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The pattern of tuberculosis in Indian, Pakistani and Bangladeshi patients in Blackburn (1978-1987) was compared with that for England and Wales (MRC Survey), with particular reference to the proportion with parenchymal lung disease, by a generalized linear model allowing for age, ethnic group and time since first entry. In Blackburn, the proportion with lung disease was higher in Pakistani/Bangladeshi (46%) compared with 28% in Indians, although in both groups this increased with age. In the MRC Survey, the proportions with lung disease were similar (Pakistani/Bangladeshi 36.5%, Indians 34%) but there was an increase in lung disease with age and year since first entry in the Indian ethnic group only. The reasons for the differences, and their implications are discussed.

Of the 4172 patients in a survey of all cases of tuberculosis notified in a six-month period in England and Wales in 1978-79, 198 had a bone or joint lesion; 79 were white and 108 were of Indian subcontinent (Indian, Pakistani or Bangladeshi) ethnic origin. The estimated annual notification rates for orthopaedic tuberculosis were 29 per 100 000 for the Indian subcontinent group and 0.34 per 100 000 in the white group, a ratio of 85 to 1. Rates increased with age in both groups. The spine was the most common site, and was affected in 30% of the white patients and 43% of the Indian subcontinent patients; the distribution of other sites was similar in both groups. Positive culture from a bone or joint lesion was obtained in 99 (50%) of the 198 patients (58% of white patients and 47% of the Indian subcontinent patients). Bacteriological or histological confirmation of tuberculosis either from a bone or joint lesion or from another site was obtained in 68% of the patients. Mycobacterium tuberculosis was isolated from the orthopaedic lesions in 79 of the 82 patients with identification test results and M. bovis in the 3 remaining patients. Of the 61 patients with M. tuberculosis and with no history of previous chemotherapy, 5 had resistant strains compared with 1 of the 18 patients who had previously received chemotherapy. All 6 patients with resistant strains were of Indian subcontinent ethnic origin.

Between special surveys in 1971 and 1978/79 the estimated annual tuberculosis notification rate for males in England fell from 30.5 per 100 000 to 22.6 per 100 000 (a decline of 3.8% per year). For females the rate fell from 18.4 per 100 000 to 15.8 per 100 000 (1.9% per year). In each survey the lowest rates were those for the white ethnic group born in the United Kingdom. The highest rates, some more than 50 times as great, occurred in immigrants from the Indian sub-continent (Indian or Pakistani/Bangladeshi). The rates for immigrants from the West Indies were 3 to 4 times as great as than those for the white group. The most rapid reductions in rate between the surveys, of about 10% per year, occurred in West Indian immigrants of both sexes and in Pakistani/Bangladeshi male immigrants. The rate for Pakistani/Bangladeshi females fell by 6.5% per year. For whites born in the U.K. the annual rate of decline was 5.1% in each sex. There was very little change for Indian immigrants of either sex. Between the surveys, continued immigration of groups from the Indian subcontinent with high notification rates considerably slowed the decline in notification rate for the whole population. The steep downward trend in notification rate for the white ethnic group may be expected to continue, but changes in the other ethnic groups are more difficult to assess because they are influenced by so many uncertain factors. In addition, the trends in the non-white ethnic groups born in the United Kingdom cannot yet be ascertained, but will become of increasing importance.

In two national surveys of tuberculosis notifications in England conducted in 1978/79 and 1983 the estimated annual notification rates for the Indian subcontinent (Indian, Pakistani, and Bangladeshi) ethnic groups were considerably higher than the rate for the white ethnic group. The mean annual decline in rates between the surveys appeared to be greater for the Indian and the Pakistani and Bangladeshi ethnic groups, 15% and 16% respectively, than for the white ethnic group (7%). Data from two small sample population surveys, the National Dwelling and Housing Survey in 1978 and the Labour Force Survey in 1983, were used to calculate the rates. However, comparison of the estimates for the population of Indian subcontinent ethnic origin in England from these surveys revealed discrepancies between them. Additional information from the Labour Force Survey on the year of first entry to the United Kingdom (UK) permitted the calculation of new estimates for the 1978 population, and based on these estimates the annual notification rates for 1978/79 were 287 per 100,000 for the Indian and 286 per 100,000 for the Pakistani and Bangladeshi ethnic groups. The rates for 1983 were 178 and 169 respectively, and the mean annual decline between the surveys was 11% for the Indian and 12% for the Pakistani and Bangladeshi ethnic groups. There were important changes in the characteristics of the population of Indian subcontinent ethnic origin in England between 1978 and 1983, and therefore the rates for both surveys have been standardised by the method of direct standardisation to a common reference population. Standardizing for year of entry to the UK, place of birth (UK or abroad), age, and sex reduced the mean annual decline in the notification rate to 4% for the Indian and 9% for the Pakistani and Bangladeshi ethnic groups. The much greater reduction in the rate of decline in the Indian ethnic group is due to the substantial decline between the surveys in the proportion of recent immigrants, the group with the highest annual notification rate, in that population. Future trends will continue to be influenced by immigration patterns, but it will also be important to monitor the rates among the increasing proportion of the population born in the UK or resident in England for more than five years.

In a survey of the chemotherapy prescribed for 1312 adult patients of white or Indian subcontinent ethnic origin with pulmonary tuberculosis only, notified in the 6 months from October 1978 to March 1979, it was found that 163 (12%) patients died before they had completed chemotherapy. Of the 163 patients who died 96% were of white ethnic origin; 15% of the 1022 white patients died compared with 2% of the 290 Indian subcontinent patients. According to the death certificate, approximately half the white patients died from tuberculosis, and in a further 31% tuberculosis was a contributory factor. Death from tuberculosis most frequently occurred in the older age groups, accounting in part for the different findings in these two ethnic groups, because of the excess of older white patients. In a step-wise multivariate discriminant analysis death from tuberculosis was found to be significantly associated in the white patients with the radiographic extent of disease before treatment, and with age, extent of cavitation and a positive sputum smear result, but not sex. Most of the deaths from tuberculosis occurred early, 38% before the end of the first week of chemotherapy and 69% by the end of 4 weeks. There was a further group of 51 adult patients with pulmonary tuberculosis notified in the same 6-month period in whom the diagnosis was not made until after death, 25 of them dying from tuberculosis. It is concluded that there is still a substantial risk of death from tuberculosis in patients with extensive disease in the older age groups.