Yazmín Hernández-Díaz

No association between ApoE and schizophrenia: Evidence of systematic review and updated meta-analysis

INTRODUCTION Schizophrenia affects between 0.3% and 2% of the worldwide population. A genetic contribution has been postulated in the development of this disorder. Genes such as ApoE have been implicated in the neurodevelopment associated with schizophrenia in case-control and meta-analysis studies, but the results remain inconclusive. Due to this, the aim of the present study was to explore the association between ApoE and schizophrenia through a meta-analysis. MATERIAL AND METHODS We collected all relevant studies by searching PubMed and EBSCO databases. The pooled odds ratios with 95% confidence intervals were calculated to estimate the association. The following models were evaluated: A) ε4 vs ε3, B) ε4 vs ε2, C) ε4 vs ε3+ε2, D) Caucasian population and E) Asian population. Statistical analyses were performed using EPIDAT 3.1 software. RESULTS The meta-analyses comprised 28 association studies, which included 4703 controls and 3452 subjects with schizophrenia. A significant protective effect was found for allele ε3 in the Asian population (OR=0.73, 95% CI=0.54-0.98). No significant associations were observed in the other models and populations analyzed. CONCLUSIONS Our meta-analysis suggests a protective association between ApoE allele ε3 and schizophrenia in the Asian population.

The role of C957T, TaqI and Ser311Cys polymorphisms of the DRD2 gene in schizophrenia: systematic review and meta-analysis

BackgroundThe association between the dopamine D2 receptor (DRD2) gene and schizophrenia has been studied though no conclusive outcomes have been attained. The aim of this study was to perform a systematic review and meta-analysis to explore the relation between three polymorphisms of the DRD2 gene (C957T, TaqI and Ser311Cys) and schizophrenia.MethodsThe search was made in PubMed and EBSCO databases (up to February 2016). The systematic review included 34 case–control association studies (34 for C957T, 16 for TaqI and 36 for Ser311Cys). The association analysis comprised the allelic, additive, dominant, and recessive genetic models. The meta-analysis was performed following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) statement.ResultsThe meta-analysis showed that TaqI (additive model: OR 0.57, 95% CI 0.30–1.14) and C957T (additive model: OR 0.75, 95% OR 0.58–0.97, recessive model: OR 0.79, 95% CI 0.64–0.98) exert a protective effect against developing schizophrenia. However, the sub-analysis for the C957T variant showed that this polymorphism exhibits a risk factor effect on Chinese individuals (allelic model: OR 1.33, 95% CI 1.04–1.70).ConclusionOur meta-analysis suggests an association of the DRD2 gene and the risk for schizophrenia, given that TaqI and C957T polymorphisms presented a protective effect against schizophrenia, and in the sub-analyses the C957T variant increased the risk for this disorder in the Chinese population.

Effects of paraoxonase 1 gene polymorphisms on heart diseases: Systematic review and meta-analysis of 64 case-control studies.

Background:Associations between paraoxonase 1 (PON1) gene polymorphisms and heart diseases (HD) risk remain inconsistent. In order to obtain address this issue we performed a meta-analysis to assess the association between the L55M and Q192R polymorphisms of PON1 gene and heart diseases risk. Methods:Relevant studies were enrolled by searching databases systematically. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to calculate the strength of association. Subgroup analyses were conducted for diagnostic and ethnicity. The heterogeneity among each of the studies was calculated by using Cochran Qtest and the inconsistency index (I2), and Beggs funnel plot and Eggers tests were performed to evaluate publication bias. Result:Sixty four studies involving a total of 19,715 cases and 33,397 controls were included in this meta-analysis. We found that the L55M polymorphism showed a significant association with heart diseases in Europeans (OR 1.44, 95%CI 1.33–1.56) and Asians (OR 1.18, 95%CI 1.03–1.35). This meta-analysis also showed a protective association of Q192R polymorphism with HD in Asian (OR 0.49, 95%CI 0.37–0.66) and African populations (OR 0.67, 95%CI 0.53–0.84). The 192R allele significantly decreased the risk of myocardial infarction (OR 0.75, 95%CI 0.57–0.99) and coronary artery disease (OR 0.91, 95%CI 0.84–0.98); however, individuals with 192Q allele had a markedly increased risk of coronary artery disease development (OR 1.38, 95%CI 1.22–1.56). Conclusion:This study demonstrated that the genetic risk for heart diseases is associated with the PON1 gene polymorphisms. L55M polymorphism is a risk factor and Q192R polymorphism is protective in certain populations. It is worth noting that the 192Q allele may be a risk factor to develop coronary artery disease.

Association between CRP and TNF-α genes Variants and Cardiovascular Heart Disease in a Mexican Population: Protocol for a Case-Control Study

Background: The C-reactive protein (CRP) and the tumor necrosis factor-alpha (TNF-α) are considered markers of inflammation and have been shown to predict the risk of incident cardiovascular events. However, few studies have undertaken a comprehensive examination of SNPs (single nucleotide polymorphisms) of the CRP and TNF-α genes; due to this, we will present a protocol study to evaluate the role of the CRP and TNF-α genes in Mexican individuals. Methods/design: we will perform a case-control study to explore the CRP and TNF-α genotype distribution as well as the serum influence of rs1800947, rs1130864, rs2794521 and rs1205 (polymorphisms of the CRP gene) and rs361525, rs1800629, rs1799724, rs1800630, rs1799964 (of the TNF-α gene) in Mexican individuals who present coronary artery disease. Ethics and dissemination: a written informed consent will be obtained from all the participating subjects. An article detailing the results of the study will be submitted for publication in an international peer-reviewed journal, in accordance with STROBE criteria.

Association between completed suicide and environmental temperature in a Mexican population, using the Knowledge Discovery in Database approach

BACKGROUND AND OBJECTIVE Suicide is a worldwide health problem and climatological characteristics have been associated with suicide behavior. However, approaches such as the Knowledge Discovery in Database are not frequently used to search for an association between climatological characteristics and suicide. The aim of the present study was to assess the association between weather data and suicide in a Mexican population. METHODS We used the information of 1357 patients who completed suicide from 2005 to 2012. Alternatively, weather data were provided by the National Water Commission. We used the Knowledge Discovery in Database approach with an Apriori algorithm and the data analyses were performed with the Waikato Environment for Knowledge Analysis software. One hundred rules of association were generated with a confidence of 0.86 and support of 1. RESULTS We found an association between environmental temperature and suicide: days with no rain and temperatures between 30 °C and 40 °C (86-104 °F) were related to males completing suicide by hanging. CONCLUSIONS In the prevention of suicidal behavior, the Knowledge Discovery in Database could be used to establish climatological characteristics and their association with suicide. This approach must be considered in future prevention strategies.

Association of G308A and G238A Polymorphisms of the TNF-α Gene with Risk of Coronary Heart Disease: Systematic Review and Meta-analysis

BACKGROUND AND AIMS It is widely acknowledged that coronary heart disease (CHD) has a genetic influence. One of the most promising candidate genes is tumor necrosis factor-alpha (TNF-α). Although there have been several positive studies associating the TNF-α gene and CHD, the evidence is not entirely consistent. The aim of the study was to evaluate the role of the TNF-α gene in CHD using combined evidence by generating a meta-analysis and a systematic review of all published data. METHODS Meta-analysis and systematic review were conducted using 27 articles of genetic association studies of the TNF-α gene variants (G308A and G238A) and CHD. To analyze the association we used allelic, additive, dominant and recessive models. Moreover, we conducted a subanalysis by populations using the same four models. RESULTS TNF-α variant G308A showed a significant association with CHD but only when the analysis comprised the whole population. In addition, the variant G238A yielded the same outcome in the Asian population. CONCLUSIONS Genetic polymorphisms at positions -308 and -238 in the promoter region of the TNF-α gene may be useful as predictive factors for CHD.

Risk Factors and Prevalence of Suicide Attempt in Patients with Type 2 Diabetes in the Mexican Population

Background: It has been proposed that the risk of death by suicide is higher in patients with diabetes than in the general population. Therefore, it is necessary to investigate the risk factors of suicidal behavior in patients with type 2 diabetes. The aim of the present study was to analyze the prevalence of suicide attempt and determine the risk factors of suicide attempt, in patients with type 2 diabetes in a Mexican population. Methods: Clinic characteristics, anthropometric measurements, biochemical levels, depression, and suicidal behavior were evaluated in 185 Mexican patients with type 2 diabetes. A multivariate logistic regression analysis was performed to find predictive factors of suicide attempt. Results: 11.4% of patients reported previous suicide attempts n = 21). Younger patients (OR: 3.63, 95% CI: 1.29–10.19), having depression (OR: 3.33, 95% CI: 1.13–9.76) and normal BMI (OR: 3.14, 95% CI: 1.11–8.83), were predictive factors of suicide attempt. No other variables in the study showed statistical significance. Conclusions: Our results showed a high prevalence of suicidal behavior in patients with type 2 diabetes. We found that younger age, depression and normal BMI could be risk factors of suicide attempt in these patients. Therefore, psychiatric interventions to prevent depression and suicidal behavior in this population are necessary. New studies using larger samples are necessary to replicate and confirm these results.

The role of the Cys23Ser (rs6318) polymorphism of the HTR2C gene in suicidal behavior: systematic review and meta-analysis

The polymorphisms of the serotonin receptor 2C (HTR2C) gene have been proposed to influence suicidal behavior. The aim of our study was to explore the role of the HTR2C gene variant Cys23Ser (rs6318) in the pathogenesis of suicidal behavior through a systematic review and meta-analysis. The search was performed using EBSCO and PubMed databases. To be included in the analysis, the studies had to evaluate suicidal behavior (attempted, ideation, or completed suicide). The results of the meta-analysis were expressed as odds ratios (ORs). Because HTR2C lies on chromosome X, pooled ORs were calculated, respectively, for each of the models used, namely: allelic, homozygous, dominant, and recessive for the female group and allelic for the male group. The meta-analysis comprised 3867 individuals, including 1668 cases and 2199 controls. The HTR2C Cys23Ser (rs6318) polymorphism did not show a significant association with suicidal behavior either in women (OR: 0.75; 95% confidence interval: 0.55–1.00) or in men (OR: 0.89; 95% confidence interval: 0.64–1.23). Similarly, nonsignificant associations were observed for all of the genetic models used in any of the populations/subgroups studied. Our findings suggest that the rs6318 (Cys23Ser) polymorphism is not associated with suicidal behavior. However, because of the study limitations, we suggest more researches should be performed, increasing the sample sizes and statistical power, to determine the association between the rs6318 variant and suicidal behavior.

Gender differences in the association between HTR2C gene variants and suicidal behavior in a Mexican population: a case–control study

Background The aim of this case–control study was to explore the association by gender between the HTR2C gene variants and suicidal behavior in a Mexican population. Subjects and methods A total of 183 suicide attempters and 208 healthy volunteers were included in this study. We genotyped five polymorphisms of HTR2C (rs547536, rs2192372, rs4272555, rs6318, and rs2428707), then measured the association by genotype, allele, and haplotype. Results In the female group, we found an association between two polymorphisms of the HTR2C (rs4272555 and rs2428707) and suicide attempts. The C allele of the single-nucleotide polymorphism (SNP) rs4272555 was associated with a decreased risk of suicide attempt (P=0.01, odds ratio =0.26, 95% confidence interval: 0.09–0.79), whereas the G allele of the SNP rs2428707 was associated with an increased risk of suicide attempt (P=0.01, odds ratio =3.68, 95% confidence interval: 1.24–10.90). No significant association was observed between the other polymorphisms studied (rs547536, rs2192372, rs6318) or haplotypes with suicide attempts. Conclusion These findings suggest a possible risk factor of the HTR2C gene in the pathology of suicidal behavior in Mexican population. More studies are necessary to confirm this association.

Prevalence and correlations between suicide attempt, depression, substance use, and functionality among patients with limb amputations

Most patients undergoing limb amputations suffer significant emotional changes. The aim of this study was to estimate the prevalence of suicide attempts and depression in a sample of Mexican patients with limb amputations and, second, to determine whether the patients’ functionality correlates with the presence of depression. We studied 40 patients who had undergone a limb amputation. The suicide attempt was evaluated using the Suicide Intent Scale. The depression was assessed using the Hamilton Depression Rating Scale, whereas the functionality of the patients was measured using the Functional Independence Measure. In this sample, 90% were men, whereas only 10% were women. In terms of the suicide behavior, we identified suicide attempts in 27.5% of the patients. The rate of depression was 92.5%. In the Functional Independence Measure, we observed that 57.5% of the patients showed complete dependence. Finally, a significant correlation was found between depression and functionality (r=−0.75, P<0.001). The findings of the present study highlight the high incidence of suicide attempts and depression in Mexican patients with limb amputations. Also, we identified a correlation between the lack of functional independence and depression. Therefore, holistic interventions are necessary in these patients: rehabilitation therapy to increase their functionality, and psychological and pharmacology therapy to decrease suicidal behavior and depression. Finally, more studies using larger samples are necessary to obtain conclusive results.