Toxic substance exposure and multiple myeloma: a case-control study

By means of a population-based, multicenter case-control investigation, certain toxic substances were evaluated as risk factors for multiple myeloma. Interviews were completed on 698 subjects with newly diagnosed multiple myeloma, and 1,683 controls were selected from the same geographic areas as those of the cases. Respondents were asked if they had ever been "highly" exposed" to one or more of a list of toxic substances or to other substances not on the list. With the aid of a toxicologist, responses were then categorized into 20 exposure groups. Those who reported past exposure to pesticides had an estimated relative risk of 2.6 for multiple myeloma [95% confidence interval (CI) = 1.5-4.6]. Subjects exposed to a variety of compounds commonly used by painters had an estimated relative risk of 1.6 (95% CI = 1.1-2.4). An increased risk also was found for those who were exposed to sources of carbon monoxide (relative risk = 1.8, 95% CI = 1.0-3.2). Associations of borderline statistical significance were found for metals and organically high polymers (plastics and elastomers). No statistically significant associations were seen for exposure to fertilizers; dyes and inks; alkalies; acids; other caustic substances; chemical asphyxiants; aliphatic, chlorinated, or aromatic hydrocarbons; aldehydes and ketones; ethers; esters; oils; dusts; or asbestos.