Acquaintance networks among leukemia and lymphoma patients.

A case-control study of clustering through acquaintanceship among lymphoma and leukemia patients was conducted for the years 1967 through 1972 in Orleans County, New York. Twenty lymphoma and 17 leukemia cases met criteria for inclusion in the study. Data on acquaintanceship linkage were gathered from the source cases and controls, and from their acquaintances yielding a data base of 13,409 unique individuals linked by acquaintance. Three different analyses were carried out: a statistical analysis of linkage via intermediaries of case pairs in comparison with control pairs; a computer simulation of disease transmission from selected source cases to selected targets and controls based on the acquaintance data; and a secondary attack rate type analysis. The first two types of analysis yielded statistically significant case-control differences at the .05 level. The third method also yielded a positive result but was not subject to quantitative hypothesis testing. An additional conclusion is that these epidemiologic methods for disease with long induction periods merit further study.

Changing risks in tuberculosis.

Past and present experience with tuberculosis in New York State exclusive of New York City is presented. TB has been on the decline since the turn of the century and reached an all-time low in 1974 with only 844 new active cases and 137 deaths reported. Although incidence rates are highest among the poor, the bulk of cases come from middle and upper socioeconomic levels. Cohort analysis shows an individual's risk of developing pulmonary or miliary TB is greatest at age 20-24, whereas the greatest risk of dying from TB is before age 5. Projections based on past experience indicate a male born in 1970-74 will have a lifetime risk of developing pulmonary or miliary TB of 80/100,000 and of dying from TB of 4/100,000. For females the respective risks are 40/100,000 and 6/100,000.