| A case-control study of non-Hodgkin's lymphoma (NHL) was conducted to determine various risk factors associated with this disease. A total of 378 HIV-negative residents of Los Angeles County diagnosed with high- or intermediate-grade NHL were compared with individually matched neighborhood control subjects. In addition, a total of 113 homosexual or bisexual men with AIDS-related NHL were compared with 50 matched control subjects with AIDS.; History of blood transfusion was not associated with risk of intermediate- or high-grade NHL in both HIV-positive and HIV-negative respondents. History of hepatitis C virus (HCV) infection was also not associated with risk of NHL in HIV-positive respondents. HCV infection was not examined in HIV-negative respondents in the current study; however, previous studies have shown a positive association between HCV and NHL.; History of using recreational drugs was examined in HIV-positive males. It was found that use of cocaine, Quaaludes, PCP, and psychedelic mushrooms were each associated with a significantly decreased risk of AIDS-related NHL. This is in contrast to a previous study of recreational drugs in HIV-negative males in which use of cocaine, amphetamines, Quaaludes, and LSD were each associated with a significantly increased risk of NHL in men. It is believed that the negative association between recreational drugs and AIDS-related NHL is due to some artifact of study design or represent an increased risk of other AIDS-defining conditions in association with drug use.; Interestingly, use of oral contraceptives was associated with a significantly decreased risk of intermediate- and high-grade NHL in women. Specific aspects of pregnancy history (i.e. parity, number of pregnancies, age at first pregnancy, etc.) were not associated with risk of NHL. Among parous women, those who had used lactation suppressants had a significantly decreased risk of NHL relative to unexposed women. The specific mechanism(s) behind these results are unknown; however, alterations in immune reactivity or cytokine expression may play a role.; NHL remains an important topic for epidemiologic study. Because NHL is composed of a heterogeneous group of neoplasms, future studies may benefit by carefully examining etiologic roles by specific subtypes of NHL. |
