© The Author 2006. Published by Oxford University Press.
CORRESPONDENCE |
Re: Carbonated Soft Drink Consumption and Risk of Esophageal Adenocarcinoma
Affiliations of authors: Istituto di Ricerche Farmacologiche "Mario Negri," Milan, Italy (SG, CLV); Unità di Epidemiologia e Biostatistica, Centro di Riferimento Oncologico, Aviano (Pordenone), Italy (RT, LDM); Cancer Prevention and Control Unit, Institut Català d'Oncologia, L'Hospitalet, Spain (EF); Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain (EF); International Agency for Research on Cancer, Lyon, France (SF); Istituto di Statistica Medica e Biometria, Università degli Studi di Milano, Milan, Italy (CLV)
Correspondence to: Silvano Gallus, ScD, Istituto di Ricerche Farmacologiche "Mario Negri," Via Eritrea, 62, 20157 Milan, Italy (e-mail: gallus{at}marionegri.it).
Mayne et al. (1) provided relevant information on the association between carbonated soft drinks (CSD) and esophageal cancer risk using data from a population-based case–control study conducted in the United States. CSD may increase gastric distension, and consequently gastroesophageal reflux disease and could hence have contributed to the increasing trend of esophageal adenocarcinoma (2), which parallels the increase in CSD consumption. However, odds ratios (ORs) for the highest (
1 drink/day) versus the lowest (<1 drink/month) quartiles of CSD consumption were 0.47 for esophageal adenocarcinoma (282 case patients), 0.74 for gastric cardia adenocarcinoma (255 case patients), 0.85 for esophageal squamous cell carcinoma (SCC, 206 case patients), and 0.65 for noncardia gastric adenocarcinoma (352 case patients), with a statistically significant inverse trend in risk for esophageal adenocarcinoma. To provide additional information to this issue, we analyzed data from a hospital-based case–control study conducted in northern Italy between 1992 and 1997 (3).
Case patients were 304 individuals (275 men and 29 women, median age = 60 years, range = 39–77 years) with incident, histologically confirmed esophageal SCC. Control subjects were 743 patients (593 men and 150 women, median age = 60 years, range = 36–77 years) admitted to the same hospitals as case patients for a wide spectrum of acute, nonneoplastic conditions, not related to smoking, alcohol consumption, or long-term modification of diet. Control subjects were frequency matched with case patients by quinquennia of age, sex, year of interview, and area of residence. Case patients and control subjects were interviewed using a standard questionnaire that included questions pertaining to sociodemographic factors and lifestyle habits, such as tobacco smoking and alcohol consumption and anthropometric measures. Subjects' usual diet during the 2 years before cancer diagnosis or hospital admission was investigated using a validated 78-item food frequency questionnaire (4,5) that included a specific question on CSD consumption. Odds ratios for CSD consumption were estimated by using unconditional multiple logistic regression models (6), including terms for age, sex, study center, education, tobacco smoking, alcohol drinking, body mass index (weight in kg/height in m2), physical activity, and total energy intake.
Case patients and control subjects were grouped according to CSD consumption, overall and in strata of sex and age (Table 1). The overall odds ratio for esophageal SCC incidence among those who drank one or more glasses of CSD per month was 0.86; it was 0.82 in men, 1.11 in women, 1.09 in subjects aged <60 years, and 0.69 in those aged 60 years. Corresponding estimates for regular CSD consumption (1 glass/day) were 0.80 overall, 0.80 in men, 0.70 in women, 0.94 in younger subjects, and 0.86 in older subjects. None of these estimates were statistically significant.
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Our study, based on a large sample size of esophageal SCC, with a high participation rate (>95% for both case patients and control subjects), a satisfactory valid and reproducible (4,5) food frequency questionnaire (for CSD, Spearman r = .61), supports the findings of Mayne et al. (1) for esophageal SCC. The two studies suggest that CSD consumption does not increase the risk of esophageal cancer and that a moderate inverse association between CSD intake and esophageal SCC risk exists.
NOTES
This work was conducted with the contribution of the Italian Association for Cancer Research, the Italian League Against Cancer, and the Italian Ministry of Education (PRIN 2005). The sponsors had no role in the study design, data collection, analysis, or interpretation.
REFERENCES
(1) Mayne ST, Risch HA, Dubrow R, Chow WH, Gammon MD, Vaughan TL, et al. Carbonated soft drink consumption and risk of esophageal adenocarcinoma. J Natl Cancer Inst 2006;98:72–5.
(2) La Vecchia C, Negri E, Lagiou P, Trichopoulos D. Oesophageal adenocarcinoma: a paradigm of mechanical carcinogenesis? Int J Cancer 2002;102:269–70.[CrossRef][Web of Science][Medline]
(3) Bosetti C, La Vecchia C, Talamini R, Simonato L, Zambon P, Negri E, et al. Food groups and risk of squamous cell esophageal cancer in northern Italy. Int J Cancer 2000;87:289–94.[CrossRef][Web of Science][Medline]
(4) Franceschi S, Negri E, Salvini S, Decarli A, Ferraroni M, Filiberti R, et al. Reproducibility of an Italian food frequency questionnaire for cancer studies: results for specific food items. Eur J Cancer 1993;29A:2298–305.
(5) Decarli A, Franceschi S, Ferraroni M, Gnagnarella P, Parpinel MT, La Vecchia C, et al. Validation of a food-frequency questionnaire to assess dietary intakes in cancer studies in Italy. Results for specific nutrients. Ann Epidemiol 1996;6:110–8.[CrossRef][Web of Science][Medline]
(6) Breslow NE, Day NE. Statistical methods in cancer research. Vol. 1. The analysis of case-control studies. Lyon (France): IARC Scientific Publications; 1980. p. 193–246.
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J Natl Cancer Inst 2006 98: 646-647.
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