Vitamina A

Cancer Causes and Control 13: 221–230, 2002. Ó 2002 Kluwer Academic Publishers. Printed in the Netherlands.

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Vitamins and carotenoids intake and the risk of basal cell carcinoma of the skin in women (United States)
Teresa T. Fung1,2,*, David J. Hunter2,3,5,6, Donna Spiegelman3,4, Graham A. Colditz3,5,6, Frank E. Speizer6 & Walter C. Willett2,3,5,6 1 Department of Nutrition, SimmonsCollege; 2Department of Nutrition; 3Department of Epidemiology; 4Department of Biostatistics; 5Harvard Center for Cancer Prevention, Harvard School of Public Health; 6Channing Laboratory, Department of Medicine, Brigham and Women’s Hospital, and Harvard School of Medicine
Received 13 February 2001; accepted in revised form 7 November 2001

Key words: carotene, diet, folate, skin cancer, vitaminA, vitamin C, vitamin E.

Abstract Objective: We examined prospectively intakes of vitamins A, C, and E, folate, and specific carotenoids in relation to the risk of basal cell carcinoma of the skin (BCC) in women. Methods: Dietary intake was assessed by food-frequency questionnaires every two–four years and the first diagnosis of BCC was ascertained by self-report every two years. We used logisticregression to model the association between dietary intake and the risk of BCC adjusting for various health, sun exposure, and sun sensitivity factors. Results: During 12 years of follow-up we recorded 5392 cases. We did not find any significant inverse associations between these dietary factors and BCC. On the contrary, weak positive trends were seen with vitamins A, C, and E, and folate. Themultivariate relative risks (RRs) comparing the top to bottom quintile were 1.20 (95% CI ¼ 1.10– 1.31) for folate, 1.16 (95% CI ¼ 1.06–1.26) for vitamin A, 1.13 (95% CI ¼ 1.03–1.23) for vitamin C, and 1.15 (95% CI ¼ 1.06–1.26) for vitamin E. Exploration of latency periods did not suggest different associations with a particular duration. Conclusions: We did not find evidence that vitamins A, C, and E,and folate, or specific carotenoids play an important protective role against the incidence of BCC. Introduction Basal cell carcinoma (BCC) of the skin is the most common cancer in humans [1]. Although BCC is rarely fatal, and metastasis is uncommon, it poses public health concerns due to frequent recurrence, disfigurement, and cost of treatment [2, 3]. In addition, the incidence has beenincreasing worldwide over the past 20 years, likely due to an increase in sun exposure from outdoor recreational activities [4–7]. Ultraviolet exposure from the sun is the dominant risk factor for BCC, and cumulative life-time exposure is especially related to the risk [8, 9]. Established risk factors include fair skin, light hair and eye color, a tendency to burn rather than
* Correspondence to: TeresaFung, Department of Nutrition, Simmons College, 300 The Fenway, Boston, MA 02115, USA. Ph.: 617-521-2712; Fax: 617-521-3137; E-mail: fung@simmons.edu

tan upon sun exposure, and history of severe sunburns [10–13]. Among these, only sun exposure is modifiable. Several dietary factors have been hypothesized to influence the development of BCC by antioxidant action or by cell differentiation.Vitamin A, in the form of retinoic acid, influences epithelial cell differentiation and may reduce skin tumor development [14, 15]. High-dose vitamin A decreases tumor burden or progression of papillomas to squamous cell carcinoma of the skin in mice [16, 17]. b-Carotene also may influence skin cancer development by conversion to vitamin A. In animals the carotenoid canthaxanthin has protected againsttumor development [16], possibly due to its antioxidant properties. However, a previous trial of b-carotene supplementation did not show a protective effect after five years of follow-up [18], although this duration of follow-up and supplementation may be too short to capture an effect of beta-carotene. Vitamin E, in its most

222 biologically active form as a-tocopherol, is a potent lipidsoluble...