Adult height and head and neck cancer: a pooled analysis within the INHANCE Consortium.

Several epidemiological studies have shown a positive association between adult height and cancer incidence. The only study conducted among women on mouth and pharynx cancer risk, however, reported an inverse association. This study aims to investigate the association between height and the risk of head and neck cancer (HNC) within a large international consortium of HNC. We analyzed pooled individual-level data from 24 case-control studies participating in the International Head and Neck Cancer Epidemiology Consortium. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated separately for men and women for associations between height and HNC risk. Educational level, tobacco smoking, and alcohol consumption were included in all regression models. Stratified analyses by HNC subsites were performed. This project included 17,666 cases and 28,198 controls. We found an inverse association between height and HNC (adjusted OR per 10 cm height = 0.91, 95% CI 0.86-0.95 for men; adjusted OR = 0.86, 95% CI 0.79-0.93 for women). In men, the estimated OR did vary by educational level, smoking status, geographic area, and control source. No differences by subsites were detected. Adult height is inversely associated with HNC risk. As height can be considered a marker of childhood illness and low energy intake, the inverse association is consistent with prior studies showing that HNC occur more frequently among deprived individuals. Further studies designed to elucidate the mechanism of such association would be warranted.

Cancer mortality among Brazilian dentists.

BACKGROUND: Previous studies have variably shown excess risks of elected cancers among dentists. METHODS: National Brazilian mortality data were used to obtain mortality patterns among dentists between 1996 and 2004. Cancer mortality odds ratios (MORs) and cancer proportional mortality ratios for all cancer sites were calculated, using the general population and physicians and lawyers as comparison groups. RESULTS: Female dentists from both age strata showed higher risks for breast, colon-rectum, lung, brain, and non-Hodgkin lymphoma. Compared to physicians and lawyers, higher MOR estimates were observed for brain cancer among female dentists 20-49 yr. Among male dentists, higher cancer mortality was found for colon-rectum, pancreas, lung, melanoma, and non-Hodgkin lymphoma. Higher risk estimates for liver, prostate, bladder, brain, multiple myeloma and leukemia were observed among 50-79 yr old male dentists. DISCUSSION: If confirmed, these results indicate the need for limiting occupational exposures among dentists in addition to establishing screening programs to achieve early detection of selected malignant tumors.

Inactivation of the putative suppressor gene DOK1 by promoter hypermethylation in primary human cancers.

The DOK1 gene is a putative tumour suppressor gene located on the human chromosome 2p13 which is frequently rearranged in leukaemia and other human tumours. We previously reported that the DOK1 gene can be mutated and its expression down-regulated in human malignancies. However, the mechanism underlying DOK1 silencing remains largely unknown. We show here that unscheduled silencing of DOK1 expression through aberrant hypermethylation is a frequent event in a variety of human malignancies. DOK1 was found to be silenced in nine head and neck cancer (HNC) cell lines studied and DOK1 CpG hypermethylation correlated with loss of gene expression in these cells. DOK1 expression could be restored via demethylating treatment using 5-aza-2'deoxycytidine. In addition, transduction of cancer cell lines with DOK1 impaired their proliferation, consistent with the critical role of epigenetic silencing of DOK1 in the development and maintenance of malignant cells. We further observed that DOK1 hypermethylation occurs frequently in a variety of primary human neoplasm including solid tumours (93% in HNC, 81% in lung cancer) and haematopoietic malignancy (64% in Burkitt's lymphoma). Control blood samples and exfoliated mouth epithelial cells from healthy individuals showed a low level of DOK1 methylation, suggesting that DOK1 hypermethylation is a tumour specific event. Finally, an inverse correlation was observed between the level of DOK1 gene methylation and its expression in tumour and adjacent non tumour tissues. Thus, hypermethylation of DOK1 is a potentially critical event in human carcinogenesis, and may be a potential cancer biomarker and an attractive target for epigenetic-based therapy.

Environmental exposure and breast cancer among young women in Rio de Janeiro, Brazil.

Increasing breast cancer rates among young women (<40 years old) have been reported by the population-based cancer registries in Brazil. A case series study was carried out in Rio de Janeiro aiming to obtain epidemiological information allowing the generation of hypotheses to be further evaluated in analytical studies. One hundred and ten women 20-35 years old diagnosed with breast cancer were interviewed to determine the role environment plays in patients cased upon residential location. A comprehensive questionnaire including personal information (medical and lifestyle antecedents, reproductive history, family history of cancer, chemical and radiation exposure) was employed, and the obtained data were further compared with data provided by controls (women without cancer). An unconditional logistic regression was further employed to ascertain the respective odds ratios (OR) and their 95% confidence intervals (CI). Seventy-one percent of cancer cases were sporadic breast cancer, and familial aggregation (first degree relatives) was observed in just 3.5% (5.5% including second-degree relatives). Forty (51.3%) of the cancer cases were reported to have resided at a distance of less than 20 m from an electrical power transformer. Bivariate analysis revealed OR = 5.62 (95% CI 2.63-12) for residential use of pesticides during adulthood, OR = 2.15 (95% CI 1.22-3.77) for dental diagnostic x-rays, and OR= 1.53 (95% 0.77-3.04) for living nearby an electrical power transformer. Further multivariate analysis showed an adjusted OR = 3.5 (95% CI 1.11-11.0) for residential use of pesticides, and an adjusted OR = 2 (95% CI 1.24-3.23) for dental diagnostic x-rays during adulthood. The observed results highlight the importance of exploring the contribution of selected environmental agents possibly involved in breast carcinogenesis among young women.

Oral health and risk of squamous cell carcinoma of the head and neck and esophagus: results of two multicentric case-control studies.

Poor oral health has been reported as a risk factor in the etiology of head and neck cancer. Data on oral health were ascertained as part of two multicenter case-control studies comprising 924 cases and 928 controls in central Europe and 2,286 cases and 1,824 controls in Latin America. Incident cases of squamous cell carcinoma of the head and neck (oral cavity, pharynx, larynx) and esophagus, as well as age (in quinquennia)- and sex frequency-matched controls, were enrolled from 1998 to 2003. Poor condition of the mouth (central Europe: odds ratio (OR) = 2.89, 95% confidence interval (CI): 1.74, 4.81; Latin America: OR = 1.89, 95% CI: 1.47, 2.42), lack of toothbrush use (Latin America: OR = 2.36, 95% CI: 1.28, 4.36), and daily mouthwash use (Latin America: OR = 3.40, 95% CI: 1.96, 5.89) emerged as risk factors for head and neck cancer, independent of tobacco use and alcohol consumption. Missing between six and 15 teeth was an independent risk factor for esophageal cancer (central Europe: OR = 2.84, 95% CI: 1.26, 6.41; Latin America: OR = 2.18, 95% CI: 1.04, 4.59). These results indicate that periodontal disease (as indicated by poor condition of the mouth and missing teeth) and daily mouthwash use may be independent causes of cancers of the head, neck, and esophagus.

Mouthwash use and cancer of the head and neck: a pooled analysis from the International Head and Neck Cancer Epidemiology Consortium.

Most mouthwashes contain alcohol, a known cause of head and neck cancer (oral cavity, pharynx, larynx), likely through the carcinogenic activity of acetaldehyde, formed in the oral cavity from alcohol. We carried out a pooled analysis of 8981 cases of head and neck cancer and 10 090 controls from 12 case-control studies with comparable information on mouthwash use in the International Head and Neck Cancer Epidemiology Consortium. Logistic regression was used to assess the association of mouthwash use with cancers of the oral cavity, oropharynx, hypopharynx, and larynx, adjusting for study, age, sex, pack-years of tobacco smoking, number of alcoholic drinks/day, and education. Compared with never users of mouthwash, the odds ratio (OR) of all head and neck cancers was 1.01 [95% confidence interval (CI): 0.94-1.08] for ever users, based on 12 studies. The corresponding ORs of cancer of the oral cavity and oropharynx were 1.11 (95% CI: 1.00-1.23) and 1.28 (95% CI: 1.06-1.56), respectively. OR for all head and neck cancer was 1.15 (95% CI: 1.01-1.30) for use for more than 35 years, based on seven studies (P for linear trend=0.01), and OR 1.31 (95% CI: 1.09-1.58) for use more than one per day, based on five studies (P for linear trend <0.001). Although limited by the retrospective nature of the study and the limited ability to assess risks of mouthwash use in nonusers of tobacco and alcohol, this large investigation shows potential risks for head and neck cancer subsites and in long-term and frequent users of mouthwash. This pooled analysis provides the most precise estimate of the association between mouthwash use and head and neck cancer.

[Reliability and accuracy of oral cancer as the reported underlying cause of death in the Municipality of Rio de Janeiro]. / Confiabilidade e validade das declarações de óbito por câncer de boca no Município do Rio de Janeiro.

Mortality statistics are frequently employed in cancer epidemiology studies. The aim of this research was to evaluate the reliability and validity of oral cavity cancer as the underlying cause of death reported on death certificates in the Municipality of Rio de Janeiro, Brazil. All death certificates since 1999 reporting this underlying cause of death were selected from the Municipal Mortality Information System. The death certificates were re-coded by an independent technician, and a standardized questionnaire was designed to collect clinical and laboratory data for diagnostic confirmation from patient records. Histopathological results and/or clinical history were considered as the gold standard to establish the diagnosis of cancer of the mouth. Reliability analysis showed a simple percentage agreement of 95.1% and a kappa coefficient of 0.93. Positive predictive value was 86.5%. Mortality statistics for oral cancer in Rio de Janeiro Municipality demonstrate good reliability and validity, possibly because diagnostic confirmation is facilitated by easy access to the tumor site.

Confiabilidade e validade das declarações de óbito por câncer de boca no Município do Rio de Janeiro / Reliability and accuracy of oral cancer as the reported underlying cause of death in the Municipality of Rio de Janeiro

As estatísticas de mortalidade constituem uma fonte bastante utilizada em estudos epidemiológicos de neoplasias. Com o objetivo de avaliar a confiabilidade e a validade da causa básica de morte "câncer de boca", no Município do Rio de Janeiro, selecionou-se no banco de dados da Secretaria Municipal de Saúde, todas as declarações de óbito (DOs) com essa causa básica, no ano de 1999. As DOs foram submetidas à nova codificação da causa básica, por técnico independente, e construiu-se formulário padronizado para coleta de dados clínicos e laboratoriais para a confirmação do diagnóstico nos prontuários médicos de cada caso. Foi considerado como padrão-ouro o diagnóstico de câncer de boca formulado com base no exame histopatológico e/ou história clínica. Observou-se concordância simples de 95,1 por cento e coeficiente kappa de 0,93. O valor preditivo positivo correspondeu a 86,5 por cento. Conclui-se que as estatísticas de mortalidade por neoplasia de boca no Município do Rio de Janeiro são confiáveis e que é boa a validade desta causa básica, possivelmente, por se tratar de sítio de fácil acesso para a inspeção direta e com maior facilidade de confirmação clínica.

Revisão dos fatores de risco para o câncer de boca e faringe / A review of risk factors for oral and pharyngeal cancer

O presente artigo realizou breve análise de perfil epidemiológico de tumores de boca e faringe no Brasil e no mundo, bem como uma revisão da literatura pertinente a seus fatores de risco. Sua incidência, geralmente, varia entre 2 porcento a 30 porcento do total dos novos casos de câncer no mundo, e é fortemente influenciada pela localização geográfica. No Brasil, é a sexta localização anatômica mais comum nos Registros de Base Populacional entre os homens, sendo que a localização envolvendo a língua corresponde a 40 porcento do total de casos. Os principais fatores de risco são o tabaco, o álcool e a interação entre ambos, que exibem forte efeito multiplicativo sobre o risco. A quantidade consumida e o tempo de exposição a estes dois fatorers exibem, comumente, gradiente crescente de risco para o câncer. Elementos da dieta são considerados fatores de proteção, especialmente o B-caroteno, enquanto estados de carência nutricional são comumente percebidos entre os casos. Condições de precária saúde bucal são achados comuns entre os casos de câncer de boca e faringe. As recentes linhas de pesquisa em patogênese e prevenção do câncer de boca e faringe têm estudado a contribuição viral e genética. o comprometimento de grupos etários mais jovens e de mulheres provavelmente deve-se à universalização dos fatores de risco, levando a esta modificação do perfil epidemiológico.