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Background: The incidence of oropharyngeal and oral tongue cancers has increased over the last 20 years which parallels increased use of marijuana among individuals born after 1950. Methods: A pooled analysis was conducted comprising individual-level data from nine case–control studies from the United States and Latin America in the INHANCE consortium. Self-reported information on marijuana smoking, demographic, and behavioral factors was obtained from 1,921 oropharyngeal cases, 356 oral tongue cases, and 7,639 controls. Results: Compared with never marijuana smokers, ever marijuana smokers had an elevated risk of oropharyngeal [adjusted OR (aOR), 1.24; 95% confidence interval (CI): 1.06–1.47] and a reduced risk of oral tongue cancer (aOR, 0.47; 95% CI, 0.29, 0.75). The risk of oropharyngeal cancer remained elevated among never tobacco and alcohol users. The risk of oral tongue cancer was reduced among never users of tobacco and alcohol. Sensitivity analysis adjusting for potential confounding by HPV exposure attenuated the association of marijuana use with oropharyngeal cancer (aOR, 0.99; 95% CI, 0.71–1.25), but had no effect on the oral tongue cancer association. Conclusions: These results suggest that the association of marijuana use with head and neck carcinoma may differ by tumor site. Impact: The associations of marijuana use with oropharyngeal and oral tongue cancer are consistent with both possible pro- and anticarcinogenic effects of cannabinoids. Additional work is needed to rule out various sources of bias, including residual confounding by HPV infection and misclassification of marijuana exposure. Cancer Epidemiol Biomarkers Prev; 23(1); 160–71. ©2013 AACR.

Background: Maternal exposure to dipyrone during pregnancy has been associated with risk of infant leukemia (IL). N-Acetyltransferase 2 (NAT2) enzyme acetylates dipyrone, resulting in a detoxified metabolite. We performed genotyping to identify the distribution of NAT2 polymorphisms in duo samples from mothers and children previously investigated in a case-controlled study of IL. Methods: Samples from 132 IL, 131 age-matched controls, mothers of cases (n = 86), and mothers of controls (n = 36) were analyzed. PCR-RFLP assays were used to determine the NAT2 variants 191G>A, 282C>T, 341T>C, 481C>T, 590G>A, 803A>G, and 857G>A. The test for case-control differences in the distribution of genotypes was based on χ2 statistics. Unconditional logistic regression was used to examine the association between maternal exposure to dipyrone during the index pregnancy, IL, and NAT2 phenotypes. Crude and adjusted odds ratios (OR) are given with the 95% confidence interval (95% CI). Results:NAT2 slow-acetylation haplotypes were associated with IL (OR, 8.90; 95% CI, 1.71-86.7). An association between IL and NAT2 phenotype was observed in IL whether the mothers reported dipyrone exposures (OR, 4.48; 95% CI, 1.88-10.7) or not (OR, 4.27; 95% CI, 1.75-10.5). The combination of NAT2 slow/slow (mother/child) phenotypes confers a higher risk of IL (OR, 30.0; 95% CI, 5.87-279.7). Conclusion: NAT2 slow-acetylation profiles are associated with IL regardless of maternal exposure to dipyrone during pregnancy. Impact: Further recommendations about medicine exposures during pregnancy should take into account that infants with the maternal NAT2 slow-acetylation genotypes might be particularly vulnerable to greater risk. Cancer Epidemiol Biomarkers Prev; 19(12); 3037–43. ©2010 AACR.

Background: Marijuana contains carcinogens similar to tobacco smoke and has been suggested by relatively small studies to increase the risk of head and neck cancer (HNC). Because tobacco is a major risk factor for HNC, large studies with substantial numbers of never tobacco users could help to clarify whether marijuana smoking is independently associated with HNC risk. Methods: We pooled self-reported interview data on marijuana smoking and known HNC risk factors on 4,029 HNC cases and 5,015 controls from five case-control studies within the INHANCE Consortium. Subanalyses were conducted among never tobacco users (493 cases and 1,813 controls) and among individuals who did not consume alcohol or smoke tobacco (237 cases and 887 controls). Results: The risk of HNC was not elevated by ever marijuana smoking [odds ratio (OR), 0.88; 95% confidence intervals (95% CI), 0.67-1.16], and there was no increasing risk associated with increasing frequency, duration, or cumulative consumption of marijuana smoking. An increased risk of HNC associated with marijuana use was not detected among never tobacco users (OR, 0.93; 95% CI, 0.63-1.37; three studies) nor among individuals who did not drink alcohol and smoke tobacco (OR, 1.06; 95% CI, 0.47-2.38; two studies). Conclusion: Our results are consistent with the notion that infrequent marijuana smoking does not confer a risk of these malignancies. Nonetheless, because the prevalence of frequent marijuana smoking was low in most of the contributing studies, we could not rule out a moderately increased risk, particularly among subgroups without exposure to tobacco and alcohol. (Cancer Epidemiol Biomarkers Prev 2009;18(5):1544–51)

Background: The magnitude of risk conferred by the interaction between tobacco and alcohol use on the risk of head and neck cancers is not clear because studies have used various methods to quantify the excess head and neck cancer burden. Methods: We analyzed individual-level pooled data from 17 European and American case-control studies (11,221 cases and 16,168 controls) participating in the International Head and Neck Cancer Epidemiology consortium. We estimated the multiplicative interaction parameter (ψ) and population attributable risks (PAR). Results: A greater than multiplicative joint effect between ever tobacco and alcohol use was observed for head and neck cancer risk (ψ = 2.15; 95% confidence interval, 1.53-3.04). The PAR for tobacco or alcohol was 72% (95% confidence interval, 61-79%) for head and neck cancer, of which 4% was due to alcohol alone, 33% was due to tobacco alone, and 35% was due to tobacco and alcohol combined. The total PAR differed by subsite (64% for oral cavity cancer, 72% for pharyngeal cancer, 89% for laryngeal cancer), by sex (74% for men, 57% for women), by age (33% for cases 60 years), and by region (84% in Europe, 51% in North America, 83% in Latin America). Conclusions: Our results confirm that the joint effect between tobacco and alcohol use is greater than multiplicative on head and neck cancer risk. However, a substantial proportion of head and neck cancers cannot be attributed to tobacco or alcohol use, particularly for oral cavity cancer and for head and neck cancer among women and among young-onset cases. (Cancer Epidemiol Biomarkers Prev 2009;18(2):541–50)

Although active tobacco smoking has been identified as a major risk factor for head and neck cancer, involuntary smoking has not been adequately evaluated because of the relatively low statistical power in previous studies. We took advantage of data pooled in the International Head and Neck Cancer Epidemiology Consortium to evaluate the role of involuntary smoking in head and neck carcinogenesis. Involuntary smoking exposure data were pooled across six case-control studies in Central Europe, Latin America, and the United States. Adjusted odds ratios (OR) and 95% confidence interval (95% CI) were estimated for 542 cases and 2,197 controls who reported never using tobacco, and the heterogeneity among the study-specific ORs was assessed. In addition, stratified analyses were done by subsite. No effect of ever involuntary smoking exposure either at home or at work was observed for head and neck cancer overall. However, long duration of involuntary smoking exposure at home and at work was associated with an increased risk (OR for >15 years at home, 1.60; 95% CI, 1.12-2.28; Ptrend < 0.01; OR for >15 years at work, 1.55; 95% CI, 1.04-2.30; Ptrend = 0.13). The effect of duration of involuntary smoking exposure at home was stronger for pharyngeal and laryngeal cancers than for other subsites. An association between involuntary smoking exposure and the risk of head and neck cancer, particularly pharyngeal and laryngeal cancers, was observed for long duration of exposure. These results are consistent with those for active smoking and suggest that elimination of involuntary smoking exposure might reduce head and neck cancer risk among never smokers. (Cancer Epidemiol Biomarkers Prev 2008;17(8):1974–81)