KEYNOTE ADDRESS BY GUEST-OF-HONOUR DR BALAJI SADASIVAN MINISTER OF STATE (HEALTH AND ENVIRONMENT)

Dr Low Cheng Hock

President, Singapore Medical Association

Ladies and Gentlemen

I am happy to be here with you today at the public forum entitled "Effective Health Screening – What You Should Know".

Health screening has been an integral part of the Ministry of Health’s clinical preventive services for many years. Since the 1980s, the Maternal and Child Health Clinics of the Ministry of Health, and later, the polyclinics provided developmental screening for infants and young children for the detection of developmental delays so that early intervention could be instituted and the child be helped to grow and develop normally. The School Health Service provides general health checks for primary and secondary school students, screening them for general health problems including defective vision, hearing impairment, heart and spine conditions. The School Dental Service provides dental screening for school children. Among the adults, the polyclinics provide cervical and breast cancer screening and screening for hypertension, diabetes and high cholesterol.

The purpose of health screening is to pick up disease conditions early among individuals who do not have any symptoms, in order to reduce the risk of disease progression or its complications. Screening tests assist "apparently" healthy individuals make more informed choices about their health. However, no screening test is 100% foolproof and it is therefore important that people have realistic expectations of what a screening test can deliver. All screening tests no matter how "good", will have a minimum irreducible number of:

1. false positives, that is, a positive screen in an individual who does not have the condition; and
2. false negatives, that is, a negative screen in an individual who actually does have the disease.

When these occur, the individual and his family inevitably go through a period of anxiety prior to the confirmation of the disease condition. In view of this, only tests which are sensitive and specific enough to detect diseases accurately should be conducted.

The World Health Organisation has drawn up a set of guiding principles for population based screening. Firstly, the disease being screened should be an important public health problem. Secondly, the history of the disease from the time where no symptoms are present to the time when symptoms appear should be understood. There should be a suitable screening test as well as treatment acceptable to the public. There should be economic balance between the cost of looking for cases, diagnosing and treating patients and the estimated expenditure on medical care if the disease was not diagnosed early through screening. And finally, looking for disease cases should be a continual process and not a "once off" project.

In Singapore, a number of new population based health screening programmes have been instituted in the last few years. Since 2000, the Check Your Health Programme, a community screening programme for persons over 50 years to detect high blood pressure, diabetes and high blood cholesterol, was implemented.

High blood pressure, diabetes and high blood cholesterol are important risk factors for coronary heart disease and stroke which are major causes of death and disability in Singapore today. The risk of getting these diseases increases with age. The 1998 National Health Survey showed that 1 in 2 ( 50%) Singaporeans in their 50s had high blood pressure compared to 1 in 10 ( 10%) in their 30s. About 20% of Singaporeans in their 50s have diabetes compared to 3% of those in their 30s.

The survey also showed that many people with diabetes and hypertension were not aware of their conditions. About 60% of diabetics and 50% of those with high blood pressure did not know they had these conditions. These diseases if undiagnosed may progress to an advanced stage, when complications set in.

For example, diabetes-related complications include eye and kidney diseases and stroke. In Singapore, diabetes-related eye disease and kidney disease are the major causes of blindness and end-stage kidney disease requiring dialysis. The financial costs for treating these complications is very high. In addition, people with these complications have a poor quality of life.

Studies show that diabetes if picked up early and treated with good control of blood glucose reduces the risk of eye disease, kidney disease and stroke. Similarly, screening to pick up hypertension and high blood cholesterol early will enable early treatment and management, reducing or delaying the onset of complications like heart disease and stroke.

We found that 60% of participants of the Check Your Health Programme had not had any health screening before and 60% of the participants had abnormal tests. I urge all those eligible to participate in the Check Your Health Programme.

Another screening test which is available is mammography for breast cancer. BreastScreen, a screening programme to detect breast cancer was launched earlier this year to encourage women to go for regular screening mammography. Mammography enables very small breast lumps to be detected so that treatment can be given early with the best chance of a cure.

Another preventable women’s cancer is cervical cancer. Pap smear screening enables pre-invasive cancer to be picked up early with very good cure rates.

Although in general, screening tests may save lives, we should be cautious and introduce new screening tests only when we are sure that it is of benefit to the community, because sometimes a screening test can do more harm than good. This was highlighted in an article in the International Herald Tribune on April 10 this year. A common cancer in children is neuroblastoma. Researchers in Japan found that a simple urine test could detect the tumour before it caused symptoms. A screening programme was started in Japan and many children with the tumour were detected. They underwent surgery. However, doctors found that the number of children dying of the cancer was still unchanged. They now believe that most of the early tumours detected by screening would have spontaneously disappeared without any treatment and that the surgery was actually unnecessary. As a result of the screening programme some of the children even died because of the unnecessary surgery. This screening programme in Japan has now been abandoned.

In conclusion, I would like to encourage all of you to lead a healthy lifestyle by exercising regularly, eating a healthy diet, maintaining a healthy weight, not smoking and managing stress. I would also like to emphasize the importance of going for regular screening for high blood pressure, diabetes and high blood cholesterol if you are over 50. Women in the eligible age groups should go for breast and cervical screening tests. These tests are available at your family doctors or polyclinics.

I commend the Singapore Medical Association for organising this public forum on the important topic of Health Screening. I wish all participants an interesting and fruitful afternoon.

Thank you.