Nonsteroidal anti-inflammatory drug use, body mass index, and anthropometry in relation to genetic and flow cytometric abnormalities in Barrett's esophagus.

A dramatic increase in the incidence of esophageal adenocarcinoma has occurred among men in the United States over the last two decades. The underlying reasons remain largely unknown, although the increasing prevalence of obesity likely plays a role. Most adenocarcinomas arise in a metaplastic epithelium termed Barrett's esophagus (BE) that develops in approximately 10% of persons who have chronic gastroesophageal reflux. Persons with BE are at high risk (0.5-1.0%/year) of progressing to cancer. In a cross-sectional study of 429 persons with BE, we evaluated the associations between increased body mass index, anthropometric measures, cigarette smoking, use of nonsteroidal anti-inflammatory drugs (NSAIDs) and markers of increased risk, including aneuploidy, increased 4N fraction, loss of heterozygosity (LOH) of 17p and 9p alleles, and high-grade dysplasia (HGD). In logistic regression models adjusting for age, gender, NSAID use, and cigarette smoking, increasing waist:hip ratio was related to increasing risk of aneuploidy (trend P = 0.01), 17p LOH (trend P = 0.005), and 9p LOH (trend P = 0.007). The odds ratios comparing highest to lowest quartiles were 4.3 [95% confidence interval (CI), 1.2-15.6] for aneuploidy, 3.9 (95% CI, 1.3-11.4) for 17p LOH, and 2.7 (95% CI, 1.2-6.3) for 9p LOH. A nonsignificant trend was also observed for increased 4N fraction, whereas little association was found for HGD. Similar patterns of risk were noted for other anthropometric measures such as waist:thigh and abdomen:thigh ratios. There was no evidence that elevated body mass index increased risk of any of the biomarkers. Suggestive evidence also was found for a protective effect of NSAID use. The odds ratios for current users, compared with those who never used NSAIDs regularly, were 0.6 (95% CI, 0.3-1.4) for increased 4N, 0.6 (95% CI, 0.3-1.3) for aneuploidy, 0.3 (95% CI, 0.1-0.7) for 17p LOH, and 0.7 (95% CI, 0.4-1.2) for HGD. There was no association between NSAID use and risk of 9p LOH. We conclude that an abdominal distribution of body fat, which is more common in men and is termed male-pattern obesity, may be a strong predictor of risk of neoplastic progression among persons with BE and may account in part for the male predominance of BE and esophageal adenocarcinoma. We also conclude that NSAID use may reduce the risk of progression to cancer in this population. Prospective studies are needed to confirm these results.

Serum selenium levels in relation to markers of neoplastic progression among persons with Barrett's esophagus.

BACKGROUND: Persons with Barrett's esophagus have a substantially greater risk of esophageal adenocarcinoma than the general population. Higher serum selenium levels have been associated with a reduced risk of several cancers; however, their association with the risk of esophageal adenocarcinoma is unknown. We used a cross-sectional study to investigate the relationship between serum selenium levels and markers of neoplastic progression among persons with Barrett's esophagus. METHODS: Medical history, blood, and esophageal tissue specimens were collected from 399 members of a cohort study of Barrett's esophagus patients undergoing endoscopic surveillance. Serum selenium levels were measured by flameless atomic absorption spectrophotometry. DNA content of tissue samples was measured by flow cytometry. Loss of heterozygosity (LOH) at 9p and 17p, chromosomal regions which include the p16 and p53 tumor suppressors, respectively, was detected by automated fluorescent genotyping. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). All statistical tests were two-sided. RESULTS: Persons with serum selenium levels in the upper three quartiles (i.e., >1.5 micro M) were less likely to have high-grade dysplasia (OR = 0.5, 95% CI = 0.3 to 0.9) or aneuploidy (OR = 0.4, 95% CI = 0.2 to 0.8) than those with levels in the lowest quartile. Serum selenium levels in the upper three quartiles were associated with similar reductions in risk of 17p (p53) LOH (OR = 0.5, 95% CI = 0.2 to 0.9) and increased 4N fraction (OR = 0.6, 95% CI = 0.3 to 1.2). By contrast, serum selenium levels were not associated with 9p (p16) LOH (OR = 1.0, 95% CI = 0.5 to 1.7), a marker that appears early in neoplastic progression. CONCLUSION: Our preliminary results, from a cross-sectional analysis with biologic markers, suggest that higher serum selenium levels may be associated with a reduced risk of esophageal adenocarcinoma among persons with Barrett's esophagus. Because serum selenium was not associated with 9p (p16) LOH, we speculate that selenium may act primarily at later stages of progression toward adenocarcinoma.