The Programme Development Group (PDG) took account of a number of factors and issues when developing the recommendations.
Evidence was presented on how to prevent or reduce the combination of modifiable risk factors that can cause cardiovascular disease (CVD). The PDG also considered evidence and expert testimony on separate key risk factors. The reviews, together with the expert testimonies, are listed in appendix A. Relevant existing NICE guidance was also summarised.
The key CVD risk factors that can be modified are: smoking, a poor diet, obesity, lack of physical activity and high alcohol consumption (Emberson et al. 2004; Yusuf et al. 2004). CVD risk factors tend to 'cluster together'. Thus people who smoke are more likely to have a poor diet and exercise less. This 'clustering' also tends to have a disproportionate effect on people who are disadvantaged, further accentuating health inequalities.
The PDG noted that approximately 100,000 people die from smoking-related diseases in the UK every year. Tobacco accounts for approximately 29% of deaths from cancer, 13% of cardiovascular deaths and 30% of deaths from respiratory disease (Action on Smoking and Health 2008). It also acknowledged that smoking accounts for over half the disproportionate burden of illnesses experienced by disadvantaged groups. The PDG strongly endorsed the national tobacco control measures set out in 'Beyond smoking kills' (Action on Smoking and Health 2008).
Approaches to helping people quit smoking, or to stop using other forms of tobacco, are covered by NICE's guideline on tobacco. As a result, tobacco issues are not covered in this guidance.
The PDG noted that nicotine replacement therapy (NRT) can help to reduce CVD among people who are addicted to nicotine. It fully endorses the Tobacco Advisory Group's recommendations on the regulation and marketing of NRT (Royal College of Physicians 2007). (The report advocates making NRT more acceptable and accessible to people who smoke and who find it impossible to quit.)
Taking a population-based approach, the PDG focused on the major contributors to CVD risk found in the typical UK diet. These include: a high intake of saturated and industrially-produced trans fatty acids and salt. It acknowledged and supports the work of the Food Standards Agency and other organisations (such as the Advertising Standards Authority) in helping to reduce general consumption of these products. However, it believes further action is essential to achieve greater reductions in premature death and disease and to reduce health inequalities.
A consistent message on lifestyle risk factors related to CVD is important.
The recommendations made in this guidance are not intended to replace existing advice to the public on diet. Rather, they will support the next stage of policy development to tackle the substantial burden of ill health from CVD and other chronic diseases (see also the section on public health need and practice). This includes the development of effective local and regional, population-level programmes to prevent CVD, diabetes, obesity, kidney disease and some common cancers.
In response to stakeholder feedback, the PDG considered the evidence on interventions targeting specific CVD risk factors. For example, in relation to salt, saturated fats and trans fatty acids.
Policies to promote physical activity were considered. However, physical activity, smoking and obesity have all been covered by other NICE guidance. In addition, as policies to increase the consumption of fresh fruit and vegetables are already agreed and widely implemented, the PDG did not consider them in detail.
CVD risk factors can be reduced in a number of ways. Two different (and frequently, complementary) approaches are often described as 'individual-' and 'population-based'. The former involves interventions which tend to give people direct encouragement to change their behaviour. It may involve providing information about the health risks of their current behaviour, advice (such as to be more active) or prescribing a treatment. Alternatively, it may involve altering the way the NHS and other organisations deliver prevention or healthcare services. Population-based interventions, on the other hand, aim to change the risks from the social, economic, material and environmental factors that affect an entire population. This can be achieved through regulation, legislation, subsidy and taxation or rearranging the physical layout of communities. The PDG focused on population-based approaches.
The NHS Health Check programme, which was being rolled out as this guidance was published, is aimed at all those aged 40 to 74. It will ensure everyone in this age range is assessed to determine their risk of heart disease, stroke, kidney disease and diabetes. It will also help them to reduce or manage that risk by providing individually tailored advice. This guidance complements the NHS Health Check programme by focusing on the CVD risk factors for an entire population. It will benefit the NHS, local authorities and industry, as well as individuals, by substantially reducing the number of people who need statin or anti-hypertensive medication. It will also enable services to focus more on those who still need treatment.
The PDG recognised that smoking cessation and other services that focus on helping individuals to change their behaviour have an important role to play in preventing CVD. Many of these services or approaches have been the focus of earlier NICE guidance.
Previously in the UK, interventions focused on individuals have tended to dominate CVD prevention activities and it is important to identify and treat those who are at higher risk. However, a much larger overall benefit could be achieved by making changes (albeit small ones) among any given population as a whole. As indicated by the Rose hypothesis, a small reduction in risk among a large number of people may prevent many more cases, rather than treating a small number at higher risk. A whole-population approach explicitly focuses on changing everyone's exposure to risk (Rose 2008).
There is growing evidence in support of the Rose hypothesis (see point above). For instance, data were recently pooled from six general population cohort studies involving 109,954 European participants. These data were analysed to compare different CVD strategies. The analysis found that a 10%, population-wide reduction in blood cholesterol, blood pressure and smoking prevalence would save approximately 9120 lives per million population over 10 years. In contrast, treating 40% of high-risk individuals with a 'polypill' (containing a statin, three half-dose anti-hypertensives and aspirin) would save about 3720 lives per million, even assuming complete, long-term adherence (Cooney et al. 2009).
It should be noted that, as indicated above, population- and individual-based approaches are both important and can be complementary. They do not have to be considered as alternatives for CVD prevention.
Both population- and individual-based approaches can influence health inequalities. However, population-based approaches may be more likely to reduce health inequalities. That is because there are many reasons why people who are disadvantaged might find it more difficult to change their behaviour than those who are affluent (Swann et al. 2009). As a result, some activities aimed at individuals may inadvertently increase health inequalities.
'Upstream', population-level interventions include: fiscal measures (such as taxation), national or regional policy and legislation (such as legislation on smokefree public places or the way food is produced); and environmental changes. They are not reliant on an individual's knowledge or ability to choose healthier options. Social and economic action can also change people's risk of CVD (in such cases, the health outcomes are side effects, albeit desirable).
The recommendations in this guidance do not, in the main, rely on individual choice. Rather, they aim to improve social environments and thus ensure the healthy choice is the easy choice. The emphasis is on changing policies, systems, regulations, the physical environment and other 'upstream' factors. This approach is likely to reduce, rather than increase, health inequalities and is congruent with NICE's guidance on behaviour change.
The financial modelling for this guidance shows that considerable cost savings could be made. Using a number of conservative assumptions, it found that halving CVD events across England and Wales (a population of 50 million) would result in discounted savings in healthcare costs of approximately £14 billion per year. Reducing mean population cholesterol or blood pressure levels by 5% would result in discounted annual savings of approximately £0.7 billion and £0.9 billion respectively. Reducing population cardiovascular risk by even 1% would generate discounted savings of approximately £260 million per year.
A 3 g reduction in mean daily salt intake by adults (to achieve a target of 6 g daily) would lead to around 14,000 to 20,000 fewer deaths from CVD annually (Strazzullo et al. 2009). Using conservative assumptions, this means approximately £350 million in healthcare costs would be saved. In addition, approximately 130,000 quality-adjusted life years (QALYs) would be gained. A mean reduction of 6 g per day would double the benefits: an annual saving of £700 million in healthcare costs and a gain of around 260,000 QALYs. A 3 g reduction in daily salt intake (a reasonably conservative estimate of what could be achieved) would reduce systolic blood pressure by approximately 2 mmHg. This would equate to a 2% decrease in the risk reduction model. Similarly, a reduction of IPTFA intake to approximately 0.7% of total fat energy might save approximately 571,000 life years, and some £2 billion.
The PDG noted that CVD death rates are no longer falling among young and middle aged people in the UK (for instance, they are no longer falling among those aged 35 to 54 in the most socially disadvantaged groups in Scotland), the USA and Australia. This reflects a combination of adverse risk factors including smoking, a poor diet and disadvantage (O'Flaherty et al. 2009).
The prevalence of obesity and overweight continues to rise (National Heart Forum 2010). This, in turn, will lead to a rise in type 2 diabetes which can increase the risk of CVD. The risk of CHD is particularly high among women with diabetes (Barrett-Connor et al. 1991).
Epidemiological studies indicate that approximately 45 to 75% of the recent fall in CVD deaths in Westernised industrialised countries was the result of a reduction in the major risk factors. This includes a reduction in smoking prevalence and salt and saturated fat consumption.
The decline in CVD deaths noted above began long before effective treatments were introduced. In Finland and Iceland, coronary heart disease mortality rates declined by 63% between 1982 and 1997. Seventy five per cent of this was attributed to a reduction in smoking, blood pressure and cholesterol levels (Aspelund et al. 2009; Laatikainen et al. 2005). Sweden also observed a large reduction in CVD-related mortality. This was attributed to dietary reductions in cholesterol and blood pressure. In contrast, blood pressure and cholesterol levels in the UK have, thus far, only fallen a modest amount (Unal et al. 2005).
The fall in blood pressure and cholesterol levels seen in many Western populations are mainly attributable to lifestyle changes and changes in the wider determinants of health, rather than to medication. Changes to the wider determinants of health have often been as a consequence of public health policy. Preventive services are unlikely to tackle these wider determinants unless supported by national policies and systems (Capewell and O'Flaherty 2008).
Data from 'natural experiments' in a whole population (where there were no randomised controlled trials to assess the results) provide compelling evidence of the links between CVD and diet. Rapid and large falls in CVD deaths have been observed in diverse populations including those living in Poland, Mauritius, Finland, Iceland and Norway. In Poland, a 26% decrease in coronary deaths followed a substantial reduction in the consumption of animal fats and increased consumption of vegetable oils and fruit after the break-up of the Soviet Union (Zatonski and Willett 2005). In Mauritius, CVD deaths fell following the introduction of legislation to make it mandatory to use polyunsaturated oils as a substitute for highly saturated cooking oils (Dowse et al. 1995). A substantial fall in CVD deaths also followed a reduction in saturated fat intake in Finland, Iceland, Norway and elsewhere (Zatonski and Willet 2005, Laatikainen et al. 2005.) Conversely, rapid rises in CVD mortality have been seen in China and elsewhere, principally due to the adoption of a Western diet rich in saturated fats (Critchley et al. 2004).
The PDG discussed the nature and quality of evidence relevant to CVD prevention in whole populations. As indicated in consideration 3.71, this evidence is not drawn from randomised trials alone. The PDG felt it important to consider natural experiments and observational studies as well. The studies had to include a known cause–effect mechanism and an association which was both strong and consistent.
The PDG noted the importance of taking action to prevent the elevation of CVD risk factors among children, by ensuring they have a healthy, balanced diet and are physically active. This supports the principle of 'primordial prevention'. In this context, this means ensuring the low cholesterol and blood pressure levels seen in normal childhood are maintained throughout life (Labarthe 1999). This is crucial to prevent risk factor 'tracking' whereby, for instance, children with obesity, elevated blood pressure or raised cholesterol are very likely to become adults with above-average risk-factor levels. There is also a strong association between early abuse and neglect and subsequent depression, drug abuse and ischemic heart disease. In addition, some evidence suggests that childhood maltreatment, including both abuse and neglect, influences depression and heart disease in ways that are gender-dependent.
Maternal and fetal nutrition may have an important influence on whether or not people develop CVD later in life. Some evidence suggests that breastfeeding may protect against the development of risk factors for CVD. For example, it is associated with small reductions in blood pressure (Martin et al. 2005) and serum cholesterol. It is also associated with a reduced risk of being overweight (Harder et al. 2005) or having type 2 diabetes. However, the evidence on breastfeeding per se as a means of preventing CVD is weak (Owen et al. 2006; 2008).
The PDG recognised the many benefits of breastfeeding (including the benefits of continuing to breastfeed beyond the recommended first 6 months after birth). However, it concluded that there was insufficient evidence to make a recommendation related to CVD prevention. Note: NICE's guideline on maternal and child nutrition is referred to in the recommendations.
The Strategy Unit report 'Food matters' (2008) concluded that some 70,000 premature UK deaths could be avoided with a healthier diet. More recently, the Food Standards Agency suggested that poor dietary health in the UK could contribute to up to 150,000 CVD deaths, and a further 155,000 cancer deaths, per year (Food Standards Agency 2009).
Much of the observational evidence that links diet to CVD is based on individual nutrients. However, the PDG recognised that their impact should also be considered in the context of the whole diet. It recognised that a 'healthier' diet is likely to comprise a favourable balance of food and nutrients and a reduction in the intake of harmful elements. In a typical Western diet, the latter include substantial amounts of salt, saturated fat and trans fats (Hu 2008).
A 'healthier' diet based on fruit, legumes, pulses, other vegetables, wholegrain foods, fish and poultry is consistently associated with lower levels of CVD risk factors (Fung et al. 2001; Lopez-Garcia et al. 2004) and lower CVD mortality (Heidemann et al. 2008; Osler et al. 2001). Vegetarian and 'Mediterranean' diets are also consistently associated with lower CVD mortality (Hu 2008; Mann et al. 2009). Interventions promoting these types of 'healthier' diet have been shown to be highly effective in reducing blood pressure, cholesterol and subsequently CVD (Appel et al. 1997; de Lorgeril et al. 1999).
The PDG emphasised its support for a healthy diet, as advocated in the 'eatwell' plate (Food Standards Agency 2007).
The PDG discussed whether it would be feasible for food labels to present calorie content in terms of the hours of physical activity required to use them up. There was no evidence to support this approach. However, there is evidence that presenting the total calorific content on food labels might help reduce intake (Ludwig and Brownell 2009).
Salt intake is a major determinant of CVD in the UK, mainly due to its effect on blood pressure. On average, 70% to 90% of people's intake comes from salt added during the manufacturing process; only 10% to 30% comes from adding it during cooking or at the table. Reducing the population's salt intake will, therefore, involve encouraging the food industry to reduce the salt used in processed foods, as well as encouraging people to reduce the salt they add themselves. The PDG believes the former will best be achieved by using a combination of voluntary and regulatory action.
The UK population's per capita daily salt intake has fallen by 0.9 g in the last 5 years (a reduction of around 2% per year). This means people are consuming an average 8.6 g of salt per day. The reduction has mainly come about as a result of public awareness campaigns and a voluntary code of practice for industry, led by the Food Standards Agency. The voluntary agreement came into force in 2004 and was followed by progressive targets (in 2006 and 2009). The campaigns, which cost just £15 million, led to approximately 6000 fewer CVD deaths per year, saving the UK economy approximately £1.5 billion per annum. The PDG noted the new targets for 2010 and 2012.
Recent evidence shows that it is feasible to reduce the salt content of foods even further and that this would lead to substantial health benefits (Appel and Anderson 2010). For example, a 10% reduction in the salt content of items like bread and soup is not detected by consumers and does not, therefore, affect consumer choice. This would reduce both strokes and cardiovascular events. A reduction in mean salt intake of 3 g per day for adults (to achieve a target of 6 g daily) would lead to around 14,000 to 20,000 fewer deaths from CVD annually (Strazzullo et al. 2009). Using conservative assumptions, this means approximately 130,000 quality-adjusted life years (QALYs) would be gained and around £350 million would be saved in healthcare costs. A reduction of 6 g per day would lead to twice the gain: some 260,000 QALYs and an annual saving of £700 million in healthcare costs.
Many children in the UK may be consuming as much salt as adults (He et al. 2008). Indeed, single helpings of soup or 'meal deals' may contain as much as 3 g of salt. Currently, it is recommended that: children aged from 1 to 3 years should consume no more than 2 g salt a day (0.8 g sodium); from 4 to 6 years they should consume no more than 3 g salt a day (1.2 g sodium); and from 7 to 10 years a maximum of 5 g salt a day (2 g sodium) (Scientific Advisory Committee on Nutrition 2003).
The PDG discussed the benefits of substituting mono-unsaturated or polyunsaturated fats for saturated fats (Hu 2008) and of reducing total fat consumption. Evidence suggests that reducing saturated fat intake from 14% to 7% of energy intake (to reach the levels seen in Japan) might prevent around 30,000 CVD deaths annually. Changes in CVD deaths are also addressed in consideration 3.27.
The PDG discussed whether to recommend 'low' rather than 'full-fat' products as there is a risk that if saturated fat is removed to create a 'low-fat' product, it could still be used in another product, with no overall reduction in the population's fat consumption. In addition, the Group felt that there was a risk that some fat content would be replaced with high levels of sugar, so losing some of the benefit of reducing calorie intake.
The PDG discussed the potential problems that might arise if low-fat milk was made cheaper than full-fat milk. In general, most of the population should aim for a low-fat diet. However, full-fat products are the 'healthier' choice for some groups. Children aged under 2, for instance, may need the additional calories and fat-soluble vitamins found in full-fat milk and the PDG noted that full-fat milk is recommended for this group when cow's milk is being used. The Group was concerned that increasing the relative price of full-fat milk (to make lower-fat milk a more attractive option) could place an added financial burden on disadvantaged groups. However, it also believed that this added burden could be addressed by the tax and benefits system.
The PDG agreed with the 2009 World Health Organization (WHO) review of industrially-produced trans fatty acids (IPTFAs), also known as partially hydrogenated vegetable oils (PHVOs). In line with the WHO review, the PDG concluded that IPTFAs are unnecessary and 'toxic' and should be eliminated from foodstuffs. The WHO review states that because IPTFAs are produced by partial hydrogenation they are not normally present naturally in foods and have no known health benefits. The review defined them as 'industrial additives'. It recommended that food services, restaurants, and food and cooking fat manufacturers should avoid their use (Uauy et al. 2009). A recent study commissioned by the European Parliament advocated that an EU-wide ban on IPTFAs should be considered. The PDG noted that IPTFAs have been successfully banned in Denmark and New York City.
The WHO review of industrially-produced trans fatty acids noted that people who use partially hydrogenated vegetable oils (PHVOs) for cooking would have mean trans fatty acids intakes considerably higher than the national average. The same would be true for those who eat a high proportion of industrially processed or 'fast food'. The review noted that '…replacing TFAs [trans fatty acids] with vegetable oils high in polyunsaturated fatty acids (PUFA) and monounsaturated fatty acids (MUFA) is the preferred option for health benefits… Eliminating use of TFA-containing PHVO [partially hydrogenated vegetable oils] should be considered as hazard removal, in line with risk management models used to address many other food safety issues.' The PDG concurred.
Assuming a linear dose response, if less than 1% of food energy came from IPTFAs, between 4500 and nearly 7000 lives might be saved in England.
The PDG commended the substantial efforts made by much of the UK-based food industry and the Food Standards Agency to remove IPTFAs from the UK food chain. It also noted the review of trans fats by the Scientific Advisory Committee on Nutrition (SACN). New concerns have now emerged, particularly in relation to imported products and fried food prepared in some settings. People from disadvantaged groups are likely consume more of these products which, in turn, could be an important contributory factor to health inequalities.
Some products (this includes fried food from take-away venues) may contain substantial levels of IPTFAs. The PDG noted that some people may be consuming this sort of meal on a frequent basis. Hence, it considered that IPTFA consumption across different population groups is relevant, and that simply looking at average intake will not suffice.
The Group discussed the links between sedentary behaviour and CVD, and the need to encourage people to be more physically active. However, evidence on how to address sedentary behaviour is not well developed and remains an area for further study.
The PDG noted the importance of ensuring physical activity is enjoyable and can be incorporated into daily life. Effective interventions to encourage physical activity are possible both nationally and locally. For example, NICE has made recommendations on how to help people to be physically active in guidelines on walking and cycling, physical activity: brief advice for adults in primary care, exercise referral schemes to promote physical activity, physical activity and the environment, physical activity in the workplace and physical activity for children and young people.
Public, private, voluntary and community sector organisations all have a role to play in preventing CVD at national level. For example, measures to encourage commercial markets to be health promoting could be highly cost saving (Abelson 2003; Catford 2009; Trust for America's Health 2008; Wanless 2004). Such measures might include: improving the content of products (re-formulation); controls on the marketing of energy-dense, nutrient-poor foods, foods high in fat, salt or sugar and processed foods; and package labelling.
Those preparing, producing and selling food have a particularly important role in improving the diet of the nation. Although such organisations must consider their commercial interests, the PDG considers it also reasonable to expect them to work with others to help prevent CVD. It takes this view in light of the diseases and deaths caused by CVD (and the consequent costs to the exchequer and society). The PDG recognised that many responsible commercial organisations are already taking positive action. Many organisations, for instance, have taken praiseworthy action to reduce the salt or saturated fat content of food, or to remove industrially-produced trans fats from their processes (Brownell and Warner 2009).
The PDG believes that more could be done to assist those sectors which have, for a variety of reasons, been unable or unwilling to take positive action. Such action would not only benefit the population, but would also help provide a 'level playing field', where all businesses work to the same standard. Brownell and Warner (2009) state: 'there is an opportunity if the industry chooses to seize it – an opportunity to talk about the moral high ground and to occupy it'.
Advertising and other marketing activities have an important influence on consumption patterns. They encourage people to change brands and they also encourage overall increases in consumption of related brands.
The PDG noted the work of the Advertising Standards Authority and others to develop the existing overarching regulatory system that controls food advertising aimed at children. Furthermore, the Group noted and praised the important work involved in developing the current UK advertising regulations. The Ofcom/Food Standards Agency restrictions on TV advertisements for foods high in salt, fat or sugar aimed at children are a good example of these regulations being put into practice. However, the PDG felt that children are particularly vulnerable and need further protection from commercial pressures. The 'Sydney principles' (developed by the International Obesity Taskforce Working Group in Sydney, Australia [Swinburn et al. 2007]) provide for the type of protection that it believes is still needed in the UK. The principles state that any action to reduce marketing to children should: support their rights; afford them substantial protection; be statutory in nature; take a wide definition of commercial promotion; guarantee commercial-free childhood settings; include cross-border media; and be evaluated, monitored and enforced. In other words, the PDG considers that a comprehensive model which includes marketing, advertising, promotion and product placement would provide the necessary protection.
Advertising restrictions are gaining support. In 2007, WHO called for recommendations to restrict food marketing to children. Examples of jurisdictions that have successfully introduced such restrictions now include Norway, Sweden, Belgium, Greece, Romania and Quebec.
National policy has an important role in changing the risk factors faced by a population (both direct, indirect and unintentional). However, the PDG recognised that developing and implementing such policy is a highly complex process: it is not linear and rarely moves simply from design to implementation. In addition, the Group acknowledged that evidence alone is rarely sufficient to bring about policy change.
The way research evidence influences the policy process and gets translated into action can be explained by a model such as Kingdon's (1995) 'policy windows'. This suggests that 'windows' open (and close) by the coupling (or de-coupling) of three 'streams': problems, policies and politics. It can be applied nationally and locally (Exworthy et al. 2002). Other policy models also provide a potentially valuable insight into this complex, non-linear process. Whichever model is applied, however, all parties concerned need to acknowledge that the problem is important. In addition, it has to be possible to devise policies to remedy it, and there has to be a political willingness to act. Examples from other countries of where policy has been successfully used to reduce CVD are particularly valuable in showing what could be achieved in the UK.
This guidance has made the case unequivocally that CVD is a major and, most significantly, a preventable problem. It has also identified policy options which would be effective at the population level.
Nationally, the campaigning activities of charities such as the British Heart Foundation, the National Heart Forum and others focused on chronic diseases are particularly influential.
Voluntary action may be effective. However, if the pace of change is insufficient mandatory measures may be needed. The success of legislation banning tobacco advertising and smoking in public places followed unsuccessful voluntary agreements with industry. This also demonstrates the effectiveness of national government action to improve the public's health.
Regional government offices and strategic health authorities could make an important contribution to CVD prevention. For example, they could negotiate to maximise the number of local area agreements (LAAs) that include 'stretch' targets related to CVD. They could also ensure all PCT 'world class commissioning' strategies for healthcare adequately address CVD prevention at a population and individual level. This involves having long-term strategies for sustainable change that avoid an over-dependence on medical solutions. There is also scope for effective action by public sector bodies at a sub-regional level. This was the case in Merseyside where, prior to the national ban on smoking in public places, a private members bill supporting local smoking restrictions had been developed in case national legislation was delayed.
Local authorities and PCTs, working with the private and 'the third sector' in local strategic partnerships (LSPs), have demonstrated their commitment to CVD prevention. (The third sector includes voluntary and community groups, social enterprises, charities, cooperatives and mutual organisations.) For example, many have established health and wellbeing partnerships. In addition, 5 of the 15 most popular improvement targets in LSP local area agreements relate directly or indirectly to CVD prevention. Fifty-one LSPs have also selected national indicator (NI) 121 (mortality rate from all circulatory diseases for those aged under 75) as an indicator for the current round of local area agreements, which runs to 2011.
Only 5 (6.7%) of the 74 green flags awarded to the 152 LSPs in England as part of their first comprehensive area assessment related to public health (green flags represent exceptional performance or outstanding improvement); 19 (30.6%) of the 62 red flags awarded related to public health. Of these, 15 (24.2%) related directly or indirectly to CVD prevention. (Red flags indicate the need to improve outcomes.) The first comprehensive area assessment reports were published in December 2009.
Local advocacy by 'third sector' groups and organisations, including the voluntary sector, is an important part of CVD prevention activities. For example, it could have an impact on planning applications for fast-food outlets.
Addressing the needs of disadvantaged groups involves working beyond geographical boundaries with different communities. The leaders of some communities may be able to deliver CVD prevention programmes effectively. However, it should not be assumed that all community leaders will be able or willing to participate, or that it would be appropriate.
Many studies considered in the reviews of effectiveness for this guidance were carried out some years ago (that is, studies reporting on regional, population-level programmes). The majority were published before 2000, with a substantial number published before 1990. This reflects, in part, the decision to include studies such as the North Karelia and HeartBeat Wales CVD population programmes which took place in the 1970s and 1980s. The age of the studies means a number of factors have to be taken into account when considering effectiveness. In particular:
The risk factor levels for CVD are likely to have changed. For instance, intake of salt and saturated fat and the prevalence of smoking may have fallen, while a sedentary lifestyle and rates of obesity may have increased.
The political and cultural environments which potentially influence the effectiveness of interventions may have changed substantially.
A number of issues have to be taken into account when considering evidence of the effectiveness of population-level interventions:
Changes may have come about inadvertently, for instance, as a result of a change in agriculture practice following economic developments. Any evaluation of such changes is likely to have been carried out after the event, using proxy data.
It is often difficult to find a suitable control population where conditions are relatively similar to those in the intervention group. Where a control group is used, there is often contamination between the two groups which can lead to an underestimation of any beneficial effects.
It is ethically wrong, and practically impossible, to randomly allocate country-wide populations to controlled trials. The best evidence available has to be gleaned from other research designs, in particular, natural experiments, epidemiological models and cost effectiveness and cost–benefit analyses.
The potential effect of any intervention may change according to the initial level of risk. For instance, it may be easier to reduce salt consumption among a population with a high intake than among a population where intakes of salt are lower. However, epidemiological modelling suggests that substantial reductions in CVD rates can be achieved by reducing the major risk factors as much as possible. This is the case even in countries where CVD mortality rates are already relatively low, such as Italy (Palmieri et al. 2009).
The economic modelling used for this guidance was based on conservative assumptions. Nevertheless, it suggested that the recommended population-based approaches are likely to be consistently cost saving (see considerations 1.33 and 1.45 and appendix C).
The PDG recognised that empirical data alone, even from the best conducted investigation, seldom provides a sufficient or complete basis for making recommendations. Rather, it requires interpretation and analysis. Therefore, the PDG developed its recommendations using the best available empirical data and inductive and deductive reasoning, using prior knowledge and understanding and existing models and theories. The development of policy to reduce mortality and morbidity from CVD flow from these inductive and deductive interpretations.
The PDG acknowledged that the traditional hierarchy of evidence does not resolve all the problems associated with empirical data. For example, while it explicates the degree of bias attributable to poor internal validity, it does not answer it completely. Nor does it deal with external validity, that is, the degree to which findings are transferable to other experimental settings or to practice. The PDG therefore, took a broad approach to the evidence available to it.
Many of the risk factors that the PDG considered are also associated with other health-related conditions including some common cancers, chronic respiratory disease, obesity, diabetes, kidney disease and mental wellbeing. The strategies discussed in this guidance are likely to help prevent some of these other health conditions. (Certainly, they are not likely to increase the risk of any common chronic diseases.) However, it was not possible to consider each of these other health conditions in detail.
Daily consumption of products containing plant sterols and stanols may reduce blood cholesterol by about 10%, and so may reduce CVD mortality substantially. However, it was not clear how a recommendation on their use might impact on inequalities in health. The PDG believes this issue deserves further attention.
Agricultural and transport policy and practice (and associated issues) has a powerful impact on people's diet and physical activity levels. It also has an impact on climate change and sustainable development (which, in turn, can affect health). An analysis of transport patterns in London and how they could be changed indicates the extent of this synergy (Woodcock et al. 2009). One scenario described a 'sustainable transport future' featuring more physically active travel and low-emission vehicles to cut CO2 emissions by three-fifths. The report points out that physically active travel could bring substantial benefits: the incidence of heart disease and stroke could fall by 10% to 20%, with reductions in breast cancer (12% to 13%), dementia (8%) and depression (5%). Reductions in air pollution would bring additional health benefits.
Agriculture and food production account for 10% to 12% of greenhouse gas emissions (Friel et al. 2009). Livestock farming is responsible for four-fifths of these emissions (including methane). A 30% fall in adult consumption of saturated fat from animal sources (and an associated fall in livestock-related greenhouse gas emissions) would reduce heart disease by around 15% in the UK. If additional, positive effects are taken into account (such as a reduction in the prevalence of obesity and diet-related cancers) the health gains might been even more substantial.
Monitoring is crucial. The PDG commended the regular Food Standards Agency/Department of Health-sponsored surveys. These include the National diet and nutrition survey (NDNS) and the Low income diet and nutrition survey (LIDNS).