Tuberculosis epidemiology in Croydon.

A survey of tuberculosis in Croydon between 1988 and 1991, using Chest Clinic health visitor records, showed that the disease occurred most frequently in those of Indian Sub-Continent (ISC) ethnic origin. Of the 222 cases during the 4-year period, 65% were of ISC ethnic origin, 22% were Caucasian and 11% Afro-Caribbean. Non-Caucasian cases were younger (P < 0.0001), and more likely to be female (P = 0.064) or present with non-pulmonary disease (P = 0.064). One-quarter of ISC patients developed active tuberculosis more than 15 years after immigration into the UK. Only seven cases were children. The contact tracing procedure resulted in three additional cases, all of whom were contacts of smear-positive index cases. There were significantly fewer Heaf or radiologically positive contacts of non-smear positive pulmonary, or non-pulmonary index cases (P = 0.0002). The value of the current contact tracing system is discussed.