**2.2.4 Lifestyle and personal and environmental factors**

Results from studies that evaluated lifestyle and personal factors are generally inconsistent, with few exceptions. Alcohol consumption appears to be inversely associated with NHL, based primarily on results from case–control studies (Chiu, et al., 1999; Chiu, et al., 2002). Further evidences from cohort studies are needed. Smoking does not appear to play an important role in the etiology of NHL overall; however, it has relation with follicular lymphoma (Bracci & Holly, 2005). Fish intake has been associated consistently with a nonsignificantly decreased risk of NHL in several studies (Zhang, et al., 1999), but intake of

**Simian Virus 40 (SV40).** Simian Virus 40 is the most well characterized member of the Polyomaviridae family, and is closely related to two human polyomaviruses (Poulin & DeCaprio, 2006).It induces an inapparent infections in immunocompetent hosts, but can produces pathologic effects in immunocompromised individuals through the destruction of infected cells (Imperiale, 2000).*Simian virus 40*, an agent that infects *Asian* ma- caques, contaminated the early poliovirus vaccines used in the United States, Europe, and other region during the mass immunization program for poliovirus in the late 1950 and early 1960 (Strickler, et al., 2003). The Norwegian study shows that between 1953 and 1997, the incidence rate of lymphoproliferative diseases increased about 3-fold in both males and females (Thu, et al., 2006), and the other study report that *polyomavirus SV40* is significantly associated with non-Hodgkin lymphoma in *HIV-1*-infected and *HIV-1-*uninfected patients and might have a role in the development of these hematological malignancies (Vilchez, et al., 2002). These observations suggest that *polyomavirus SV40* might be causing infections in human beings long after the use of the contaminated vaccines. There is no documented

Family history and genetic factors increase risk of NHL in people whose relatives previously were diagnosed with NHL, but hereditary factors are hypothesized to account only for a small percentage of NHL and are unlikely to explain the increase in NHL incidence. Tumor suppressor genes, oncogenes and DNA repair genes may play a role in NHL carcinogenesis, and some genes may interact with environmental exposures that affect NHL risk (Fisher & Fisher, 2004). In a US multicenter case–control study, Chatterjee *et. al* showed *(Chatterjee, et al., 2004)* the strongest associations were found among siblings (HR = 7.6, 95% CI: 0.98–58.8) and male relatives (HR = 6.2, 95% CI: 0.77–50.0) of NHL cases. For a parental history of histopathologically concordant lymphoma, the strongest associations with lymphoma risk among offspring were found for B-cell lymphoma (SIR = 11.8, 95% CI: 2.2–34.8) and follicular

Several genetic polymorphisms associated with the risk of NHL suggest that single nucleotide polymorphisms (SNPs) in tumor necrosis factor (TNF) and interleukin-10 (IL10) are associated with risk of NHL, especially diffuse large B –cell lymphoma. Relatively few studies have examined the potential interaction between germline susceptibility and environmental or lifestyle factors in the etiology of NHL (Alexander, et al., 2007). The mechanism (s) by which genetic predisposition or gene-environment interactions may enhance or reduce the risk of developing NHL remains a largely unexplored area of

Results from studies that evaluated lifestyle and personal factors are generally inconsistent, with few exceptions. Alcohol consumption appears to be inversely associated with NHL, based primarily on results from case–control studies (Chiu, et al., 1999; Chiu, et al., 2002). Further evidences from cohort studies are needed. Smoking does not appear to play an important role in the etiology of NHL overall; however, it has relation with follicular lymphoma (Bracci & Holly, 2005). Fish intake has been associated consistently with a nonsignificantly decreased risk of NHL in several studies (Zhang, et al., 1999), but intake of

lymphoma (SIR = 6.1, 95% CI: 1.1–18.0) *(Altieri, Bermejo, & Hemminki, 2005).*

**2.2.4 Lifestyle and personal and environmental factors** 

study around it in Asian countries.

research (Alexander, et al., 2007).

**2.2.3 Genetic factors and family history** 

omega-3 fatty acids from fish was not associated with reduced risk of NHL in one cohort study (Purdue, Bassani, Klar, Sloan, & Kreiger, 2004). Several but not all studies have reported positive association with red meat intake. Data are limited, and results have not been consistent, for estimates of associations with specific types of red meat or with preparation or cooking methods (Chang, et al., 2006; Ward, et al., 1994). Saturated fat intake was associated positively (Chang, et al., 2006), however vegetable consumption was associated inversely, with NHL risk in most studies (Chang, et al., 2005; Mozaheb & Aledawood, 2011). Biological mechanisms for these dietary factors have not been established*.* Neither obesity nor physical activity has been associated consistently with NHL (Alexander, et al., 2007).

Certain workers have a slightly increased risk of developing NHL, including farmers; pesticide applicator; miller; meat worker; wood and forestry worker; chemists; painters; mechanics; printers; and worker in the petroleum, rubber, plastics, and synthetics industries (Alexander, et al., 2007). Some of these occupations are more common in Asian countries such as farmers, pesticide applicator, wood worker, worker in petroleum; on the other hand exposure is more because of low educational program in these places. Also There is significant relationship between hair dye use and NHL risk (Altekruse, Jane Henley, & Thun, 1999).
