Monday, April 1, 2013 C7
HEALTH
THE PRESSURE AND
Ask the doctors
THE PAIN
................................................ Dr Ignatius Mark life@scmp.com Q: I know getting too little sleep is bad for you, but is it possible to get too much sleep? A: For a healthy person, it is not possible to get too much sleep. Sleep is controlled by the brain under the influence of a chemical called adenosine and the circadian rhythm. Adenosine builds up during wakefulness and causes sleepiness. The level of adenosine is reduced in the brain when a body has had enough sleep, and this will cause the person to wake up. If a person is sleeping more than normal or feeling excessively sleepy, there may be an underlying sleep disorder.
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Hypertension affects one in six adults in Hong Kong, but as its symptoms rarely show, most cases go undiagnosed, writes Sasha Gonzales
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s your blood pressure normal? There’s a one-insix chance that you have hypertension (high blood pressure), and you don’t know it. With this finding from a University of Hong Kong study last year – and in line with the theme of hypertension for Sunday’s World Health Day – the Health Department is launching a city-wide publicity and public education campaign tomorrow. Nearly 50 organisations, including medical associations and district councils, have pledged their support of the campaign to raise awareness of hypertension and encourage healthy living. Some are organising community blood pressure checking activities. The large-scale cohort study by HKU’s School of Public Health revealed that among those with hypertension documented in the study (about 32 per cent of adults aged 20 and above), only about half of them (46 per cent) were ever diagnosed as hypertensive. Even so, Dr Wayne Lam, an in-house physician at Hong Kong Adventist Hospital, says hypertension cases are typically diagnosed in a doctor’s office only incidentally because it is usually asymptomatic. The HKU study also found that the management of hypertension is suboptimal. Among those diagnosed, 70 per cent were prescribed blood pressure lowering medication, but only 42 per cent of this treated group attained good control of blood pressure. The study confirmed the “rule of halves” in hypertension: roughly half of all hypertensive cases are diagnosed, half of those diagnosed are treated, and half of those treated are well-controlled.
Equally worrying is the fact that hypertension patients in Hong Kong are getting younger. A recent fitness survey by the Leisure and Cultural Services Department (LCSD) identified 4.1 per cent of primary school students as being at risk of hypertension. For those aged 13-19, the figure was 7.5 per cent for boys and 1.2 per cent for girls.
Among those diagnosed, 70 per cent were prescribed medication but only 42 per cent of these attained good blood pressure control “Although the numbers are low,” say the researchers, “caution should be raised, as healthy children should not have such a chronic disease.” Dr Tony Wong of The London Medical Clinic adds: “We would expect the number of younger people with high blood pressure to go up along with their rising obesity rates.” A high-sodium diet raises blood pressure, which is a contributor to the development of cardiovascular disease. Eating too much salt contributed to 2.3 million deaths globally from heart attacks, strokes and other heart-related diseases in 2010, according to a new American Heart Association report. Being obese – that is, having a body mass index of 30 or more –
also increases the risk of developing the disease, says Dr Boron Cheng, specialist in cardiology at Matilda International Hospital. If you have a family history of hypertension, especially if a firstdegree relative suffers from it, your risk is increased because genetics is believed to play a role. Age is another factor. As we get older, our blood vessels tend to lose their elasticity, and this can affect blood pressure. The LCSD survey found a significant increase in hypertension risk from young to old adulthood. Among adults aged 20 to 39, 16.4 per cent of men and 6.3 per cent of women suffered hypertension risk. This increased to 40 per cent and 35.1 per cent among men and women aged 60 to 69. Other people at high risk, says Wong, include those with chronic kidney disease and mothers who developed preeclampsia during pregnancy – a condition characterised by high blood pressure, significant amounts of protein in the urine, and swelling of the hands, feet and face. Your lifestyle also may
The number of gene regions linked to high blood pressure found so far
determine whether you develop high blood pressure later in life. Lam points out that having two alcoholic drinks a day makes you up to twice as likely to develop hypertension than a nondrinker. He adds that smoking 15 cigarettes or more a day is associated with a transient rise in blood pressure, with the effect more pronounced in the first cigarette of the day. Chronic stress, too, can cause your blood pressure to spike, one theory being that stress hormones produced by the body can damage blood vessels and predispose you to hypertension. There are four main classes of medication used to treat hypertension, but studies have found that most people will eventually need more than a single drug to control their blood pressure. As such, combinations of agents have been developed with two or even three drugs in one pill. This makes it more convenient for the patient and allows the drugs to work synergistically.
Much is also being done in the area of genetic research. To date, 28 gene regions associated with high blood pressure have been discovered. This may pave the way to developing specific gene-targeted therapy in the future, says Wong, but more work still needs to be done. New treatments in the form of implantable blood pressure devices are being tested in the US and may prove useful for patients who don’t respond well to standard medications. “The pocket-sized Rheos machine is effectively a pacemaker for blood pressure,” says Wong. “When it detects high blood pressure it sends electrical impulses to the carotid artery in the neck, stimulating the body’s natural systems to reduce blood pressure.” Another new procedure involves the introduction of a wire into an artery in the groin that burns off a group of nerves
associated with high blood pressure. Results have proved promising for the group of patients who have tried it. High blood pressure can be controlled with modifications in diet and lifestyle. Minimising your salt intake will help greatly. Lam says reducing your daily salt intake from 4 grams to 2.3 grams can reduce blood pressure by 5/3mm of mercury in hypertensive people. Lose weight if you are overweight or obese, quit smoking, and limit your intake of saturated fat and sugary snacks. As vitamin D deficiency has been linked with high blood pressure, a daily supplement might be useful. Exercise helps, too. Lam points out that regular cardiovascular exercise can reduce your blood pressure by as much as 5mm to 15mm of mercury, although this drop is associated more with the intensity of the exercise rather than frequency. life@scmp.com
Illustration: Ken Cheng
life@scmp.com
Weighing up the costs Doctors vs mechanics Like car repair, medical care is a credence service: the professional (mechanic or doctor) has far more knowledge than the client (car owner or patient), and not only recommends a service, but also provides the service, and then charges for providing it. The client doesn’t know whether the service is needed at all, or, if needed, whether the particular service option is correct, and whether the fee charged is appropriate. Naturally, this causes great anxiety on the part of the client – especially when it is one’s own body rather than one’s car which is to be serviced. How can patients be sure they are receiving the right service at the right price? It is not easy, but economists have some answers.
To avoid over-treatment, economists recommend that you choose a doctor who is busy. A doctor will get into less trouble by providing treatment of some kind (whether it’s necessary or only superficial), whereas withholding treatment or providing inappropriate treatment is likelier to cause a lawsuit. Doctors vs refrigerators This same simple economic model works for minor or straightforward medical problems, which any doctor of the appropriate speciality can treat. Thus, the medical service can be regarded as a commodity, like a refrigerator. If your problem is rare or complex, the treatment is no longer a commodity. Patients wish to avoid under-treatment (or, more precisely, too much of the wrong treatment instead of the right amount of the right treatment). Some treatments are easy to deliver – for example, painkillers – and some are not, such as large and complex operations or powerful drugs with dangerous side effects.
Photo: Corbis
LAB REPORT ........................................... Jeanette Wang jeanette.wang@scmp.com
Weight of education Children of parents with low and medium education levels eat fewer vegetables and fruit, and more processed products and sweet drinks, according to a study published in the journal Public Health Nutrition, which involved nearly 15,000 children aged between two and nine from eight European countries.
Fountain of youth mapped The focus of this Sunday’s World Health Day is the global problem of high blood pressure.
FROM THE EXPERTS DR JASON BROCKWELL
Not very long ago, medical care was mostly ineffective, but safe and cheap. Now it is mostly effective, but dangerous and expensive. Unfortunately, it is hard to know exactly how effective, how dangerous and how expensive.
Dr Ignatius Mark is an ENT surgeon and director of sleep services at Ascent Ear Nose Throat Specialist Group, Mount Elizabeth Medical Centre in Singapore
Medical care is a credence service: the professional (mechanic or doctor) has far more knowledge than the client (car owner or patient)
If the doctor is too busy to sort out your complex problem, or does not have the experience or training to treat it, you hope that he or she will refer you to another doctor who can help. Unfortunately, your doctor may not know your diagnosis and, therefore, may not be able to refer appropriately, or does not know who to refer you to, because he or she is not aware of the expertise in the medical community. Under-servicing vs over-servicing Under-servicing is arguably more of a problem than over-servicing, as failure to receive needed treatment is usually more detrimental to patients’ health than receiving unnecessary services. Unnecessary services are usually safe; otherwise, the doctor could end up in court. (There is no big legal or moral difference between providing unnecessary
services which are safe versus risky, but there is a practical difference: with risky services there is a greater risk of coroner’s inquests and the like.) Hong Kong has two local problems for which I can offer no good solution. The smaller problem is that doctors are very poorly paid for thinking and relatively well paid for doing, so doctors who perform procedures lose money consulting. This discourages them from spending too much time with a patient with a complex problem. It’s better to see a dozen patients with simple problems. The other problem is medical advertising and the fact that it is banned by the Medical Council. This makes it very difficult for both patients and doctors to find out what services are available. Patients ask around, while doctors refer them to colleagues from medical school or their church or club. It’s hard to find out if a particular doctor has just returned from training at the
University of Copenhagen researchers and more than 1,000 researchers have taken a step forward in the fight against cancer with the mapping of the cellular “fountain of youth”: the enzyme telomerase. The study, published in Nature Genetics, took blood samples from more than 200,000 people. The enzyme creates new ends on chromosomes called telomeres. Researchers have found a genetic correlation between cancer and telomere length.
world’s best centre for that subject, or perhaps has done extensive research on something that is too complex or obscure for mass media. The government vs the people Economists tell us there are significant costs to preventing the free flow of information. These costs are, of course, hidden. The cost of the Medical Council’s over-regulation of advertising is paid by the government, which funds it apparently without limit. (It provides figures only on special request, and even then, it buries the big ones.) On the other side are some doctors attempting to circumvent the advertising restrictions, who may end up facing disciplinary inquiries, and sometimes court cases (usually judicial reviews of Medical Council decisions). Who really pays? Well, if you are a patient, you pay the doctor’s costs, and if you are a taxpayer, you pay the government’s. So you pay for both sides. Dr Jason Brockwell is a hip and pelvic surgeon in Hong Kong
More fibre, less stroke risk Eating more fibre may decrease your risk of first-time stroke, according to a study in the American Heart Association journal Stroke. It found that each seven gram increase in total daily fibre intake – equivalent to one serving of whole wheat pasta, plus two servings of fruit or vegetables – was associated with a 7 per cent decrease in the risk of firsttime stroke. The association recommends at least 25 grams of dietary fibre per day, or six to eight servings of grains and eight to 10 servings of fruit and vegetables.