Wrba H. Stimulation of immune response in lung cancer patients by sitamin A therapy. Oncology 197734:234-8-