Promoting Prevention - and Barriers to Prevention

Prevention is better than cure. Everyone knows the adage. Everyone agrees. So where does the problem lie?

• Sometimes it is a matter of ignorance about appropriate behaviour although, more often the individual chooses to ignore prevention. No one can claim to be ignorant of the risks of smoking, unhealthy eating or taking illicit drugs, including the addictive nature of heroin and cocaine in particular. Often people are unaware of the true level of risk.
• Sometimes there is no choice as in parts of the world where the options are dirty water or no water.
• The decision to take risks is enforced by cultural pressures including the risk taking behaviour of young people, especially young males.

Prevention may be classified as primary of secondary:

• Primary prevention is aimed at healthy individuals to prevent disease from occurring. This may include vaccinations or the compulsory wearing of seatbelts. It also includes the encouragement of a healthy lifestyle with a good diet, a suitable weight, regular exercise and avoiding smoking, alcohol excess, illicit drugs and unsafe sex.
• Secondary prevention is aimed at patients with an existing pathology to reduce the risk of recurrence or progression. It includes the prescription of aspirin in arterial disease or beta blockers and ACE inhibitors after myocardial infarction or cessation of smoking in someone who already has COPD or arterial disease.
• Many interventions may be either primary or secondary, depending upon the circumstances. Thus it is better to stop smoking before myocardial infarction or COPD, but it is never too late to stop. Statins may be primary or secondary prevention. The distinction relates more to the person than to the intervention.
• Secondary prevention tends to be dealing with a smaller population at rather higher risk than primary prevention and so the numbers needed to treat (NNT) for a positive outcome tend to be smaller. On the other hand, it is preferable to prevent the initial occurence.

The higher risk in the group for secondary prevention may mean that interventions that are appropriate for this group are inappropriate for primary prevention. An example is the use of aspirin for CHD. In the following example, the numbers are purely to illustrate a point and should not be taken as the actual figures. Suppose that the number needed to treat to prevent 1 myocardial infarction by giving aspirin at 75mg a day for 5 years was 100 when given for secondary prevention but 10,000 when given for primary prevention in a low risk group. Suppose also that the risk of adverse effects such as gastro-intestinal haemorrhage is such that the number needed to harm (NNH) is 1 in 1,000 in both groups. In the high risk group the NNT is 100 and the NNH is 1,000. Therefore the intervention may be justified. In the low risk group, the NNT is 10,000 and the NNH is 1,000, so the intervention is not justified. A high NNT also means greater expense per positive outcome. Accepted wisdom is now that aspirin in primary prevention is effective in high risk groups¹ but is not recommended for the community as a whole.

Another way of classifying prevention is according to the level at which action is taken. Thus it can be at the national, local or personal level.

• At the national level, interventions include legislation such as compulsory seatbelts or motor cycle crash helmets. Taxation can influence activity.² In other countries it may involve the eradication of mosquitoes or the provision of clean drinking water and sewage disposal. In the UK only 5% of water supplies are fluorinated.³ This is discussed further in some dental and periodontal problems. Governments may also initiate education campaigns.
• At the local level, the provision of cycle paths and sports centres facilitates exercise, and healthy eating should be an easy option in canteens in schools and places of work.
• At work, health and safety is overseen by the Health and Safety Executive. They are a helpful organisation who prefer to facilitate but where regulations are breached, causing danger, they have the powers to be punitive too.
• At the personal level, it is the individual who must make the personal decision about lifestyle. It is the individual who consults with a health professional who may advise about diet and smoking, who may discover undiagnosed hypertension or diabetes or who advises on such matters as drugs to help prevention in the individual.

Wherever possible, doctors as individuals and as a profession should encourage national government, local government or other organisations in measures to prevent disease and to promote health but most interventions by health professionals will be at the personal level with the individual patient. Doctors should also set an example. The obese or smoking doctor is a poor advertisement.

The scope for the prevention of diseases is enormous. Many people in the developed world are dying of diseases related to smoking and obesity whilst many people elsewhere in the world suffer from malnutrition and infectious diseases. AIDS has caused devastation throughout much of sub-Sahara Africa and has killed many more in many other parts of the world. As governments and people eventually awake to the dangers of tobacco, this evil industry turns its attention to the developing world. China is an enormous and lucrative market. In many parts of the world where clean water and wholesome food are in short supply, Kalashnikov assault rifles and other deadly weapons are in plentiful supply.

Almost every article about a disease, on the EMIS Mentor system, has a concluding paragraph about prevention of that disease. This may include the barriers to prevention. A number of articles are of note. Accidents and their prevention discusses the prevention of many types of accident. Diving accidents also focusses on prevention. Health promotion for young children examines the benefits of early interventions and the establishment of appropriate attitudes. Antenatal care is preventative medicine. Gunshot injuries examines laws concerning firearms licensing in different countries. Prevention of falls in the elderly is self-explanatory. Stroke prevention is all about prevention. Our Health and social class record examines many of the issues of uptake of a healthy lifestyle. Of the various articles about AIDS and HIV, the one simply called AIDS contains much about prevention and barriers to prevention. Obesity management discusses prevention and barriers to prevention. Physical training examines the benefits of activity and how to advise about appropriate training. Sexually transmitted diseases examines transmission. There are articles on the primary prevention of cardiovascular disease and helping patients with smoking cessation. Childhood immunisations and other vaccinations are prevention. On a global scale, prevention of hepatitis B is prevention of hepatocellular carcinoma. Cervical screening is unique in that it aims to detect changes before they become malignant.

There are a number of criteria that must be fulfilled for a screening procedure to be viable. Cervical cytology and breast screening ⁴ both fulfill these criteria.

• The disease must be sufficiently common within the group to be screened that a reasonable number of cases can be expected to be detected.
• There is benefit in early detection. This may mean offering treatment at a more favourable stage or taking action to prevent or ameliorate the disease. There is no point in detecting pathology if there is nothing that can be done about it.
• The screening procedure must be cheap, easy and acceptable. The last is a problem with regard to faecal occult blood for colorectal carcinoma or prostatic biopsy for carcinoma of prostate. It is also a problem for cervical cytology amongst some ethnic groups.
• The screening test is not usually the gold standard for diagnosis and so there must be an acceptably small number of false positive results. Low specificity will overload the system with further investigation and lead to unnecessary anxiety.
• There must be a very low level of false negatives. Low sensitivity with too many false reassurances will bring the test into disrepute.

The problem with sensitivity and specificity is that there may be some overlap between normal and abnormal results. If the arbitrary line to divide the two is set too far in one direction, there will be too many false positives and if it is set too far the other way there will be too many false negatives. It is important that the public should realise that a screening test is not infallible and that false positives will occur and also some false negatives. When mammography detects 94% of tumours in the group screened, we should applaud the 94% detected and so treated earlier. Bewailing the 6% missed may undermine a very effective system.

Screening for prostate cancer is a problem.⁵ Estimation of PSA is insufficiently discriminative whilst transrectal ultrasound may have difficulties with uptake and many detectable malignancies would not advance to clinical significance in the patient's lifetime. Hence it would not benefit the individual.

A database containing family histories allows screening for hypertension and hypercholesterolaemia in those with close relatives with heart disease. Early mammography may be appropriate in women with a mother, aunt or sister with breast cancer before 50 years of age.⁶

In the not far distant past, health promotion within the consultation was, at best, an optional extra, with more emphasis on getting the patient in and out as swiftly as possible. Seminal works such as The doctor, the patient and his illness,⁷ as well as Doctors talking to patients⁸ and Consultation analysis⁹ considered the issue of health promotion within the consultation. Financial incentives are a strong way to influence behaviour and they were used to influence practice in reforms of both 1990 and again in 2003.

Some primary preventative measures can be effective when aimed at anyone. Advice on diet and exercise¹⁰ is beneficial to virtually everybody. Some measures need to be targeted so that they can be cost effective and clinically sound. Giving statins to everybody over 21 years of age would probably save lives eventually but it would be prohibitively expensive. There is also a possibility that adverse events may exceed benefits. Giving them to virtually everyone who has CHD is cost-effective and standard practice. Anticoagulation of patients with atrial fibrillation is very effective but in the elderly, the dangers of anticoagulation must also be considered.¹¹

Registration

An up-to-date practice database is the essential tool for primary prevention. Even the simplest of lists will have the patient's age and sex so that they can be invited for an over 70s check. More advanced databases will allow searching by disease so that at-risk patients can be called for annual flu vaccinations.

Opportunistic Screening

This is the most widely used form of risk identification where a patient presents for a routine consultation and the opportunity is taken to check weight and blood pressure. It is rather non-specific but can be useful in reaching patients who do not take advantage of screening initiatives or perhaps would not be included in the at-risk group. Not everyone with a disease is in the high risk group. It is probably the best way to promote smoking cessation with patients.¹²

Taxation

Chancellors of the Exchequer love to pretend that when they raise taxation on tobacco and alcohol their motivation is purely the health of the nation and that taxation on cars and fuel is purely for the sake of the planet. Raising cost by raising taxation does reduce consumption. Only a minority of drinkers are "problem drinkers" but there is a spectrum of drinking habits. As total alcohol consumption rises or falls, the number of people in the "problem drinker" category rises or falls too.² Over 40 years since the Royal College of Physicians published Smoking and Health there are still many people who smoke tobacco, including a substantial number who were not even born when the report was produced. Some are hopeless addicts and some have mental health problems. Smoking tends to be a more a habit of lower social classes and raising the price may simply cause more deprivation in those sections of society that do not abstain. Raising taxation on tobacco and alcohol by a large amount may have a number of consequences:

• Consumption may fall so much that total revenue from that source falls.
• It may be very unpopular with the electorate and in a democracy politicians have to be constantly aware of the effects of their actions in terms of votes won or lost.
• It will increase smuggling, especially across open EEC borders.

To think the unthinkable we may even question the desirability of a nation without smokers. The major economic problem facing all developed nations today, is not the price of oil but the longevity of its people. More old people put more strain on health and social services and deficits in pension funds are a gaping chasm as a significant number of people now spend a quarter of their lives as old age pensioners. Smokers pay substantially more tax over the years and tend to spend rather less time drawing pensions and enjoying the fruits of retirement. It is often argued that smoking related disease costs the NHS a considerable amount of money but this overlooks a very important fact. We shall all get ill and die one day. Smokers simply do it sooner than the rest. Can society afford to be without these "lemmings" who choose to pay significantly more tax and to live significantly less long?

Of course, not all interventions have the twin advantages of raising taxation whilst appearing to promote health. Most cost money. This may include screening programmes or advertising campaigns. Screening programmes include the cost of dealing with all the positive results, including the further investigation of the false positives before reassuring them. New immunisations or extending current ones cost money.

The Black Report¹³ was a careful study of health inequalities with a long list of recommendations. It achieved almost iconic status for how governments "bury bad news", being released with a misleading press statement on an August Bank Holiday Monday. Senior civil servants warned ministers that the implications were far too expensive to implement. The matter was discussed rather more fully in health and social class. It also examines "the inverse care law".¹⁴

Other Political Barriers

Politicians have to be aware of the popularity of their actions as they face periodic performance reviews at elections. This crass means of assessment is one of the shortcomings of democracy. It was because of pressure from the "freedom to choose" lobby that compulsion to wear seat belts in the rear of cars used to be restricted to those under 12. The wearing of seatbelts in the rear became compulsory for all in 1991 leading to an increase in wearing from 10 to 40% compared with over 90% who wear a seatbelt in the front.¹⁵ There are still 60% who break the law. There are certain sections of the press who are always ready to lambast the "nanny state". These are the same sections who advocate other government measures more suited to a dictatorship than a democracy. Politicians were wary about the feasibility and acceptability of restricting smoking in public places. Experience in a number of countries have shown it to be surprisingly effective and acceptable. Even smokers accept that they do need pressure to make them quit and non-smokers enjoy the freedom of not being smoked over in pubs, restaurants and other public places.

Financial and political pressures may also impair activity to promote healthy living at the local government level. At all levels there is a finite income and decisions have to be made about where to spend it. Employers might also see the facilitation of healthy eating and safety at work as unnecessary expense. Some industries have considerable financial interest in promoting unhealthy living.

There are still some industries in which it is quite acceptable to stop work to take a cigarette break but it is unacceptable simply to take a break.

Cost

Many people feel that expense is an impediment to a healthy lifestyle. Food labelled as "organic" is substantially more expensive and benefits are often dubious. "Convenience" or "junk food" is often not cheap and fresh fruit and vegetables are cheaper than even poor quality meat. White bread is significantly cheaper than wholemeal bread and a change in government subsidy of flour is well overdue. Healthy eating does not have to be expensive. Alcohol should be seen as a luxury and tobacco as a foul, polluting killer.

Deciding what is healthy and what is unhealthy food can sometimes be difficult. Processed food, in particular, may contain a great deal of added salt, sugar and unnecessary colouring. Contents of fat, unsaturated fat, salt, sugar, etc are often on the package but may be in ways that are difficult to comprehend, even for doctors. Salt may be given as grams of salt, grams of sodium or milliequivalents. Fat content may be per package, per 100 grams of per serving. There are commercial pressures to keep high the additives in food and to keep from consumers just how unhealthy some foods are.

The cost of sport and exercise does not have to be exorbitant. It is possible to choose recreations and pastimes that are both healthy and moderately priced. The idea that healthy living is "too expensive" is a fallacy and it is often the poorest members of society who choose to smoke and to drink alcohol to excess.

Cycling to work is cheaper than taking the car and promoted as a healthy option but there are a number of problems:

• Work must be a reasonable cycling distance away.
• The car must not be required once at work.
• People may get to work hot and sweaty and there are no facilities to shower and change.
• They may get soaked in the rain.

Social Barriers

In the early years the tobacco industry tried hard to discredit the research that exposed its dangers and to present its product as desirable. It always had a strong ally in the films from Hollywood that continued to portray smoking as "cool", sophisticated and desirable. Their code of practice prevented them from showing naked bodies but they were allowed to glorify violence and smoking. Young people will not see the dangers of smoking as applicable to themselves as they cannot imagine even wanting to be the wrong side of 40. That is why it has to be portrayed as filthy, despicable and incompatible with physical prowess and sexual allure.

Peer pressure is what drives young people to experiment with drugs and to drive dangerously. Alcohol consumption amongst the young is a major concern and the associated problems are discussed in the article on cirrhosis. As well as physical disease there are accidents and violence. Binge drinking, especially by young women who go "clubbing", is a particular cause for concern. Peer pressure may also lead to unsafe sex.

Sometimes it is ignorance that leads people to ignore a healthy lifestyle. Sometimes they are too lazy and make lame excuses. Sometimes they are the subject of disinformation. Both the BBC and ITV have persisted in trying to undermine the MMR vaccine by always referring to it as "the controversial MMR vaccine", pretending that some scientific uncertainty persists. The Daily Mail persists in its groundless antagonism whilst The Times has always been sensible on the issue. Failure to have eradicated doubts is a serious failing from a government that has always prided itself on presentation but the profession should also be much more strident on the issue.

Administrative Barriers

Badly run prevention programmes are often responsible for lack of effectiveness. Inadequate lists, unachievable targets and lack of follow-up for non-responders are typical problems. The greatest barrier to effective prevention is lack of effectiveness in modifying the risk factors in patients identified as at risk. The "rule of halves" is often quoted. It is applied classically to the management of hypertension but is valid for many chronic conditions.¹⁶ "Half of patients with hypertension are identified, half of these receive any treatment and only half of these are treated effectively". This notion is rather old and we should be doing rather better by now but we may not be.¹⁷

Prevention is better than cure. It has to be, but the management of change is a complex and difficult issue, not least transformation of lifestyles. There is ignorance. There is indolence. There are social and commercial pressures. The words of the General Confession in Archbishop Cramner's Book of Common Prayer seem most apt. We have done those things that we ought not to have done and we have left undone those things that we ought to have done and there is no health in us.

Doctors, educators and politicians have a duty to ascertain that the facts are delivered to the populace in a form that they can comprehend. What is rather more contentious is the degree to which prevention should be enforced. If a Jehovah's Witness is allowed to refuse a life-saving blood transfusion, is not a "couch potato" allowed to choose indolence and an early death? "You can take a horse to water but you cannot make it drink."

In recent decades General Practice has, quite appropriately, embraced prevention to help produce a National Health Service, rather than just a National Sickness Service. What has been achieved is most laudable although much more is possible. It is wrong to hold doctors responsible for the shortcomings of their patients but we have to do out best to convince even the stubborn and sceptic. Hence a half hearted approach to prevention is useless. You have to believe in your message with an evangelical vigour.