Racial differences in the relationship between tobacco, alcohol, and squamous cell carcinoma of the head and neck

PURPOSE: Tobacco and alcohol use are well-known risk factors for squamous cell carcinoma of the head and neck (SCCHN), but there has been little examination of disparities in SCCHN and racial patterns of tobacco and alcohol use, especially for African-Americans. The Carolina Head and Neck Cancer Study, a population-based case-control study, was utilized to determine if relationships between tobacco and alcohol use and SCCHN differed by race. METHODS: Using a rapid case ascertainment system, cases were recruited from 46 contiguous counties in North Carolina from 2002–2006. Controls, selected from motor vehicle records, were frequency-matched to cases on age, sex, and race. This analysis was based on 989 white and 351 African-American cases and 1114 white and 264 African-American controls. Analyses were performed using unconditional logistic regression, adjusting for age, sex, race, education and fruit and vegetable consumption. RESULTS: The association between SCCHN and ever tobacco use among African-Americans (odds ratio (OR) 9.68 95% confidence interval (CI) 4.70, 19.9) was much greater than that observed in whites (OR:1.94 95% CI 1.51, 2.50). Smaller differences were observed when examining ever alcohol use (African-Americans OR: 3.71 CI 1.65, 8.30 Whites OR: 1.31 CI 0.96, 1.78). African-Americans consistently had greater effect measure estimates when examining common levels of duration and intensity metrics of tobacco and alcohol use, both independently and jointly. No racial differences in the effects of environmental (passive) tobacco smoke were observed. CONCLUSIONS: These findings suggest racial differences in SCCHN are not solely explained by differences in consumption patterns, and tobacco and alcohol may have greater impact in African-Americans

Single nucleotide polymorphisms in nucleotide excision repair genes, cancer treatment, and head and neck cancer survival

PURPOSE: Head and neck cancers (HNC) are commonly treated with radiation and platinum-based chemotherapy, which produce bulky DNA adducts to eradicate cancerous cells. Because nucleotide excision repair (NER) enzymes remove adducts, variants in NER genes may be associated with survival among HNC cases both independently and jointly with treatment. METHODS: Cox proportional hazards models were used to estimate race-stratified (White, African American) hazard ratios (HRs) and 95 % confidence intervals for overall (OS) and disease-specific (DS) survival based on treatment (combinations of surgery, radiation, and chemotherapy) and 84 single nucleotide polymorphisms (SNPs) in 15 NER genes among 1,227 HNC cases from the Carolina Head and Neck Cancer Epidemiology Study. RESULTS: None of the NER variants evaluated were associated with survival at a Bonferroni-corrected alpha of 0.0006. However, rs3136038 [OS HR = 0.79 (0.65, 0.97), DS HR = 0.69 (0.51, 0.93)] and rs3136130 [OS HR = 0.78 (0.64, 0.96), DS HR = 0.68 (0.50, 0.92)] of ERCC4 and rs50871 [OS HR = 0.80 (0.64, 1.00), DS HR = 0.67 (0.48, 0.92)] of ERCC2 among Whites, and rs2607755 [OS HR = 0.62 (0.45, 0.86), DS HR = 0.51 (0.30, 0.86)] of XPC among African Americans were suggestively associated with survival at an uncorrected alpha of 0.05. Three SNP-treatment joint effects showed possible departures from additivity among Whites. CONCLUSIONS: Our study, a large and extensive evaluation of SNPs in NER genes and HNC survival, identified mostly null associations, though a few variants were suggestively associated with survival and potentially interacted additively with treatment

Returns to investment in education: a further update

Returns to investment in education based on human capital theory have been estimated since the late 1950s. In the 40-plus year history of estimates of returns to investment in education, there have been several reviews of the empirical results in attempts to establish patterns. Many more estimates from a wide variety of countries, including over-time evidence, and estimates based on new econometric techniques, reaffirm the importance of human capital theory. This paper reviews and presents the latest estimates and patterns as found in the literature at the turn of the century. However, because the availability of rate of return estimates has grown exponentially, we include a new section on the need for selectivity in comparing returns to investment in education and establishing related patterns.