? ? Non-Hodgkin lymphoma (NHL) incidence and mortality have been increasing worldwide during the last two decades. The causes of this trend are unknown, and the current knowledge on the etiology of NHL is still poor. Studies focusing on occupational risk factors have generated useful etiologic hypotheses (e.g. pesticides and solvents exposure), but study findings have not been consistent. We will conduct a pooled analysis of 9 NHL case-control studies from North America, Europe, and Australia, to study the association between occupational risk factors and NHL, in different populations. Specifically, we will: """"""""Aim 1 - investigate occupational risk factors previously found to be associated with NHL"""""""", using uniformly defined indicators for occupational exposure. We will also: """"""""Aim 2 - evaluate risk by NHL subtype"""""""", using a standard NHL classification based upon histologically confirmed diagnoses. Pooling of the data from the 9 case-control studies conducted in 11 countries, will yield a study population of 9,490 cases and 10,971 controls, representing the largest NHL study to date. We will develop uniformly defined variables for occupations and occupational exposures, particularly pesticides, solvents, and infectious agents at work and study the association between occupation and occupational exposure and NHL and NHL subtypes through unconditional logistic regression. The case-control studies are part of the InterLymph consortium, which was established to facilitate the cooperation between epidemiological studies of NHL. The InterLymph collaboration has as particular strength that the cases of included studies have been classified into a standard scheme, thus enabling valid grouping of NHL suptypes over all studies. The studies include population or hospital controls, for which information on occupational risk factors and potential confounders has already been collected and computerized. This large study conducted by an international team of expert collaborators will provide sufficient study power to reach the outlined aims and contribute to the knowledge of the etiology of NHL. ? ? ?
