Incidence of pulmonary disease caused by mycobacteria other than tuberculosis in British Columbia.
BACKGROUND
The incidence of pulmonary disease due to mycobacteria other than tuberculosis (TB) in Canada has not been documented.


OBJECTIVE
To determine the incidence of pulmonary disease due to mycobacteria in the nonimmunocompromised population of British Columbia.


METHODS
A retrospective cohort study of 110 cases of mycobacteria infection other than TB identified from 1991 to 1995.


METHODS
British Columbia Centre for Disease Control, Division of TB Control.


RESULTS
The overall incidence rate of infection with mycobacteria other than TB was 0.63 10-5/year. This incidence rate was significantly higher among women (relative risk [RR]=2, P=0.0006) and in those aged 55 years or older (RR=8, P<0.00001). In contrast with TB, patients were more frequently born in Canada (P<0.00001) or in industrialized countries other than Canada (P<0.00001), and were less likely to be Aboriginal (P=0.0007) or foreign born from Asia (P<0.0001). The most common organism isolated in British Columbia was Mycobacterium avium-intracellulare (82.7%). Overall, 78 (71%) cases had underlying lung disease. Drug intolerance was very common (42%). After treatment, 55% and 41% of the patients were rendered smear negative or culture negative, respectively. Radiological improvement was noted in 55% of patients, and 60% of patients responded symptomatically to treatment.


CONCLUSIONS
The overall incidence of pulmonary disease is low. It is a disease predominantly of women 55 years and older, and targets completely different ethnic groups than TB, suggesting a protective effect of infection with Mycobacterium tuberculosis. M avium-intracellulare was the most common pathogen isolated. Further investigation is required into the natural history of so-called 'colonizers'. Considerable morbidity may be prevented with earlier intervention.
Elwood
R Kevin
RK
British Columbia Centre for Disease Control, Division of Tuberculosis Control, Vancouver, Canada. kevin.elwood@bccdc.ca
Opazo Saez
Anabelle M
AM
Lentini
Vittorio
V
Shadmani
Ramak
R
D001955:British Columbia / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D008171:Lung Diseases / Q000453:epidemiology* / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D009164:Mycobacterium Infections / Q000453:epidemiology*; D015270:Mycobacterium avium-intracellulare Infection / Q000453:epidemiology; D012189:Retrospective Studies