Paraskevi Rodopoulou

Variants of the Arachidonate 5-Lipoxygenase-Activating Protein (ALOX5AP) Gene and Risk of Stroke: A HuGE Gene-Disease Association Review and Meta-Analysis

Variants of the arachidonate 5-lipoxygenase-activating protein (ALOX5AP) gene have been implicated as a risk factor for stroke. However, genetic association studies that have examined the association between ALOX5AP gene variants (HapA haplotype, HapB haplotype, and SG polymorphisms) and stroke have produced conflicting results. Therefore, the authors performed a meta-analysis of all studies with ALOX5AP genotyping (5,194 stroke cases and 4,566 controls). The meta-analysis showed significant heterogeneity among studies (P(Q) = 0.03, I(2) = 63%) and a nonsignificant association between the HapA haplotype (SG13S25G-SG13S114T-SG13S89G-SG13S32A) and stroke risk (random-effects (RE) odds ratio (OR) = 1.13, 95% confidence interval (CI): 0.88, 1.45). Regarding the HapB haplotype (SG13S377A-SG13S114A-SG13S41A-SG13S35G), there was no association with stroke risk (RE OR = 1.03, 95% CI: 0.77, 1.37). The SG13S114, SG13S89, SG13S25, SG13S32, SG13S35, and SG13S42 polymorphisms were not associated with stroke. The SG13S106 and SG13S377 polymorphisms revealed evidence of marginal association (RE OR = 1.23 (95% CI: 1.03, 1.46) and RE OR = 1.25 (95% CI: 1.04, 1.50), respectively). However, cumulative meta-analysis for the HapA haplotype showed a downward trend of odds ratios over time, and recursive cumulative meta-analysis indicated insufficient evidence for claiming or denying an association. Tests for bias revealed no evidence of biases. Rigorous genetic association studies investigating gene-gene-environment interactions may generate more conclusive claims about the genetics of stroke.

Impact of dietary shift to higher-antioxidant foods in COPD: a randomised trial

Chronic obstructive pulmonary disease (COPD) is characterised by increased oxidative stress. Dietary factors, such as ample consumption of foods rich in antioxidants, such as fruit and vegetables, might have beneficial effects in COPD patients. The association between dietary shift to foods rich in antioxidants and lung function in COPD was investigated in a 3-yr prospective study. A total of 120 COPD patients were randomised to follow either a diet based on increased consumption of fresh fruit and vegetables (intervention group (IG)) or a free diet (control group (CG)). The mean consumption of foods containing antioxidants was higher in the IG than in the CG throughout the study period (p<0.05). The relationship between consumption of foods rich in antioxidants and percentage predicted forced expiratory volume in 1 s was assessed using a general linear model for repeated measures; the two groups overall were different in time (p = 0.03), with the IG showing a better outcome. In investigating the effect of several confounders (sex, age, smoking status, comorbid conditions and exacerbation) of group response over time, nonsignificant interactions were found between confounders, group and time. These findings suggest that a dietary shift to higher-antioxidant food intake may be associated with improvement in lung function, and, in this respect, dietary interventions might be considered in COPD management.

Randomized trials of dopamine agonists in restless legs syndrome: A systematic review, quality assessment, and meta-analysis

BACKGROUND The use of dopamine agonists (DAs) for the treatment of restless legs syndrome (RLS) has been assessed in numerous randomized clinical trials (RCTs). OBJECTIVES The aims of this study were to assess the reporting quality of published RCTs according to the Consolidated Standards of Reporting Trials (CONSORT) statement and to synthesize the study results in terms of efficacy and tolerability to inform the clinical management of RLS. METHODS PubMed and Cochrane Controlled Trials Register were searched for English-language RCTs that assessed the effects of DAs in RLS. Quality of reporting was measured using the proportion of 17 CONSORT checklist items included in each study. The 2 primary outcomes were pooled mean change from baseline in International RLS (IRLS) Study Group rating scale score (Deltamu) (95% CI) and relative risk (RR) (95% CI) of response based on the Clinical Global Impression-Improvement (CGI-I) scale score. The pooled proportions of adverse events (PAEs) (95% CI) were also estimated. RESULTS Eighteen RCTs (N = 2848 patients) were included. Two of the 17 CONSORT checklist items were reported in 7 studies (39%) and 9 of the 17 items were reported in all 18 studies (100%). The differences in the IRLS scores and RR for CGI-I were significantly greater with pramipexole, ropinirole, rotigotine, and cabergoline compared with placebo. Results for heterogeneity were nonsignificant. The difference in Deltamu (95% CI) was significant with pramipexole (-6.63 [-9.15 to -4.10]) versus ropinirole (-3.64 [-4.76 to 2.51]) (P = 0.04). The difference between pramipexole and rotigotine was nonsignificant. The pooled PAEs (95% CI) for pramipexole, ropinirole, and rotigotine were 4.8% (2.0% to 8.7%), 10.2% (2.6% to 22.1%), and 7.6% (1.3% to 18.5%), respectively. In the trial of sumanirole, the PAE value was 2% (0% to 5.4%). CONCLUSION Based on the findings from the meta-analysis, DAs were significantly more efficacious in the treatment of RLS compared with placebo.

BsmI, TaqI, ApaI and FokI Polymorphisms in the Vitamin D Receptor (VDR) Gene and the Risk of Osteoporosis: A Meta-Analysis

A meta-analysis regarding BsmI, TaqI, ApaI and FokI polymorphisms in the vitamin D receptor (VDR) gene and their associations with osteoporosis in females is reported. The meta-analysis involved 14, seven, seven and three studies for BsmI, TaqI, ApaI and FokI polymorphisms, respectively. The studies were association studies with osteoporotic cases and controls free of osteoporosis that provided the genotype distribution of individual cases and controls. For the BsmI polymorphism, the allele contrast b vs. B showed heterogeneity among studies (p < 0.01, I2 > 50%) and the random effects (RE) pooled odds ratio (OR) was non-significant: 0.94 [95% confidence interval (CI) 0.63–1.38]. Caucasians, postmenopausal cases and studies with WHO diagnostic criteria showed no association under any genetic contrast. However, in East Asians, the OR for the dominant model [fixed effects OR = 0.14 (95% CI 0.04–0.50) and RE OR = 0.16 (95% CI 0.03–0.84)] was significant, indicating prevention. Overall, for the TaqI, ApaI and FokI polymorphisms, the allele contrast showed heterogeneity and the pooled RE ORs were non-significant [OR = 1.06 (95% CI 0.71–1.60), OR = 0.99 (95% CI 0.72–1.37) and OR = 1.17 (95% CI 0.76–1.80), respectively]. The allele contrast for Caucasians, East Asians, postmenopausal cases and studies with WHO diagnostic criteria showed no association for TaqI, ApaI, and FokI. The allele contrast of homozygotes, and the recessive and dominant models the results followed the same pattern as the allele contrast. Therefore, the relationship between the VDR polymorphisms and osteoporosis remains an unresolved issue and other probable genetic-environmental risk factors interacting with the above polymorphisms should be investigated.

Variants in C-reactive protein and IL-6 genes and susceptibility to obstructive sleep apnea in children: a candidate-gene association study in European American and Southeast European populations.

BACKGROUND Preliminary evidence indicates that variants of the C-reactive protein (CRP) and IL-6 genes might be associated with the presence of obstructive sleep apnea (OSA) in childhood. Thus a candidate-gene association study was conducted to investigate the association of four variants of the CRP gene (1444C/T, -717T/C, 1861C/T, and 1919A/T) and two variants of the IL-6 gene (-174G/C and 597G/A) with OSA in a cohort of European American and Greek children. METHODS The genetic risk effects were estimated based on the odds ratio (OR) of the allele contrast and the generalized odds ratio (ORG), which is a model-free approach. The mode of inheritance was assessed using the degree of dominance index. The impact of haplotypes was also examined. RESULTS In the American population, the allele contrast and the model-free approach produced significant ORs for the CRP 1444C/T variant (OR, 3.82 [95% confidence interval {CI}, 1.91-7.63] and ORG, 4.37 [95% CI, 1.96-9.76]), respectively, and the mode of inheritance was recessiveness of allele T. Significance was also shown for the CRP 1919A/T variant (OR, 2.45 [95% CI, 1.23-4.85] and ORG, 2.76 [95% CI, 1.26-6.03]) with the mode of inheritance being nondominance of allele T. For the IL-6-174G/C variant, there was an indication of recessiveness of allele C. Finally, the IL-6-174C/IL-6 597A haplotype was associated with OSA. In the Greek population, no association was detected for any variant or haplotype. CONCLUSIONS Genetic variation in the IL-6/CRP pathway was associated with increased risk for OSA in European American children and may account for the higher CRP levels in the context of pediatric OSA compared to Greek children.

The role of MTHFR gene in multiple myeloma

AbstractCase-control studies investigating associations between multiple myeloma (MM) and the C677T and A1298C polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) have provided controversial results. In an attempt to interpret these results, a meta-analysis of all available studies was performed. In the meta-analysis the pooled odds ratios (OR) were estimated using fixed effects (FE) and random effects (RE) models. The heterogeneity between studies, the sources of potential bias and the consistency of genetic effects across ethnicities were explored. Cumulative meta-analysis was also performed. The meta-analysis revealed non-significant heterogeneity between studies (Pq ≥ 0.65). The dominant model for the effect of 677T allele produced significant association overall [FE OR = 1.23 (1.04–1.47)] and in Caucasians [FE OR = 1.54 (1.14–2.08)], but not in East Asians [FE OR = 1.05 (0.82–1.34)]. Although the cumulative meta-analysis for the dominant model of 677T allele showed a downward trend of RE OR for the period 2000–2007, the association still remained significant. Analysis of the A1298C polymorphisms revealed lack of association both in Caucasians and in East Asians. There is an indication of potential bias: a differential magnitude of effect in large versus small studies emerged. In conclusion, the accumulated evidence indicated an association between MTHFR C677T polymorphism and MM in Caucasians under a dominant model.

Synopsis and meta-analysis of genetic association studies in osteoporosis for the focal adhesion family genes: the CUMAGAS-OSTEOporosis information system

BackgroundFocal adhesion (FA) family genes have been studied as candidate genes for osteoporosis, but the results of genetic association studies (GASs) are controversial. To clarify these data, a systematic assessment of GASs for FA genes in osteoporosis was conducted.MethodsWe developed Cumulative Meta-Analysis of GAS-OSTEOporosis (CUMAGAS-OSTEOporosis), a web-based information system that allows the retrieval, analysis and meta-analysis (for allele contrast, recessive, dominant, additive and codominant models) of data from GASs on osteoporosis with the capability of update. GASs were identified by searching the PubMed and HuGE PubLit databases.ResultsData from 72 studies involving 13 variants of 6 genes were analyzed and catalogued in CUMAGAS-OSTEOporosis. Twenty-two studies produced significant associations with osteoporosis risk under any genetic model. All studies were underpowered (<50%). In four studies, the controls deviated from the Hardy-Weinberg equilibrium. Eight variants were chosen for meta-analysis, and significance was shown for the variants collagen, type I, α1 (COL1A1) G2046T (all genetic models), COL1A1 G-1997T (allele contrast and dominant model) and integrin β-chain β3 (ITGB3) T176C (recessive and additive models). In COL1A1 G2046T, subgroup analysis has shown significant associations for Caucasians, adults, females, males and postmenopausal women. A differential magnitude of effect in large versus small studies (that is, indication of publication bias) was detected for the variant COL1A1 G2046T.ConclusionThere is evidence of an implication of FA family genes in osteoporosis. CUMAGAS-OSTEOporosis could be a useful tool for current genomic epidemiology research in the field of osteoporosis.

Variants of the MTHFR gene and susceptibility to acute lymphoblastic leukemia in children: A synthesis of genetic association studies

BACKGROUND Acute lymphoblastic leukemia (ALL) is a complex disease with genetic background. The genetic association studies (GAS) that investigated the association between ALL and the MTHFR C677T and A1298C gene variants have produced contradictory or inconclusive results. MATERIALS AND METHODS In order to decrease the uncertainty of estimated genetic risk effects, a meticulous meta-analysis of published GAS related the variants in the MTFHR gene with susceptibility to ALL was conducted. The risk effects were estimated based on the odds ratio (OR) of the allele contrast and the generalized odds ratio (OR(G)). Cumulative and recursive cumulative meta-analyses were also performed. RESULTS The analysis showed marginal significant association for the C677T variant, overall [OR=0.91 (0.82-1.00) and OR(G)=0.89 (0.79-1.01)], and in Whites [OR=0.88 (0.77-0.99) and OR(G)=0.85 (0.73-0.99)]. The A1298C variant produced non-significant results. For both variants, the cumulative meta-analysis did not show a trend of association as evidence accumulates and the recursive cumulative meta-analysis indicated lack of sufficient evidence for denying or claiming an association. CONCLUSION The current evidence is not sufficient to draw definite conclusions regarding the association of MTHFR variants and development of ALL.

Interleukin-1B and interleukin-1 receptor antagonist gene polymorphisms in Greek multiple sclerosis (MS) patients with bout-onset MS

AbstractWe investigated the association of specific polymorphisms of the interleukin IL-1b (AvaI −511 and TaqI +3,953) and IL-1 receptor antagonist (IL-1RN) (a variable number of tandem repeats; VNTR) genes with both the susceptibility to and the clinical characteristics in Greek multiple sclerosis (MS) patients cohort with bout-onset. Genotypes were determined from 351 patients with clinically definite MS and 375 age- and sex-matched healthy controls. Our results showed no significant differences in the distribution of these polymorphisms between MS patients and controls. Furthermore, stratification for clinical characteristics, such as age at disease onset, clinical course, sex, and severity did not provide significant differences between patients and controls. Together, our findings suggest that IL-1B and IL-1RN gene polymorphisms may not be relevant to the susceptibility to MS or the clinical characteristics of Greek MS patients.

Field Synopsis and Synthesis of Genetic Association Studies in Osteoarthritis: The CUMAGAS-OSTEO Information System

A comprehensive and systematic assessment of the current status of genetic association studies (GAS) for osteoarthritis was conducted. Data from 327 GAS involving 187 distinct genetic variants were analyzed and cataloged in CUMAGAS-OSTEO, a Web-based information system (http://biomath.med.uth.gr) that allows the retrieval and synthesis of data from GAS on osteoarthritis. In individual studies, 66 variants (mostly single nucleotide polymorphisms) showed significant associations with osteoarthritis risk. For 19 variants, the association was significant at P < 0.01, with an increased risk greater than 30%. Only 2.4% of studies had statistical power greater than 50% to detect a modest genetic effect. Nineteen variants were investigated by 4 or more studies, and their results were subjected to meta-analysis. Significant associations were derived for 2 variants (GDF5 rs143383, LRCH1 rs912428) in the main meta-analysis and for 2 other variants (TXNDC3 rs4720262, ESR1 rs2234693) in subgroup analysis by ethnicity or osteoarthritic body site. Heterogeneity ranged from none to high. In general, there was consistency of genetic effects across ethnic groups and body sites, and there was no differential magnitude of effect in large studies versus small studies. CUMAGAS-OSTEO may be a useful tool for identifying pertinent gene-osteoarthritis associations and providing an updated summary of risk effects.