Hospital-based Case-control Studies Research Articles

Antibiotic Drug Use and the Risk of Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis: A Population-Based Case-Control Study

Abstract Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare, life-threatening mucocutaneous adverse drug reactions. Sulphonamide antibiotics are commonly accepted as one of the primary causes of SJS/TEN. This notion is based on results from two hospital-based case-control studies that identified the combined antibiotic cotrimoxazole (sulfamethoxazole and trimethoprim) as the cause of several SJS/TEN cases. Associations were also reported for penicillins, quinolones, cephalosporins, macrolides, tetracyclines, and metronidazole. Using data from the UK-based Clinical Practice Research Datalink, we conducted a 1:4-matched case-control study including 480 previously validated SJS/TEN cases (1995-2013) to quantify the association between SJS/TEN and antibiotics. We further quantified absolute risks of SJS/TEN within separate cohorts of antibiotic users and assessed causality in each exposed case using an adapted version of the algorithm of drug causality in epidermal necrolysis (ALDEN). We observed a strong association between SJS/TEN and trimethoprim alone (odds ratio=9.44, 95% CI 3.83-23.25; absolute risk: 0.98 cases/100’000 users), which suggests that the previously reported association between cotrimoxazole and SJS/TEN is at least partly attributable to the non-sulphonamide antibiotic trimethoprim, which is frequently prescribed as a single agent in the UK. Our study further corroborates previously reported associations between SJS/TEN and use of penicillins, quinolones, cephalosporins, and macrolides.

Processed meat and selected hormone-related cancers

To assess and quantify the association between processed meat consumption and cancers of the breast, endometrium, ovary, and prostate. Data were derived from an integrated network of hospital-based case-control studies conducted between 1982 and 2006 in various Italian areas. These studies included 5981 cases of cancer of the breast, 992 of the endometrium, 2002 of the ovary, 1582 of the prostate, and a total of 16 394 controls with data on processed meat. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by unconditional multiple logistic regression models, adjusted for major recognized confounders for each cancer site. The median consumption of processed meat in this population was 2 portions per wk in each cancer-specific cases, controls, and overall, corresponding to 100 g/wk. The OR for the highest (≥20 g/d) compared with lowest (<10 g/d) category of processed meat consumption was 1.16 (95% CI 1.06-1.28) for breast, 1.31 (95% CI 1.07-1.60) for endometrial, 1.49 (95% CI 1.30-1.71) for ovarian, and 0.89 (95% CI 0.74-1.07) for prostate cancer. In this case-control study, we found some excess risks of high processed meat consumption with female hormone-related cancers. Conversely, no association with prostate cancer was found in men.

Coffee Consumption and the Risk of Thyroid Cancer: A Systematic Review and Meta-Analysis.

An inverse association has been reported between coffee consumption and the risk of several cancers. However, the association between coffee and thyroid cancer is controversial. Thus, this study aimed to evaluate the association between coffee consumption and the risk of thyroid cancer through a systematic review and meta-analysis. Published studies were examined from PubMed, Embase, Cochrane Central, and the reference lists of the retrieved articles. The summary odds ratio (OR) for the association between coffee consumption was categorized as highest versus lowest consumption, and thyroid cancer risk was calculated using a fixed effects model. Subgroup analyses by study design, geographic location, source of controls, and adjusted variables were performed. A total of 1039 thyroid cancer cases and 220,816 controls were identified from five case-control studies and two cohort studies. The summary OR for the association between coffee consumption and thyroid cancer risk was 0.88 (95% confidence interval (CI) = 0.71–1.07). There was no significant heterogeneity among the study results (I² = 0%, p = 0.79). However, the beneficial effect of coffee consumption on thyroid cancer was found only in hospital-based case-control studies (OR= 0.59, 95% CI= 0.37–0.93). There was no significant association between coffee consumption and thyroid cancer risk according to our meta-analysis results. These findings should be interpreted with caution because of potential biases and confounding variables. Further prospective studies with a larger number of cases are encouraged to confirm these results.

Association between cooking oil fume exposure and lung cancer among Chinese nonsmoking women: a meta-analysis.

Lung cancer has been the main cause of cancer death around the world. Cigarette smoking has been identified as a risk factor for lung cancer in males. However, the etiological factors in nonsmoking women remain elusive. A meta-analysis was conducted to evaluate the relationship between cooking oil fume exposure and lung cancer among Chinese nonsmoking women. Thirteen articles containing three population-based case–control and ten hospital-based case–control studies were included in this meta-analysis. These studies with a total of 3,596 lung cancer women and 6,082 healthy controls were analyzed by RevMan 5.3. Fixed effects model or random effects model was used to obtain pooled estimates of risk ratio. The risk ratios with a 95% CI were 1.74 (95% CI =1.57–1.94) and 2.11 (95% CI =1.54–2.89), respectively. Cooking oil fume exposure as well as not using a kitchen ventilator when cooking was significantly associated with lung cancer among nonsmoking women (Z=10.07, P<0.00001; Z=4.65, P<0.00001). Cooking oil fume exposure, especially lacking a fume extractor, may increase the risk of lung cancer among Chinese nonsmoking women.

Dietary Flavonols Intake and Risk of Esophageal and Gastric Cancer: A Meta-Analysis of Epidemiological Studies.

Background: Esophageal cancer (EC) and gastric cancer (GC) are common cancers and leading causes of cancer deaths worldwide. Many studies have investigated the association between dietary flavonols intake and the risk of EC and GC, but the results are inconsistent. Hence, we conducted a systematic analysis of relevant population-based studies to assess the association and derive a more precise estimation. Methods: The Cochrane, PubMed and Embase databases were searched to identify articles published through January 2016 that met the predetermined inclusion criterion. Twelve studies involving 4593 patients and 519,378 controls were included. Results: The summary odds ratios (ORs) of EC, GC and the two combined were respectively 0.88 (95% CI: 0.73–1.08), 0.80 (95% CI: 0.70–0.91) and 0.83 (95% CI: 0.74–0.92) for the highest category of dietary flavonols intake compared with the lowest. No significant heterogeneities were observed in these studies. Further analysis showed that the pooled ORs of EC and GC for cohort, population-based case-control and hospital-based case-control studies were 0.90 (95% CI: 0.61–1.34), 0.92 (95% CI: 0.72–1.18), 0.68 (95% CI: 0.38–1.24) and 0.83 (95% CI: 0.65–1.06), 0.84 (95% CI: 0.45–1.59), 0.70 (95% CI: 0.56–0.88). The subgroup analyses revealed a significant association of flavonol intake with a reduced risk of noncardia gastric adenocarcinoma but not gastric cardia adenocarcinoma. Moreover, significant inverse associations of flavonol intake with GC risk were observed in women but not in men, in smokers but not in nonsmokers, in European populations but not in American populations. Similarly, a significant inverse association of flavonols intake with EC risk was also observed in smokers but not in nonsmokers. Conclusion: High intake of dietary flavonols is significantly related to a reduced risk of GC, especially in women and smokers.

Lack of association between polymorphisms in the CYP1A2 gene and risk of cancer: evidence from meta-analyses.

BackgroundPolymorphisms in the CYP1A2 genes have the potential to affect the individual capacity to convert pre-carcinogens into carcinogens. With these comprehensive meta-analyses, we aimed to provide a quantitative assessment of the association between the published genetic association studies on CYP1A2 single nucleotide polymorphisms (SNPs) and the risk of cancer.MethodsWe searched MEDLINE, ISI Web of Science and SCOPUS bibliographic online databases and databases of genome-wide association studies (GWAS). After data extraction, we calculated Odds Ratios (ORs) and 95 % confidence intervals (CIs) for the association between the retrieved CYP1A2 SNPs and cancer. Random effect model was used to calculate the pooled ORs. Begg and Egger tests, one-way sensitivity analysis were performed, when appropriate. We conducted stratified analyses by study design, sample size, ethnicity and tumour site.ResultsSeventy case-control studies and one GWA study detailing on six different SNPs were included. Among the 71 included studies, 42 were population-based case-control studies, 28 hospital-based case-control studies and one genome-wide association study, including total of 47,413 cancer cases and 58,546 controls. The meta-analysis of 62 studies on rs762551, reported an OR of 1.03 (95 % CI, 0.96–1.12) for overall cancer (P for heterogeneity < 0.01; I2 = 50.4 %). When stratifying for tumour site, an OR of 0.84 (95 % CI, 0.70–1.01; P for heterogeneity = 0.23, I2 = 28.5 %) was reported for bladder cancer for those homozygous mutant of rs762551. An OR of 0.79 (95 % CI, 0.65–0.95; P for heterogeneity = 0.09, I2 = 58.1 %) was obtained for the bladder cancer from the hospital-based studies and on Caucasians.ConclusionsThis large meta-analysis suggests no significant effect of the investigated CYP1A2 SNPs on cancer overall risk under various genetic models. However, when stratifying according to the tumour site, our results showed a borderline not significant OR of 0.84 (95 % CI, 0.70–1.01) for bladder cancer for those homozygous mutant of rs762551. Due to the limitations of our meta-analyses, the results should be interpreted with attention and need to be further confirmed by high-quality studies, for all the potential CYP1A2 SNPs.

Variants of FGFR2 and their associations with breast cancer risk: a HUGE systematic review and meta-analysis.

Extensive epidemiological studies have demonstrated that there are associations between variants in intron 2 of FGFR2 and the breast cancer risk in various populations; however, the relationships are not yet conclusively established. To comprehensively review the epidemiological studies showing associations between the variants of FGFR2 and the breast cancer risk, and to establish correlations via a meta-analysis. The PubMed and MEDLINE databases were searched for eligible studies. The associations between the variants and breast cancer risk were evaluated using a random-effects model. The heterogeneity among the studies and the potential publication bias were also evaluated. Fifty-three studies with a total of 121,740 cases and 198,549 controls have examined the associations between 23 variants in intron 2 of FGFR2 and the breast cancer risk. The relationships for the 10 most frequently evaluated variants-rs1078806, rs11200014, rs1219648, rs2420946, rs2981578, rs2981579, rs2981582, rs3135718, rs10736303, and rs3750817-were synthesized based on a meta-analysis. Interestingly, we found that all 10 variants were significantly associated with the risk of breast cancer. In studies stratified by ethnicity, we found that the associations were more notable in Caucasians and Asians compared to Africans. Similar pooled results were found in population-based and hospital-based case-control studies and in studies with small and large sample sizes. FGFR2 is a breast cancer susceptibility gene, and various variants of FGFR2 are significantly associated with the breast cancer risk. However, the biological mechanisms underlying the associations need to be elucidated in future studies.

A Meta-Analysis of the Association Between the I148M Variant of Patatin-Like Phospholipase Domain Containing 3 Gene and the Presence of Chronic Hepatitis C.

Context:The objective of the current study was to evaluate the association between the I148M variant of patatin-like phospholipase domain-containing protein 3 (PNPLA3) and the presence of Chronic Hepatitis C (CHC) across different populations.Evidence Acquisition:This study was a meta-analysis of all relevant researches published in the literature from year 2000 to 2015. The odds ratios (ORs) of PNPLA3 allele distributions in CHC patients were analyzed and compared with healthy controls. The meta-analysis Revman 5.2 software was applied for investigating heterogeneity among individual studies and for summarizing all the studies. The meta-analysis was carried out according to the Cochrane Reviewers’ Handbook recommendations. A total of 120 clinical trials or reports were retrieved, yet only five trials met the study selection criteria.Results:Five hospital-based case-control studies were included in the final analysis. The overall frequency of PNPLA3 gene polymorphisms was 20.4% (205/1005) in CHC and 10.23% (53/518) in controls. The summary odds ratio for the association of gene polymorphisms of PNPLA3 with the risk for CHC was determined as 2.20 (95% CI: 1.56 -3.11) and was statistically significant (P < 0.05).Conclusions:The current meta-analysis showed an association between frequency of GG genotype of PNPLA3 and the risk of development of CHC in various populations throughout the world.

Modelling body mass index and endometrial cancer risk in a pooled-analysis of three case-control studies.

To quantify the relation between body mass index (BMI) and endometrial cancer risk, and to describe the shape of such a relation. Pooled analysis of three hospital-based case-control studies. Italy and Switzerland. A total of 1449 women with endometrial cancer and 3811 controls. Multivariate odds ratios (OR) and 95% confidence intervals (95% CI) were obtained from logistic regression models. The shape of the relation was determined using a class of flexible regression models. The relation of BMI with endometrial cancer. Compared with women with BMI 18.5 to <25 kg/m(2) , the odds ratio was 5.73 (95% CI 4.28-7.68) for women with a BMI ≥35 kg/m(2) . The odds ratios were 1.10 (95% CI 1.09-1.12) and 1.63 (95% CI 1.52-1.75) respectively for an increment of BMI of 1 and 5 units. The relation was stronger in never-users of oral contraceptives (OR 3.35, 95% CI 2.78-4.03, for BMI ≥30 versus <25 kg/m(2) ) than in users (OR 1.22, 95% CI 0.56-2.67), and in women with diabetes (OR 8.10, 95% CI 4.10-16.01, for BMI ≥30 versus <25 kg/m(2) ) than in those without diabetes (OR 2.95, 95% CI 2.44-3.56). The relation was best fitted by a cubic model, although after the exclusion of the 5% upper and lower tails, it was best fitted by a linear model. The results of this study confirm a role of elevated BMI in the aetiology of endometrial cancer and suggest that the risk in obese women increases in a cubic nonlinear fashion. The relation was stronger in never-users of oral contraceptives and in women with diabetes.

Aspirin use and risk of breast cancer: systematic review and meta-analysis of observational studies.

Previous studies concerning the association between aspirin use and breast cancer risk yielded inconsistent results. We aimed to investigate the association by meta-analysis. PubMed and EMBASE were searched for relevant studies. We calculated the summary relative risks (RR) and 95% confidence intervals (CI) using random-effects models. Seventeen cohort studies and 15 case-control studies were included. The overall result showed that aspirin use decreased risk of breast cancer (RR, 0.90; 95% CI, 0.85-0.95). However, there was evidence of publication bias and heterogeneity and the association disappeared after correction using the trim-and-fill method. When stratified by study design, a significant benefit for aspirin users was only found in population-based and hospital-based case-control studies but not in cohort or nest case-control studies. Further subgroup analyses showed that aspirin use could decrease risk of in situ breast tumors or hormone receptor-positive tumors and reduce risk of breast cancer in postmenopausal women. Aspirin use may not affect overall risk of breast cancer, but decrease risk of in situ breast tumors or hormone receptor-positive tumors and reduce risk of breast cancer in postmenopausal women. Considering between-study significant heterogeneity and publication bias, confirmation in future studies is also essential.

The P275A Polymorphism in the Macrophage Scavenger Receptor 1 Gene and Prostate Cancer Risk: a Meta-Analysis.

Published data regarding associations between the P275A polymorphism in the macrophage scavenger receptor 1 (MSR1) gene and prostate cancer (PCa) risk are inconclusive. The aim of this study was to comprehensively evaluate the genetic risk of P275A polymorphism in MSR1 gene for PCa. A systematic literature search was carried out in Pubmed, Medline (Ovid), Embase, CBM, CNKI, Weipu, and Wanfang databases, covering all available publications (last search was performed on Apr 27, 2015). Statistical analysis was performed using Revman 5.2 and STATA 10.1 software. A total of 5,017 cases and 4,869 controls in 12 case-control studies were included in this meta-analysis. When all groups were pooled, there was no evidence that the P275A polymorphism had a significant association with PCa under dominant (OR=0.93, 95%CI=0.81-1.06, and p=0.28), co-dominant (homogeneous OR=0.97, 95%CI=0.56-1.68, and p=0.92; heterogeneous OR=0.93, 95%CI=0.74-1.15, and p=0.49), recessive (OR=1.10, 95%CI=0.65-1.87, and p=0.73), over-dominant (OR=0.93, 95%CI=0.75-1.15, and p=0.50), and allelic (OR=0.95, 95%CI=0.77-1.16, and p=0.61) genetic models. For stratified analyses by ethnicity and study design, no significant associations were found in the white race, the yellow race, the black race and mixed ethnicity, and the population-based case-control (PCC) and hospital-based case-control (HCC) studies under all genetic models. Based on our meta-analysis, the P275A polymorphism in the MSR1 gene is unlikely to be a risk factor for PCa.

Associations between NBS1 Polymorphisms and Colorectal Cancer in Chinese Population.

As the central protein of the double strand breaks (DSB)-induced DNA repair pathway, NBS1 participates in detecting the DSBs and plays an essential role in maintaining genomic stability. Single nucleotide polymorphisms (SNPs) in NBS1 gene were commonly tested that associated with the susceptibility to multiple cancers, but the results remained controversial. Thus, we conducted two independent hospital-based case–control studies comprising 1,072 colorectal cancer patients and 1,263 controls to evaluate the association between four NBS1 SNPs and colorectal cancer risk. The result showed that rs2735383C/G polymorphism in the 3’-untranslated region (UTR) of NBS1 was significantly associated with risk of colorectal cancer using logistic regression (P<10-4). Furthermore, we observed that rs2735383CC genotype was associated with substantially increased risk of colorectal cancer (odds ratio=1.55, 95% confidence interval=1.27–1.94), compared with the rs2735383GC+GG genotypes. Further functional experiments demonstrated that the rs2735383C allele in the NBS1 disrupted the binding affinity of has-miR-509-5p to the NBS1 3’-UTR in colorectal cancer cells, affecting the NBS1 transcriptional activity and expression level. In conclusion, current evidence suggests that the rs2735383C/G polymorphism might contribute to the risk for colorectal cancer.

Coffee consumption and the risk of lung cancer: an updated meta-analysis of epidemiological studies.

Coffee is one of the most popularly consumed beverages worldwide. Many epidemiological studies have investigated the association between coffee consumption and lung cancer risk, but the results are inconsistent. Hence, we conducted a systematic analysis of relevant population-based studies to examine this association and derive a more precise estimation. The Cochrane library, PubMed and Embase databases were searched to identify studies published through Mar 2015 that met the predetermined inclusion criterion. Seventeen studies (5 cohort and 12 case-control studies) involving 12 276 cases and 102 516 controls were included. The summary odds ratio (OR) of lung cancer was 1.17 (95% confidence interval (CI): 1.03-1.33) for coffee drinkers compared with nondrinkers and 1.31 (95% CI: 1.11-1.55) for the highest category of coffee consumption compared with the lowest category. Compared with nondrinkers, the pooled ORs for lung cancer were 1.10 (95% CI: 0.92-1.31) for ⩽1 cup per day, 1.10 (95% CI: 0.93-1.30) for 2-3 cups per day and 1.20 (95% CI: 1.02-1.39) for ⩾3 cups per day. Further analysis showed that the ORs for hospital-based case-control studies, population-based case-control studies and prospective cohort studies were 1.36 (95% CI: 1.10-1.69), 0.99 (95% CI: 0.77-1.28) and 1.59 (95% CI: 1.26-2.00), respectively. Significant associations for high coffee intake with increased risk of lung cancer were observed in men (OR=1.41 95% CI: 1.21-1.63), but not in women (OR=1.16, 95% CI: 0.86-1.56), in American (OR=1.34 95% CI: 1.08-1.65) and Asian populations (OR=1.49 95% CI: 1.28-1.74), but not in European populations (OR=1.12, 95% CI: 0.74-1.67), and in smokers (OR=1.24, 95% CI: 1.00-1.54), but not in nonsmokers (OR=0.85, 95% CI: 0.64-1.11). Particularly over the last 5 years, studies have consistently indicated that lung cancer risk is significantly increased by 47% in the population with the highest category intake of coffee compared with that with the lowest category intake (OR=1.47, 95% CI: 1.21-1.79). The present study suggested that coffee intake was associated with an increased risk of lung cancer.

Combined effect of tobacco smoking and alcohol drinking in the risk of head and neck cancers: a re-analysis of case-control studies using bi-dimensional spline models.

The synergistic effect of tobacco smoking and alcohol consumption on the risk of head and neck cancers has been mainly investigated as a cross-product of categorical exposure, thus leading to loss of information. We propose a bi-dimensional logistic spline model to investigate the interacting dose-response relationship of two continuous exposures (i.e., ethanol intake and tobacco smoking) on the risk of head and neck cancers, representing results through three-dimensional graphs. This model was applied to a pool of hospital-based case-control studies on head and neck cancers conducted in Italy and in the Vaud Swiss Canton between 1982 and 2000, including 1569 cases and 3147 controls. Among never drinkers and for all levels of ethanol intake, the risk of head and neck cancers steeply increased with increasing smoking intensity, starting from 1 cigarette/day. The risk associated to ethanol intake increased with incrementing exposure among smokers, and a threshold effect at approximately 50g/day emerged among never smokers. Compared to abstainers from both tobacco and alcohol consumption, the combined exposure to ethanol and/or cigarettes led to a steep increase of cancer risk up to a 35-fold higher risk (95% confidence interval 27.30-43.61) among people consuming 84g/day of ethanol and 10 cigarettes/day. The highest risk was observed at the highest levels of alcohol and tobacco consumption. Our findings confirmed a combined effect of tobacco smoking and alcohol drinking on head and neck cancers risk, providing evidence that bi-dimensional spline models could be a feasible and flexible method to explore the pattern of risks associated to two interacting continuous-exposure variables.

Incidence and Risk Factors of Twin Pregnancy at Jimma University Specialized Hospital, Southwest Ethiopia

Background: The incidence of twin pregnancy is increasing all over the world because of assisted reproductive technology or spontaneously as a result of numerous risk factors. It is associated with increased risk of maternal and neonatal complications both in the developed and developing countries, which in turn increase financial, emotional, personal and social costs to the twins themselves and their families. Thus, determining its magnitude and identifying the risk factors are crucial for possible prevention and better interventions. Method: Hospital-based prospective and case-control studies were conducted. To determine the incidence of twin pregnancy, all the 3812 deliveries conducted from December 01, 2012 to November 30, 2013 at Jimma University Specialized Hospital were followed from the time of admission to labor ward to the expulsion of fetus. To identify the risk factors for twin pregnancies, all 144 twin deliveries happened were taken as cases and 288 controls were randomly selected from the 3668 single ton-deliveries happened, with the ratio of 1:2. All the necessary data were collected by interviewing mothers, for both the cases and controls, by using structured questionnaire. The data were analyzed by using SPSS for windows version 20.0. Multivariate logistic regression analysis was done to identify risk factors for twin pregnancy. Odds ratios with 95% confidence intervals were used as measure of associations. Results: From 3812 deliveries conducted in the year period, 144 were twins making an incidence of 37.7 per 1000 deliveries. Family history of twinning (OR=9.16, 95% CI: 4.73, 17.74), oral contraceptive pill use prior to pregnancy (OR=2.14, 95% CI: 1.12, 4.08), household monthly income of 50-100 USD (OR=1.94, 95% CI: 1.08, 3.50) and >100 USD (OR=2.18, 95% CI: 1.10, 4.33) were found to increase the risk of twin pregnancy significantly. Conclusion: The study found high incidence of twin pregnancy. Family history of twinning, household income of ≥50 USD and oral contraceptive use prior to pregnancy were identified as risk factors for twin pregnancy. Mothers with identified risk factors should be targeted by nearby health facility in order to make the diagnosis of twin pregnancy earlier so that complications can be picked earlier and managed.

Reproductive Factors but Not Hormonal Factors Associated with Thyroid Cancer Risk: A Systematic Review and Meta-Analysis

Many studies have investigated the association between hormonal and reproductive factors and thyroid cancer risk but provided contradictory and inconclusive findings. This review was aimed at precisely estimating this association by pooling all available epidemiological studies. 25 independent studies were retrieved after a comprehensive literature search in databases of PubMed and Embase. Overall, common hormonal factors including oral contraceptive and hormone replacement therapy did not alter the risk of thyroid cancer. Older age at menopause was associated with weakly increased risk of thyroid cancer in overall analysis (RR = 1.24, 95% CI 1.00–1.53, P = 0.049); however, longer duration of breast feeding was related to moderately reduced risk of thyroid cancer, suggested by pooled analysis in all cohort studies (RR = 0.7, 95% CI 0.51–0.95, P = 0.021). The pooled RR in hospital-based case-control studies implicated that parous women were more susceptible to thyroid cancer than nulliparous women (RR = 2.30, 95% CI 1.31–4.04, P = 0.004). The present meta-analysis suggests that older age at menopause and parity are risk factors for thyroid cancer, while longer duration of breast feeding plays a protective role against this cancer. Nevertheless, more relevant epidemiological studies are warranted to investigate roles of hormonal and reproductive factors in thyroid carcinogenesis.

Lack of association of the cyclooxygenase-2 gene 8473T>C polymorphism with breast cancer risk: a meta-analysis.

Associations between the 8473T>C polymorphism (rs5275) in the cyclooxygenase-2 (COX-2) gene and breast cancer (BC) risk are still inconclusive and ambiguous. The aim of this meta-analysis was to comprehensively estimate the genetic risk of 8473T>C polymorphism in the COX-2 gene for BC. We searched PubMed, Web of Science, Medline, Chinese biomedical (CBM), Weipu, China national knowledge infrastructure (CNKI), and Wanfang databases, covering all publications (last search was updated on Aug 17, 2014). Statistical analyses were performed using Revman 5.3 and STATA 10.0 software. A total of 6,720 cases and 9,794 controls in 12 studies were included in this study. The results indicated no significant associations between the 8473T>C polymorphism of the COX-2 gene and BC risk for the CC+TC vs TT model (pooled odds ratio (OR)=0.97, 95% confidence interval (CI)=0.90-1.03, and p=0.29). On subgroup analysis, we also found that subdivision on ethnicity among Caucasians, Asians and others also revealed no relationship with BC susceptibility. With the study design (CC+TC vs TT), no significant associations were found in either population-based case-control studies (PCC), or hospital-based case-control studies (HCC). This present meta-analysis suggests that the 8473T>C polymorphism in the COX-2 gene is not a conspicuous low- penetrant risk factor for developing BC.

The Pin1 gene polymorphism and the susceptibility of oral squamous cell carcinoma in East China

Pin1 is a peptidylprolyl isomerase that specifically recognizes phosphorylated Pro-directed Ser/Thr (pSer/Thr-Pro) peptide sequences. Genetic variants in the Pin1 gene may alter protein function and cancer risk. In this study, we genotyped the two common promoter polymorphisms -842G/C (rs2233678) and -667T/C (rs2233679) in two independent hospital-based case-control studies conducted in Eastern Chinese populations, including 209 patients with oral squamous cell carcinoma and 444 cancer-free controls. We found -667TT heterozygotes had a significantly increased risk of oral squamous cell carcinoma (P=0.028, OR=1.66, 95%CI=1.02-2.69). However, there was no risk significant associated with the -842G/C polymorphism. Further large population-based studies are needed to confirm these results.

Does cigarette smoking alter the risk of pterygium? A systematic review and meta-analysis.

To determine the association of cigarette smoking with pterygium. Potentially eligible studies published from the year 1946 to December 28, 2013 were identified from MEDLINE, EMBASE, and Cochrane Library databases, and reference lists. All studies that evaluated smoking as an independent factor for pterygium were identified. Study-specific odds ratios (ORs) were combined using the random-effects model when P < 0.1 in the test for heterogeneity, or otherwise the fixed-effects model was used. Meta-regression, sensitivity analysis, and evaluation of potential biases were undertaken. The ORs with 95% confidence intervals (CIs) of smoking as an associated factor for pterygium were analyzed. We included 24 articles incorporating 95,279 participants from 20 cross-sectional studies, 2 hospital-based case-control studies, and 2 population-based cohort studies. The combined OR of cigarette smoking (current or ever smoked) for risk of pterygium was 0.82 (95% CI, 0.69-0.97; P = 0.025). The results remained consistent among current smokers (OR, 0.68; 95% CI, 0.61-0.76; P = 4.57 × 10(-12)), but not in ex-smokers (OR, 1.05; 95% CI, 0.87-1.27; P = 0.59). The impact of ultraviolet light (UV) exposure (P = 0.082) and sex (P = 0.553) on the effect of smoking was insignificant in meta-regression. Sensitivity analysis confirmed the protective effect and nonrelevance of these two study-level variables. Begg's funnel plots and Egger's test showed minimal publication bias. The results of this meta-analysis show that cigarette smoking was associated with a reduced risk of pterygium, especially in current smokers. This effect may be independent of UV exposure and sex. Investigations are needed to unveil its molecular basis serving therapeutic purposes.

Association between Dairy Intake and Gastric Cancer: A Meta-Analysis of Observational Studies

PurposeObservational studies have given inconsistent findings on the relationship between intake of dairy products and gastric cancer. We therefore conducted a systematic review with a meta-analysis of observational studies to summarize available evidence on this point.MethodsWe searched the electronic literature databases of PubMed (Medline), EMBASE and the Chinese Biomedical Literature Database up until August 30, 2013. All studies were limited to the English language. Random-effects models were used to pool study results between dairy products consumption and the risk of gastric cancer. We also performed subgroup, publication bias and sensitivity analysis.ResultsEight prospective studies and 18 case-control studies were included in our analysis, with a total number of 7272 gastric cancer cases and 223,355 controls. Pooled relative risks of all studies showed no significant association between dairy intake and gastric cancer (odds ratio [OR]: 1.09, 95% confidence interval [CI]: 0.96–1.25). When study design was separately analyzed, population-based case-control studies showed a positive association between dairy intake and gastric cancer risk (OR: 1.36; 95% CI: 1.07–1.74), whereas no associations were shown by hospital-based case-control studies (OR: 0.86, 95% CI: 0.72–1.02) or cohort studies (OR = 1.01, 95% CI = 0.91–1.13).ConclusionsThe meta-analysis shows that no clear association apparently exists between consumption of dairy products and gastric cancer risk. Further well-designed cohort and intervention studies should be conducted to verify this lack of association.