Meta-analysis on the association between non-steroidal anti-inflammatory drug use and ovarian cancer

AIM

Animal and in vitro studies suggest that the use of non-steroidal anti-inflammatory drugs (NSAIDs) may be associated with reduced risk for ovarian cancer. However, results from these studies have been inconsistent. The aim of our study was to review and summarize the evidence provided by longitudinal studies on the association between NSAID use and ovarian cancer risk.

METHODS

A comprehensive literature search for articles published up to December 2011 was performed. Prior to performing a meta-analysis, the studies were evaluated for publication bias and heterogeneity. Relative risk (RR) or odds ratios (OR) were calculated.

RESULTS

Seventeen reports (13 case–control studies, one clinical trial and three cohort studies), published between 1998 and 2011 were identified. There was no evidence of an association between aspirin use and ovarian cancer risk based on a random-effects model (RR = 0.91, 95% confidence interval (CI) 0.82, 1.01) or a fixed-effects model (RR = 0.94, 95% CI 0.87, 1.01). Similarly, we did not find strong evidence of an association between non-aspirin NSAID use and ovarian cancer using a random-effects model (RR = 0.89, 95% CI 0.74, 1.08) or a fixed-effects model (RR = 0.86, 95% CI 0.76, 0.98). Furthermore, our analysis did not show a strong association between frequency or duration of non-aspirin-NSAID use and ovarian cancer.

CONCLUSIONS

Our findings indicate that there is no strong evidence of an association between aspirin/NA-NSAID use and ovarian cancer. However, this subject deserves further investigation.     

Paracetamol use and risk of ovarian cancer: a meta-analysis

AIM: Ovarian cancer remains the most fatal gynaecological malignancy. Several observational studies have examined paracetamol as a potential chemopreventive agent. The nonconclusive nature of the epidemiological evidence prompted us to conduct a detailed meta-analysis of the studies published on the subject in peer-reviewed literature. METHODS: A comprehensive search for articles published up to 2004 was performed, reviews of each study were conducted and data were abstracted. Prior to meta-analysis, the studies were evaluated for publication bias and heterogeneity. Pooled relative risk estimates (RR) and 95% confidence intervals (CIs) were calculated using the random and the fixed-effects models. RESULTS: Eight studies (four case-control and four cohort studies), published between 1998 and 2004, were included. We found no evidence of publication bias or heterogeneity among the studies. The analysis revealed an inverse association between paracetamol use and ovarian cancer risk. This association was marginally significant assuming a random-effects model (RR=0.84, 95% CI 0.70, 1.00), but not statistically significant assuming a fixed-effects model (RR=0.90, 95% CI 0.80, 1.01). When the analysis was stratified into subgroups according to study design, the association was inverse in both case-control and cohort studies, but only in the former was it statistically significant. The sensitivity analysis strengthened our confidence in the validity of this association. Furthermore, our results provided evidence for a dose effect; 'regular use' was associated with a statistically significant 30% reduction in the risk of developing ovarian cancer compared with non-use (RR=0.70, 95% CI 0.51, 0.95). CONCLUSIONS: Our meta-analysis supports a protective association between paracetamol use and ovarian cancer, and provides evidence for a dose effect. However, the question of paracetamol's potential association with ovarian cancer deserves further verification, since proof of chemoprevention would represent a major public health advance.     

Do nonsteroidal anti-inflammatory drugs affect the risk of developing ovarian cancer? A meta-analysis

AIM: The relationship between the use of nonsteroidal anti-inflammatory drugs (NSAIDs), including aspirin, and the risk of ovarian cancer has been controversial. This study examines the strength of this association by conducting a detailed meta-analysis of the studies published in peer-reviewed literature on the subject. METHODS: A comprehensive search for articles published up to April 2004 was performed, reviews of each study were conducted and data were abstracted. Prior to meta-analysis, the studies were evaluated for publication bias and heterogeneity. Pooled relative risk estimates (RR) and 95% confidence intervals (CIs) were calculated. RESULTS: Ten reports (six case-control and four cohort studies), published between 1998 and 2004, were identified. There was no evidence of an association between aspirin use and ovarian cancer risk either assuming a random-effects model (RR = 0.92, 95% CI 0.80, 1.06), or a fixed-effects model (RR = 0.93, 95% CI 0.81, 1.06). Similarly, we did not find evidence of an association between non-aspirin NSAID use and ovarian cancer, both on the basis of a random-effects model (RR = 0.86, 95% CI 0.68, 1.08), and on the basis of a fixed-effects model (RR = 0.88, 95% CI 0.76, 1.01). When the analyses were stratified into subgroups, there was no evidence that study design substantially influenced the estimate of effects. Furthermore, our analysis did not show decreasing risks with increasing frequency or duration of use, features often associated with causal relationships. CONCLUSIONS: Our meta-analysis findings do not support that NSAID use plays a role in the chemoprevention of ovarian cancer. Future research should examine potential relationships between specific NSAIDs and ovarian cancer, taking into account the possible biases that may have affected this meta-analysis.     

Insulin therapy and the risk of colorectal cancer in patients with type 2 diabetes: a meta-analysis of observational studies

Aims

Several epidemiological studies have reported inconsistent associations between insulin therapy and the risk of colorectal cancer (CRC) in patients with type 2 diabetes mellitus. We performed this meta-analysis of observational studies to evaluate the effect of insulin therapy on the risk of CRC.

Methods

We carried out a systematic search of PubMed, Embase and the Cochrane Library Central database between January 1966 and August 2013. Fixed-effects and random-effects models were used to estimate the pooled relative risk (RR) and corresponding 95% confidence interval (CI).

Results

A total of 12 epidemiological studies were included in the present meta-analysis, involving a total of 7947 CRC cases and 491 384 participants. There was significant heterogeneity among the studies, but no publication bias. Insulin therapy significantly increased the risk of CRC [RR = 1.69, 95% CI (1.25, 2.27)]. When the various studies were stratified by study design, we found that insulin use was associated with a statistically significant 115% higher risk of CRC among case–control studies [RR = 2.15, 95% CI (1.41, 3.26)], but not among cohort studies [RR = 1.25, 95% CI (0.95, 1.65)]. Furthermore, a significant association was noted among studies conducted in USA [RR = 1.73, 95% CI (1.15, 2.60)] and Asia [RR = 2.55, 95% CI (2.14, 3.04)], but not in Europe [RR = 1.20, 95% CI (0.92, 1.57)].

Conclusions

The present meta-analysis suggests that insulin therapy may increase the risk of CRC. More prospective cohort studies with longer follow-up durations are warranted to confirm this association. Furthermore, future studies should report results stratified by gender and race and should adjust the results by more confounders.     

Bisphosphonate use and risk of colorectal cancer: a systematic review and meta-analysis

Aim

A growing body of evidence suggests that bisphosphonates may have chemopreventive potential against colorectal cancer. Our aim was to examine this association through a meta-analysis of observational studies.

Methods

A comprehensive search for relevant articles published up to October 2012 was performed, reviews of each study were conducted and data were abstracted. Prior to meta-analysis, the studies were evaluated for publication bias and heterogeneity. Pooled relative risk (RR) estimates and 95% confidence intervals (CIs) were calculated using the random effects and the fixed effects models. Subgroup and sensitivity analyses were also performed.

Results

Eight large population-based epidemiological studies (one case-control, two nested case-control analyses within a cohort and five cohort studies), involving more than 630 000 participants, contributed to the analysis. We found no evidence of publication bias. However, significant heterogeneity was detected among the cohort studies. The analysis revealed a significant protective association between bisphosphonate use and colorectal cancer risk (fixed RR = 0.85, 95% CI 0.80, 0.90, random RR = 0.85, 95% CI 0.75, 0.96). When the analysis was stratified into subgroups according to study design, the association was inverse in both case-control and cohort studies, but only in the former was it statistically significant. The sensitivity analysis confirmed the stability of our results. Furthermore, we found evidence for a dose effect; Long term bisphosphonate use was associated with a 27% decrease in the risk of developing colorectal cancer as compared with non-use (RR = 0.73, 95% CI 0.57, 0.93).

Conclusion

Our findings support a protective effect of bisphosphonates against colorectal cancer. However, further evidence is warranted.     

Statin use and risk of kidney cancer: a meta-analysis of observational studies and randomized trials

Aim

Clinical studies have shown that statin use may modify the risk of kidney cancer. However, these studies yielded different results. To quantify the association between statin use and risk of kidney cancer, we performed a detailed meta-analysis of published studies regarding this subject.

Methods

A literature search was carried out using MEDLINE, EMBASE and the Cochrane database between January 1966 and October 2012. Prior to performing a meta-analysis, the studies were evaluated for publication bias and heterogeneity. Fixed effect and random effect models were used to estimate summary relative risks (RR) and the corresponding 95% confidence intervals (CIs). Subgroup analyses and sensitivity analysis were also performed.

Results

A total of 12 (two randomized controlled trials, five cohort, and five case–control) studies contributed to the analysis. There was heterogeneity among the studies but no evidence of publication bias. Pooled results indicated a non-significant decrease of total kidney cancer risk among all statin users (RR = 0.92, 95% CI 0.71, 1.19). Long term statin use did not significantly affect the risk of total kidney cancer (RR = 1.01, 95% CI 0.83, 1.22). In our subgroup analyses, the results were not substantially affected by study design, confounder adjustment and gender. Furthermore, sensitivity analysis confirmed the stability of the results.

Conclusion

The findings of this meta-analysis suggested that there was no association between statin use and risk of kidney cancer. More studies, especially randomized controlled trials and high quality cohort studies with larger sample size and well controlled confounding factors, are needed to confirm this association in the future.     

Association between nonsteroidal anti-inflammatory drug use and brain tumour risk: a meta-analysis

Aims

Several epidemiological studies have evaluated the association between nonsteroidal anti-inflammatory drugs (NSAIDs) and brain tumour risk. However, results from these studies have been inconsistent. The aim of this detailed meta-analysis is to review and summarize the evidence on this association.

Methods

A comprehensive search for articles published up to September 2013 was performed. Studies evaluating the association between exposure to NSAIDs and risk of brain tumours were included. Random-effects meta-analytical models were used to calculate the relative risk (RR) and corresponding 95% confidence intervals (CIs). Sensitivity analyses, Galbraith plots and subgroup analyses were also performed.

Results

Ten studies (six case–control studies, three cohort studies and one randomized controlled trial), published between 2003 and 2013, were included in this analysis. Compared with non-use, overall use of NSAIDs was not statistically significantly associated with brain tumour risk based on the random-effects models (RR = 1.01; 95% CI = 0.89, 1.15). No differences were observed when analyses were stratified by gender and brain tumour subtype. Specific analysis for aspirin and non-aspirin NSAIDs yielded similar results. However, a slightly increased risk of brain tumour in NSAID users was observed in cohort studies (RR = 1.32; 95% CI = 1.06, 1.64; P = 0.014). Furthermore, our analysis did not show a significant association between frequency and dose of aspirin use and brain tumour risk.

Conclusions

Use of NSAIDs (aspirin and non-aspirin NSAIDs) does not appear to be associated with brain tumour risk, but larger studies are needed to substantiate this relationship.     

Use of statins and risk of haematological malignancies: a meta-analysis of six randomized clinical trials and eight observational studies

AIMS: Statins have been suggested to prevent haematological malignancies. Several epidemiological studies have evaluated this association, while randomized controlled trials (RCTs) on cardiovascular outcomes have provided relevant data as secondary end-points. Our aim was to examine the strength of this association through a detailed meta-analysis of the studies published in peer-reviewed literature. METHODS: A comprehensive search for articles published up to December 2006 was performed, reviews of each study were conducted and data abstracted. Prior to meta-analysis, the studies were evaluated for publication bias and heterogeneity. Pooled relative risk (RR) estimates and 95% confidence intervals (CIs) were calculated using the random effects model. RESULTS: Fourteen studies (six RCTs, seven case-control and one cohort study) contributed to the analysis. Studies were grouped on the basis of study design, and two separate meta-analyses were conducted. There was no evidence of an association between statin use and haematological malignancies among either RCTs (RR = 0.92, 95% CI 0.72, 1.16) or the observational studies (RR = 0.83, 95% CI 0.53, 1.29). Similarly, we found no evidence of publication bias. However, high heterogeneity was detected among the observational studies. CONCLUSION: Our meta-analysis findings do not support a potential role of statins in the prevention of haematological malignancies.     

Impact of antidepressants use on risk of myocardial infarction: A systematic review and meta-analysis

Aims:The aim of the study was to perform a systematic review and meta-analysis to determine the association between antidepressants use and risk of myocardial infarction (MI), and whether this association differs between tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs).Methods:A PubMed/MEDLINE search was conducted for studies published up to December 2013. Included studies were evaluated for publication bias and heterogeneity. Depending on the presence of heterogeneity, a random or fixed effects model was used to identify the pooled relative risk (RR) with 95% confidence intervals (CIs). Cumulative meta-analysis, subgroup and sensitivity analyses were also performed. All analyses were performed using comprehensive meta-analysis software.Results:Fourteen (five cohort and nine case–control) studies were included. There was heterogeneity among the studies (P_{heterogeneity} = 0.02; I² = 68%) but no publication bias (Begg''s P = 0.30 and Egger''s P = 0.45). Antidepressants use significantly increases the risk of myocardial infarction (MI) (RR = 2.03; 95% CI = 1.30–3.18; P < 0.01). On subgroup analysis by study design, cohort studies show significant positive association (RR = 2.16; 95% CI = 1.42–3.29; P < 0.01), but not case–control studies (RR = 2.47; 95% CI = 0.69–8.90; P = 0.17). Sensitivity analysis and cumulative meta-analysis confirmed the stability of results. TCAs users are having 36% increased risk of MI after excluding one outlier (RR = 1.36; 95% CI = 1.10–1.67; P < 0.01), but SSRIs showing no association (RR = 0.84; 95% CI = 0.57–1.22; P = 0.35).Conclusions:We found evidence that the use of antidepressants was associated with elevated risk of MI. Further research is needed to identify the underlying biological mechanisms.KEY WORDS: Myocardial infarction, selective serotonin reuptake inhibitors, tricyclic antidepressants     

Serum carbohydrate antigen (CA) 19-9 as a prognostic factor in cholangiocarcinoma: a meta-analysis

This study was performed to determine the prognostic role of preoperative serum carbohydrate antigen (CA) 19-9 levels in the survival of patients with cholangiocarcinoma. Articles published up to June 1^st, 2010 that evaluated preoperative CA19-9 levels and the prognosis of cholangiocarcinoma were collected for meta-analysis. The required information for calculating individual relative risk (RR) was extracted from the studies, and a combined overall RR was estimated. Nine eligible studies were included. One study dealt with extra-hepatic cholangiocarcinoma, while the other eight studies analyzed intra-hepatic cholangiocarcinoma. The mean methodological quality score was 74.1%, ranging from 65.5% to 82.5%. The overall RR for the nine studies was 1.28 (95% confidence interval = 1.10–1.46), and the Z-score for overall effect was 13.83 (P<0.001). The association between serum CA19-9 level and lymph node involvement was also assessed. The combined RR was 1.471 (95% confidence interval = 0.411–5.264) and Z-score for overall effect was 0.59 (P = 0.553). CA19-9 levels were associated significantly with the prognosis of patients with cholangiocarcinoma. This meta-analysis shows that elevation of preoperative CA19-9 levels is correlated with a poor prognosis of patients with cholangiocarcinoma. However, larger scale and randomized studies are needed to draw a more substantive conclusion.     

沙库巴曲缬沙坦对肾功能保护作用的系统评价和meta分析

目的 系统评价沙库巴曲缬沙坦相比血管紧张转换酶抑制剂(angiotensin-converting enzyme inhibitors,ACEI)或血管紧张素受体拮抗剂(angiotensin receptor blockers,ARB)对肾功能的保护作用。目的 方法检索万方、知网、PubMed、Embase、ClinicalTrials.gov和The Cochrane Library等数据库,收集使用沙库巴曲缬沙坦和ACEI/ARB治疗患者的随机对照试验。检索期限为自建库起至2021年6月12日。由2位研究者独立进行文献筛选、资料提取,根据Cochrane协作网系统评价员手册的风险偏倚评价工具对纳入研究进行评价,采用RevMan 5.3软件进行meta分析。将数据归纳为二分类变量和95%置信区间,采用I²检验评估异质性。目的 结果11项研究符合研究标准,包括18 966例患者。与ACEI/ARB相比,沙库巴曲缬沙坦降低肾功能恶化的风险[RR=0.89,95% CI (0.80,0.99),P=0.03];沙库巴曲缬沙坦可降低心衰患者肾功能恶化的风险[RR=0.87,95% CI (0.78,0.97),P=0.02],但不能降低非心衰患者肾功能恶化的风险[RR=1.04,95% CI (0.80,1.37),P=0.76];沙库巴曲缬沙坦降低了射血分数保留的心衰患者肾功能恶化的风险[RR=0.85,95% CI (0.74,0.97),P=0.02],降低了射血分数减低的心衰患者肾功能恶化的风险[RR=0.91,95% CI (0.75,1.10),P=0.34];在心衰患者中,沙库巴曲缬沙坦与ACEI相比降低了肾功能恶化的风险[RR=0.95,95% CI (0.83,1.10),P=0.51],与ARB相比降低了肾功能恶化的风险[RR=0.74,95% CI (0.61,0.89),P=0.002]。目的 结论本研究结果表明沙库巴曲缬沙坦对心衰患者的肾功能保护优于ACEI/ARB,但在不同心衰类型和对照药物中差异不同,而对非心衰患者的肾功能保护与ACEI/ARB相似     

A systematic review of epidemiologic studies of styrene and cancer

Previous epidemiology reviews of exposure to styrene and the risk of cancer considered studies published through 13 November 2013. Since then, additional relevant research has been published. No review has included meta-analyses. The current systematic review considered research published through June 2017; included meta-analyses of the relationship between any exposure to styrene and cancers identified as being of concern, including non-Hodgkin lymphoma (NHL), leukemia and cancers of the esophagus, pancreas, lung and kidney; and evaluated several other forms of cancer. Meta-relative risks for all studies were 1.14 (95% confidence interval (CI), 0.91–1.43) for NHL, 1.00 (95% CI, 0.80–1.26) for multiple myeloma, 0.98 (95% CI, 0.87–1.09) for all leukemia, 1.03 (95% CI, 0.92–1.15) for esophageal cancer, 1.02 (95% CI, 0.93–1.12) for pancreatic cancer, 1.09 (95% CI, 0.95–1.24) for lung cancer and 1.10 (95% CI, 0.99–1.22) for kidney cancer. Individual studies provided little evidence of exposure-response or induction time trends. Limitations of the available research and of the meta-analyses included reliance in most studies on mortality data rather than on incidence data, lack of quantitative estimates of styrene exposure for individual subjects and lack of information on lifestyle factors. Consideration of all pertinent data, including substantial recent research, indicates that the epidemiologic evidence on the potential carcinogenicity of styrene is inconclusive and does not establish that styrene causes any form of cancer in humans.     

Non-steroidal antiinflammatory drugs and the risk of acute myocardial infarction

Whether non-aspirin non-steroidal antiinflammatory drugs (NSAIDs) affect the risk of myocardial infarction is unclear. Also, it is unknown whether the effect varies by individual NSAIDs. To summarize the evidence from published observational studies on the risk of myocardial infarction associated with both traditional NSAIDs (tNSAIDs) and selective inhibitors of cyclooxygenase-2 (Coxibs), the authors conducted a systematic review of cohort and case-control studies on NSAIDs and myocardial infarction published between 2000 and 2005. Sixteen original studies were selected according to predefined criteria. Two researchers independently extracted the data on individual study characteristics and results. The authors calculated pooled relative risk (RR) estimates of myocardial infarction for specific NSAIDs compared with no NSAID use, tested the heterogeneity of effects, and evaluated potential reasons for heterogeneity. The pooled RR of myocardial infarction was 0.98 (95% confidence interval (CI): 0.92-1.05) for naproxen, 1.07 (95% CI: 1.02-1.12) for ibuprofen, 1.44 (95% CI: 1.32-1.56) for diclofenac, 0.96 (95% CI: 0.90-1.02) for celecoxib, and 1.26 (95% CI: 1.17-1.36) for rofecoxib (all doses). The pooled RR for rofecoxib at doses >25 mg/day was 1.78 (95% CI: 1.36-2.34), and 1.18 (95% CI: 1.07-1.31) for doses < or =25 mg/day. The RR associated with naproxen was 0.83 (95% CI: 0.72-0.90) among non-users of low-dose aspirin. The RR associated with rofecoxib (all doses) was 1.39 (95% CI: 1.25-1.54) among subjects without a history of myocardial infarction. The risk of myocardial infarction varies with individual NSAIDs. An increased risk was observed for diclofenac and rofecoxib, the latter one with a clear dose-response trend. There was a suggestion of a small increased risk with ibuprofen. Also, data suggest a small reduced risk for naproxen present only in non-users of aspirin, mainly people free of clinically apparent vascular disease.     

Metformin versus insulin for gestational diabetes mellitus: a meta-analysis

The aim of the present meta-analysis was to determine the efficacy and safety of metformin for the treatment of women with gestational diabetes mellitus (GDM). We searched databases, including PubMed, Embase and the Cochrane Central Register of Controlled Trials, for randomized controlled trials (RCTs) comparing metformin and insulin treatments in women with GDM. We carried out statistical analyses using RevMan 2011 and used the Grading of Recommendations, Assessment, Development, and Evaluations profiler to rate the quality of evidence of the primary outcomes. We analysed eight studies involving 1592 subjects. Meta-analysis of the RCTs showed that metformin had statistically significant effects on pregnancy-induced hypertension [PIH; risk ratio (RR) 0.54; 95% confidence interval (CI) 0.31, 0.91]. However, its effects on neonatal hypoglycaemia (RR 0.80; 95% CI 0.62, 1.02), rate of large-for-gestational age infants (RR 0.77; 95% CI 0.55, 1.08), respiratory distress syndrome (RR 1.26; 95% CI 0.67, 2.37), phototherapy (RR 0.94; 95% CI 0.67, 1.31) and perinatal death (RR 1.01; 95% CI 0.11, 9.53) were not significant. Our analyses suggest that there is no clinically relevant difference in efficacy or safety between metformin and insulin; however, metformin may be a good choice for GDM because of the lower risk of PIH. The advantages of metformin in terms of glycaemic control, PIH incidence and gestational age at birth are unclear, and should be verified in further trials.     

Upper gastrointestinal complications among users of paracetamol

Non-steroidal anti-inflammatory drugs (NSAIDs) have been associated with upper gastrointestinal complications such as bleeding or perforation. Paracetamol has been traditionally considered a safer alternative to NSAIDs. In a previous case-control study we found that paracetamol at high doses increased the risk of upper gastrointestinal complications. We proposed to review all studies addressing the association between paracetamol and upper gastrointestinal complications and placed our results in the context of existing literature. We conducted a nested case-control study using the United Kingdom General Practice Research Database during the period between April 1993 and October 1998. Then we performed a systematic review of the literature indexed in MEDLINE published between 1980 and 2004. We identified a total of twelve studies that assessed the association between paracetamol and upper gastrointestinal complications. We used a fixed effects model to calculate a summary estimate of these studies. In the nested case control study, use of paracetamol was associated with a small elevated risk of upper gastrointestinal complications (relative risk (RR), 1.3; 95% confidence interval (CI), 1.1-1.5). The RR was 3.6 (95% CI, 2.6-5.1) among paracetamol users of more than 2 g daily, whereas smaller doses did not increase the risk. Among the twelve studies identified in the systematic review, estimates ranged from 0.2 through 2.0 with a summary estimate of 1.3 (95% CI, 1.2-1.5). Our findings indicate that use of paracetamol at the doses most commonly used confer little or no increased risk of upper gastrointestinal complications. More data are needed to confirm or refute the suggestion that high-dose paracetamol is associated with an increased risk of upper gastrointestinal complications of the same magnitude as the one observed with traditional NSAIDs.     

H2受体拮抗剂应用与肺炎发生危险的Meta分析

目的:评估H2受体拮抗剂(histamine-receptor antagonists,H2RA)应用是否增加肺炎的发生危险。方法:应用计算机检索EMBASE、CENTRAL(the Cochrane central register of con-trolledtrials)、Medline、万方数据库、中国生物医学文献数据库系统(CBM)、中国期刊全文数据库(CNKI)等,搜集公开发表的关于H2RA应用与肺炎发生危险的随机对照研究(randomized con-troled trials,RCT)。以受试者肺炎发生的相对危险度(relative risk,RR)及相应的95%置信区间(95%confidence interval,95%CI)作为效应指标进行合并统计量。各研究间的统计学异质性采用Q统计量的I2检验来分析,双侧P>0.05认为各研究间不存在明显的统计学异质性,采用固定效应模型进行分析,反之采用随机效应模型进行分析。应用Egger法对发表偏倚进行量化检测。结果:共有18篇研究符合纳入标准,2974例受试者,H2RA组1508例,对照组1466例。Me-ta分析显示,H2RA可增加受试者肺炎的发生风险(RR=1.22,95%CI=1.05～1.41,Z=2.61,P=0.009);亚组分析,H2RA与安慰剂相比,使受试者的肺炎风险增加21%(RR=1.21,95%CI=1.02～1.45,Z=2.17,P=0.03),H2RA与硫糖铝相比并不增加受试者肺炎的发生风险(RR=1.22,95%CI=0.93～1.60,Z=1.45,P=0.148)。结论:H2RA的应用可能是肺炎发生的一个危险因素。     

Reduced colorectal cancer incidence in type 2 diabetic patients treated with metformin: a meta-analysis

Context: Diabetic patients have a higher risk of colorectal cancer (CRC). The role of metformin in CRC incidence among type 2 diabetes mellitus (T2DM) remains controversial.

Objective: A meta-analysis was performed to evaluate the role of metformin treatment in the occurrence of CRC among T2DM patients.

Methods: Search was performed throughout PubMed, Embase, Springer databases up to November 2014. The search terms were (biguanides or metformin) and (bowel or colon or rectal or colorectal) and (cancer or neoplasm or neoplasia). Relative risk (RR) and 95% confidence interval (CI) was pooled using random-effects model or fixed-effect model basing on heterogeneity, which was calculated basing on Q statistics and χ² test. In addition, subgroup analyses were performed according to region, study design and control treatment. Finally, publication bias was evaluated using Egger’s regression test and trim and fill analysis.

Results: A total of 11 studies, including eight cohort studies and three case-control studies, were enrolled in the meta-analysis. Obvious heterogeneity was noted, and a 25% lower CRC incidence was found among diabetic patients treated with metformin (pooled RR=0.75, 95% CI: 0.66-0.86), using the random-effects model. Subgroup analyses showed that CRC incidence significantly reduced among T2DM in different regions, non-metformin treatment and cohort studies. Evidence supported significant publication for studies investigating from Egger’s regression test. Conversely, no missing data were found using trim and fill analysis.

Conclusion: In conclusion, the meta-analysis suggests metformin may reduce CRC incidence among diabetics, which is useful medical information for clinicians.     

The association between chronic exposure to traffic-related air pollution and ischemic heart disease

Increasing evidence links air pollution to the risk of cardiovascular disease. This study investigated the association between ischemic heart disease (IHD) prevalence and exposure to traffic-related air pollution (nitrogen dioxide [NO?], fine particulate matter [PM?.?], and ozone [O?]) in a population of susceptible subjects in Toronto. Local (NO?) exposures were modeled using land use regression based on extensive field monitoring. Regional exposures (PM?.?, O?) were modeled as confounders using inverse distance weighted interpolation based on government monitoring data. The study sample consisted of 2360 patients referred during 1992 to 1999 to a pulmonary clinic at the Toronto Western Hospital in Toronto, Ontario, Canada, to diagnose or manage a respiratory complaint. IHD status was determined by clinical database linkages (ICD-9-CM 412-414). The association between IHD and air pollutants was assessed with a modified Poisson regression resulting in relative risk estimates. Confounding was controlled with individual and neighborhood-level covariates. After adjusting for multiple covariates, NO? was significantly associated with increased IHD risk, relative risk (RR) = 1.33 (95% confidence interval [CI]: 1.2, 1.47). Subjects living near major roads and highways had a trend toward an elevated risk of IHD, RR = 1.08 (95% CI: 0.99, 1.18). Regional PM?.? and O? were not associated with risk of IHD.     

Occupational exposures to polycyclic aromatic hydrocarbons and respiratory and urinary tract cancers: an updated systematic review and a meta-analysis to 2014

Exposure to polycyclic aromatic hydrocarbons (PAHs) has been associated with an excess risk of respiratory tract and bladder cancers in several industries, but the issue requires further quantification. We updated a previous systematic review by reviewing in details cohort studies on workers employed in selected industries with potential PAH exposure published between 2006 and 2014, and we summarized through a meta-analytic approach the main results of all available cohort studies published between 1958 and 2014 investigating cancers of the respiratory and urinary tracts. Thirteen papers on cohort studies investigating cancer risk in workers exposed to PAHs were retrieved through the literature search. These included workers from aluminum production industries (seven studies), iron and steel foundries (two studies), asphalt workers (two studies), and carbon black production (two studies). In the meta-analysis, an excess risk of respiratory tract cancers (mainly lung cancer) was found in iron and steel foundries [pooled relative risk (RR) 1.31, 95 % confidence interval (CI) 1.08–1.59 from 14 studies], while a weak excess risk (pooled RR 1.08, 95 % CI 0.95–1.23 from 11 studies) emerged for aluminum production. A borderline increase risk was also observed for cancer of the bladder in the aluminum production (pooled RR 1.28, 95 % CI 0.98–1.68 from 10 studies) and in iron and steel foundries (pooled RR 1.38, 95 % CI 1.00–1.91 from 9 studies). This updated review and meta-analysis confirm the increased risk from respiratory tract and bladder cancers in selected PAH-related occupations. It cannot be ruled out whether such excesses are due, at least in part, to possible bias or residual confounding.     

Do older adults using NSAIDs have a reduced risk of colorectal cancer?

BACKGROUND AND OBJECTIVES: Colorectal cancer (CRC) is primarily a disease of older adults. Although NSAIDs are thought to protect from CRC, and long-term use of NSAIDs is common in the elderly, little is known about the impact of NSAID use on CRC risk at advanced age. We specifically reviewed current evidence regarding the effects of NSAIDs on CRC risk in individuals aged > or =65 years, a rapidly growing age group. STUDY DESIGN: We searched all articles in PubMed published before August 2005. Studies were included if a subgroup analysis of older adults (> or =65 years of age) was performed, or if long-term use of NSAIDs for > or =5 years and CRC risk was investigated. From the selected studies, relevant information, including sample characteristics and association with CRC risk, was extracted and compared. RESULTS: Altogether 19 studies were identified. Only four studies specifically considered NSAID use in people > or =65 years of age; of these, two showed risk reduction for CRC comparable to that seen in younger age groups or in all age groups. The most informative observational studies found decreasing relative risk of CRC with increasing duration of NSAID use, suggesting substantial risk reduction after 10-20 years of regular use. CONCLUSIONS: The available data on long-term effects of NSAID use in elderly people are sparse but predominantly indicate risk reduction for CRC comparable to that seen in younger age groups or all ages. Whether and to what degree initiating NSAID use in old age prevents CRC is essentially unknown. In light of the potential adverse effects of NSAIDs, including recent data on adverse cardiovascular outcomes, more information is needed on the minimum effective dose of NSAIDs and the duration of use required in order to evaluate individual risks and benefits in older adults.