A case-control study of multiple myeloma in whites: chronic antigenic stimulation, occupation, and drug use

A hospital-based case-control study of multiple myeloma in whites (100 cases and 100 controls from seven Baltimore hospitals) was conducted to examine a number of postulated risk factors. Cases and controls were matched on age, sex, hospital, and year of diagnosis. Distributions by marital status and religious affiliation were found to be similar. Educational levels of cases were similar to controls except for postcollege schooling, where there was a slight excess of cases (6%) compared to controls (3%). No statistically significant associations were found between multiple myeloma and prior history of medical conditions believed to cause prolonged stimulation of the immune system including chronic bacterial infections [odds ratio (OR) = 0.8], autoimmune disorders (OR = 1.0), allergy-related disorders (OR = 1.0), or lymphoid tissue surgery (OR = 1.2). Statistically significant positive associations were found for occupational exposure to petroleum products (OR = 3.7; 1.3-10.3) and asbestos (OR = 3.5; 1.0-12.0). No increased risk was found for cigarette smoking or alcohol consumption or for employment in a variety of industries and occupations implicated in earlier studies. A significantly elevated risk was found for prior use of laxatives (OR = 3.5; 1.1-11.1), and elevated (OR greater than or equal to 1.8) but nonsignificant risks were found for use of other medications including diphenylhydantoin, phenobarbital, diazepam, propranolol, ibuprofen, and diet drugs and stimulants. These findings require clarification in larger, population-based studies.