Re: "Interaction Between Tobacco and Alcohol Consumption and the Risk of Cancers of the Upper Aero-Digestive Tract in Brazil"

Abstract

Hereditary hemochromatosis (HHC) is an autosomal recessive disorder of iron metabolism characterized by increased iron absorption and deposition in the liver, pancreas, heart, joints, and pituitary gland. Without treatment, death may occur from cirrhosis, primary liver cancer, diabetes, or cardiomyopathy. In 1996, HFE, the gene for HHC, was mapped on the short arm of chromosome 6 (6p21.3). Two of the 37 allelic variants of HFE described to date (C282Y and H63D) are significantly correlated with HHC. Homozygosity for the C282Y mutation was found in 52-100% of previous studies on clinically diagnosed probands. In this review, 5% of HHC probands were found to be compound heterozygotes (C282Y/H63D), and 1.5% were homozygous for the H63D mutation; 3.6% were C282Y heterozygotes, and 5.2% were H63D heterozygotes. In 7% of cases, C282Y and H63D mutations were not present. In the general population, the frequency of the C282Y/C282Y genotype is 0.4%. C282Y heterozygosity ranges from 9.2% in Europeans to nil in Asian, Indian subcontinent, African/Middle Eastern, and Australasian populations. The H63D carrier frequency is 22% in European populations. Accurate data on the penetrance of the different HFE genotypes are not available. Extrapolating from limited clinical observations in screening studies, an estimated 40-70% of persons with the C282Y homozygous genotype will develop clinical evidence of iron overload. A smaller proportion will die from complications of iron overload. To date, population screening for HHC is not recommended because of uncertainties about optimal screening strategies, optimal care for susceptible persons, laboratory standardization, and the potential for stigmatization or discrimination. Am J Epidemiol 2001;154:193-206.

Perception on the Relationship between Cancer and Usage of Tobacco and Alcohol in Hail, Saudi Arabia

“…However, the respective contributions of these risk factors to head and neck cancer risk are difficult to study because these two habits are strongly associated with each other [17]. So understanding of the independent associations between cigarette smoking and alcohol drinking and the risk of cancer has important role to explain the mechanisms of carcinogenesis and for assessing the effects of interventions to modify these risk factors.…”

Alcohol drinking in never users of tobacco, cigarette smoking in never drinkers and the risk of head and neck cancer: pooled analysis in the international head and neck cancer epidemiology consortium

“…At least 75% of head and neck cancers diagnosed in Europe, the United States, and other industrialized regions are attributable to the combination of cigarette smoking and alcohol drinking (2,3). However, the respective contributions of these risk factors to head and neck cancer risk are diffi cult to study because these two habits are strongly associated with each other (4,5). A precise understanding of the independent associations between cigarette smoking and alcohol drinking and the risk of head and neck cancer has important implications for elucidating the mechanisms of head and neck carcinogenesis and for assessing the effects of interventions to modify these risk factors.…”