Environmental and biological monitoring of organochlorine pesticides in the city of Salamanca, Mexico.

The former Tekchem Industrial Unit located in the city of Salamanca, Mexico, constitutes an environmental liability in which the presence of high levels of organochlorine pesticides (OCPs) has been reported. In the present study, levels of OCPs were quantified using gas chromatography-mass spectrometry in 52 soil samples and in 88 blood samples from school-age children in the city of Salamanca. A median concentration of 70.6 ng/g (6.93-3299) was obtained for total OCPs in soil, while for the total sum of dichlorodiphenyltrichloroethane (DDT) the value was 49.6 ng/g (6.93-3276). In children, the median level of the total sum of OCPs was 390 ng/g lipid (7.34-14,895), and for the total sum of DDT was 175 ng/g lipid (< LOD-14,802). The OCPs that resulted in highest concentrations in soil were DDT and its metabolites, as well as aldrin and heptachlor epoxide, while in blood the highest levels corresponded to 4,4'-dichlorodiphenyltrichloroethane (4,4'-DDT) and its metabolites, followed by heptachlor and heptachlor epoxide. The spatial distribution of the concentrations of OCPs in soil shows that the facilities of Tekchem may be a significant potential source for the dispersion of these compounds toward the metropolitan area of Salamanca. The results obtained in the present study demonstrate the presence of OCPs in soil and in child population, providing important bases to study the problem from a broader perspective, while reiterating the importance of continuing efforts to generate resolute and precautionary measures with respect to the environmental liability of Tekchem.

Diagnostic accuracy of three placement sites for the cold test in subjects amongst different age groups.

BACKGROUND: The cold test is a specific test of pulp sensitivity and is part of the endodontic diagnosis. The aim of this study was to identify the diagnostic accuracy including sensitivity, specificity, accuracy, positive predictive value and negative predictive value in three sites for the cold test in teeth with a need for endodontic treatment within different age groups from both genders. METHODS: A cross-sectional study was performed, evaluating 425 subjects. Two hundred and fifty-eight subjects from both genders from the ages of 17-27, 28-39, 40-50, and 51-65 years-old participated in the study. The cold test studied was 1, 1, 1, 2-tetrafluoroethane, and the gold standard was established through direct pulp inspection. The sites evaluated in the study were: The sites evaluated in the study were: a) the middle third of the buccal surface; b) the cervical third of the buccal surface, and c) the middle third of the lingual surface. RESULTS: The highest diagnosted accuracy was observed on the middle third buccal surface with an accuracy of = 0.97, a sensitivity of = 1.00, a specificity of 0.95, a predictive value of = 0.95 and a negative predictive value of = 1.00. This was in the female group aged from 40 to 50 years old. CONCLUSION: The tables of this study can be used as an auxiliary for pulp sensitivity tests.

Pilot Monitoring of Lead in Umbilical Cord Blood of Newborns Associated With the Use of Glazed Ceramics from Guanajuato, Mexico.

The use of lead-glazed pottery for cooking and storing food, a widespread practice in Mexico, represents a risk of exposure to lead from the human intrauterine stage. Therefore, a pilot study was carried out by means of the measurement of lead in umbilical cord blood by inductively coupled plasma mass spectrometry (ICP-MS) including 69 newborns from the Mexican state capital of Guanajuato, Guanajuato City, where the use of glazed clay is still widespread. Lifestyle and sociodemographic data were collected by interviewing the participating mothers. Hematological parameters and the anthropometry of the newborns and their mothers were analyzed; likewise, the G177C polymorphism in the ALAD gene was genotyped by PCR-RFLP as a marker of genetic vulnerability to lead. The geometric mean of lead in umbilical cord blood was 0.7 µg/dL (< limit of detection = 0.01-28.22). Boys presented higher values than girls (p = 0.03). Only 5.8% of these were above the safety value of the US Centers for Disease Control and Prevention (CDC) of 3.5 µg/dL. Correlations among lead concentrations, maternal age, weeks of gestation, newborn anthropometry, and hematological parameters were not found; however, the participating mothers who reported using glazed ceramics for cooking or storing food had the highest cord-blood lead concentrations (p = 0.04). Regarding genotyping, 97% had ALAD 1, while 3% had ALAD 1, 2; unfortunately, the sample size did not allow analysis of genetic vulnerability to lead. The preparation and conservation of food in handcrafted clay pottery increased the risk of having cord-blood lead values higher than those recommended by the CDC of 3.5 µg/dL (OR = 5; 95% CI:1.3-23; p = 0.01). Our preliminary results suggest that there continues to be intrauterine exposure to lead in Guanajuato.

Assessment of DDT and DDE levels in soil, dust, and blood samples from Chihuahua, Mexico.

The aim of this study was to assess levels of DDT and DDE in two environmental matrices (soil and dust) and to investigate the blood levels of these insecticides in exposed children living in a north Mexican state (Chihuahua) where DDT was sprayed several years ago during (1) health campaigns for the control of malaria and (2) agricultural activities. DDT and DDE were analyzed by gas chromatography/mass spectrometry. In general, lower levels were found in household outdoor samples. The levels in outdoor samples ranged from 0.001 to 0.788 mg/kg for DDT and from 0.001 to 0.642 mg/kg for DDE. The levels in indoor samples ranged from 0.001 to 15.47 mg/kg for DDT and from 0.001 to 1.063 mg/kg for DDE. Similar results to those found in indoor soil were found in dust, in which the levels ranged from 0.001 to 95.87 mg/kg for DDT and from 0.001 to 0.797 mg/kg for DDE. Moreover, blood levels showed that all of the communities studied had been exposed to DDT and/or DDE, indicating a general past or present exposure to DDT. It is important to note that the quotient DDT/DDE in all matrices was always >1. Whether the people living in our study area are at risk is an issue that deserves further analysis. However, applying precautionary principles, it is important to initiate a risk-reduction program to decrease exposure to DDT and its metabolites in people living in this area.

Polymorphisms of the genes ABCG2, SLC22A12 and XDH and their relation with hyperuricemia and hypercholesterolemia in Mexican young adults.

Background: Hyperuricemia is a pathological condition associated with risk factors of cardiovascular disease. In this study, three genetic polymorphisms were genotyped as predisposing factors of hyperuricemia. Methods: A total of 860 Mexicans between 18 and 25 years of age were genotyped for the ABCG2 (rs2231142), SLC22A12 (rs476037), and XDH (rs1042039) polymorphisms, as predisposing factors of hyperuricemia. Biochemical parameters were measured by spectrophotometry, while genetic polymorphisms were analyzed by real-time PCR. An analysis of the risk of hyperuricemia in relation to the variables studied was carried out using a logistic regression. Results: Male sex, being overweight or obese, having hypercholesterolemia or having hypertriglyceridemia were factors associated with hyperuricemia ( p ≤ 0.05). The ABCG2 polymorphism was associated with hyperuricemia (OR = 2.43, 95% CI: 1.41-4.17, p = 0.001) and hypercholesterolemia (OR = 4.89, 95% CI: 1.54-15.48, p = 0.003), employing a dominant model, but only in male participants. Conclusions: The ABCG2 (rs2231142) polymorphism increases the risk of hyperuricemia and hypercholesterolemia in young Mexican males.

Novel Adiposity and Biochemical-Anthropometric Indices to Identify Cardiometabolic Risk and Metabolic Syndrome in Mexican Adults.

Although several indices used in clinical practice identify cardiometabolic risk (CR) and metabolic syndrome (MetS), it is imperative to develop indices for specific populations. Therefore, we proposed and validated sex-specific indices to identify CR associated with visceral adipose tissue (VAT) accumulation or MetS in Mexican adults. Additionally, a cut-off value for the visceral fat area (VFA) to identify CR was proposed. Clinical, anthropometric, biochemical, and body composition variables were evaluated in 904 subjects (25-45 years old) (84.4% men). Multiple and logistic regressions were used to model the indices and ROC curve analysis to determine predictive performance. An additional cohort (n = 186) was used for indices validation, and Cohen's kappa coefficient was employed for agreement analysis. The proposed sex-specific indices, called Mexican adiposity indices (MAIs) and biochemical-anthropometric indices (BAIs), were good predictors for CR and MetS. The kappa coefficients showed a moderate agreement level. The VFA cut-off value chosen to identify CR was 100.3 cm2 because it had the best combination of sensitivity (66.8%) and specificity (64.4%). MAIs and BAIs could be clinical tools to identify either CR associated to VAT accumulation or MetS, respectively. A VFA cut-off value of 100.3 cm2 could identify CR in Mexican men.

TNF-α detection using gold nanoparticles as a surface-enhanced Raman spectroscopy substrate.

Background: TNF-α is a cytokine involved in inflammation. Surface-enhanced Raman spectroscopy (SERS) could be useful in its detection. Aim: Identify the TNF-α in an aqueous solution, using gold nanoparticles (AuNPs) as a SERS substrate. Materials & methods: Raman and SERS spectra were obtained from TNF-α samples, combined with AuNPs, with decreasing concentrations of TNF-α. The samples were analyzed using optical transmission spectroscopy, dynamic light scattering, and transmission electron microscopy. Results: Transmission electron microscopy/dynamic light scattering determined a change in the average diameter of the TNF-α/AuNPs (∼9.6 nm). Raman bands obtained were associated with aromatic amino acid side chains. We observe Raman signals for TNF-α concentrations as low as 0.125 pg/ml. Conclusion: TNF-α signal at physiological concentrations was determined with SERS.

Exposure to arsenic and lead in children from Salamanca México, effects on telomeric lengthening and mitochondrial DNA.

Levels of urinary arsenic and levels of lead in blood were measured in children attending elementary schools located in an industrial zone in Salamanca, México. Its possible effects using telomere length and mitochondrial DNA copy number as biomarkers of genomic disequilibrium by oxidative stress were studied. Eighty-eight children (6-15 years old) were included and urine samples were collected for quantification of arsenic, while lead was measured in blood samples using inductively coupled plasma mass spectrometry (ICP-MS). DNA was isolated from peripheral blood and relative telomere length and the mitochondrial DNA copy number were determined by real-time PCR. The geometric mean of urinary arsenic was 54.16 µg/L (11.7-141.1 µg/L). Ninety-eight percent of the children were above 15 µg/L (biomonitoring equivalent value). With respect to the concentration of lead in blood, the mean was 3.78 µg/dL (LOD-22.61), where 24.5% of the participants had equal or above the reference value (5 µg/dL; Mexican Official Norm NOM-199-SSA1-2000, 2017). A positive association between urinary arsenic and telomere length was found (ß = 0.161; 95% CI: 0.12; 0.301; P = 0.034), while lead blood concentrations were negatively associated with mitochondrial DNA copy number (ß = - 0.198; 95% CI: - 2.81; - 0.17; P = 0.019), after adjusting by age, sex, and total white blood cell count. Differences in the mitochondrial DNA content were observed in children with lead blood levels from 2.5 µg/dL, (P ≤ 0.001), suggesting an effect at lead exposure levels considered acceptable (< 5 µg/dL). In conclusion, children living in an industrial area in Salamanca showed an exposure to arsenic and lead and an impact on telomere length and mitochondrial DNA content associated with arsenic and lead exposure, respectively.

Macrophage migration inhibitory factor gene polymorphisms as exacerbating factors of apical periodontitis.

BACKGROUND: Two polymorphisms in the macrophage migration inhibitory factor (MIF) gene have been associated with inflammatory diseases (-794 CATT5-8 and -173G>C); however, so far there are no reports of studies related to oral health. OBJECTIVES: To genotype the -794 CATT5-8 and -173G>C MIF polymorphisms in Mexican patients with apical periodontitis as a genetic risk of exacerbation. MATERIAL AND METHODS: The study involved 120 patients with apical periodontitis: 60 with a diagnosis of acute apical periodontitis (Group A) and 60 without previous episodes of exacerbation (Group B). Allelic discrimination was performed from peripheral blood DNA; the repeat polymorphism -794 CATT5-8 was genotyped with sequencing, while the -173G>C polymorphism was determined using real-time polymerase chain reaction (RT-PCR) using TaqMan probes. The associations between MIF polymorphisms, haplotypes and the risk of exacerbated apical periodontitis were assessed. RESULTS: The allele CATT7 was associated with the risk of a stage of acute inflammation (OR = 4.13; 95% CI = 1.82-9.63; p =< 0.001). Regarding the -173G >C polymorphism, a process of inflammation exacerbation was only associated with the CC genotype (OR = 4.1; 95% CI = 1.02-20.84; p = 0.045). The analysis of the haplotype showed that the combination CATT7/C increases the risk of exacerbation of apical periodontitis (OR = 3.57; 95% CI = 1.038-13.300; p = 0.021). CONCLUSIONS: The polymorphisms -794 CATT5-8 and -173G>C MIF seem to significantly influence the development of a state of exacerbated inflammation in patients with apical periodontitis.

[Level of exposure to fluorides by the consumption of different types of milk in residents from an area of Mexico with endemic hydrofluorosis]. / Dosis de exposición a fluoruros por el consumo de diferentes tipos de leche en residentes de una zona con hidrofluorosis endémica en México.

INTRODUCTION: Several studies have shown the presence of fluorosis (DF) in primary dentition, suggesting an exposure to fluorides (F-) in early childhood. Breast milk is recommended as an exclusive food until 6 months of age. Although it is mentioned that only a small amount of F- can be eliminated by breast milk, studies have shown the presence of this element in milk of women living in contaminated areas, as well as in infant formulas. The objective of this project was to evaluate the exposure level to F- through milk in children living in an area with endemic hydrofluorosis. METHODOLOGY: The study included 110 children between 6 and 36 months of age from the municipality of Lagos de Moreno, Jalisco. Water samples were collected from the homes, as well as samples of milk (maternal, formula, whole or raw), and urine. Measurments were made with a selective ion electrode. The exposure level of F- for milk intake was calculated using the Oracle Crystal Ball package. RESULTS: Levels greater than the reference level for DF were observed in infant formula reconstituted with public supply water, pasteurised cow's milk (whole) and untreated cow's milk treatment (raw) in the 90th, 70th, and 50th percentile, respectively, with a correlation being found between the levels of F- in milk and F- in urine (r=0.41, P<.001). CONCLUSIONS: The identification of sources of F- in the early stages of child development could reduce the risk of developing DF.

Dental fluorosis and a polymorphism in the COL1A2 gene in Mexican children.

OBJECTIVE: To determine the allelic and genotypic frequencies of rs 412777 polymorphism in the Collagen type I alpha 2 chain (COL1A2) gene and the association with the severity of dental fluorosis in children between 6 and 12 years old in the State of San Luis Potosi, Mexico. DESIGN: A cross-sectional study was designed; participants were 230 children from two rural communities of San Luis Potosí. Fluoride in drinking water and urine samples was quantified using a potentiometric method with a selective ion electrode. Dental fluorosis was diagnosed using the Thylstrup-Fejerskov index while the identification of the polymorphism was made by allelic discrimination, using allele-specific probes by real-time Polymerase chain reaction (PCR). Statistical analysis was carried out with Student's t-test and Chi-square and Odds Ratio (OR). A confidence interval of 95% and a value of p < 0.05 were considered. RESULTS: The concentration of fluoride in drinking water was 2.36 ± 0.02 mg/L in Ojo Caliente and 4.56 ± 0.07 mg/L in La Reforma, the concentration of fluoride in urine was 2.05 ± 0.62 mg/L and 2.99 ± 0.99 mg/L respectively. The prevalence of dental fluorosis was 100% and the frequency of alleles was 67% wild-type and 33% mutant allelic, alleles were found in Hardy-Weinberg equilibrium (X2 = 0.33, p = 0.89). The association between the degree of dental fluorosis and the evaluated polymorphism was statistically significant (OR = 7.10, 95% CI = 3.96-12.70, p < 0.05). CONCLUSIONS: An association of rs 412777 polymorphism in the COL1A2 gene with dental fluorosis was found. Therefore, genetic variants represent a relevant risk factor to develop dental fluorosis, as it was proven in this study conducted in Mexican children.

DNA methylation changes in Mexican children exposed to arsenic from two historic mining areas in San Luis potosí.

Arsenic is a carcinogen and epimutagen that threatens the health of exposed populations worldwide. In this study, we examined the methylation status of Alu and long interspersed nucleotide elements (LINE-1) and their association with levels of urinary arsenic in 84 Mexican children between 6 and 12 years old from two historic mining areas in the State of San Luis Potosí, Mexico. Urinary arsenic levels were determined by atomic absorption spectrophotometry and DNA methylation analysis was performed in peripheral blood leukocytes by bisulfite-pyrosequencing. The geometric mean of urinary arsenic was 26.44 µg/g Cr (range 1.93-139.35). No significant differences in urinary arsenic or methylation patterns due to gender were observed. A positive correlation was found between urinary arsenic and the mean percentage of methylated cytosines in Alu sequences (Spearman correlation coefficient r = 0.532, P < 0.001), and a trend of LINE-1 hypomethylation was also observed (Spearman correlation coefficient r = -0.232, P = 0.038) after adjustment for sex and age. A linear regression model showed an association with log-normalized urinary arsenic for Alu (ß = 1.05, 95% CI: 0.67; 1.43, P < 0.001) and LINE-1 (ß = -0.703, 95% CI: -1.36; -0.38, P = 0.038). Despite the low-level arsenic exposure, a subtle epigenetic imbalance measured as DNA methylation was detected in the leukocytes of Mexican children living in two historic mining areas. Environ. Mol. Mutagen. 57:717-723, 2016. © 2016 Wiley Periodicals, Inc.

Association of Leukocyte Telomere Length and Mitochondrial DNA Copy Number in Children from Salamanca, Mexico.

AIM: The purpose of this study was to determine if there is a correlation between telomere length (TL) and mitochondrial DNA copy number (mtDNAcn) in children. METHODS: Leukocyte TL and mtDNAcn were measured by real-time PCR in 98 Mexican children 6-12 years of age from Salamanca, México. RESULTS: A positive association was found between TL and mtDNAcn after a natural log transformation (Pearson correlation r = 0.72; p < 0.0001). No correlation between age and body mass index (BMI) biomarkers was found, and no differences according to sex were observed. After adjustment for these variables, a linear regression model showed an association between TL and mtDNAcn (ß = 0.739, 95% confidence interval 0.594; 0.885, p < 0.0001). CONCLUSIONS: A strong positive correlation between TL and mtDNAcn was found in the study population; age, sex, and BMI seemed to have no effect on this correlation.

Q192R polymorphism of paraoxonase 1 gene associated with insulin resistance in Mexican children.

BACKGROUND AND AIMS: The SNP rs662 in the paraoxonase 1 gene (PON1 Q192R) has been associated with obesity, dyslipidemia and cardiovascular risk. In this study, DNA samples of 117 children aged 6 to 12 years from San Luis Potosí, México were genotyped for Q192R polymorphism of the PON1 gene. METHODS: Genotypic frequencies were determined by allelic discrimination assay by real-time PCR using TaqMan fluorogenic probes. Anthropometry, lipid profile, glucose and insulin were analyzed by genotype. RESULTS: The distribution of allele frequency in the population was Q = 65 and R = 35 following the Hardy Weinberg equilibrium (χ(2) = 3.15, p = 0.076). The Homeostasis Model Assessment for Insulin Resistance (HOMA-IR) index showed statistically significant differences among QQ/QR/RR genotypes (p = 0.032). The odds ratio for the carriers of the RR genotype was associated with HOMA-IR corresponding to the 95(th) percentile or higher for Mexican children based on sex and age (OR = 4.68; 95% confidence intervals, 1.23-17.8; p = 0.016). When the absolute mean of HOMAR-IR was set as the cutoff, an increased odds was observed (OR = 6.52; 95% confidence intervals, 1.68-25.3; p = 0.008). CONCLUSIONS: According to our results, PON1 Q192R polymorphism is a risk marker for insulin resistance, a pathological factor involved in the development of metabolic syndrome.

Dosis de exposición a fluoruros por el consumo de diferentes tipos de leche en residentes de una zona con hidrofluorosis endémica en México / Level of exposure to fluorides by the consumption of different types of milk in residents from an area of Mexico with endemic hydrofluorosis

Introducción: Diversos estudios han demostrado la presencia de fluorosis (FD) en la dentición primaria, lo que puede indicar una exposición a los fluoruros (F-) en la primera infancia. La leche materna se recomienda como alimento exclusivo hasta los 6 meses de edad. Aunque se menciona que solo una pequeña cantidad de F- puede eliminarse por leche materna, estudios han demostrado la presencia de este elemento en leche de mujeres residentes de zonas contaminadas, así como en leche de fórmulas comerciales. El objetivo del proyecto fue evaluar la dosis de exposición a F- a través de leche en niños residentes de una zona con hidrofluorosis endémica. Metodología: Un total de 110 niños de entre 6 y 36 meses de edad del municipio de Lagos de Moreno, Jalisco, México, participaron en el estudio. Se colectaron muestras de agua de los hogares, leche y orina. Las muestras se cuantificaron con el electrodo de ion selectivo. Se calculó la dosis de exposición a F- a través del programa Oracle Crystal Ball. Resultados: Se observaron dosis superiores a la dosis de referencia para FD en la leche de fórmula reconstituida con agua de abastecimiento público, de vaca pasteurizada (entera) y de vaca sin tratamiento sanitario (cruda) en el percentil 90, 70 y 50, respectivamente, así como una correlación entre los niveles de F- en leche y F- en orina (r = 0,41; p < 0,001). Conclusiones: La identificación de fuentes de F- en etapas tempranas del desarrollo infantil podría reducir el riesgo de presentar FD

Introduction: Several studies have shown the presence of fluorosis (DF) in primary dentition, suggesting an exposure to fluorides (F-) in early childhood. Breast milk is recommended as an exclusive food until 6 months of age. Although it is mentioned that only a small amount of F- can be eliminated by breast milk, studies have shown the presence of this element in milk of women living in contaminated areas, as well as in infant formulas. The objective of this project was to evaluate the exposure level to F- through milk in children living in an area with endemic hydrofluorosis. Methodology: The study included 110 children between 6 and 36 months of age from the municipality of Lagos de Moreno, Jalisco. Water samples were collected from the homes, as well as samples of milk (maternal, formula, whole or raw), and urine. Measurments were made with a selective ion electrode. The exposure level of F- for milk intake was calculated using the Oracle Crystal Ball package. Results: Levels greater than the reference level for DF were observed in infant formula reconstituted with public supply water, pasteurised cow's milk (whole) and untreated cow's milk treatment (raw) in the 90th, 70th, and 50th percentile, respectively, with a correlation being found between the levels of F- in milk and F- in urine (r = 0.41, P < .001)

Epigenetic markers of exposure to polycyclic aromatic hydrocarbons in Mexican brickmakers: a pilot study.

A pilot cross-sectional study was carried out in a group of 39 male brick manufacturers in San Luis Potosi, Mexico to identify epigenetic biomarkers of exposure to polycyclic aromatic hydrocarbons (PAHs). A questionnaire was used to compile the smoking and drinking habits, clinical history, working time, and socioeconomic characteristics of the participants. 1-Hydroxypyrene (1-OHP) levels were measured from urine samples using high-performance liquid chromatography, and genomic DNA was isolated from blood samples for methylation analysis using pyrosequencing. The mean 1-OHP level was 0.18 µg g(-1) creatinine (range 0.023-1.11), which was below the expected occupational exposure level. After adjusting for potential confounders, the 1-OHP urine concentration was negatively associated with DNA methylation of the interleukin 12 (ß=-1.57; 95% CI: -2.9 to -0.23; p=0.02) and p53 gene promoters (ß=-2.7; 95% CI: -5.46-0.06; p=0.055). Suggestive negative associations were also found for the TNF-α gene (ß=-3.9; 95% CI:-8.28-0.48; p=0.08) and Alu sequences (ß=-0.55; 95% CI:-1.25-0.16; p=0.12). Although the individual exposures to PAHs as estimated by urinary 1-OHP concentrations were low, changes in specific and global DNA methylation were observed.

p,p'-DDE, a DDT metabolite, induces proinflammatory molecules in human peripheral blood mononuclear cells "in vitro".

In a recent study, our group demonstrated that when peripheral blood mononuclear cells (PBMCs) were treated "in vitro" with p,p'-DDE, a DDT metabolite, an antioxidant response and biomarkers of inflammation were induced at the mRNA level, indicating a proinflammatory state. Thus, the aim of this study was to evaluate the induction of proinflammatory molecules at the protein level in PBMCs exposed to p,p'-DDE "in vitro". The main finding was that "in vitro" exposure to p,p'-DDE enhanced the expression of proinflammatory cytokines (TNF-α, IL-1ß, IL-6) at the protein level in PBMCs. We also observed COX-2 induction at the protein level. Considering that p,p'-DDE has been identified as a persistent metabolite and is frequently found in the population, it is important to evaluate early inflammation biomarkers in populations exposed to DDT and to estimate the true risk of inflammatory disease development.

Epigenetics and lifestyle.

The concept of 'lifestyle' includes different factors such as nutrition, behavior, stress, physical activity, working habits, smoking and alcohol consumption. Increasing evidence shows that environmental and lifestyle factors may influence epigenetic mechanisms, such as DNA methylation, histone acetylation and miRNA expression. It has been identified that several lifestyle factors such as diet, obesity, physical activity, tobacco smoking, alcohol consumption, environmental pollutants, psychological stress and working on night shifts might modify epigenetic patterns. Most of the studies conducted so far have been centered on DNA methylation, whereas only a few investigations have studied lifestyle factors in relation to histone modifications and miRNAs. This article reviews current evidence indicating that lifestyle factors might affect human health via epigenetic mechanisms.