17.11.2013 Advances in genetics
Human genetics is today the most exciting and possibly the most important area of study not only for eventual disease prevention but also for the possible cure
By Syed Mansoor Hussain
What is ‘health’ is an interesting question. For most physicians, it is the absence of disease and physical impairment. The broadest definition is probably the one given by the World Health Organisation (WHO) in 1946 when it defined health as “a state of complete physical, mental, and social wellbeing and not merely the absence of disease or infirmity.” (Wikipedia)
During the last few decades things have started to change. The most important change is the greater emphasis on ‘mental health’ issues. For centuries, mental health was never fully understood or treated as a real disease. Advances in neuro-chemistry and ‘live brain imaging’ have added considerably to the understanding of mental problems. With the development of medicines that can affect brain chemistry, many of the well-known ‘psychiatric’ problems have become amenable to treatment.
Unfortunately as happens with almost every advance in medicine, there is the possibility of excessive and perhaps inappropriate use of medical treatments. Over the last few decades, increasing number of people are receiving psychiatric diagnosis and are being treated with medications that makes one wonder as to why there is this sudden ‘epidemic’ of mental problems that did not exist a generation ago.
Since ‘psychiatry’ is not my area of professional expertise so I will not expound on this issue. But as a physician and a concerned citizen, I must admit that there is probably a tendency towards over diagnosis and possibly overtreatment of ‘mental health’ problems. I will give two examples. First of the overactive child who is now labelled as ‘hyperactive’ and placed on medications or the adult who after bereavement or emotional upheaval becomes ‘sad’ and is treated for depression. In spite of these reservations, it is important to understand that from a ‘health’ point of view, mental problems are still vastly under diagnosed and undertreated especially in a poor country like Pakistan.
The WHO definition of health cited above includes ‘social wellbeing’ as another aspect of health. Clearly, physicians and even society in general cannot bring about social wellbeing through legislation or government intervention. However, it must be stated that poverty is one of the greatest detriment to social wellbeing. As such poverty alleviation not only improves virtually every parameter of social wellbeing but also improves health in all ages by providing education as well as greater access to ‘formal’ healthcare.
So now to some more interesting changes that have occurred about our conceptual understanding of health. The ‘apparent’ absence of disease or infirmity at a particular point in time does not necessarily make a person healthy. For instance, a 50-year-old man walking around with a significantly blocked heart artery might seem quite healthy until the time he has a major heart attack. As physicians often say, everybody is healthy until they get sick. If we exclude malnutrition, accidents, trauma and infections, almost all causes of future or ‘imminent’ disease are already present in our bodies. It is for this reason that ‘preventive medicine’ is becoming increasingly prominent.
The most frequently discussed prelude to ‘continued’ good health can be summed up as ‘life style choices’. Eating well, being physically active and avoiding smoking and excessive alcohol consumption among others are well known to promote good health. Being excessively overweight is a risk for future disease especially adult onset diabetes, high blood pressure and heart disease and is probably the most well-known result of improper life style choices.
The important point to make here is that an excessively overweight but otherwise ‘healthy’ person will in all likelihood develop medical problems with age. The same is true of a ‘heavy’ smoker or of somebody who drinks too much. But not all obese people will end up with the diseases mentioned above, and not all smokers will end up with lung cancer or breathing problems, nor will all heavy drinkers end up with liver problems.
Even though these ‘life style’ choices definitely increase the chance of developing serious medical problems as time passes, the opposite is also a fact. People who have never been overweight can still develop adult onset diabetes, high blood pressure or heart disease. And even non-smokers can develop lung cancer or breathing problems.
Perceptions about being overweight are to some degree also a cultural problem and often change over time. More than a generation ago, for patients ‘thin’ doctors were unlikely to be good doctors since they obviously did not make enough money to eat well. Today, overweight doctors are looked upon as people who cannot be good doctors since they cannot even take care of themselves.
When it comes to women, even being slightly overweight is now looked upon with some distaste. But an interesting medical reality is that people who are slightly overweight do much better when they become seriously sick than those who are thin. So we have to separate the really overweight from those that society and ‘fashion’ magazines think are overweight. An important point worth remembering is that ‘central obesity’ (belly fat) or collection of fat deposits around the abdomen and especially within abdomen around the stomach and intestines is much worse than fat spread all over the body.
One of the most important causes of future disease in healthy people is genetics or inherited tendencies. The fact that heart disease and many forms of cancer runs in families was always well known. As we study human genetics and the connection between inherited tendencies and disease, we realise how interconnected these two really are. It would seem that many evidently healthy people are possibly destined to develop serious disease in time. These can range from brain diseases, heart disease, many forms of cancer and the gamut of what we call ‘autoimmune’ disease.
Recent advances in genetics especially after the human ‘genome’ was mapped have provided greater impetus to this form of study. Frankly, human genetics is today the most exciting and possibly the most important area of study not only for ‘eventual’ disease prevention but also for the possible ‘cure’ of many types of disease through development of ‘individualised’ medicines. And one of the more interesting areas under consideration is prolongation of life.
Perhaps the most well-known example of the basic point I have tried to make of apparently healthy people not being really healthy is when it comes to particular types of genes that predispose women to breast cancer. Recently, the famous actress Angelina Jolie underwent a ‘prophylactic’ or preventive removal of both her breasts because of her family history and because the presence of a particular gene (BRCA 1) increased her chance of developing breast cancer up to almost ‘87 per cent’ over time.
However, the important thing to understand about genetics is that while we have a tremendous amount of information becoming rapidly available, we still don’t know how to use much of this information as far as prevention or treatment of a particular disease is concerned. Many times in the past, medical developments have promised a lot but over time we were disappointed. After all, when antibiotics were discovered almost 70 years ago we thought that infections will be gone forever but it has not happened.
The writer is former professor and chairman Department of Cardiac Surgery, KEMU/Mayo Hospital, Lahore. smhmbbs70@yahoo.com