Diet and body mass, and oral and oropharyngeal squamous cell carcinomas: Analysis from the IARC multinational case–control study

Abstract

Tobacco and alcohol use are the main risk factors for oral and oropharyngeal cancers, yet, dietary habits may also be of importance. Data from a series of case-control studies conducted in 9 countries worldwide (1,670 cases and 1,732 controls) were used to investigate the role of several food groups and body mass index (BMI). Low BMI significantly increased the odds ratio (OR) of cancer more than 2-fold among ever-and never-tobacco users and ever-and never-alcohol drinkers. After adjustment for potential confounders, high intake of fruits and vegetables significantly reduced the OR of cancer compared to low intake among evertobacco users (OR 0.4, 95% confidence interval [CI] 0.3-0.6), although not among never-tobacco users (OR 1.1, 95% CI 0.6-2.0). Similarly, the protective effect of high fruit and vegetable consumption was present among ever-drinkers (OR 0.4, 95% CI 0.3-0.6), but not among never-drinkers (OR 1.0, 95% CI 0.6-1.6). In conclusion, low BMI increases the risk of oral cancer, and vegetables and fruits may modulate the carcinogenic effects of tobacco and alcohol. ' 2005 Wiley-Liss, Inc.Key words: fruit and vegetable consumption; diet; body mass index; leanness; oral cancer; oropharyngeal cancer; case-control study Tobacco smoking and alcohol drinking are the major risk factors for oral and oropharyngeal squamous cell carcinomas (SCCs) and have been shown to account for over 90% of these cancers in several populations. 1,2 Paan chewing and use of betel-quid are also associated with these cancers, particularly in India. 3 Beyond these established risk factors, poor diet, characterised by low fruit and vegetable intake and high meat and fat consumption, has also been related to increased oral SCCs. [4][5][6][7][8][9][10][11] In a summary analysis of all oral cancer case-control studies that investigated fruit and/or vegetable consumption, the International Agency for Research on Cancer (IARC) reported a significantly reduced risk of oral cancer among individuals with high intake of fruits and vegetables compared to individuals with low intake. 12 While these findings were consistent across studies, doubt remains as to whether the confounding effects of the main risk factors, or even other important socioeconomic factors, had been adequately controlled for. It is known that individuals who smoke or drink commonly consume a diet low in fruits and vegetables. 13 Because of the inability to rule out the potential for the confounding effects of tobacco on diet, high fruit and vegetable intake were characterised as ''possibly protective against oral cancer''. 12 Obesity or high body mass index (BMI), commonly associated with increased risk of cancer at several sites, 14 was similarly investigated as a risk factor for oral cancer by the IARC. However, the data were deemed ''inadequate'' to reach conclusions regarding the cancer risk associated with BMI because of the paucity of available studies. However, some studies showed that high BMI was inversely associated with the risk of oral and oropharyngeal SCCs 15...

Fatores dietéticos e câncer oral: estudo caso-controle na Região Metropolitana de São Paulo, Brasil

“…No entanto, os resultados dos estudos epidemiológicos são inconsistentes, e a avaliação da possível contribuição quantitativa para a diminuição do risco permanece incerta 7,12 . Nos estudos de Kjaerheim et al 6 , Franceschi et al 13 e Garrote et al 14 , as leguminosas associaram-se positivamente ao câncer, enquanto Petridou et al 15 , Kreimer et al 16 e De Stefani et al 17 observaram associação negativa para leguminosas. Nos estudos de Chyou et al 18 , Garrote et al 14 , De Stefani et al 17 , o consumo mais freqüen-te de arroz e massas associou-se com aumento do risco para o câncer oral.…”

“…Tal achado deve ser recebido com cautela, devendo ser melhor investigado. Pode significar uma substituição das refeições estruturadas, em geral mais variadas e com maior aporte nutritivo, por bebidas lácteas e lanches, mais monótonas e com maior consumo de embutidos, em geral implicados como fatores de risco 13,16 .…”

“…Consistente com os estudos anteriores 14,16,20,21,22 , a categoria de consumo mais elevado para os vegetais crus apresentou aproximadamente metade do risco para o câncer oral. Além dos vegetais crus, as evidências para o efeito protetor dos vegetais são consistentes para cenoura, vegetais verdes e amarelos e tomates 14,19,21 , mas fraca para crucíferas, para as quais efeitos nulos ou de risco foram descritos 14 , possivelmente devido às propriedades antioxidantes e, no caso de compostos com atividade de vitamina A como o beta-caroteno, ao papel na diferenciação das células epiteliais 23 .…”

“…São Paulo, Brasil, 1998-2002. os alimentos em si, a combinação dos mesmos, associados ao estilo de vida podem ser fatores determinantes na etiologia do câncer oral. Entre os achados mais consistentes dos estudos epidemiológicos que investigaram o cân-cer oral e a dieta, estão os efeitos protetores das frutas e vegetais: praticamente todos os estudos relataram associações inversas 5,7,13,14,16,17,20,25 . A mais alta categoria de freqüência de consumo mostra aproximadamente metade do risco.…”

Apple intake and cancer risk: a systematic review and meta-analysis of observational studies

“…General characteristics of case-control and cohort studies are shown in Tables 1 and 2, respectively. Case-control studies were published between 1994 and 2014; three were conducted in Italy (13,19,22) , two each in Iran (10,15) , China (12,23) and Australia (14,29) , and one each in Poland (16) , Spain (11) , Czech Republic (17) , Brazil (18) , UK (20) , India (24) , Hawaii (25) , Mexico (26) , Sweden (27) and Uruguay (28) . One was a multinational study conducted in nine countries worldwide (Italy, Spain, Poland, Northern Ireland, India, Cuba, Canada, Australia and Sudan) (21) Cohort studies were published between 1998 and 2012; nine were conducted in the USA (30,31,(34)(35)(36)(37)39,40,45) and eight were conducted in Europe (32,33,38,(41)(42)(43)(44)46) . Pooled analysis were conducted in the USA, Canada, Europe and Australia and included from seven to fourteen prospective studies (47)(48)(49)(50) .…”