Poor areas' TB rates 60 times higher than rich

Residents of poor suburbs in Auckland are 60 times more likely to be infected with tuberculosis (TB) than people in "posh" areas, say scientists.

"TB is a disease of poverty," said the Auckland medical officer of health, Dr Lester Calder. "The poorer you are, the more likely you are to get infected."

Analysis of Auckland data showed that the residents of the least affluent suburbs had rates of TB 60 times higher than those in the most affluent areas.

Using census data to compare suburbs on the basis of household incomes and access to facilities such as telephones, Auckland Healthcare had broken the city into 10 groupings according to a "deprivation score" between 1 and 10.

On this basis, suburbs scoring in the best three groupings had very low incidence of TB per 100,000 population. But in the bottom three groups, the incidence was over 20 cases per 100,000, 40 cases and over 60 cases, respectively.

Dr Calder said the average rate of incidence of TB in Auckland had been fluctuating around 20 per 100,000 people for the past 20 years, but rates varied markedly according to a range of factors, including ethnicity and local authority.

The affluent areas of Papakura and North Shore had relatively low levels of infection, while Rodney had low rates of infection among Europeans and Maori, but much higher rates among Pacific Islanders and other ethnic groups.

Dr Calder said there were higher rates of TB infection among younger adults, probably because there were more people in this age group coming from countries with a high incidence of the disease.

A major factor in Auckland's TB outbreaks had been waves of immigration from areas of the world where TB was common - the Pacific, Asia and Africa.

New Zealand's TB rate of 9.1 cases for each 100,000 people is higher Australia's (5.9) but low compared with many Pacific and Asian countries, such as Samoa (21.3) and the Philippines (400.6).

In New Zealand, the European rate is 2.7 per 100,000; for Maori, 10.5; Pacific Islanders, 27.1, while for "others," mainly Asians and Africans, it is 82.1. But Dr Calder said the proportion of TB among the New Zealand-born population had increased over the past two years and there had been a rise in infection among youngsters.

About 400 cases of TB a year have been reported in New Zealand for the past 10 years.

In an Auckland Healthcare newsletter for doctors, Dr Calder said the most important risk group which should be considered for vaccination was babies who might be exposed to TB, although South Auckland's Middlemore Hospital was the only one running a satisfactory level of vaccination for them. - NZPA