Blood lipid concentrations and other cardiovascular risk factors: distribution, prevalence, and detection in Britain

Effect on plasma lipid levels of different classes of mutations in the low-density lipoprotein receptor gene in patients with familial hypercholesterolemia

We used the single-strand conformational polymorphism method to screen 311 patients with familial hypercholesterolemia from London lipid clinics and Southampton and South West Hampshire health district for mutations in the 3' part of exon 4 of the low-density lipoprotein (LDL) receptor gene. This part of the gene codes for repeat 5 of the binding domain of the LDL receptor, which is known to be critical for the receptor-mediated removal of both triglyceride-rich lipoprotein remnants and LDL. Six previously described mutations were identified in 29 apparently unrelated individuals (9.3%), with the mutations all lying within a 50-bp fragment of the gene. Three of the mutations are null alleles producing no protein, and the other three lead to production of a defective protein. The effect of the different gene mutations on lipid levels was examined, after the data were combined with information on previously reported mutations in this patient group. Mean LDL cholesterol levels were highest in those individuals with a mutation creating a null allele (9.54 mmol/L) and were similar to levels in those individuals with a mutation affecting repeat 5 that resulted in the production of a defective protein (9.37 mmol/L). In this sample, previously identified patients with a defective protein mutation outside repeat 5 had lower mean levels of LDL cholesterol (7.78 mmol/L), which were similar to levels seen in patients in whom the specific mutation had not been identified (7.31 mmol/L). Overall, these differences were highly statistically significant (P < .001).(ABSTRACT TRUNCATED AT 250 WORDS)

Using cost-effectiveness analysis for formulary decision making: from theory into practice

The growth of expenditures on healthcare and pharmaceutical products is a concern to third-party payers because of the absence of market discipline (price signals that consumers face). Cost-effectiveness analysis is a method that allows third-party payers to systematically make judgements about the 'value for money' of these products. It moves beyond simple unit price comparisons of alternate interventions/products to consider the full stream of relevant cost and benefits. As formulary committees begin to adopt the systematic use of cost-effectiveness analyses to inform the debate, the exercise will move from an academic to a more practical application. This transition will require several important changes including defining the purpose of cost-effectiveness analysis, measurement of outcomes and data, format of reports, and contractual arrangements between the pharmaceutical industry and analysts. As more 'real world' experience is gained in the practical application of cost-effectiveness analysis, the quality of data will improve as will its value as an aid to decision making.

Serum lipid and apolipoprotein distributions in Hong Kong Chinese

STUDY OBJECTIVE

The aim was to describe the distribution of lipids and apolipoproteins in the Chinese population in Hong Kong.

DESIGN

This was a prospective, cross sectional, population based survey.

SETTINGS

The study was conducted in a single, self referred, out patient screening centre.

PARTICIPANTS

Altogether 825 Chinese adults aged > or = 20 years were screened. One hundred subjects who had previously had lipid measurement and 29 who were taking lipid modifying drugs were excluded but 289 men and 407 women remained for further analysis.

MAIN RESULTS

Age standardised mean (SEM) lipids concentrations for Hong Kong Chinese were total cholesterol: men, 5.48 (0.05) mmol/l and women, 5.46 (0.06) mmol/l; triglycerides: men, 1.22 (1.03) mmol/l and women, 1.00 (1.03) mmol/l; high density lipoprotein (HDL) cholesterol: men, 1.25 (0.02) mmol/l and women, 1.42 (0.02) mmol/l; low density lipoprotein (LDL) cholesterol: men, 3.56 (0.05) mmol/l and women, 3.50 (0.06) mmol/l; apolipoprotein A-I (apo A-I): men, 1.34 (0.01) g/l and women, 1.46 (0.01) g/l; and apolipoprotein B (apo B): men, 1.15 (0.02) g/l and women, 1.06 (0.02) g/l. The total to HDL cholesterol ratios were men, 4.62 (0.07) and women, 4.10 (0.08); and apo B to apo A-I ratios (apo B/A) were men, 0.88 (0.02) and women, 0.75 (0.02). While levels of total cholesterol, LDL cholesterol, apo B, triglycerides, total/HDL cholesterol, and apo B/A were positively associated with age in both sexes and were higher in men before the age 50-59 years, they rose steeply thereafter in women to cross over the levels in men. In contrast, HDL cholesterol decreased with age while apo A-I remained constant, and both were consistently higher in women than in men in all age groups.

CONCLUSIONS

Hong Kong Chinese have attained lipid profiles similar to those in other developed western populations. Environmental factors seem influential in this regard. Faced with the increasing coronary mortality of recent years, there should be a major effort to reduce the cholesterol concentrations in this population.

Hypercholesterolemia in bulimia nervosa

Patients with bulimia nervosa may present with serum cholesterol levels higher than the recommended range. Giving advice on dietary modification to reduce cholesterol levels runs contrary to the cognitive behavioral strategies used to treat bulimia nervosa. This would not be a problem if it were found that cholesterol levels fell with clinical improvement in the eating disorder.

Health-based reference values of the Mini-Finland Health Survey: 2. Cholesterol in total serum and in different lipoprotein fractions

The reference values for cholesterol concentrations in the whole serum and in its VLDL, LDL and HDL fractions have been produced based on the data obtained in the Mini-Finland Health Survey. The lipoprotein fractions were separated with ultracentrifugation. The aim was to obtain reference values for the apparently healthy, ambulatory population. Two health-derived criteria were used to select subjects for reference populations: those based on the literature available and those based on the recommendations published by the Committee on Reference Values of the Scandinavian Society for Clinical Chemistry and Clinical Physiology, with slight modifications. The 95% inner reference intervals of total serum cholesterol in all the subjects and in the two selection groups were 4.2-9.0, 4.2-8.4, and 4.2-8.5 mmol l-1 for men, and 4.2-9.4, 4.1-8.6, and 4.2-9.0 mmol l-1 for women, respectively. The corresponding medians were 6.3, 6.2 and 6.2 mmol l-1 in men, and 6.4, 6.0 and 6.1 mmol l-1 in women, respectively. Frequency distribution curves showed clear skewness to the right in VLDL cholesterol and slight skewness in LDL and HDL cholesterol. In women there was a clear rise in total, VLDL and LDL cholesterol after the early middle age, whereas HDL cholesterol was lower in the older age groups. In men the age dependency was not as prominent; total cholesterol levels showed lower levels in older men. Of the background lifestyle factors alcohol consumption, smoking, obesity and physical exercise had negligible associations with total, VLDL, LDL and HDL cholesterol reference intervals.

Relative risk of factors for coronary heart disease in population with low cholesterol levels

We studied the odds ratios of seven leading risk variables in a population essentially having a 'low' cholesterol concentration. In a cross-sectional population-based study of 3689 Turkish adults 20 years of age or over, 90 men and 83 women were diagnosed to have definite or suspected coronary heart disease. The criteria were based on history, cardiovascular examination and on Minnesota coding of electrocardiograms. Potential risk factors studied were: plasma total cholesterol (> or = 240 mg/dl), fasting triglycerides (> or = 200 mg/dl), diabetes mellitus, hypertension (asystolic > or = 160 mmHg, diastolic > or = 95 mmHg, or both, or subjects reporting to take antihypertensive medication), smoking currently or in the past, obesity (body mass index > or = 30 kg/m2), and physical inactivity. Hypertension and lack of physical exercise constituted the most important risk factors in both sexes being valid for all age groups and having high attributable risks; odds ratios in men and women, respectively, were 3.16 and 2.6 for hypertension, and 2.16 and 3.49 for physical inactivity. Hypertriglyceridemia followed these factors in men with an odds ratio of 2.15. In women an additional significant factor was obesity (odds ratio 1.76), while diabetes and hypercholesterolemia revealed to be significant only in those aged 20-59 years, and smoking in women aged 30-59 years. Among men, smoking was a borderline significant risk factor for coronary disease, whereas hypercholesterolemia did not prove to be so. These findings, somewhat at variance with those of industrialized nations, may have significance for policy of cardiovascular disease prevention in third-world populations.

Risk factors for acute myocardial infarction in a southern Chinese population

Although the mortality rate from coronary artery disease in Hong Kong is only one-fourth of that of northern Europe and the United States, the disease has been and remains the second major cause of death (after all cancers combined). Beginning in 1987, we have conducted a case-control study of acute myocardial infarction in four Hong Kong hospitals. This study, one of the biggest case-control studies conducted in the Chinese population of both men and women, confirms the importance of several risk factors--cigarette smoking, history of hypertension, history of diabetes, body fatness, and lack of physical activity--previously described in data collected in western populations. In addition, more adverse childhood experience was also found to be an important risk factor of acute myocardial infarction. Further research in appropriate intervention measures in education in the prevention and cessation of smoking, the control of blood pressure, diabetes, and overweight, and adequate exercise could significantly help reduce the risk of acute myocardial infarction in the Hong Kong Chinese population.

Garlic as a lipid lowering agent--a meta-analysis

Garlic supplements may have an important role to play in the treatment of hypercholesterolaemia. To determine the effect of garlic on serum lipids and lipoproteins relative to placebo and other lipid lowering agents, a systematic review, including meta-analysis, was undertaken of published and unpublished randomised controlled trials of garlic preparations of at least four weeks' duration. Studies were identified by a search of MEDLINE and the ALTERNATIVE MEDICINE electronic databases, from references listed in primary and review articles, and through direct contact with garlic manufacturers. Sixteen trials, with data from 952 subjects, were included in the analyses. Many of the trials had methodological shortcomings. The pooled mean difference in the absolute change (from baseline to final measurement in mmol/l) of total serum cholesterol, triglycerides, and high-density lipoprotein (HDL)-cholesterol was compared between subjects treated with garlic therapy against those treated with placebo or other agents. The mean difference in reduction of total cholesterol between garlic-treated subjects and those receiving placebo (or avoiding garlic in their diet) was -0.77 mmol/l (95% CI: -0.65, -0.89 mmol/l). These changes represent a 12% reduction with garlic therapy beyond the final levels achieved with placebo alone. The reduction was evident after one month of therapy and persisted for at least six months. In the dried garlic powders, in which the allicin content is standardised, there was no significant difference in the size of the reduction across the dose range of 600-900 mg daily. Dried garlic powder preparations also significantly lowered serum triglyceride by 0.31 mmol/l compared to placebo (95% CI: -0.14, -0.49).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiovascular risk in adult Melbourne Chinese

Chinese migrants have low cardiovascular mortality, particularly in their first 10 years of residence in Australia. The apparent increase in cardiovascular deaths among Asian migrants who have lived in Australia for more than 10 years suggests that cardiovascular risk transition may occur soon after migration. In this descriptive study, we found that Melbourne Chinese were not low in cardiovascular risk factors as usually defined. The prevalence of hyperlipidaemia (7.7 per cent for men and 5.2 per cent for women) was similar to the prevalence for other Australians (6.8 per cent for men and 4.4 per cent for women). In spite of low mean blood pressure (systolic blood pressure 114 +/- 23 mmHg (mean +/- standard deviation) and diastolic blood pressure 67.3 +/- 10.6 mmHg), Melbourne Chinese women were hypertensive as often as their Australian counterparts. The prevalence of cigarette smoking in men (26.9 per cent) was also comparable to prevalence for Australian males (24.1 per cent). Being slim is the only recognised cardiovascular protection that Melbourne Chinese may have. A high waist-to-hip ratio (0.91 +/- 0.054 for men and 0.88 +/- 0.077 for women), however, may outweigh the potential benefit of lower prevalence of overweight (17.7 per cent for men and 14.1 per cent for women). Melbourne Chinese men had a multiple risk-factor profile similar to their Australian counterparts. Differences in multiple risk factors in women were attributable to fewer Chinese women having a single risk factor (15.4 per cent versus 30.1 per cent).(ABSTRACT TRUNCATED AT 250 WORDS)

Growth hormone treatment improves serum lipids and lipoproteins in adults with growth hormone deficiency

The effects of 6 months' treatment with recombinant human growth hormone (rhGH) on serum lipids and lipoproteins were assessed in 24 adult patients with GH deficiency in a double-blind, placebo-controlled trial. Compared with age-, weight-, and sex-matched controls, the patients had significantly higher serum concentrations of total cholesterol (P = .002), low-density lipoprotein (LDL) cholesterol (P < .001), apolipoprotein B ([apoB] P = .011), and triglyceride (P = .017), and lower concentrations of high-density lipoprotein (HDL) cholesterol (P < .001). The prevalence of elevated serum cholesterol, triglyceride, LDL cholesterol, and apo B levels was 39%, 26%, 39%, and 25%, respectively; 75% of patients had decreased concentrations of HDL cholesterol. Treatment with rhGH (0.07 U/kg daily) resulted in decreases in total cholesterol level (5.8 +/- 0.3 to 5.1 +/- 0.3 mmol.L-1 over 6 months; P = .01 compared with placebo), LDL cholesterol level (4.22 +/- 0.25 to 3.19 +/- 0.23 mmol.L-1; P = .0003), LDL:HDL cholesterol ratio (5.57 +/- 0.47 to 3.29 +/- 0.33; P = .03), apo B level (1.07 +/- 0.06 to 0.84 +/- 0.07 g.L-1; P = .003), and apo B: A-1 ratio (0.73 +/- 0.05 to 0.69 +/- 0.05; P = .01). HDL cholesterol and apo A-1 levels did not change following rhGH treatment. The changes in lipid and lipoprotein levels were not significantly related to changes in insulin, thyroid hormones, insulin-like growth factor-1 (IGF-1), or indices of adiposity.(ABSTRACT TRUNCATED AT 250 WORDS)

Breast cancer prevention through modulation of endogenous hormones

The use of exogenous sex-steroids for hormonal contraception is important to the way of life of many modern women. The widespread use of hormonal contraceptives represents a unique opportunity to have a substantial positive impact on women's health. The observation that users of oral combination type contraceptives have a reduced risk of ovarian cancer should encourage the extension of contraceptive development to address the most important malignancy facing modern women, breast cancer. Epidemiological evidence strongly suggests that both estrogens and progestogens contribute to breast cancer risk, and account for the steep rise in risk seen during the premenopausal years. Studies of normal breast epithelial cell proliferation confirm that progestogens are breast mitogens, and explain why current contraceptives, which are progestogen dominant, do not prevent breast cancer. A long-acting depot contraceptive can be developed which releases: 1) an agonist of gonadotropin releasing hormone to suppress ovarian function; and 2) sex-steroids at doses below those in current contraceptives, and below those associated with ovulation. Such a contraceptive should provide substantial life-time protection against both breast and ovarian cancer, and would retain many of the other health benefits of current contraceptives.

Metabolic and clinical characteristics of south Asians and Europeans in Coventry

A house to house survey in Foleshill, Coventry, compared risk factors for Type 2 diabetes and ischaemic heart disease (IHD) among adult United Kingdom Europeans (n = 5508, 64% screened) and South Asians (n = 4395, 84% screened). Those with a high glucose and a randomized 10% of others had a glucose tolerance test while those with previously diagnosed diabetes (104 Europeans, 223 South Asians) were re-interviewed in more detail. By the age of 29 years, South Asians had higher 2 h glucose 5.4 +/- 1.0 vs 4.84 +/- 1.2 mmol l-1, p < 0.005) and insulin (45.6 vs 23.8 mU l-1, p < 0.001) concentrations and in males, a higher cholesterol concentration (5.1 +/- 0.9 vs 4.6 +/- 1.2 mmol l-1, p < 0.05). South Asians with known Type 2 diabetes had an earlier age at diagnosis (48 +/- 11 vs 57 +/- 14 years, p < 0.001), a lower body mass index in the past (29.0 +/- 4.8 vs 32.1 +/- 6.9 kg m-2, p < 0.001) and currently (27.1 +/- 3.7 vs 29.1 +/- 6.4 kg m-2, p < 0.001), were more likely to present with acute symptoms, were less likely to attend the hospital clinic (14% vs 31%, p < 0.001), and were less likely to be treated with diet alone (14% vs 21%) or with insulin (9% vs 16%) than Europeans. Glycaemic control was similar in the two ethnic groups. These findings suggest an earlier onset of the disease processes involved in diabetes in South Asians. Important ethnic differences in patterns of care exist that make clinical comparisons difficult.

Predicting the uptake of health checks in general practice: invitation methods and patients' health beliefs

General practice is in an ideal position to encourage people to adopt healthier lifestyles. One way in which this might be achieved is through the offering of health checks. This paper sought to identify some of the factors which may be important in predicting the uptake of health checks. These were seen to fall into two broad areas--the way in which patients are invited and patients' health beliefs. For the purposes of the study, 299 middle-aged male patients registered at a single practice were randomly allocated to be invited to a health check via two invitation methods. In the first, patients were sent an invitation letter with an appointment. In the second patients' notes were tagged so that they could be invited opportunistically by their GP. After one year, 63.5% of patients invited opportunistically had attended a health check compared with 61.2% of patients sent an invitation letter. However, only 51.6% of the opportunistic group had been invited after one year, meaning that the letter invitation method produced twice as many patients at the health check over the same period of time. Examination of health belief questionnaires sent to patients prior to the commencement of the health checks (50.2% response rate) indicated that attenders had a stronger initial intention to attend and placed a greater value on their health. More detailed analysis revealed intention to show strong relationships with beliefs about the benefits of, and barriers to, attendance at a health check. These results suggest that in order to increase uptake of health checks letter invitations need to be employed.(ABSTRACT TRUNCATED AT 250 WORDS)

Lipoprotein compositional abnormalities and insulin resistance in type II diabetic patients with mild hyperlipidemia

Lipoprotein composition was determined using ultracentrifugation in 20 non-insulin-dependent (NIDDM) diabetic patients on diet only (D), 20 NIDDM patients on diet and sulfonylurea therapy (T), and 20 nondiabetic control subjects (C), all of whom had total plasma cholesterol concentrations < 6.5 mmol/L and total plasma triglyceride concentrations < 3.0 mmol/L. Although the groups were well matched for age, body mass index, total triglyceride levels, and total cholesterol concentrations, there were significant compositional abnormalities in the low-density lipoprotein (LDL) fractions of diabetic subjects. The LDL total lipid to apolipoprotein B weight ratio (representing the density distributions of LDL particles) was reduced in both diabetic groups: 3.75 +/- 0.3, 3.50 +/- 0.28, and 3.54 +/- 0.22 in C, D, and T groups, respectively (mean +/- SD; P < .05). This was associated with a significant shift in the hydrated density distributions of LDL in the diabetic groups, with the average peak densities being 1.0320 g/mL (in C), 1.0365 g/mL (in D), and 1.0380 g/mL (in T) (P < .05). The LDL particles were also smaller in the NIDDM patients: 21.1 +/- 0.7, 20.4 +/- 0.5, and 20.6 +/- 0.5 nm in C, D, and T groups, respectively (P < .05). When the NIDDM groups were analyzed together, the LDL peak density was found to correlate with both insulin resistance (measured by a modified Harano technique; r = 0.37, P < .015) and total triglyceride concentrations (r = 0.40, P < .01). The results show that diabetic patients have small, dense LDL particles, which may be related to insulin resistance, and that these occur with minimal elevations of total triglyceride concentrations. These potentially atherogenic changes may contribute to the increased coronary heart disease in diabetic patients with mild hyperlipidemia.

Effectiveness of programme for reducing cardiovascular risk for men in one general practice

OBJECTIVES

To assess the effectiveness of a programme for reducing cardiovascular risk in men in terms of clinical measurements and perceptions of patients.

DESIGN

Collection of paired data on men attending well person clinics over three to five years. Questionnaire to determine changes in risk related habits.

SETTING

Well person clinics in rural general practice with five partners in mid-Wales.

SUBJECTS

The first 687 men seen in the clinic: analysable data obtained on 520. Initial age range 28-60 years.

MAIN OUTCOME MEASURES

Analysis of serum cholesterol concentration (mmol/l) and blood pressure (mm Hg). Changes in diet, exercise, smoking, and drinking.

RESULTS

Mean (SD) cholesterol concentration for all subjects increased from 5.8 (1.0) to 6.0 (1.0), p < 0.001. Overall percentage of ideal weight and mean systolic blood pressure also increased. Mean diastolic blood pressure was unchanged at 84 mm Hg. Professed dietary change, age, and number of visits all had significant effects on final cholesterol concentration. Those seen more often showed a significant decrease in cholesterol concentrations (in those seen more than twice mean (SD) initial value 6.7 (0.9) mmol/l v final value 6.5 (1.0) mmol/l, p < 0.001). Those over 45 years at start of study showed a significant decrease in diastolic blood pressure (mean (SD) initial value 89 (9) mm Hg v final value 86 (7) mm Hg, p < 0.001).

CONCLUSIONS

These clinics are not effective in achieving a reduction in mean cholesterol concentration or blood pressure, despite evidence that the message of reduction in risk had been successfully transmitted. Success was achieved in older patients and those in whom a definite problem was identified. Identification of high risk groups and clinical case finding with appropriate long term follow up may be more cost effective in reducing cardiovascular risk than non-specific screening of the whole population.

The relationship between serum cholesterol and serum thyroid hormones in male patients with suspected hypothyroidism

The relationship between serum cholesterol, thyrotropin, thyroxine and triiodothyronine was investigated in 456 male patients with suspected hypothyroidism. The correlation between serum cholesterol and serum thyroxine (r = 0.0572) and between serum cholesterol and serum triiodothyronine (r = 0.1136) were not significant but the correlation between serum cholesterol and TSH (r = 0.0376) was significant (P < 0.001). The mean serum cholesterol was only significantly increased in the patient groups with a serum TSH greater than 20 mU/L. In 26 patients treated for hypothyroidism with thyroxine replacement there was a significant correlation between the decrease in serum cholesterol and the decrease in serum TSH (r = 0.5334, P < 0.01) but there was poor correlation between the decrease in cholesterol and either the increase in serum triiodothyronine or the increase in serum thyroxine.

Ethnic differences in risk markers for heart disease in Bradford and implications for preventive strategies

OBJECTIVES

To assess and compare the prevalence of established risk markers for ischaemic heart disease in a sample of Asian and non-Asian men and to relate these observations to preventive strategies.

SETTING

Two factories in the textile industry in Bradford, West Yorkshire, UK. Subjects--288 male manual workers aged 20 to 65 years.

DESIGN

Cross sectional study within one occupational/social class stratum.

MEASUREMENTS AND MAIN RESULTS

Age, body mass index, plasma lipids, fibrinogen and serum insulin values, blood pressure, smoking habits, alcohol consumption, and exercise routines were recorded. Plasma total cholesterol concentrations were significantly lower in Asian than non-Asian men (5.3 mmol/l v 5.8 mmol/l respectively, p < 0.0001), as were low density lipoprotein cholesterol concentrations (3.4 mmol/l v 3.7 mmol/l, p = 0.0150), and high density lipoprotein (HDL) cholesterol (1.1 mmol/l v 1.3 mmol/l, p < 0.0001). Hypercholesterolaemia (concentration > 6.5mM) was present in nearly one quarter of non-Asians but less than one eighth of Asian men. Triglyceride values were not significantly higher in Asians. Smoking rates were high in non-Asians (43.8%) and only slightly lower in Asians (39.1%). Asian smokers smoked fewer cigarettes per day on average (9.3 v 16.1, p = 0.0001). Almost a quarter of non-Asian men (23.1%) and 26.6% of Asian men had raised blood pressure. Systolic pressures were higher in non-Asian men (138.3 mmHg v 133.0 mmHg, p = 0.0070), but diastolic pressures showed no ethnic differences. Diabetes was more prevalent in Asian men (10.9% v 4.4% p < 0.05), who also showed higher serum insulin concentrations after glucose loading (22.3 mU/l v 10.2 mU/l, p < 0.0001). Plasma fibrinogen values were higher in non-Asian men (2.9 g/l v 2.6 g/l, p < 0.0001) and these were associated with smoking. Nearly all non-Asians (92.5%) consumed alcohol at some time whereas 62.5% of Asians habitually abstained from alcohol consumption. Among the drinkers, non-Asian men consumed on average, 23.9 units per week and Asian men 18.4 units per week (p = 0.083). The mean body mass index for Asian men was 24.5 kg/m2 which was not significantly different to the mean in non-Asian men (25.2 kg/m2). The frequency of exercise in leisure time was low in both groups with 44.4% of non-Asian and 21.1% of Asian men taking moderate exercise weekly, and even fewer, regular strenuous exercise (16.3% and 8.6% respectively).

CONCLUSIONS

The plasma cholesterol and fibrinogen concentrations, prevalence of hypertension, smoking habits, alcohol intakes, and infrequency of exercise in leisure time in these non-Asian men in Bradford were consistent with an increased risk of heart disease. The pattern of risk markers was clearly different in Asian men. Only their lower HDL cholesterol concentrations, marginally higher triglyceride values, higher prevalence of diabetes, and very low frequency of exercise in leisure time would be consistent with a higher risk of heart disease compared with non-Asians. The implications of these observations for heart disease preventive strategies are discussed.

Hypoalphalipoproteinaemia and polymorphisms associated with reduced expression of the apolipoprotein A-I gene and resolution of disputed paternity in a large English family

A Pst-I RFLP polymorphism adjacent to the 3' end of the apolipoprotein A-I gene is reported to associate with hypoalphalipoproteinaemia with dominant inheritance in families identified through accelerated coronary heart disease. This association was not apparent in a large English family identified through voluntary health screening, and with no evident premature coronary disease. Any association could, however, be masked by sex, or by further undetermined variation affecting Pst-I restriction sites. Analysis of this and other polymorphisms present also led to resolution both of disputed paternity and of a long-standing family feud.

Is diabetes mellitus related to undernutrition in rural Tanzania?

OBJECTIVE

To investigate the relation between undernutrition and diabetes.

DESIGN

Survey of glucose tolerance in rural Tanzania.

SETTING

Eight villages in three widely separated regions of Tanzania.

SUBJECTS

8581 people aged 15 and above: 3705 men and 4876 women.

MAIN OUTCOME MEASURES

Oral glucose tolerance, body mass index, height, and low haemoglobin and cholesterol concentrations.

RESULTS

In the eight villages 42.7-56.9% of all men and 30.0-45.2% of all women had a body mass index below 20 kg/m2; the lowest quintile was 18.2 kg/m2 in men and 18.6 kg/m2 in women. The prevalence of diabetes did not change significantly from the lowest to the highest fifths of body mass index in men (lowest 1.6% (95% confidence interval 0.8% to 2.9%) v highest 1.3% (0.7% to 2.5%)) or women (1.1% (0.6% to 2.1%) v 0.5% (0.2% to 1.2%)). In men and in women prevalence of impaired glucose tolerance was greater in the lowest fifths of height (8.2% (6.3% to 10.6%), and 11.1% (9.2% to 13.3%)) respectively and body mass index (9.6% (7.5% to 12.1%), and 8.4% (6.7% to 10.5%)) than in the highest fifths (impaired glucose tolerance 4.7% (3.4% to 6.5%); and 5.1% (3.9% to 6.7%); body mass index 5.1% (3.7% to 7.0%), and 7.7% (6.2% to 9.6%).

CONCLUSION

Rates of diabetes were not significantly associated with low body mass index or height, but overall rates were much lower than those in well nourished Western populations. Increased impaired glucose tolerance in the most malnourished people may reflect the larger glucose load per kilogram weight. The role of undernutrition in the aetiology of diabetes must be questioned.

Plasma lipids and their interrelationship in Turkish adults

STUDY OBJECTIVE

The aim was to describe the plasma total cholesterol and triglyceride profiles in a random sample of Turkish adults and analyse the effects of certain coronary risk factors on these levels.

DESIGN

This was a cross sectional population based survey.

SETTING

59 communities scattered in all seven geographical regions of Turkey were surveyed in the summer of 1990.

SUBJECTS

A random sample of 3689 men and women 20 years of age and over was studied.

MEASUREMENTS AND MAIN RESULTS

Plasma total cholesterol, triglycerides, glucose (using Reflotron and with partial validation in reference laboratory), weight, height, and blood pressure were measured, and information on smoking, physical activity, and family income obtained. Hypercholesterolaemia (> or = 6.5 mmol/litre, 250 mg/dl) prevailed in 8.5%, and hypertriglyceridaemia (> 2.25 mmol/litre, 200 mg/dl) in 16.6% among men and women aged 40-59 years of age. Age adjusted total cholesterol values were 4.8 mmol/litre (185 mg/dl) in men and 5 mmol/litre (192 mg/dl) in women. A steep rise appeared in mean cholesterol levels between the ages of 20-29 and 40-49 years, in a ratio greater than the available data from some other populations indicated. Mean total cholesterol values increased substantially in both genders with diminishing grades of physical activity, rising serum triglyceride levels, in urban (opposed to rural) residents, in men with increasing income levels, and in the younger adults with rising body mass index.

CONCLUSIONS

Turkish adults have comparatively low levels of total cholesterol and medium to moderately high levels of triglycerides. Lifestyle factors affect these levels in Turks as in other populations.

Risk factors for coronary heart disease: a study in inner London

A survey was carried out among 281 men and women aged between 30 and 64 years randomly selected from five general practices located in the inner London borough of Tower Hamlets, to determine the prevalence of risk factors for coronary heart disease. Smoking and obesity were both more pronounced in Tower Hamlets than in comparable national studies: 51% of men and 44% of women were smokers and 57% of these were smoking 20 or more cigarettes per day. A body mass index of 30 or more was present in 18% of men and 10% of women and a body mass index of 25 or more in 71% of men and 49% of women. Two or more risk factors for coronary heart disease (smoking and/or hypertension and/or raised cholesterol levels) were present in 25% of men and 22% of women. For every person known by their general practitioner to have established cardiovascular disease, there were an additional two people also at risk on the basis of multiple risk factors. In this inner city population the prevalence of cardiovascular risk, for women as well as men, has major resource and organizational implications for primary care. A strategy for change requires action based on graded multiple risks for both men and women.

Choosing the preventive workload in general practice: practical application of the Coronary Prevention Group guidelines and Dundee coronary risk-disk

OBJECTIVE

To determine the workload implications for general practice of the Coronary Prevention Group and British Heart Foundation action plan for preventing heart disease.

DESIGN

Computer simulation of plan, including calculation of Dundee risk scores, with data from OXCHECK trial.

SUBJECTS

4759 patients aged 35-64 who had health checks during 1989-91.

MAIN OUTCOME MEASURE

Effect of using different risk scores as thresholds on workload and coverage of patients at known risk. Thresholds of 6-20 were used for cholesterol screening (nearset) and 4-16 for special care (preset).

RESULTS

On the basis of workload a nearset of 8 and preset of 12 would be reasonable. This implies cholesterol measurement in 1794 (37.7%) patients and special care in 1074 (22.6%). However, many patients with single risk factors were not allocated to special care at these thresholds: 11 (37.9%) patients with cholesterol concentrations > or = 10 mmol/l, 21 (33.9%) with systolic pressure > or = 180 mm Hg, and 213 (40.7%) heavy smokers (> 20 cigarettes/day) were missed. The distribution of scores was similar in those at established clinical risk, those with family history of heart disease, and others.

CONCLUSION

The guidelines may help to make best use of resources within specific age-sex groups but sound protocols for unifactorial risk assessment and modification remain essential.

Young infarct patients with single-vessel occlusion do not have an underlying prothrombotic state to explain their coronary occlusion

To determine the importance of a prothrombotic state in the pathogenesis of coronary occlusion in young infarct patients, assessment of risk factor profile and thrombotic tendency was undertaken in 25 young male patients (age less than 45 yr) who were shown at angiography, following myocardial infarction, to have occlusion of a single coronary. Comparison was made with a control group of symptomatic males aged greater than 55 yr, who at angiography had significant disease in two or more coronary arteries (multi-vessel disease control group). At the time of the study more patients in the single-vessel disease study group smoked cigarettes (n = 12) compared to the control group (n = 5) (p less than 0.01). Serum cholesterol and triglycerides were higher, and high density lipoprotein-cholesterol lower, in the single-vessel disease group but the difference reached significance only with the high density lipoprotein-cholesterol. Quantitative platelet aggregability was similar in the two groups. Although the level of beta-thromboglobulin, was higher in the single-vessel disease study group the difference was not significant. There were also no significant differences between these groups in levels of fibrinogen, Factor XII and alpha-2 antiplasmin. Patients in the multi-vessel disease group, however, had increased Factor VII levels (p less than 0.01). There were no significant differences between the two groups in fibrinolytic potential or in levels of antithrombin III. Coronary occlusion in the young appears likely to be due primarily to an arterial (plaque) related event as opposed to an abnormal coagulation response to minor arterial plaque damage.

Hypertension, coronary artery disease and insulin resistance--linked disorders with an impact on treatment

Coronary artery disease is a very common disorder for which hypertension is a well-recognized risk factor. However many trials of antihypertensive therapy have failed to demonstrate a reduction in the incidence of coronary events. One explanation is that hypertension is a disorder associated with hyperinsulinaemia, obesity and non-insulin dependent diabetes. Furthermore certain antihypertensive drugs, notably thiazide diuretics, increase the hyperinsulinaemia and thereby increase one of the other coronary risk factors. In this review the links between hypertension and hyperinsulinaemia are explored and the mechanisms whereby an increased plasma insulin can lead to the more rapid development of coronary artery disease are explained. These observations may influence the choice of drugs used to treat hypertension.

Status incongruence and serum cholesterol in an English general practice

The relationship between status incongruence and serum cholesterol was examined in a case-control study carried out in an English general practice population. Patients (n = 54) with elevated serum cholesterols (greater than or equal to 7.0 mmol/l) were compared to age and sex matched controls (n = 54). A specific type of status incongruence--lifestyle incongruity--was measured as the degree to which style of life (material consumption and status-enhancing behaviors) exceeded occupational status. Lifestyle incongruity was associated with higher serum cholesterol and an increased odds of being a case. This association was independent of age, sex, the body mass index, family history of cardiovascular disease, alcohol use, and, for women, menopausal status. Implications of these results for research on social inequality and the risk of cardiovascular disease are discussed.

Microalbuminuria and associated cardiovascular risk factors in the community

The prevalence of microalbuminuria and relationship to cardiovascular risk factors was examined in a cross-sectional community survey of cardiovascular risk factors. Microalbuminuria (when classified as albumin concentration greater than 20 micrograms/ml) was present in 6.3% of subjects but in conjunction with an albumin/creatinine ratio greater than 3.5 in only 2.2%. Diastolic blood pressure, prevalence of abnormal electrocardiographs, and to a lesser extent systolic blood pressure and fibrinogen concentration, were greater in those with albuminuria concentrations greater than 20 micrograms/ml. The strongest positive univariate correlates of albumin/creatinine ratios in those with detectable albuminuria were age, fibrinogen, blood pressure, total- and low density lipoprotein-(LDL) cholesterol, apo B and alcohol intake, whereas fasting insulin and insulin resistance were inversely correlated. Multiple regression analysis revealed that age, gender, systolic blood pressure and insulin resistance independently accounted for 37% of the variability in albumin/creatinine ratios. When those 10 subjects with microalbuminuria and albumin/creatinine ratios greater than 3.5 were matched with 20 with normoalbuminuria for age, gender and body mass index, the microalbuminuric subjects had significantly lower LDL cholesterol/apo B ratios and a tendency to lower high density lipoprotein (HDL) cholesterol and HDL cholesterol/apo A1 ratios. Microalbuminuria is uncommon in the general population, and is related to ageing, blood pressure and other vascular risk factors. It may reflect the presence of established cardiovascular disease.

Guidelines for the management of hyperlipidaemia in general practice. Towards the primary prevention of coronary heart disease. Royal College of General Practitioners

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Which measures of skewness and kurtosis are best?

Indices of distributional shape based on linear combinations of order statistics have recently been described by Hosking. Their usefulness as tools for practical data analysis is examined. They are found to have several advantages over the conventional indices of skewness and kurtosis (square root of b1 and b2) and no serious drawbacks. It is proposed, therefore, that they should replace square root of b1 and b2 in routine data analysis. To implement this suggestion, action by the developers of standard statistical software is needed.

Plasma triglyceride and low density lipoprotein metabolism

This study examines the relationship between plasma triglyceride and low density lipoprotein (LDL) levels by measuring the turnover of the native and 1,2 cyclohexanedione-treated lipoprotein in 25 healthy adults. Plasma triglyceride showed a strong positive correlation with circulating LDL apoprotein (apo LDL) mass. In order to achieve a satisfactory fit to the kinetic data it was necessary to postulate the existence of two plasma apo LDL pools (A and B). When subjects were grouped in quintiles on the basis of circulating apo LDL mass, pool A predominated in those in the lowest quintile. The fractional catabolic rate (FCR) of apo LDL from this pool was high (FCR = 0.57 +/- 0.06 pools day-1). As plasma triglyceride and apo LDL mass rose, apoprotein accumulated in the more slowly metabolized pool B as a result of an increase in the rate of input of apo LDL into the latter. The fractional clearance rate of protein from this pool remained unchanged at 0.26 +/- 0.04 pools day-1. Synthesis of apo LDL into pool B correlated with plasma triglyceride (r = 0.553, P less than 0.01), suggesting that the protein in this pool was derived from large, triglyceride-rich very low density lipoprotein.

Risk of fatal coronary heart disease in familial hypercholesterolaemia. Scientific Steering Committee on behalf of the Simon Broome Register Group

OBJECTIVES

(a) To determine the excess mortality from all causes and from coronary heart disease in patients with familial hypercholesterolaemia; (b) to examine how useful various criteria for selective measurement of cholesterol concentration in cardiovascular screening programmes are in identifying these patients.

DESIGN

Prospective cohort study.

SETTING

Eleven hospital outpatient lipid clinics in the United Kingdom.

PATIENTS

282 men and 244 women aged 20-74 with heterozygous familial hypercholesterolaemia.

MAIN OUTCOME MEASURE

Standardised mortality ratio, all adults in England and Wales being taken as standard (standardised mortality ratio = 100 for standard population).

RESULTS

The cohort was followed up for 2234 person years during 1980-9. Fifteen of the 24 deaths were due to coronary heart disease, giving a standardised mortality ratio of 386 (95% confidence interval 210 to 639). The excess mortality from this cause was highest at age 20-39 (standardised mortality ratio 9686; 3670 to 21,800) and decreased significantly with age. The standardised mortality ratio for all causes was 183 (117 to 273) and also was highest at age 20-39 (standardised mortality ratio 902; 329 to 1950). There was no significant difference between men and women. Criteria for measurement of cholesterol concentration in cardiovascular screening programmes (family history, presence of myocardial infarction, angina, stroke, corneal arcus, xanthelasma, obesity, hypertension, diabetes, or any of these) were present in 78% of patients.

CONCLUSIONS

Familial hypercholesterolaemia is associated with a substantial excess mortality from coronary heart disease in young adults but may not be associated with a substantial excess mortality in older patients. Criteria for selective measurement of cholesterol concentration in cardiovascular screening programmes identify about three quarters of patients with the clinically overt condition.

GnRH agonists as contraceptive agents: predicted significantly reduced risk of breast cancer

Gonadotrophin-releasing hormone agonists (GnRHAs) were investigated as contraceptive agents from the late 1970's to the mid-1980's. They were abandoned as they appeared to offer no advantage over conventional combination-type oral contraceptives (COCs). This conclusion appears to be incorrect. We propose here a contraceptive regimen of a depot formulation of a GnRHA plus add-back estrogen and intermittent progestogen. The dose of add-back sex-steroids is substantially less than that in COCs; this reduction in sex-steroids should lead to a major reduction in lifetime breast cancer occurrence.

Estimating departure from normality

Departure of a sample from a normal distribution should be assessed by a quantity that is meaningful in terms of the data, rather than merely by the P-value from a test statistic. Indices of departure based on the Shapiro-Francia W' and the Shapiro-Wilk W statistics are derived, and shown to have a natural interpretation in relation to the normal probability plot. A new diagnostic plot is proposed. An example is given which shows the relationship between one of the new indices and errors in calculated reference ranges due to non-normality of the data.

Screening for hyperlipidaemia in diabetes mellitus. Relationship to glycaemic control

Diabetic patients have an increased risk of developing cardiovascular disease which, in part, may be due to lipid abnormalities. Our aim was to establish from an initial screening programme what proportion of diabetic patients attending a routine diabetic outpatient clinic had hyperlipidaemia despite having good or acceptable glycaemic control. We screened 299 randomly selected diabetic patients to assess the prevalence of hyperlipidaemia and its relationship to glycaemic control. Twenty-eight per cent had hyperlipidaemia (defined as cholesterol greater than 6.5 mmol/L and/or non-fasting triglycerides greater than 3 mmol/L). Of these hyperlipidaemic patients, 71% had good or acceptable glycaemic control as defined by a glycated haemoglobin value of less than 10%. Approximately 40% of type 2 diabetic patients had body mass index values outside recommended targets indicating the potential of weight reduction in this group as a treatment modality. Our results indicate that the majority of hyperlipidaemic diabetic patients had good or acceptable glycaemic control, and as such these patients are potential candidates for specific lipid lowering therapy.

Screening for presymptomatic disease

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Prevalence of risk factors for heart disease in OXCHECK trial: implications for screening in primary care. Imperial Cancer Research Fund OXCHECK Study Group

OBJECTIVE

To describe the outcome of offering health checks systematically to a general practice adult population, in terms of age and sex specific prevalence of risk factors, follow up workload, and selective screening of cholesterol concentration.

DESIGN

Descriptive analysis of data obtained by postal questionnaire and by personal interview and clinical examination by a trained nurse.

SUBJECTS

2205 patients aged 35-64 who attended for a health check in 1989-90 from an invited random sample of 2777 patients from five urban general practices in Bedfordshire.

RESULTS

Overall, almost three quarters of patients (78% of men, 68% of women) needed specific advice or follow up. Smoking, a high fat diet, and being overweight (body mass index greater than or equal to 25 kg/m2) were common characteristics exhibited by 35%, 31%, and 55% respectively of men and 24%, 18%, and 48% of women. The total cholesterol concentration was greater than or equal to 6.5 mmol/l in 37% of patients and greater than or equal to 8 mmol/l in 8%. In terms of workload 13% needed dietary advice only, 15% needed only follow up of hyperlipidaemia or hypertension, and 9% needed advice on smoking only. A further 35% needed follow up for a combination of risk factors. The proportion of patients in whom cholesterol concentration would be measured if a selective screening policy were adopted would vary from 29% to 71%, according to different criteria, but (particularly in men) no combination would be much better than random testing as a means to detect patients with a total cholesterol concentration greater than or equal to 8 mmol/l.

CONCLUSIONS

If the entire adult population of a practice is offered health checks systematically the acceptance rate is lower and the follow up workload higher than previously understood. The resource implications depend on the age and sex of patients screened and the selective criteria adopted for cholesterol measurement. Health checks are only the beginning of a successful preventive programme--the challenge is to provide effective intervention and follow up.

Management of newly diagnosed non-insulin-dependent (type 2) diabetes mellitus: a retrospective audit

A retrospective survey of the case records of 130 patients with newly diagnosed non-insulin-dependent diabetes mellitus (NIDDM) was performed to assess the effect of 1 year of clinical attendance on blood glucose control, body weight, lipid profile and blood pressure. The mean age of these patients was 63 +/- (SE) 0.1 years and 45% were 65 years or older. Body mass index (BMI) was 28.3 +/- 0.49 kg m-2 and 72% were overweight or obese. Sixty-seven percent of the patients were hypertensive (WHO criteria). Serum cholesterol was 6.0 +/- 0.2 mmol/l, HDL cholesterol 1.0 +/- 0.0 mmol/l and triglycerides 3.14 +/- 0.29 mmol/l (non-fasting). Seventy-two percent of the patients were managed on diet alone and 23% by diet plus sulphonylurea. The remaining 5% were treated by metformin or a combination of metformin plus sulphonylurea. After one year, glycated haemoglobin (HbA1) decreased from 10.7 +/- 0.3% to 8.2 +/- 0.2% (P less than 0.01; normal less than 7.5%). The sulphonylurea groups showed similar decreases in HbA1. Overall there was a small but significant fall in BMI (-0.5 +/- 0.2 kg m-2; P less than 0.05). However, the diet treated patients showed a significant decrease in BMI (-0.8 +/- 0.3 kg m-2; P less than 0.01) whilst BMI increased in the sulphonylurea treated group (+0.7 +/- 0.2 kg m-2; P less than 0.01). Serum lipid concentrations remained unchanged in both groups. The proportion of patients with hypertension remained the same. Hence after one year of clinical attendance, HbA1 improved but there was minimal change in the associated cardiovascular risk factors.(ABSTRACT TRUNCATED AT 250 WORDS)

The potential and limitations of opportunistic screening: data from a computer simulation of a general practice screening programme

Given the continuing emphasis on preventive medicine in general practice, there is considerable interest in the relative effectiveness of different ways of inviting patients to attend for screening. Recently, opportunistic methods have been advocated as being particularly useful but these methods often fail to reach a high proportion of the target population. Many patients do not consult and when they do they are not always invited to attend for screening. In this study a computer simulation model has been used to examine the effects of these variables in more detail. The notes of a random sample of 190 patients (97 women, 93 men) aged 30-50 years, registered with one general practitioner, were used to provide data for the model. The simulation model showed that increasing the number of screening appointments available each week has only a small effect on screening rates and that a ceiling is reached when 25 appointments per 1000 patients are available. In contrast, increasing the proportion of eligible consulting patients who are invited has a substantial effect such that it could take nearly 12 years to screen 90% of a target population if only one out of every four patients were invited compared with under four years if three out of every four patients were invited. The results suggest therefore that opportunistic screening methods are unlikely to achieve desired screening rates within acceptable time limits. It is argued that to achieve target levels of screening, practices will need to combine opportunistic methods with more formal methods of invitation.

Constructing time-specific reference ranges

Reference ranges which take time (such as age) into account are often required in medicine, but simple, systematic and efficient statistical methods for constructing them are lacking. A method is described which is based on low order polynomial curves (linear, quadratic or occasionally cubic), together with guidelines for when and how to apply a logarithmic transformation to the variable analysed, testing for departures from normality, and assessment of the adequacy of the reference range which is constructed from the regression line plus or minus a multiple of the standard deviation. Standard statistical packages may be used to carry out the calculations. The question of comparing two or more groups of patients is addressed. Three examples are discussed in detail.

Cholesterol screening and life assurance

OBJECTIVES

To examine how insurance companies assess proposals for life assurance from applicants with raised cholesterol concentrations and to determine the excess mortality rating applied.

DESIGN

Survey of 49 companies underwriting term life assurance.

SETTING

United Kingdom.

SUBJECTS

Four fictional men aged 30 seeking 20 year term policies paying benefit only on death. Two had total cholesterol concentrations of 6.4 and 8.1 mmol/l but no other cardiovascular risk factors; one was overweight, hypertensive, smoked 20 cigarettes daily, and had a total cholesterol concentration of 8.1 mmol/l; and one had possible familial hypercholesterolaemia and a total cholesterol concentration of 10.7 mmol/l after treatment.

MAIN OUTCOME MEASURE

Percentage excess mortality rating.

RESULTS

All companies used explicit criteria to assess the mortality risk associated with hyperlipidaemias, and 47 companies applied the same criteria to men and women. No excess mortality rating was imposed on an applicant with a total cholesterol concentration of 6.4 mmol/l, but a small excess was applied to an applicant with a concentration of 8.1 mmol/l (median excess 50%, range 0-75%). When multiple cardiovascular risk factors were present the same concentration of 8.1 mmol/l resulted in a substantial excess (median 135%, range 50-200%). A smaller but more variable excess was applied to an applicant with possible familial hypercholesterolaemia (median 75%, range 0-200%).

CONCLUSIONS

Despite considerable differences among companies in the excess mortality ratings applied, increases in term life assurance premiums are likely to be restricted to patients with severe hypercholesterolaemia, in particular those with familial hypercholesterolaemia. In the absence of other cardiovascular risk factors milder hypercholesterolaemia is unlikely to result in higher premiums.