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|Commentary on Lifestyle for CVD prevention|
Lifestyle for CVD prevention: the priority is sustaining change
Lifestyle intervention is pivotal to cardiovascular disease (CVD) prevention. The benefits of a Mediterranean diet have long been extolled, supported by extensive reports that this dietary pattern is associated with a wide range of benefits for both cardiovascular and non-cardiovascular diseases, as well as reduced risk of developing type 2 diabetes.1 4 In support, the ‘proof-of-concept’ PREDI-MED study demonstrated a 30% reduction in the risk of stroke in high CV risk primary prevention patients by the addition of nuts or extra virgin olive oil to the diet, reaffirming the importance of diet quality in primary prevention of CVD.5
Yet lifestyle intervention goes beyond diet, with regular physical activity also a key component. Recent work has refocused on the relevance of cardiorespiratory fitness, especially in the context of evaluation of persistence with exercise in the overweight patient with metabolic changes.6,7
The combination of all lifestyle factors has multiplicative benefits. A recent report from Swedish researchers highlights this.8 Adhering to five simple lifestyle behaviours – a healthy diet, moderate alcohol intake, no smoking, regular physical activity and maintaining a healthy weight - can prevent the majority of first coronary events in the general population (without pre-existing CVD). Indeed, nearly two-thirds of the risk reduction was attributed to the adoption of four factors: a healthy diet, moderate alcohol intake, no smoking and regular physical activity.
About this study
This was a general-population prospective cohort study of 20,721 Swedish men (aged 45- to 79-years) without pre-existing history of cancer, CVD, diabetes, hypertension, or hypercholesterolaemia. All individuals had completed a detailed questionnaire on diet and lifestyle at baseline. During the study, diet and lifestyle were assessed by validated questionnaires; a healthy diet was defined according to a recommended food score,9 and physical activity at work and during leisure time was evaluated. Healthy lifestyle behaviours were identified as:
During a follow-up of 11 years there were 1,361 new myocardial infarctions (MIs). In men with a healthy lifestyle involving all five healthy lifestyle behaviours, there was 86% (95% CI 57-96%) reduction in risk of MI compared with individuals who do not adhere to these behaviours, and 79% (95% CI 34-93%) reduction in MI risk compared with the general population. Key findings are summarised in Box 1. The study had a number of important strengths, including the large cohort size recruited from a general population, prospective study design, and validated assessment of lifestyle behaviours. All of these features add to the generalizability of the findings from the study; a clearly relevant message for cash-strapped healthcare systems in Europe and beyond.
However, there is another salutary lesson from these data. Only 1% of individuals in this cohort were able to sustain all five healthy lifestyle behaviours in the long-term. Similarly, the Doetinchem Cohort Study in 5,574 individuals without CVD (aged 20-59 years) provides further evidence that sustaining lifestyle change is the real challenge. In this study, only 7% of the cohort maintained a low cardiovascular risk over an 11 year follow-up period; these individuals had 7-fold lower risk of CVD than those with a long-term high risk profile.10
This issue is at the crux of all lifestyle programmes. Many studies have attempted to address this lack of adherence, for example by the use of computer or mobile telephone-based motivational approaches such as in the POWER or HEART studies,11,12 or by intensive behavioural counselling,13 with varying success. Yet do we perhaps need to change focus and re-direct accountability to the individual? Certainly, in the case of lifestyle diseases such as obesity and type 2 diabetes, education is critical so that the individual realises that adherence or not with a healthy lifestyle has important consequences. With this in mind, the recent adoption of a ‘Heart Age’ score by the Joint British Societies is clearly relevant.14 This approach offers a number of advantages, not least its applicability to assessment of risk in younger adults which is a recognised deficiency of current risk estimation scores.
Yet again, there is a further conundrum, as it is well recognised that health education fails to reach those in most need, in lower socio-economic groups. A recent study has suggested that tailored education about lifestyle that was logical for the individual, taking into account personal circumstances, raised awareness of his or her weight or health status, and was supported by the involvement of others, may be as relevant for those of lower or higher socio-economic status.15 The financial cost of lifestyle changes also needs to be considered in this context, as borne out by data from Spain showing that deterioration in the economic situation in Spain has impacted adherence with a Mediterranean diet, leading to replacement with cheaper, less healthy alternatives. Similarly, in Brazil, a region in economic transition, the diet of lower-income groups has shifted to include more processed, calorie-dense, and high-sugar foods and beverages, which are more accessible and cheaper than healthier alternatives, an effect compounded by lack of education about a healthy diet and a bias in public policy to prevention of undernutrition.16
In an accompanying editorial to the study by Åkesson et al (2014), Professor Dariush Mozaffarian, Tufts University, Boston, USA makes the case for doing more to implement a healthy lifestyle in the general population.17 We have an abundance of evidence that lifestyle intervention is the first fundamental step in CVD prevention, the challenge for now is to ensure that these behaviours are implemented and maintained by the general population.
We need to shift our focus from preventing disease to promoting health, involving not only healthcare providers and patients, but also third party payers and public policy makers. Successful implementation and maintenance of a healthy lifestyle will not only prevent clinical events but also will substantially reduce the societal and economic burden of CVD.