ABSTRACT:

Objectives:

To estimate the fraction of head and neck cancer (HNC) attributable to tobacco and alcohol in cities in the Midwest, Southeast and South regions of Brazil.

Methods:

Case-control study including 1,594 cases of HNC and 1,292 hospital controls. The association of HNC with tobacco and alcohol was estimated by the odds ratio and respective 95% confidence intervals through non-conditional logistic regression, adjusted for age, sex, schooling, consumption of fruits and vegetables, alcohol drinking (to examine the tobacco effect), and tobacco smoking (to examine the alcohol effect). The proportions of HNC attributable to tobacco and alcohol were estimated through the attributable fraction (AF) calculation. Separate estimates were made for Goiânia (Midwest), Rio de Janeiro and São Paulo (Southeast) and Pelotas and Porto Alegre (South).

Results:

The HNC fraction attributable to smoking was slightly higher in Goiânia (AF = 90%) than in cities in the Southeast (AF = 87%) and South (AF = 86%). The HNC fraction attributable to the consumption of alcoholic beverages presented similar and higher results in the cities of Southeast (AF = 78%) and South (AF = 77%) than in Goiânia (AF = 62%).

Conclusion:

The HNC fractions attributable to smoking were more expressive than for alcohol consumption. Although with discrete distinctions between them, the AFs to tobacco smoking and alcohol consumption in HNC observed in the cities of these three Brazilian regions were similar to those obtained in Latin America studies, but they were higher than in other parts in the world.

Keywords:
Tobacco; Alcohol; Head and neck neoplasms; Brazil; Attributable risk

INTRODUCTION

Head and neck cancer (HNC) is the generic denomination for the set of tumors in the oral cavity, pharynx and larynx, whose incidence rises to about 680 thousand cases, and mortality rates reach 500 thousand a year around the world¹1. World Health Organization. International Agency for Research on Cancer. Globocan 2012: Cancer Incidence and Mortality Worldwide. IARC Cancer Base; 2012 [citado 7 jan. 2016]. Disponível em: Disponível em: http://globocan.iarc.fr/Default.aspx
http://globocan.iarc.fr/Default.aspx... . These numbers express the relevance of the disease for public health. In Brazil, the estimates from Instituto Nacional do Câncer (INCA) for the years 2016-2017 show about 15,490 new cases a year for oral cavity, being 11,140 in men and 4,350 in women²2. Brasil. Ministério da Saúde. Instituto Nacional do Câncer José Alencar Gomes da Silva. Estimativa 2016/2017: incidência de câncer no Brasil [citado 7 jan. 2016]. Disponível em: Disponível em: http://www.inca.gov.br/estimativa/2016
http://www.inca.gov.br/estimativa/2016... .

Smoking and alcohol consumption are the main risk factors for these tumors, and the interaction of these two factors with other variables, such as diet³3. Marchioni DML, Fisberg RM, Góis Filho JF de, Kowalski LP, Carvalho MB de, Abrahão M, et al. Padrões dietéticos e risco de câncer oral: estudo caso-controle em São Paulo. Rev Saúde Pública. 2007; 41(1): 19-26. http:// dx.doi.org/10.1590/S0034-89102007000100004
http:// dx.doi.org/10.1590/S0034-8910200... and occupational exposures⁴4. Koifman S, Wünsch Filho V, Koifman RL, Lorenzi RL, Silva IF, Santos SS. Tumores malignos relacionados com o trabalho. In: Mendes R. (Org.). Patologia do Trabalho. São Paulo: Atheneu; 2013. 29. p. 917-88., characterizes specific patterns of incidence in the populations. The magnitude of the risks of tobacco and alcohol in HNC are different depending on the region of the world, and on specific anatomic locations⁵5. Szymanska K, Hung RJ, Wünsch Filho V, Eluf-Neto J, Curado MP, Koifman S, et al. Alcohol and tobacco, and risk of cancers of the upper aerodigestive tract in Latin America: a case-control study. Cancer Causes Control. 2011; 22(7): 1037-46. https://doi.org/10.1007/s10552-011-9779-7
https://doi.org/10.1007/s10552-011-9779-... . There are also variations according to the socioeconomic conditions of the populations⁶6. Conway DI, Brenner DR, Mc Mahon AD, Macpherson LM, Agudo A, Ahrens W, et al. Estimating and explaining the effect of education and income on head and neck cancer risk: INHANCE Consortium pooled analysis of 31 case-control studies from 27 countries. Int J Epidemiol. 2015; 136(5): 1125-39. https://dx.doi.org/10.1002%2Fijc.29063
https://dx.doi.org/10.1002%2Fijc.29063... , which influence the behavioral attitudes and lifestyle of the individuals⁷7. Buss PM, Pellegrini Filho A. A saúde e seus determinantes sociais. Physis. 2007; 17(1): 77-93. http://dx.doi.org/10.1590/S0103-73312007000100006
http://dx.doi.org/10.1590/S0103-73312007... . Different prevalence rates in the intake of alcohol, in time and space, generate different risks of cancer⁸8. Goldstein BY, Chang SC, Hashibe M, La Vecchia C, Zhang ZF. Alcohol consumption and cancers of oral cavity and pharynx from 1988 to 2009: an update. Eur J Cancer Prev. 2010; 19(6): 431-65. https://doi.org/10.1097/CEJ.0b013e32833d936d
https://doi.org/10.1097/CEJ.0b013e32833d... ^,99. Wünsch Filho V, Camargo EA. The burden of mouth cancer in Latin America and the Caribbean: epidemiologic issues. Semin Oncol. 2001; 28(2): 158-68.^,1010. Muwonge R, Ramadas K, Sankila R, Thara S, Thomas G, Vinoda J, et al. Role of tobacco smoking, chewing and alcohol drinking in the risk of oral cancer in Trivandrum, India: A nested case-control design using incident cancer cases. Oral Oncol. 2008; 44(5): 446-54. https://doi.org/10.1016/j.oraloncology.2007.06.002
https://doi.org/10.1016/j.oraloncology.2... . In Hungary, where the consumption of distilled drinks is more common than in other regions, high incidence and mortality rates were found for oral cancer¹¹11. Ferlay J, Steliarova-Foucher E, Lortet-Tieulent J, Rosso S, Coerberg JW, Comber H, et al. Cancer Incidence and mortality patterns in Europe: estimates for 40 countries in 2012. Eur J Cancer. 2013; 49: 1374-403. https://doi.org/10.1016/j.ejca.2012.12.027
https://doi.org/10.1016/j.ejca.2012.12.0... . Higher risks of larynx cancer were found in the Italian population, which consumes wine more often¹²12. La Vecchia C, Zhang ZF, Altieri A. Alcohol and laryngeal cancer: an update. Eur J Cancer Prev. 2008; 17: 116-124. https://doi.org/10.1097/CEJ.0b013e3282b6fd40
https://doi.org/10.1097/CEJ.0b013e3282b6... . In Brazil, most of the consumption of tobacco involves manufactured cigarretes¹³13. Szklo AS, Sampaio MMA, Fernandes EM, Almeida LM. Perfil de consumo de outros produtos de tabaco fumado entre estudantes de três cidades brasileiras: há motivo de preocupação? Cad Saúde Pública. 2011; 27(11): 2271-5. http://dx.doi.org/10.1590/S0102-311X2011001100020
http://dx.doi.org/10.1590/S0102-311X2011... . In rural areas, there are more users of hand-rolled cigars in comparison to industrial cigars, more common in urban areas (13.8 and 3.6%, respectively)¹⁴14. Brasil. Instituto Nacional do Câncer José Alencar Gomes da Silva. Global Adult Tobacco Survey. Rio de Janeiro: INCA, 2010. 208 p.. Variations also occur regarding the intake of alcohol. Even though beer is the most consumed drink by the Brazilian population, in some areas of the North and the Northeast distilled drinks present higher proportions¹⁵15. Laranjeira R, Pinsky I, Sanches M, Zaleski M, Caetano R. Alcohol use patterns among Brazilian adults. Rev Bras Psiquiatria. 2010; 32(3): 231-41. http://dx.doi.org/10.1590/S1516-44462009005000012
http://dx.doi.org/10.1590/S1516-44462009... .

Smoking has decreased in the Brazilian population since the late 1980s, and this can affect the reduction of morbidity and mortality by HNC in the future¹⁶16. Wünsch Filho V, Mirra AP, Lopez RVM, Antunes LF. Tabagismo e o câncer no Brasil: evidências e perspectivas. Rev Bras Epidemiol. 2010; 13(2): 175-87. http://dx.doi.org/10.1590/S1415-790X2010000200001
http://dx.doi.org/10.1590/S1415-790X2010... . From 2006 to 2015, the prevalence of smoking in Brazil fell from 20.2 to 12.8% among men, and, for women, from 13.0 to 8.3%¹⁷17. Brasil. Ministério da Saúde. Vigilância de Fatores de Risco e Proteção para Doenças Crônicas por Inquérito Telefônico (Vigitel 2006). 2006 [citado 10 jun. 2017]. Disponível em: Disponível em: http://www.saude.gov.br
http://www.saude.gov.br... ^,1818. Brasil. Ministério da Saúde. Vigilância de Fatores de Risco e Proteção para Doenças Crônicas por Inquérito Telefônico (Vigitel 2015). 2015 [citado 10 jun. 2017]. Disponível em: Disponível em: http://www.saude.gov.br
http://www.saude.gov.br... . The frequency of the smoking habit in the population (adults ≥ 18 years) is different in the capitals of the Brazilian states, for example: Goiânia (7.6%), Porto Alegre (14.9%), Rio de Janeiro (12.5%) and São Paulo (13.7%)¹⁸18. Brasil. Ministério da Saúde. Vigilância de Fatores de Risco e Proteção para Doenças Crônicas por Inquérito Telefônico (Vigitel 2015). 2015 [citado 10 jun. 2017]. Disponível em: Disponível em: http://www.saude.gov.br
http://www.saude.gov.br... . Even though the frequency of smoking is decreasing in the population, the highest fraction of cancer in Brazil, in general, is attributed to tobacco. In a study conducted to estimate the population attributable fraction (PAF) of modifiable risk factors for 25 types of cancer, there were PAFs of 95.0 and 80.2% for oral cavity and larynx cancer, respectively¹⁹19. Azevedo e Silva G, de Moura L, Curado MP, Gomes FS, Otero U, Rezende LFM, et al. The fraction of cancer attributable to ways of life, infections, occupation and environmental agents in Brazil in 2020. PLoS One. 2016; 11(2): e 0148761. https://doi.org/10.1371/journal.pone.0148761
https://doi.org/10.1371/journal.pone.014... , for the Brazilian population as a whole.

The prevalence of abusive alcohol consumption is around 17.2% among adults in the Brazilian population¹⁸18. Brasil. Ministério da Saúde. Vigilância de Fatores de Risco e Proteção para Doenças Crônicas por Inquérito Telefônico (Vigitel 2015). 2015 [citado 10 jun. 2017]. Disponível em: Disponível em: http://www.saude.gov.br
http://www.saude.gov.br... and, unlike smoking, presents an increasing trend. Between 2006 and 2015, the abusive alcohol consumption rose from 16.1 to 25.3% among men, and 8.1 to 10.2% among women¹⁷17. Brasil. Ministério da Saúde. Vigilância de Fatores de Risco e Proteção para Doenças Crônicas por Inquérito Telefônico (Vigitel 2006). 2006 [citado 10 jun. 2017]. Disponível em: Disponível em: http://www.saude.gov.br
http://www.saude.gov.br... ^,1818. Brasil. Ministério da Saúde. Vigilância de Fatores de Risco e Proteção para Doenças Crônicas por Inquérito Telefônico (Vigitel 2015). 2015 [citado 10 jun. 2017]. Disponível em: Disponível em: http://www.saude.gov.br
http://www.saude.gov.br... . The abusive alcohol consumption among adults in Brazilian capitals is uneven, for instance: Goiânia (18.6%), Porto Alegre (14.4%), Rio de Janeiro (20.7%) e São Paulo (14.8%)¹⁸18. Brasil. Ministério da Saúde. Vigilância de Fatores de Risco e Proteção para Doenças Crônicas por Inquérito Telefônico (Vigitel 2015). 2015 [citado 10 jun. 2017]. Disponível em: Disponível em: http://www.saude.gov.br
http://www.saude.gov.br... .

The objective of this study was to examine the fraction of HNC attributable to tobacco and alcohol exposure in cities of three major Brazilian regions.

METHODS

The estimation of the attributable fraction (AF) was based on the data from the “Multicenter Latin American Study Virus and Cancer of the Oral Cavity and Larynx”, coordinated by the International Agency for Research on Cancer, of the World Health Organization (IARC/OMS)²⁰20. Boffeta P, Brennan P, Herrero R. International study of environment, viruses and cancer of oral cavity and larynx: study protocol. France: International Agency for Research on Cancer; 1998., with the objective of investigating multiple risk factors for HNC. In this hospital-based case-control study, carried out from September 1998 to March 2003, data from five Brazilian cities were used: Goiânia (Center-West region), Rio de Janeiro and São Paulo (Southeast Region), Pelotas and Porto Alegre (South region).

To be included in the study, the cases had to be of patients diagnosed with primary invasive head and neck cancer, confirmed by histology, without previous treatment, of both genders; and they had to be living in the study cities for at least one year before the date of the interview. Cases were selected in four hospitals of Goiânia, four hospitals in Rio de Janeiro, seven hospitals in São Paulo, seven hospitals in Pelotas and one hospital in Porto Alegre. The cases were classified according to tumor topography, based on the tenth revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-10)²¹21. Organização Mundial da Saúde. Classificação Estatística Internacional de Doenças e Problemas Relacionados à Saúde. São Paulo: Editora da Universidade de São Paulo; 1995., including codes C00 to C14. Cases such as lip (codes C00.0, C00.1, and C00.2), parotid gland (C07), large salivary glands (C08) and nasopharyngeal (C11) neoplasms were excluded for presenting different etiology from the other head and neck neoplasms²²22. Franceschi S, Bidoli E, Herrero R, Muñoz N. Comparison of cancers of the oral cavity and pharynx worldwide: etiological clues. Oral Oncol. 2000; 36(1): 106-15. https://doi.org/10.1016/S1368-8375(99)00070-6
https://doi.org/10.1016/S1368-8375(99)00... ^,2323. Hashibe M, Brennan P, Benhamou S, Castellsague X, Chen C, Curado MP, et al. Alcohol drinking in never users of tobacco, cigarette smoking in never drinkers, and the risk of head and neck cancer: pooled analysis in the International Head and Neck Cancer Epidemiology Consortium. J Natl Cancer Inst. 2007; 99(10): 777-89. https://doi.org/10.1093/jnci/djk179
https://doi.org/10.1093/jnci/djk179... .

Controls were selected among hospitalized patients or those being followed-up in outpatient clinics in the same hospitals recruiting the cases or in other hospitals in the same city. The selection of controls was carried out according to the frequency of cases by sex and age group (in five-year periods) and hospitals. The tracking of controls was simultaneous to the detection of cases and possible adjustments; and to guarantee the minimum number required in each stratum, they consented after the final recruitment of the cases. Patients diagnosed with conditions not related to the main risk factors examined in the study - tobacco and alcohol - were selected, and those with suspicious clinical recent or older history of HNC were excluded.

The individuals who met the inclusion criteria were invited to participate in the study and signed the Informed Consent Form. Each patient was informed that the adherence to the study was voluntary, and all information provided would be anonymous, treated in the analysis as a whole. Trained interviewers applied the same structured questionnaire to case and control patients, to obtain information about smoking, alcohol consumption, schooling and diet. The interviews were also conducted for suspicious cases which were not confirmed.

From the initial data base, with 1,919 cases and 1,410 interviewed controls, 27 cases were excluded for not meeting the inclusion criteria (living for at least 1 year in the city of residence; previous treatment for cancer; or cancer diagnosis before 1998, year when the study began). Other 74 cases were excluded for being diagnosed with lip (C00.0, C00.1, C00.2), parotid gland (C07); and other large salivary glands and non-specified (C08) and nasopharyngeal neoplasms (C11). The analysis also excluded 224 cases of esophageal cancer (C15), all originated from a single hospital. Among controls, 76 were excluded for diagnoses of diseases related with the consumption of tobacco and alcohol, and 15 for living in the city of diagnosis for less than 1 year. Twenty-seven cases of HNC diagnosed with histological confirmation, which had been classified, were also excluded as controls, as a mistake. After the exclusions, the analysis had 1,594 cases and 1,292 controls. The study was conducted based on ethical criteria, and approved by the National Research Ethics Committee (CONEP), and by the Research Ethics Committee of the Public Health School of Universidade de São Paulo.

Individuals considered smokers were those who informed to smoke at least one cigarette, cigar or pipe every day for at least one year. Three categories of smokers were used in the analysis: never smoked; former smoker (the ones who interrupted the smoking habit for 12 months or more in relation to the date of the interview); smoker (current smokers, and also the ones who informed having stopped for less than 12 months). The use of cigars (1.4%) and pipe smoking (3.4%) was reduced among the study participants.

Alcohol consumers were considered when they reported intaking alcohol at least once a month. The consumption was categorized as: never had alcohol; consumed some in the past year (those who stopped consuming it for 12 months or more, prior to the date of the interview); and current consumers (current consumer and the ones who stopped drinking for less than 12 months). The variables age, sex, schooling, vegetable consumption, fruit intake, tobacco (at the analysis of alcohol effect) and alcohol (at the analysis of the effect of tobacco) were considered as confounding variables.

Age, in full years until the time of the study, was separated in the following class intervals in years: ˂ 50, 50 to 59, 60 to 69, and 70 or more. Schooling was examined in three levels: did not attend; studied until elementary school; until high/higher education. The intake of vegetables was categorized in three strata: consumption less than once a week; consumption at least once a week; consumption at least twice a week. The intake of fruits was treated dichotomically: consumption less than once a week; consumption at least once a week. For all of the studied variables, the reference category was the one that, according to the literature, presented lower risk for NHC.

STATISTICAL ANALYSIS

First, we conducted a descriptive analysis of the variables, using the absolute and relative frequencies, separately, according to the cities: Goiânia (Center-West), Rio de Janeiro and São Paulo (Southeast), and Pelotas and Porto Alegre (South).

Then, a univariate analysis using the χ² test was carried out to examine the association of each independent variable with NHC²⁴24. Siegel S, Castellan NJ. Nonparametric statistics. 2ª ed. Nova York: McGraw-Hill; 1998..

Odds ratio (OR) and respective 95% confidence intervals (95%CI) to estimate the odds ratio resulting from tobacco and alcohol in HNC, in the studied cities, were calculated by non-conditional logistic regression, using the stepwise forward method²⁵25. Hosmer DM, Lameshow S. Applied logistic regression. Nova York: John Willey & Sons; 1989..

The independent models were adjusted for each set of studied cities. The final model maintained all of the variables which, in at least one stratum, presented p < 0.05.

To estimate the proportions of HNC attributable to smoking and the intake of alcoholic beverages in the cities of the three studied regions, AF was calculated using the OR as the approximation of the relative risk in the equation²⁶26. Kale PL, Costa AJL, Luiz RR. Medidas de associação e medidas de impacto. In: Medronho RA, Bloch KV, Luiz RR, Werneck GL. Epidemiologia. São Paulo: Atheneu; 2009. p. 181-192.: [AF = OR -1/ORx 100].

The statistical package Stata, version 9.1 (Stata Corporation, College Station, United States) was used to conduct the statistical analyses.

RESULTS

The characteristics of cases and controls, according to the cities studied in the three Brazilian geographic regions, are presented in Table 1. The sample comprised 341 cases and 239 controls in Goiânia (Center-West region), 938 cases and 665 controls in Rio de Janeiro and São Paulo (Southeast), and 315 cases and 388 controls in Pelotas and Porto Alegre (South). Male individuals, aged between 50 to 59 years, with higher proportion of low schooling levels (illiterate and elementary school) were prevalent among the cases. Controls reported consumption of vegetables and fruits at least once a week in higher proportions than cases in all of the studied cities.

By comparing to the cases of people who have never smoked, estimates of non-smokers and former-smokers were higher among controls. Regarding the consumption of alcohol, the proportion of cases in the categories referring to those who drank in the past, and to the ones who still drink, were higher among controls in all of the analyzed cities.

Laynx was the most common anatomic location of HNC in all of the Brazilian cities analyze - Goiânia (Center-West), 20.9%; Rio de Janeiro and São Paulo (Southeast), 19.5%; Pelotas and Porto Alegre (South), 18.3% - followed by oral cavity (12.1, 12.3, and 16.1%, respectively), and oropharynx (9.1; 10.8, and 3.1%, respectively).

Data not shown in Table 1.

The odds ratio was higher among smokers in Goiânia (OR = 13.6; 95%CI 6.4 - 28.6), compared to São Pauo and Rio de Janeiro (OR = 6.6; 95CI% 4.5 - 9.7) and Pelotas and Porto Alegre (OR = 8.8; 95%CI 4.7 - 16.2). The fraction of HNC attributable to smoking was slightly higher in Goiânia (AF = 90%) than in São Paulo and Rio de Janeiro (AF = 87%), and Pelotas and Porto Alegre (AF = 86%) (Table 2).

Among alcohol consumers, São Paulo and Rio de Janeiro and Pelotas and Porto Alegre presented higher odds ratio than Goiânia. The fractions of HNC attributable to the consumption of alcohol were more expressive in São Paulo and Rio de Janeiro (AF = 78%), and Pelotas and Porto Alegre (AF = 77%), in relation to Goiânia (AF = 62%) (Table 3).

DISCUSSION

The AFs calculated in this study consist on the percentage of cases of HNC that could be preventing by removing the habits of smoking or drinking alcohol from the studied populations²⁶26. Kale PL, Costa AJL, Luiz RR. Medidas de associação e medidas de impacto. In: Medronho RA, Bloch KV, Luiz RR, Werneck GL. Epidemiologia. São Paulo: Atheneu; 2009. p. 181-192.. In the cities of the three geographic regions, the fractions of HNC attributable to smoking were more expressive than that of alcohol consumption. The most remarkable difference was detected in Goiânia (90% attributable to tobacco, and 62%, to alcohol).

In a study carried out in Brazil to estimate the PAF of modifiable risk factors for 25 types of cancer, it was observed that highest PAF was related to smoking, followed by infections, low intake of fruits and vegetables, lack of physical activities, overweight and obesity¹⁹19. Azevedo e Silva G, de Moura L, Curado MP, Gomes FS, Otero U, Rezende LFM, et al. The fraction of cancer attributable to ways of life, infections, occupation and environmental agents in Brazil in 2020. PLoS One. 2016; 11(2): e 0148761. https://doi.org/10.1371/journal.pone.0148761
https://doi.org/10.1371/journal.pone.014... . The differences in HNC fractions attributable to tobacco and alcohol found in this study are similar to those observed for Latin America⁵5. Szymanska K, Hung RJ, Wünsch Filho V, Eluf-Neto J, Curado MP, Koifman S, et al. Alcohol and tobacco, and risk of cancers of the upper aerodigestive tract in Latin America: a case-control study. Cancer Causes Control. 2011; 22(7): 1037-46. https://doi.org/10.1007/s10552-011-9779-7
https://doi.org/10.1007/s10552-011-9779-... , however, higher than the ones detected in other regions of the world¹⁰10. Muwonge R, Ramadas K, Sankila R, Thara S, Thomas G, Vinoda J, et al. Role of tobacco smoking, chewing and alcohol drinking in the risk of oral cancer in Trivandrum, India: A nested case-control design using incident cancer cases. Oral Oncol. 2008; 44(5): 446-54. https://doi.org/10.1016/j.oraloncology.2007.06.002
https://doi.org/10.1016/j.oraloncology.2... ^,2323. Hashibe M, Brennan P, Benhamou S, Castellsague X, Chen C, Curado MP, et al. Alcohol drinking in never users of tobacco, cigarette smoking in never drinkers, and the risk of head and neck cancer: pooled analysis in the International Head and Neck Cancer Epidemiology Consortium. J Natl Cancer Inst. 2007; 99(10): 777-89. https://doi.org/10.1093/jnci/djk179
https://doi.org/10.1093/jnci/djk179... ^,2727. Castellsagué X, Quintana MJ, Martínez MC, Nieto A, Sánchez MJ, Juan A, et al. The role of tobacco and type of alcoholic beverage in oral carcinogenesis. Int J Cancer. 2004; 108(5): 741-49. https://doi.org/10.1002/ijc.11627
https://doi.org/10.1002/ijc.11627... ^,2828. Hashibe M, Brennan P, Chuang SC, Boccia S, Castellsague X, Chen C, et al. Interaction between tobacco and alcohol use and the risk of head and neck cancer: pooled analysis in the International Head and Neck Cancer Epidemiology Consortium. Cancer Epidemiol Biomarkers Prev. 2009; 18(2): 541-50. https://doi.org/10.1158/1055-9965.EPI-08-0347
https://doi.org/10.1158/1055-9965.EPI-08... ^,2929. Hashibe M, Hunt J, Wei M, Buys S, Gren L, Lee Y-CA. Tobacco, alcohol, body mass index, physical activity, and the risk of head and neck cancer in the prostate, lung, colorectal, and ovarian (PLCO) cohort. Head Neck. 2013; 35(7): 914-22. https://doi.org/10.1002/hed.23052
https://doi.org/10.1002/hed.23052... , and may be the expression of local patterns and habits of tobacco and alcohol consumption in the cities analyzed in the Center-West, Southeast and South regions. There is great variation in the occurrence of HNC in the world³⁰30. Bray F, Ferlay J, Laversanne M, Brewster DH, Gombe Mbalawa C, Kohler B, et al. Cancer incidence in five continents: inclusion criteria, highlights from volume X and global status of cancer registration. Int J Cancer. 2015; 137(9): 2060-71. https://doi.org/10.1002/ijc.29670
https://doi.org/10.1002/ijc.29670... ^,3131. Winn DM, Lee YC, Hashibe M, Boffetta P, INHANCE Consortium. The INHANCE Consor tium: toward a better understanding of the causes and mechanisms of head and neck cancer. Oral Dis. 2015; 21(6): 685-93. https://doi.org/10.1111/odi.12342
https://doi.org/10.1111/odi.12342... .

There were variations in Brazil as well³²32. Wünsch Filho V. The epidemiology of oral and pharynx cancer in Brazil. Oral Oncol. 2002; 38(8): 737-46.^,3333. Wünsch Filho V. The epidemiology of laryngeal cancer in Brazil. São Paulo Med J. 2004; 122(5): 188-94. http://dx.doi.org/10.1590/S1516-31802004000500002
http://dx.doi.org/10.1590/S1516-31802004... . In a systematic review about the consumption of alcohol and HNC, there were asymmetries in the occurrence of the disease by geographic regions, related to the prevalent consumption habits in the populations⁸8. Goldstein BY, Chang SC, Hashibe M, La Vecchia C, Zhang ZF. Alcohol consumption and cancers of oral cavity and pharynx from 1988 to 2009: an update. Eur J Cancer Prev. 2010; 19(6): 431-65. https://doi.org/10.1097/CEJ.0b013e32833d936d
https://doi.org/10.1097/CEJ.0b013e32833d... . In Switzerland and Italy, higher risks of oral cavity and oropharynx cancer were associated with the consumption of wine; however, in Sweden, more expressive risks were detected for the consumption of beer and liqueur⁸8. Goldstein BY, Chang SC, Hashibe M, La Vecchia C, Zhang ZF. Alcohol consumption and cancers of oral cavity and pharynx from 1988 to 2009: an update. Eur J Cancer Prev. 2010; 19(6): 431-65. https://doi.org/10.1097/CEJ.0b013e32833d936d
https://doi.org/10.1097/CEJ.0b013e32833d... . In Brazil, among the different alcoholic beverages, distilled drinks, especially cachaça, were associated with high risks of HNC³⁴34. Schlecht NF, Pintos J, Kowalski LP, Franco EL. Effect of type of alcoholic beverage on the risks of upper aerodigestive tract cancers in Brazil. Cancer Causes Control. 2001; 12(7): 579-87. https://doi.org/10.1023/A:1011226520220
https://doi.org/10.1023/A:1011226520220... .

In this study, the occurrence ratio of HNC between sexes ranged from 4.2 men per woman in Goiânia, and 5.9 in São Paulo and Rio de Janeiro, and 6.3 in Pelotas and Porto Alegre. These results are consistent with the ones observed in other studies, which reported occurrence ratios of HNC between sexes always higher than two men per one woman³⁵35. Mehanna H, Paleri V, West CML, Nutting C. Head and neck cancer- Part 1: Epidemiology, presentation, and prevention. Clin Otolaryngol. 2011; 36(1): 65-8. https://doi.org/10.1111/j.1749-4486.2010.02231.x
https://doi.org/10.1111/j.1749-4486.2010... . The highest incidence among men is the direct expression of the higher prevalence of smoking and drinking alcohol in the male population.

Socioeconomic determinants may influence behaviors and lifestyles⁷7. Buss PM, Pellegrini Filho A. A saúde e seus determinantes sociais. Physis. 2007; 17(1): 77-93. http://dx.doi.org/10.1590/S0103-73312007000100006
http://dx.doi.org/10.1590/S0103-73312007... , submitting the populations to different levels of exposure to carcinogens. Studies with migrants corroborate the physical, social and cultural influence of risk factors in the occurrence of cancer³⁶36. Kolonel LN, Wilkens LR. Migrant Studies. In: Schottenfeld D, Fraumeni Jr. JF. Cancer, Epidemiology and Prevention. 3ª ed. Oxford: Oxford University Press; 2006. P. 189-201.. In this study, schooling was used as an indicator of socioeconomic status. In the cities of the Southeast and South regions, with higher level of industrialization, individuals who had studied until elementary school were more present in relation to Goiânia, where most participants had never attended school. According to a population survey carried out in Brazil¹⁸18. Brasil. Ministério da Saúde. Vigilância de Fatores de Risco e Proteção para Doenças Crônicas por Inquérito Telefônico (Vigitel 2015). 2015 [citado 10 jun. 2017]. Disponível em: Disponível em: http://www.saude.gov.br
http://www.saude.gov.br... , smoking presented a positive correlation with low schooling levels, whereas the intake of alcohol was more frequent in strata presenting higher schooling levels.

The magnitude of the HNC fraction attributable to smoking was slightly higher in Goiânia. A possible explanation for this fact, besides the lower schooling levels, would be the form of tobacco consumption. According to the National Household Sample Survey, especially regarding smoking (2008)³⁷37. Instituto Brasileiro de Geografia e Estatística. Pesquisa Nacional por Amostra de Domicílio - Tabagismo 2008. Rio de Janeiro: IBGE; 2009., the Center-West region was one of the Brazilian regions where the practice of smoking hand-rolled cigars was more frequent. As mentioned by some authors, the different types of tobacco consumption lead to varied risks of HNC³⁸38. Wyss A, Hashibe M, Chuang SC, Lee YCAL, Zhang ZF, Yu GP, et al. Cigarette, cigar and pipe smoking and the risk of head and neck cancers: pooled analysis in the International Head and neck Cancer Epidemiology Consortium. Am J Epidemiol. 2013; 178(5): 679-90. https://doi.org/10.1093/aje/kwt029
https://doi.org/10.1093/aje/kwt029... ^,3939. Franco EL, Kowalski CP, Oliveira BV, Curado MP, Pereira RN, Silva ME, et al. Risk factors for oral cancer in Brazil. Int J Cancer. 1989; 43(6): 992-1000..

The HNC fractions attributable to the consumption of alcohol were higher in São Paulo and Rio de Janeiro; Pelotas and Porto Alegre. The positive correlation between the intake of alcohol and levels of industrialization and urbanization⁴⁰40. Roswall N, Weiderpass E. Alcohol as a risk factor for cancer: existing evidence in a global perspective. J Prev Med Public Health. 2015; 48(1): 1-9. https://dx.doi.org/10.3961%2Fjpmph.14.052
https://dx.doi.org/10.3961%2Fjpmph.14.05... is, at least partly, a possible explanation for the results.

The pattern of alcohol consumption between Brazilian regions is very heterogeneous, both in frequency and in type of beverage¹⁵15. Laranjeira R, Pinsky I, Sanches M, Zaleski M, Caetano R. Alcohol use patterns among Brazilian adults. Rev Bras Psiquiatria. 2010; 32(3): 231-41. http://dx.doi.org/10.1590/S1516-44462009005000012
http://dx.doi.org/10.1590/S1516-44462009... . The South Region reveals a pattern of frequent consumption of alcohol, but in lower amounts; on the other hand, in the Center-West, Northeast and North regions, the intake is higher per each occasion. In the South region, wine is more consumed, whereas in the North, Northeast and Center-West, the consumption of distilled drinks, especially cachaá, is more common¹⁵15. Laranjeira R, Pinsky I, Sanches M, Zaleski M, Caetano R. Alcohol use patterns among Brazilian adults. Rev Bras Psiquiatria. 2010; 32(3): 231-41. http://dx.doi.org/10.1590/S1516-44462009005000012
http://dx.doi.org/10.1590/S1516-44462009... . Higher risks of HNC have been observed among cachaça drinkers, and the absence or reduction of risk were detected among moderate wine consumers³⁵35. Mehanna H, Paleri V, West CML, Nutting C. Head and neck cancer- Part 1: Epidemiology, presentation, and prevention. Clin Otolaryngol. 2011; 36(1): 65-8. https://doi.org/10.1111/j.1749-4486.2010.02231.x
https://doi.org/10.1111/j.1749-4486.2010... ^,4141. Purdue MP, Hashibe M, Berthiller J, La Vecchia C, Dal Maso L, Herrero R, et al. Type of alcoholic beverage and risk of head and neck cancer--a pooled analysis within the INHANCE Consortium. Am J Epidemiol. 2009; 169(2): 132-42. https://doi.org/10.1093/aje/kwn306
https://doi.org/10.1093/aje/kwn306... .

There are some limitations in this study. A hospital-based case-control study was carried out (1998-2003) with data collected retrospectively, using a questionnaire; however, it was subjected to selection and information bias. Despite the large sample size, it was not possible to carry out analyses per specific anatomic locations of the head and the neck. The sample was also a limiting factor for the analysis of the combined effect of tobacco and alcohol, which requires the division of the study population in smaller strata, thus reducing the number of observations in each level. Another limitation was the absence of the North and Northeast regions in the analysis, which reduces the amplitude of the interpretative potential of the studied phenomena.

CONCLUSION

To sum up, according to the results of this study, the HNC fractions attributable to smoking were more expressive than those attributable to alcohol, in all analyzed cities. Especially in Goiânia, the difference was more expressive: 90% attributable to tobacco, and 62%, to alcohol. On the other hand, the HNC fraction attributable to the intake of alcohol in Goiânia was less expressive than in Rio de Janeiro and São Paulo (78%) and Pelotas and Porto Alegre (77%).

Based on these results, it is possible to conclude that, even though smoking has presented a reduction in the Brazilian population, in population subgroups such as the individuals affected by HNC, this practice is highly prevalent. On the other hand, the intake of alcohol has increased in the population. Considering that the genetic load in the occurrence of cancer is 5 to 10%, and that 90 to 95% are a result of modifiable risk factors, the results in this study about HNC fractions attributable to tobacco and alcohol show that the removal of one of these two factors can reduce the load of cases in the population; therefore, it is important to conduct articulated programs to control these two risk factors. Strategies of education, in order to be effective, need to reach the entire population, considering socioeconomic and cultural specificities, since these can lead to behaviors and habits related to the consumption of tobacco and alcohol.

References

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