Non-Hodgkin’s Lymphomas and Organic Solvents Marco Antoˆ nio Vasconcelos Reˆ go, MD, PhD Cla´ udio Se´ rgio Campos Sousa, MD, MSc Mina Kato, MSc Albertinho Barreto de Carvalho, MSc Dana Loomis, PhD Fernando Martins Carvalho, MD, PhD Organic solvents have been suggested as a possible risk factor for non-Hodgkin’s lymphomas (NHL). We studied 109 NHL incident cases and 276 controls with other cancers (1990/1996) in the city of Salvador, Brazil. Occupational exposure to organic solvents was evaluated through standardized questionnaires and defined by indus- trial hygienists, taking into account individuals’ lifetime history. An association between occupational exposure to organic solvents and NHL was observed, OR  1.67 (95% CI, 0.97 to 2.87), especially among individuals less than 64 years, OR  1.91 (95% CI, 0.99 to 3.67), and among those who used domestic insecticides, OR  2.24 (95% CI, 1.01 to 3.97). Odds ratios were similar for nodal and diffuse NHL. These results suggest that organic solvents may contribute to the causation of NHL, especially among young individuals, and that synergism may play a role in the process of lymphomagenesis. (J Occup Environ Med. 2002;44:874 – 881) T he increasing incidence rate of the non-Hodgkin’s lymphoma (NHL) all over the world has been character- ized as epidemic, 1 but without con- sensus about its underlying causes. In general, the incidence of NHL is higher in Europe, the United States, and Australia than in Asia. 2,3 Expo- sure to solvents has been cited as one of the risk factors involved in the occurrence of NHL, 4 and several studies suggest this association. 5–12 Other studies did not find positive results, however. 13–19 It is recommended greater atten- tion to exposure to workplace agents upon reporting an increase in inci- dence in the period from 1935 to 1989 in Connecticut, USA, which was not explainable by known risk factors. 20 Exposure to pesticides, hair dyes, and solvents has been cited as risk factors responsible for part of this increase. 21 Nevertheless, there are difficulties related to exposure and disease definition regarding the epidemiology of chemically induced neoplasias of the lymphatic and he- matopoietic system, due mainly to diverse forms of the disease. 22 Information about NHL incidence, mortality, survivorship, and risk fac- tors is particularly scarce in develop- ing countries, with few studies of occupational exposure to carcino- gens, despite the fact that all chemi- cal agents, occupations, and indus- trial processes classified in group 1 or 2A of the International Agency for Research on Cancer (IARC) are found in those countries. 23,24 The main objective of this study is to investigate the association of NHL and occupational exposure to organic From the Workers Health Center—CESAT, Health Department of Bahia State; Department of Preventive Medicine, Medical School, Federal University of Bahia (Dr Reˆgo); Octa´vio Mangabeira Hospital, Health Department of Bahia State (Dr Sousa); Industrial Higienist of the Fundacentro, Ministry of Labor of Brazil (Dr Kato, Dr de Carvalho); Department of Epidemiology, School of Public Health, University of North Carolina (Dr Loomis); Department of Preventive Medicine, Medical School, Federal University of Bahia (Dr Carvalho). Address correspondence to: Marco Antoˆ nio Vasconcelos Reˆgo, MD, PhD, CESAT, Rua Pedro Lessa 123, Canela, Salvador—BA, Brasil 40-110-050; mrego@lognet.com.br. Copyright © by American College of Occupational and Environmental Medicine DOI: 10.1097/01.jom.0000030985.00778.27 874 NHL and Organic Solvents • Reˆ go et al