American Journal of Clinical Nutrition, Vol. 71, No. 2, 599a-600,
February 2000
© 2000 American Society for Clinical Nutrition
Reply to WB Grant
Esteve Fernandez,
Carlo La Vecchia,
Liliane Chatenoud,
Eva Negri and
Silvia Franceschi
Institut Universitari de Salut Pública de Catalunya, Universitat de Barcelona, L'Hospitalet (Barcelona), Catalonia, Spain, E-mail: efernandez{at}bell.ub.es
Istituto di Ricerche Farmacologiche "Mario Negri" and Istituto di Statistica Medica e Biometria, Università degli Studio di Milano, Milan, Italy
Istituto di Ricerche Farmacologiche "Mario Negri", Milan, Italy
Centro di Riferimento Oncologico, Aviano, Italy
Dear Sir:
We appreciate Grant's interest in our recent article on fish consumption and cancer risk (1) as well as his comments on the relation between fish consumption and Alzheimer disease. As Grant pointed out, several but not all cancers considered were inversely related to fish consumption (Figure 1
). The findings from the case-control studies conducted between 1983 and 1996 in northern Italy have been reproduced in recent case-control studies of cancers of the oral cavity, pharynx, and colorectum. These recent case-control studies were conducted in several regions of Italy and in the Swiss canton of Vaud and used a method similar to ours with a validated food-frequency questionnaire and questions recalling fish consumption (2). For colorectal cancer, there was an inverse association with fish consumption in both the Italian study [odds ratio (OR) = 0.7 for the highest consumption level (3)] and the Swiss study [OR = 0.9 (4)]. The inverse association was even more apparent for cancers of the oral cavity and pharynx, with an OR of 0.6 in the Italian study (5) and of 0.5 in the Swiss study (6). There is, therefore, consistent evidence that fish consumption is a favorable indicator of cancer risk in these European populations.
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FIGURE 1. Odds ratios (ORs) and 95% CIs for selected neoplasms among subjects in the highest versus the lowest category of fish consumption in Milan, Italy, 1983–1996.
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With reference to the beneficial effect of fish consumption and n-3 fatty acid intakes on the development of Alzheimer disease, scarce epidemiologic information is available to date. Besides the ecologic analysis of Grant (7), a prospective cohort study from the Netherlands (8) showed that fish consumption is inversely related to incident dementia [relative risk (RR) = 0.4] and to Alzheimer disease (RR = 0.3). The results of other studies, however, are contradictory (9). Although some reasonable biological mechanisms have been postulated, analytic epidemiologic studies aimed at addressing the role of fish consumption and other dietary factors (including food groups, nutrients, and micronutrients) would contribute to the investigation of the etiology of Alzheimer disease.
REFERENCES
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Fernandez E, Chatenoud L, La Vecchia C, Negri E, Franceschi S. Fish consumption and cancer risk. Am J Clin Nutr 1999;70:85–90.[Abstract/Free Full Text]
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Franceschi S, Negri E, Salvini S, et al. Reproducibility of an Italian food frequency questionnaire for cancer studies: results of specific food items. Eur J Cancer 1993;29A:2298–305.
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Franceschi S, Favero A, La Vecchia C, et al. Food groups and risk of colorectal cancer in Italy. Int J Cancer 1997;72:56–61.[Medline]
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Levi F, Pasche C, La Vecchia C, Lucchini F, Franceschi S. Food groups and colorectal cancer risk. Br J Cancer 1999;79:1283–7.[Medline]
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Franceschi S, Favero A, Conti E, et al. Food groups, oils and butter, and cancer of the oral cavity and pharynx. Br J Cancer 1999; 80:614–20.[Medline]
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Levi F, Pasche C, La Vecchia C, Lucchini F, Franceschi S, Monnier P. Food groups and risk of oral and pharyngeal cancer. Int J Cancer 1998;77:705–9.[Medline]
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Grant WB. Dietary links to Alzheimer's disease. Alzheimer Dis Rev 1997;2:42–55.
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Kalmijn S, Launer LJ, Ott A, Witteman JC, Hofman A, Breteler MM. Dietary fat intake and the risk of incident dementia in the Rotterdam Study. Ann Neurol 1997;42:776–82.[Medline]
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Giem P, Beeson WL, Fraser GE. The incidence of dementia and intake of animal products: preliminary findings from the Adventist Health Study. Neuroepidemiology 1993;12:28–36.[Medline]
