Comparison between attenders and non-attenders at the Danish mass tuberculosis campaign, 1950-52. Tuberculosis morbidity and general mortality in two groups during the first four years of follow-up.

A previous study by the Danish Tuberculosis Index reported the incidence of pulmonary tuberculosis among attenders at the Danish mass campaign in 1950-52 during the first four years after the campaign. Since it is important to know whether the attenders can be regarded as representative of the general population, from the point of view of case-finding surveys after mass campaigns, a further study was undertaken in which the attenders at the campaign were compared with the persons who were invited to attend, but failed to do so.The first part of this study presents a comparison between attenders and non-attenders at the time of the mass campaign. Analysis according to sex, age, residence, occupation and previous vaccination with BCG showed a striking uniformity between attenders and non-attenders.The second part compares the tuberculosis morbidity and general mortality in the two groups after the mass campaign. The incidence of tuberculosis in a follow-up period of four years was found to be lower among the attenders. This is largely due to the case-finding during the mass campaign and cannot be regarded as indicating that the non-attenders form a "high risk" group. During the follow-up period, the general mortality was also higher among the non-attenders.