The genetics of coronary heart disease: The contribution of twin studies

Despite the decline in coronary heart disease in many European countries, the disease remains an enormous public health problem. Although we know a great deal about environmental risk factors for coronary heart disease, a heritable component was recognized a long time ago. The earliest and best known examples of how our genetic constitution may determine cardiovascular risk relate to lipoprotein(a), familial hypercholesterolaemia and apolipoprotein E. In the past 20 years a fair number of polymorphisms assessed singly have shown strong associations with the disease but most are subject to poor repeatability. Twins constitute a compelling natural experiment to establish the genetic contribution to coronary heart disease and its risk factors. GenomEUtwin, a recently funded Framework 5 Programme of the European Community, affords the opportunity of comparing the heritability of risk factors in different European Twin Registries. As an illustration we present the heritabilities of systolic and diastolic blood pressure, based on data from over 4000 twin pairs from six different European countries and Australia. Heritabilities for systolic blood pressure are between 52 and 66% and for diastolic blood pressure between 44 and 66%. There is no evidence of sex differences in heritability estimates and very little to no evidence for a significant contribution of shared family environment. A non-twin based prospective case/cohort study of coronary heart disease and stroke (MORGAM) will allow hypotheses relating to cardiovascular disease, generated in the twin cohorts, to be tested prospectively in adult populations. Twin studies have also contributed to our understanding of the life course hypothesis, and GenomEUtwin has the potential to add to this.

Systematic review of the effect of diet and exercise lifestyle interventions in the secondary prevention of coronary heart disease.

The effectiveness of lifestyle interventions within secondary prevention of coronary heart disease(CHD)remains unclear.This systematic review aimed to determine their effectiveness and included randomized controlled trials of lifestyle interventions, in primary care or community settings, with a minimum follow-up of three months, published since 1990. 21 trials with 10,799 patients were included; the interventions were multifactorial (10), educational (4), psychological (3), dietary (1), organisational (2), and exercise(1). The overall results for modifiable risk factors suggested improvements in dietary and exercise outcomes but no overall effect on smoking outcomes. In trials that examined mortality and morbidity,significant benefits were reported for total mortality (in 4 of 6 trials;overall risk ratio(RR) 0.75 (95%confidence intervals (CI) 0.65, 0.87)), cardiovascular mortality (3 of 8 trials; overall RR 0.63(95%CI 0.47, 0.84)), and nonfatal cardiac events(5 of 9 trials; overall RR 0.68(95%CI 0.55, 0.84)). The heterogeneity between trials and generally poor quality of trials make any concrete conclusions difficult. However, the beneficial effects observed in this review are encouraging and should stimulate further research.

Coronary heart disease: health knowledge and behaviour

Objective To determine the current level of knowledge and understanding of CHD in the general public in Northern Ireland and to identify factors that are associated with higher knowledge levels. Setting Six provincial centres in Northern Ireland. Methods The data in the present study were collected using an interview administered questionnaire. 1,000 members of the general public were interviewed face-to-face. CHD knowledge was computed as a continuous variable, i.e. higher score represents better CHD knowledge. Main outcome measure CHD knowledge in the general public in Northern Ireland. Results Study respondents displayed limited knowledge and understanding of CHD. Study respondents who achieved higher CHD knowledge scores were more likely to report: exercising for 30 min three times or more per week, paying attention to their diet, being overweight, having a family history of CHD, living in a higher socioeconomic area (according to postcode) and having attended tertiary education. Respondents in the present study while recognising the role that community pharmacists had to play in helping patients manage their prescribed medicines, did not recognise the community pharmacists' role in other aspects of CHD detection or management. Conclusion The deficit in CHD knowledge could translate into inadequate preventative behaviour patterns and suboptimal clinical outcomes. If community pharmacists wish to become increasingly involved in public health delivery relating to CHD they need to develop effective and accessible services and promote these to the public who at present do not recognise this role of the community pharmacist.