Ageing, crowding hampering fight against TB

PUBLISHED : Saturday, 24 March, 2007, 12:00am
UPDATED : Saturday, 24 March, 2007, 12:00am

The ageing population and crowded living conditions are key obstacles to lowering incidence of the disease, which is much higher than in some developed countries, health chiefs say.

Health Department figures show the incidence rate is 83.7 per 100,000 population, with a death rate of 4.2. This is a much higher than in the US (5), Britain (12), Japan (30) and Singapore (40), as estimated by the World Health Organisation in 2004.

'The incidence rate has shown dramatic improvement when compared with the 1950s and 1960s, during which more than 10,000 people developed tuberculosis each year,' the senior medical and health officer of the department's tuberculosis and chest service, Chang Kwok-chiu, said on the eve of World Tuberculosis Day today. 'But in the past 15 years, the decline rate has been slower.'

Dr Chang said tuberculosis had started to become an epidemic in Hong Kong in the 1940s, nearly 200 years later than in western countries, and thus it was natural epidemiologically that the city's incidence rate was higher now.

Crowded living conditions and the ageing population were two challenges to further lowering the incidence rate, Dr Chang said.

'Tuberculosis is an air-borne infectious disease that can be spread easily in a crowded place,' he said.

'The incubation period can be very long, up to 10 years. It is estimated that about one-third of the population has a latent tuberculosis infection. Those with weaker immune systems, such as elderly people, tend to develop the disease more easily.'

Dr Chang said treatment was the best way to control and prevent tuberculosis.

The department was therefore providing free diagnosis, treatment and medicine to tuberculosis patients.

The department is also implementing a strategy of closely monitoring those under treatment, which is strongly recommended by the WHO. Every dose of drug is taken under direct supervision of trained personnel.

Dr Chang said treatment for tuberculosis could be at least six months, and every one or two days the patient had to take 13 or 14 pills, so the adherence rate could be low.

If patients take the medicine on their own, only two or three in 10 complete the treatment, compared to eight under the directly observed treatment.

Dr Chang said patients failing to take all drugs in a course increased the risk of drug-resistant tuberculosis strains developing. Such strains accounted for 10 per cent of TB patients in the city.

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