Authors’ Response

Abstract

To the Editor: We thank Dr Miller for his letter regarding our publication on multiple myeloma (MM) in World Trade Center (WTC) responders. Dr Miller observes that the occurrence of four cases of MM in young WTC responders “does not prove causation from WTC exposure.” We wholeheartedly agree. Indeed, in our report, we carefully stated that “it is too early to say whether the risk of MM is truly increased among WTC responders.” Because all four of the young WTC responders in our case series were police officers, Dr Miller asks reasonably whether there exist any previous reports of an increased incidence of MM in members of the law enforce-ment professions. We carefully searched the medical literature and were unable to find any such reports. Dr Miller opines that our report may be “subject to selection bias.” We recognize this possibility, and we carefully weigh it in our report. The magnitude of any selection bias depends in part on the size of the population of WTC responders. We estimated the response proportion as 50% to 70% of those eligible, which is reasonably high but still vulnerable to selective participation. Although selective response would not fully account for the excess found among younger participants, it may have influenced the patterns to some extent. Some cases presented after they had been diagnosed with MM. Others, however, developed MM after they had already been evaluated and are not subject to selection bias. It is also possible that other participants in the program have developed MM and have not returned for follow-up evaluations. Continued follow-up of this cohort as well as linkages with cancer registries should better inform us of disease rates in the upcoming years. Jacqueline M. Moline, MD, MSc Robin Herbert, MD Laura Crowley, MD Kevin Troy, MD Mount Sinai School of Medicine New York, NY Erica Hodgman, BA Mount Sinai School of Medicine New York, NY Emory University School of Medicine Atlanta, GA Gauri Shukla, MPH Mount Sinai School of Medicine New York, NY Iris Udasin, MD Environmental and Occupational Health Sciences Institute University of Medicine & Dentistry of New Jersey Piscataway, NJ Benjamin Luft, MD State University of New York at Stony Brook Stony Brook, NY Sylvan Wallenstein, PhD Philip Landrigan, MD, MSc David A. Savitz, PhD Mount Sinai School of Medicine New York, NY