Benzene is one of the most important substances for assessment, due to its significant use, the environmental contamination resulting from its emission and the effects on human health. It is classified by the International Agency for Research on Cancer (IARC) as a known carcinogen to humans (group 1) and associated with the development of leukemia. In general, the population is exposed to this substance by inhaling contaminated air, which varies according to the location and intensity of its potential sources. The petrochemical industry is one of the most important sources of this compound. The municipality of Duque de Caxias, specifically the Campos Elíseos district, in Rio de Janeiro State, Brazil, houses the Industrial Complex of Campos Elíseos (PICE), a grouping of over 25 industries, which includes the second largest oil refinery in Brazil. Environmental contamination from the PICE has been recognized, but there is a lack of studies concerning its impact on the health of the surrounding population. S-phenylmercapturic acid (S-PMA) concentrations ranging from 0.80 to 8.01μg.g-1 creatinine were observed in the local population, apparently related to hematological changes also observed in exposed population. The quantifiable presence of urinary S-PMA from the benzene metabolism is associated with the fact that 60% of the participants present specific hematological changes, which may be due to the environmental benzene exposure. The allele and genotype frequencies of the CYP2E1 and NQO1 enzymes observed in the study population were similar to those reported in other studies. The presence of the variant allele in the NQO1 genotype may be a risk factor for the observed hematological changes.

Tobacco smoking is a major risk factor of several diseases such as lung cancer, stroke, chronic obstructive pulmonary disease and increases the susceptibility to infectious diseases. The understanding of smoking addiction requires phenotyping and genotyping studies. Variations in CHRNA5/CHRNA3 can alter receptor responses to nicotine and thus interfere with smoking behavior and risk. Therefore, this study aimed to investigate the association of CHRNA5 rs16969968 and CHRNA3 rs578776 with smoking behavior in a Brazilian population sample, comprising 449 subjects. Smoking data was obtained from a questionnaire. The polymorphisms were genotyped by Polymerase Chain Reaction (PCR). Associations were verified using logistic and linear regression analyses. We found that women with the variant AA genotype for CHRNA5 rs16969968 were at significantly increased risk of smoking, with an OR of 3.09 (95% CI: 1.09-8.76; p= 0.033). The variant TT genotype of CHRNA3 rs578776 showed protection against smoking and later smoking initiation in the overall population and in women, with an OR of 0.41 (95% CI: 0.19-0.88; p=0.022). In conclusion, CHRNA5 rs16969968 and CHRNA3 rs578776 were associated with increased risk and protective effect against smoking, respectively, in a Brazilian population sample. Gender and recessive homozygosis of the polymorphisms variants resulted in a significant effect regarding the results.

Introduction: Tobacco smoking represents the leading preventable cause of morbidity and mortality in adults. Nicotine is responsible for tobacco addiction and is known to elevate brain dopamine, leading to feelings of pleasure and reward. The MAOA enzyme is responsible for degrading dopamine. It is known that a polymorphism in the promoter region of the MAOA gene has been implicated in smoking behavior. In this study, we investigated the association between the MAOA VNTR polymorphism and smoking behavior in Brazilian males. Methods:A cross-sectional study was conducted with 121 Brazilian males over 18 years of age. The polymorphism was genotyped using PCR. Multiple logistic regression were used to verify the association of MAOA gene polymorphisms with smoking status. Results:We not found significant association between the MAOA polymorphism and smoking status. Likewise, no association of the VNTR polymorphism with elements of smoking behavior, such as smoking duration, smoking initiation, relapses, smoking cessation, and degree of nicotine dependence, was observed. Conclusions:In conclusion, no association was observed between the MAOA polymorphism, smoking status and smoking behavior in population of Brazilian males studied. Further studies with larger sample sizes will be needed to elucidate these issues.

Background: Smoking dependence is a chronic disease and a public health problem. The neurobiology of nicotine addiction can explain smoking behavior. This system has genetic variability that has been associated with vulnerability to dependence. Genetic variability in the neurobiology of smoking can help to understand why individuals exposed to drugs may or may not become addicted. Objective: This study aims to address genetic variability in the neurobiology of smoking addiction with a focus on polymorphic genes related to the nicotinic response and the dopaminergic reward pathway. Method: This work involved a search of the main scientific research on genetic variability in the neurobiology of smoking and its effects on smoking behavior. One hundred and five studies were selected, most of which highlighted polymorphisms in the genes of nicotinic receptors, dopamine receptors, and nicotine metabolism. Results: The majority of studies have focused on genes related to the activation of the dopaminergic reward system by nicotine. Combinations between different polymorphisms were also highlighted, showing that interactions can determine a genetic profile of predisposition to smoking addiction. Additionally, gender and ethnicity were identified as relevant factors. Conclusion: Knowledge of the genetic bases involved in the individual response to smoking can enable a better understanding of inter-individual differences in smoking behavior, and contribute to improving the treatment of addiction.

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Uma série de fatores sociais, ambientais, psicológicos e genéticos estão associados à dependência da nicotina e às doenças tabaco-relacionadas. A relação entre raça e tabagismo talvez seja um dos tópicos mais inexplorados e menos discutidos no âmbito do controle do tabaco no Brasil. Este trabalho realizou uma análise qualitativa retrospectiva, a fim de verificar os dados disponíveis na literatura sobre a relação entre raça/etnicidade e tabagismo no Brasil. Os resultados encontrados demonstraram que as pessoas de origem africana têm maior risco de se tornarem tabagistas e de desenvolverem doenças tabaco-relacionadas. Apesar desse risco, foi verificado que poucos estudos, a respeito dessa relação, foram publicados no Brasil e se, por um lado, os determinantes sociais podem influenciar tal associação, por outro, estudos apontam também uma possível influência de fatores genéticos no tabagismo. Mais estudos seriam necessários para entender a relação raça e tabagismo e para se pensar políticas mais efetivas contra o tabagismo. Os resultados também apontam que possivelmente, em virtude do racismo estrutural, a população com ancestralidade africana no Brasil se tornou “invisível” para pesquisadores e formuladores de políticas de controle do tabaco.

Great response variability caused by genetic and/or environmental factors has been observed among organisms exposed to hazardous chemicals. This subject has been a topic of intense discussion in the USA since President Obama announced support for an “era of precision medicine”, which consists in the inclusion of genetic data of patients in the treatment design, imposing a new approach to risk assessment. Personalized evaluation must consider the phenotypic factors of an individual. Among the markers that have been developed to evaluate any alteration in the structure or function of organisms, biomarkers of susceptibility are of great importance because they indicate the natural characteristics of a given organism which make it more sensitive to a specific adverse effect or disease, or more responsive to exposure to a specific chemical/drug. The ‘-omics’ technologies provide an insight into the relationship between chemical effects and molecular mechanisms of action. These technologies are the pillars for a personalized toxicology and precision medicine. Predictive toxicology requires a more comprehensive knowledge on specific individual factors or susceptibilities predisposing to diseases, enabling personalized risk assessment and adequate medical treatment.