Alcohol and tobacco, and the risk of cancers of the upper aerodigestive tract in Latin America: a case-control study.

BACKGROUND: Cancers of the upper aerodigestive tract (UADT; including oral cavity, pharynx, larynx and oesophagus) have high incidence rates all over the world, and they are especially frequent in some parts of Latin America. However, the data on the role of the major risk factors in these areas are still limited. METHODS: We have evaluated the role of alcohol and tobacco consumption, based on 2,252 upper aerodigestive squamous-cell carcinoma cases and 1,707 controls from seven centres in Brazil, Argentina, and Cuba. RESULTS: We show that alcohol drinkers have a risk of UADT cancers that is up to five times higher than that of never-drinkers. A very strong effect of aperitifs and spirits as compared to other alcohol types was observed, with the ORs reaching 12.76 (CI 5.37-30.32) for oesophagus. Tobacco smokers were up to six times more likely to develop aerodigestive cancers than never-smokers, with the ORs reaching 11.14 (7.72-16.08) among current smokers for hypopharynx and larynx cancer. There was a trend for a decrease in risk after quitting alcohol drinking or tobacco smoking for all sites. The interactive effect of alcohol and tobacco was more than multiplicative. In this study, 65% of all UADT cases were attributable to a combined effect of alcohol and tobacco use. CONCLUSIONS: In this largest study on UADT cancer in Latin America, we have shown for the first time that a prevailing majority of UADT cancer cases is due to a combined effect of alcohol and tobacco use and could be prevented by quitting the use of either of these two agents.

TP53 and EGFR mutations in combination with lifestyle risk factors in tumours of the upper aerodigestive tract from South America.

Cancers of the upper aerodigestive tract [(UADT): oral cavity, pharynx, larynx and oesophagus] have high incidence rates in some parts of South America. Alterations in the TP53 gene are common in these cancers. In our study, we have estimated the prevalence and patterns of TP53 mutations (exons 4-10) in 236 UADT tumours from South America in relation to lifestyle risk factors, such as tobacco smoking and alcohol drinking. Moreover, we have conducted a pilot study of EGFR mutations (exons 18-21) in 45 tumours from the same population. TP53 mutation prevalence was high: 59% of tumours were found to carry mutant TP53. We found an association between TP53 mutations and tobacco smoking and alcohol drinking. The mutation rate increased from 38% in never-smokers to 66% in current smokers (P-value for trend = 0.09). G:C>T:A transversions were found only in smokers (15%). Alcohol drinkers carried more G:C>A:T transitions (P = 0.08). Non-exposed individuals were more probable to carry G:C>A:T transitions at CpG sites (P = 0.01 for never-smokers and P < 0.001 for never-drinkers). EGFR mutations were found in 4% of cases. Inactivation of TP53 by mutations is a crucial molecular event in the UADT carcinogenesis and it is closely related to exposure to lifestyle risk factors. EGFR mutations do not appear to be a common event in UADT carcinogenesis in this population.

Acute leukemia in early childhood.

Acute leukemia in early childhood is biologically and clinically distinct. The particular characteristics of this malignancy diagnosed during the first months of life have provided remarkable insights into the etiology of the disease. The pro-B, CD10 negative immunophenotype is typically found in infant acute leukemia, and the most common genetic alterations are the rearrangements of the MLL gene. In addition, the TEL/AML1 fusion gene is most frequently found in children older than 24 months. A molecular study on a Brazilian cohort (age range 0-23 months) has detected TEL/AML1+ve (N = 9), E2A/PBX1+ve (N = 4), PML/RARA+ve (N = 4), and AML1/ETO+ve (N = 2) cases. Undoubtedly, the great majority of genetic events occurring in these patients arise prenatally. The environmental exposure to damaging agents that give rise to genetic changes prenatally may be accurately determined in infants since the window of exposure is limited and known. Several studies have shown maternal exposures that may give rise to leukemogenic changes. The Brazilian Collaborative Study Group of Infant Acute Leukemia has found that mothers exposed to dipyrone, pesticides and hormones had an increased chance to give birth to babies with infant acute leukemia [OR = 1.48 (95%CI = 1.05-2.07), OR = 2.27 (95%CI = 1.56-3.31) and OR = 9.08 (95%CI = 2.95-27.96)], respectively. This review aims to summarize recent clues that have facilitated the elucidation of the biology of early childhood leukemias, with emphasis on infant acute leukemia in the Brazilian population.

Survival analysis in a sample of oral cancer patients at a reference hospital in Rio de Janeiro, Brazil.

This article gives the results of a 5-year survival analysis of 371 oral cancer patients who received medical care at a cancer reference hospital in Rio de Janeiro between 1986 and 1987. Patient profiles based on selected risk factors for oral cancer and 5-year survival based on prognostically relevant variables are described.

Electromagnetic fields: a cancer promoter?

This paper discusses some of the current questions observed in updated research analyzing the association of electromagnetic fields (EMF) exposure and cancer. It reveals the predominant efforts toward obtaining more accurate levels of EMF exposure as a crucial key to gain knowledge about that association. A general picture of a molecular biological model of cancer is presented, showing that EMF presents certain compatible characteristics of a cancer promoter. Further, we raise the hypothesis that EMF action is probably linked with other unknown initiator agents, rather than acting alone as presently assumed in epidemiologic studies. Finally this paper reinforces the importance of strong descriptive analysis of potential factors acting together on EMF and cancer association.

[Evaluation of the nutritional status of the Parkatêjê indigenous community in Bom Jesus do Tocantins, Pará, Brazil]. / Avaliação do estado nutricional da comunidade indígena Parkatêjê, Bom Jesus do Tocantins, Pará, Brasil.

The nutritional status of the Mãe-Maria indigenous community in Bom Jesus do Tocantins, Pará State, Brazil, was ascertained in a descriptive study in which ninety percent of the total population (278 individuals) agreed to participate. Weight-for-height and height-for-age indices and Body Mass Index (BMI) were ascertained for children and adults by gender, respectively, as were weight and height means in adolescents. Compared to NCHS curves, overweight and chronic malnutrition were observed, respectively, in 6.7 and 8.6 % of all children under 10 years old (104). Weight means were similar among Indians and NCHS adolescents, while height means were lower among the former. Overweight prevalence (BMI 25 to 29) was 23.7% among male adults and 50.0% among female adults, and obesity (BMI > 30) was observed in 12.5% of adult females.

[Electric power generation and transmission: the impact on indigenous peoples in Brazil]. / Geração e transmissão da energia elétrica: impacto sobre os povos indígenas no Brasil.

This paper presents an overview of the effects of electric power generation and transmission on indigenous communities in Brazil. According to data from FUNAI (the Brazilian government's Board of Indian Affairs), there are 156 cases of direct impact, present or future, of the electric power sector on Indian settlements geographically distributed throughout Brazil, 65% of which are located in the Northern Region of the country. The principal complaints by indigenous communities relate to the direct effects of flooding following construction of hydroelectric dams, destruction of sacred sites like cemeteries, mosquito proliferation, and health-related hazards such as malaria and other infectious diseases, decrease in game for hunting, crowding out of farm land, and increased invasion of indigenous lands. Future perspectives include a scenario with further construction of hydroelectric dams, especially in the Amazon region, with possible similar effects on indigenous communities.

[Association between dietary factors and brain tumors in adults: a review]. / Associação entre fatores da dieta e tumores de cérebro em adultos: uma revisão da literatura.

This paper reviews the scientific literature published from 1986 to 1999 assessing the relationship between dietary factors and brain tumors in adults. The work aimed to describe the estimated associations and to discuss methodological aspects that might influence the results. The studies generally appear to show a moderate association between dietary factors and brain tumors. There is evidence that N-nitroso compounds enhance the risk of developing such tumors and that consumption of fruits and vegetables can inhibit them. Use of proxies in most of the studies may have introduced bias, thereby contributing to some inconsistent observations. Epidemiological research on diet and brain tumors should consider other components of food besides N-nitroso compounds. It is important to carefully assess exposure periods and to prevent bias related to control selection and recall.

Smoking in Latin America: a major public health problem.

Smoking has become a major public health problem in Latin America, and its scope varies from country to country. Despite difficulty in obtaining methodologically consistent data for the region, we analyzed the results from prevalence surveys in 14 Latin American countries. We observed that smoking prevalence among men varied from 24.1% (Paraguay) to 66.3% (Dominican Republic) and among women from 5.5% (Paraguay) to 26,6% (Uruguay). By applying point prevalence data to the stage model of the tobacco epidemic in developed countries, we concluded that the Latin American countries are in stage 2, i.e., with a clearly rising prevalence among men, a prevalence for women that is beginning to increase, and mortality attributable to smoking among men still not reflecting peak prevalence. None of the countries analyzed appeared to have reached stage 3, in which one observes a downward trend in prevalence of smoking among men and peak prevalence among women, with broad impact on tobacco-related mortality. The only exception appears to be Paraguay, which is still emerging from stage 1, i.e., with low prevalence rates among men, too. Nevertheless, high lung cancer mortality rates in Uruguay and Argentina are comparable to those of the developed countries.

Familial aggregation of breast/ovarian cancer: age of onset along subsequent generations in Brazil.

Antecedents of family aggregation of breast and ovarian cancer are observed in only 5-8% of all breast cancer cases. Nevertheless, this variable displays one of the highest risk ratios associated to breast cancer outcome. Despite recent identification of genetic mutations associated with family aggregation of these tumors, mainly at BRCA1 and BRCA2 genes, knowledge on the interaction between environmental agents in these families remains quite unclear. In this paper we ascertained the correlation among ages of the onset of breast/ovarian cancer in 260 Brazilian families with those cancer aggregations. Further we estimated the median age of the onset of breast cancer among four generations. We observed that the higher the number of family cancer cases, the highest is the correlation of ages for the onset of breast cancer. We also observed a 8-10 year decline in the mean age-of-onset of breast/ovarian cancer from one generation to another in the studied families. If these results could be confirmed elsewhere, we believe that the hypothesis of interaction between environmental risks factors in families indeed showing breast/ovarian cancer aggregation is reinforced.

[AIDS in adult women in the Municipality of Rio de Janeiro]. / AIDS em mulheres adultas no município do Rio de Janeiro.

This paper presents the main epidemiological characteristics of AIDS cases observed among adult women in Rio de Janeiro Municipality (Rio) during 1980-89. Higher incidence rates as compared to Brazilian and Canadian women, rising participation of either sexual transmission and EV drug addiction and an increasing involvement of young women were also observed. The disease does not present a random spatial distribution in Rio, and case clusters in definite high risks areas were shown. Tuberculosis was found to be the second most frequent opportunistic infection detected among cases. Finally, some of the main trends and questions related to AIDS control among women in the studied area are discussed.

[Risk factors for breast cancer among rural Teréna Indian women in the State of Mato Grosso do Sul, Brazil]. / Fatores de risco para câncer de mama em mulheres indígenas Teréna de área rural, Estado do Mato Grosso do Sul, Brasil.

In order to evaluate the distribution of selected risk factors for breast cancer among Teréna Indian women in the State of Mato Grosso do Sul, Brazil, two samples were interviewed, respectively, in 1995 (330 women from ten Indian villages) and 1997 (40 women from the Limão Verde village). Reproductive history, diet characteristics, and family and personal medical history were investigated and body mass index was measured. In the larger sample, mean age at menarche was 12.3 years (30% at 13 years old or later), 86% of women reported one or more pregnancies (42% reporting 5 or more), 71% reported three or more pregnancies, mean age at first pregnancy was 18.9 years (3.8% after 28 years), mean duration of breastfeeding was 84 months, and 70% reported menopause before age 50. Dietary pattern in the smaller sample revealed a high intake of fruits, vegetables, pasta, and tubers and scarce intake of red meat and chicken; 50 of the women (95% CI: 34.1-65.9) presented overweight (BMI 25-29) and 27% (95% CI: 15.1-44.1) obesity (BMI > 29).

Cancer cluster among young Indian adults living near power transmission lines in Bom Jesus do Tocantins, Pará, brazil.

A case study was carried out to explore the occurrence of a cancer cluster in 1992 among young indian adults adults living in an Amazonian village near two 500 kV power transmission lines that began operating a decade ago. Current blood levels of DDT and organophosphorus pesticides and metal levels in hair samples were measured. Extremely low magnetic field exposure was determined during current daily activities carried out by the Indian villagers. Taking into account the cancer incidence rates in different Brazilian cities, the probability of the occurrence of this cluster by chance was considered remote (p< 0.003, Poisson distribution). High blood levels of p,p'-DDT (median levels ranging from 26 to 58 ppb) were observed. As a whole, this community showed a pattern of low exposure to organophosphorus pesticides, and high recent exposure was only observed in a few blood samples. Continuous exposure to extremely low electromagnetic fields originated in the power transmission lines (which reached 95.0 mG under the lines) was observed on several opportunities during daily activities carried out by Indian villagers. Further observational studies should evaluate the interaction between exposure to extremely low electromagnetic fields and prior exposure to tumor initiators in cancer development.

[Using food frequency questionnaire in past dietary intake assessment]. / Uso do questionário de freqüência na avaliação do consumo alimentar pregresso.

This paper aims to discuss which one is the best estimator of past diet: a retrospective report or a recent diet recall. The analysis included 13 articles published between 1984-1997 and selected from a MEDLINE search and from other reviews on this subject. The selection criterion was the use of a food frequency questionnaire (FFQ) in a validation study of retrospective report of dietary intake in remote past. Literature review shows that even taking into account misclassification, retrospective report of diet usually yields to a more reliable estimate of past diet pattern than current report. Past diet recall was strongly influenced by current intake and by diet patterns change. Analyzed investigations indicate that agreement between original and retrospective report was higher either for foods eaten rarely or frequently and lower for foods moderately consumed. This review allows considering the FFQ as a valuable instrument when studying the role of diet on the etiology of chronic diseases.

[Cancer mortality among electricity utility workers in a the state of Sao Paulo, Brazil]. / Mortalidade por câncer em trabalhadores de companhia geradora de eletricidade do estado de São Paulo, Brasil.

A number of epidemiologic studies have observed an association between exposure to 50-60 Hz electromagnetic fields and the development of specific types of cancer. In Brazil, a preliminary report from a study of electricity facility workers in Rio de Janeiro (RJ) has mentioned relatively similar results. An exploratory analysis of death certificates obtained from a sample of electricity workers in S. Paulo was made. Data was analysed by using the Proportional Mortality Ratio (PMR) and the Proportional Cancer Mortality Ratio (PCMR). A slightly elevated all-sites cancer mortality was observed among these workers (PMR 1.11; 95% CI 0.91-1.35). Site specific analysis has shown a statistically significant higher mortality of laryngeal cancer (PCMR 2.04; 95% CI 1.05-4.20). An excess of deaths was also seen for cancers of the buccal cavity/pharynx, prostate, bladder, brain and Hodgkin's disease, although the results lacked statistical significance. When analysed by categories of estimated exposure to magnetic fields, an excess of deaths from bladder cancer (PCMR 4.17; 95% CI 1.35-9.72), neoplasms of the brain (PCMR 7.7; 95% CI 1.02-9.65) and Hodgkin's disease (PCMR 5.55; 95% CI 1.14-16.21) was observed in the group with probably higher exposure to EMF. A comparison of cancer mortality between these workers and petrochemical employees has shown a higher PCMR for larynx tumours (PCMR 3.51; 95% CI 3.02-15.51) and bladder cancer (PCMR 7.53; 95% CI 3.02-15.51). For brain tumours, however, a PCMR of 0.74 (95% CI 0.27-1.61) was noted. Although restrictions related to sample size in the study and the lack of information about known confounders must be considered, the results of this study do not fully disagree with others previously mentioned in the literature.

Prevalence of BRCA1 and BRCA2 gene mutations in families with medium and high risk of breast and ovarian cancer in Brazil.

Of all malignant neoplasias affecting women, breast cancer has the highest incidence rate in Brazil. The objective of the present study was to determine the frequency of genetic modifications in families with medium and high risk for breast and ovarian cancer from different regions of Brazil. An exploratory, descriptive study was carried out on the prevalence of the BRCA1 and BRCA2 mutations in case series of high-risk families for breast and/or ovarian cancer. After heredogram construction, a blood sample was taken and DNA extraction was performed in all index cases. The protein truncation test was used to screen for truncated mutations in exon 11 of the BRCA1 gene and in exons 10 and 11 of the BRCA2 gene. Of the 612 individuals submitted to genetic testing, 21 (3.4%), 19 women and 2 men, had mutations in the BRCA1 or BRCA2 genes. Of the 19 BRCA1 mutations found in the 18 participants, 7 consisted of ins6kb mutations, 4 were 5382insC, 3 were 2156delGinsCC, 2 were 185delAG, 1 was C1201G, 1 was C3522T, and 1 was 3450del4. With respect to the BRCA2 gene, 3 mutations were found: 5878del10, 5036delA and 4232insA (one case each). The prevalence of germline mutations in the BRCA1 and BRCA2 genes found in the present study was lower than reported by other studies on high-risk Brazilian populations. The inclusion of individuals with medium risk may have contributed to the lower prevalence observed.