Objective To explore the correlation between overweight, obesity and incidence of type 2 diabetes mellitus (T2DM). Methods Databases including PubMed, EMbase, The Cochrane Library (Issue 3, 2012), CNKI, VIP, CBM and WanFang Data were searched from inception to May, 2012 to collect the cohort studies on the correlation between overweight, obesity and incidence of T2DM. The studies were screened according to the inclusion and exclusion criteria by two researchers independently, the quality was evaluated, the data were extracted, and then meta-analysis was performed using RevMan 5.1 and Stata 11.0 software. Results A total of 8 studies involving 101 864 participants were included. The results of meta-analysis showed that, compared with the normal weight population, the onset risk of T2DM was obviously higher in the overweight (RR=2.59, 95%CI 2.11 to 3.19, Plt;0.000 01), and obese (RR=6.28, 95%CI 4.99 to 7.91, Plt;0.000 01) populations. In the subgroup analysis, the onset risk of T2DM was higher in the western obese population (RR=6.91, 95%CI 5.59 to 8.56) than the eastern obese population (RR=4.19, 95%CI 2.93 to 5.99). Based on the Grading of Recommendations Assessment, Development and Evaluation (GRADE), the quality of the included studies on T2DM developed by overweight and obesity was low and medium respectively. Conclusion Overweight and obesity can increase the onset risk of T2DM which is higher in the female and western obese populations than the male and eastern obese populations respectively.
Objective To assess the value of vascular endothelial growth factor (VEGF) expression in the prognosis of esophageal cancer. Methods PubMed and EMbase were searched for collecting retrospective cohort studies on the correlation between VEGF expression and prognosis of esophageal cancer, and relevant articles were also retrieved from inception to June, 2012. Two reviewers independently screened the literature, extracted the data, and evaluated the quality. Then the meta-analysis was performed by using RevMan5.0 software, and the publication bias of literature was evaluated by means of Begg’s funnel plot and Egger’s method. Results Finally 10 cohort studies involving 811 patients were included. The meta-analysis showed that, patients with high level of VEGF had poor overall survival (HR=1.55, 95%CI 1.25 to 1.91). The results of subgroup analyses including VEGF subtype, critical value of VEGF and source of patient showed that: a) there was no correlation between patient’s prognosis and high level of VEGF-C; b) The high level of VEGF subtype in cancer tissue indicated a higher risk of death when the critical value was 10%, while it was not related to the prognosis when the critical value was 30%; and c) The high level of VEGF in cancer tissue was more valuable to predict the prognosis of esophageal cancer for Chinese patients rather than non-Chinese patients. Conclusion The level of VEGF’s expression in cancer tissue is valuable to predict the prognosis of esophageal cancer.
Objective To systematically evaluate the correlation between coffee and risk of endometrial cancer. Methods Such databases as CBM, CNKI, WanFang data, PubMed, EMbase and The Cochrane Library (Issue 5, 2012) were searched to collect the prospective cohort studies about correlation between coffee and endometrial cancer. The retrieval time was by the end of May 2012, and the references of the included literature were also retrieved. Two evaluators independently screened the literature according to the inclusion and exclusion criteria, extracted the data, and assessed the quality, and then the statistical analysis was conducted by using Stata 12.0 software. Results A total of 10 cohort studies involving 4 484 patients with endometrial cancer were included. The results of meta-analysis showed that, compared with the women who didn’t drink coffee or drank in the lowest dose, the women who drank coffee in the highest dose had a decreased risk of endometrial cancer (RR=0.69, 95%CI 0.62 to 0.78), same as the women who drank coffee frequently (RR=0.83, 95%CI 0.77 to 0.89). The results of dose-response analysis revealed that, when there was an increase of 2 more cups of coffee per day, there was the risk of endometrial cancer decreased by 12%. Conclusion Drinking coffee frequently (more than 2 cups per day) can decrease the risk of endometrial cancer which can be significantly decreased when drinking in a big dose (more than 5 cups per day).
Objective To systematically evaluate the effectiveness and accuracy of brain natriuretic peptide (BNP) for predicting postoperative cardiovascular events of non-cardiac surgery. Methods Databases including The Cochrane Library, PubMed, Ovid, EMbase, WanFang Data and CNKI were searched electrically to collect literature published from 2000 to 2011, and relevant periodicals and references of the included studies were also manually retrieved. According to the inclusion and exclusion criteria, related cohort studies were selected, data were extracted, and quality of the included studies was evaluated by two reviewers independently. Then meta-analysis was conducted using RevMan 5.0 software. Results A total of 11 studies involving 3 649 patients were included. The results of meta-analysis showed that, compared with patients with lower BNP levels than the cut-off point before surgery, patients with higher BNP levels than the cut-off point before surgery suffered from a higher incidence of cardiovascular events, with a significant difference (OR=27.54, 95%CI 17.49 to 43.35, Plt;0.000 01), while the result of N-terminal pro-brain natriuretic peptide (NT-proBNP) was similar to that of BNP (OR=19.53, 95%CI 13.54 to 28.17, Plt;0.000 01). Conclusion Postoperative higher levels of BNP and NT-BNP can be used to predict postoperative cardiovascular events of non-cardiac surgery patients. This conclusion needs to be further proved by more high quality studies due to the quality limitation of the included studies.
Objective To compare the risk of bone fractures in proton pump inhibitor users and nonusers, so as to evaluate the effects of proton pump inhibitors on the risk of bone fractures. Methods We searched PubMed, MEDLINE and EMbase databases to March 1st 2011 to identify case-control studies or cohort studies evaluating the risk of fracture in proton pump inhibitor users and nonusers. We conducted systematic review and meta-analysis according to the fracture site, duration of exposure, average daily dose and time of last use. Summary odds ratios (OR) and 95% confidence interval (CI) were calculated by RevMan 5.0.25 software. We also calculated and looked for heterogeneity. Results Eleven studies were identified from ten literatures, including seven case-control studies and four cohort studies. In case-control studies, the risk of total fractures increased by 36% in proton pump inhibitor users as compared with nonusers (OR=1.36, 95%CI 1.20 to 1.55). The risk of hip fracture increased by 39% (OR=1.39, 95%CI 1.13 to 1.71). In cohort studies, the risk of total fractures increased by 59% (OR=1.59, 95%CI 1.47 to 1.73). The risk of non-hip fractures increased by 65% (OR=1.65, 95%CI 1.47 to 1.85). As compared with nonusers, fracture risk increased by 41% in current users and by 38% in past users whose last use was at least 1 year ago. There was no significant difference between the two groups. Conclusion Proton pump inhibitors increase the risk of fracture to a certain degree. The effect does not fade away by discontinuation of PPI use for at least one year. Stricter clinical trials are needed to exclude confounding factors.
Objective To assess the correlation between obstructive sleep apnea-hypopnea syndrome (OSAHS) and hypertension. Methods Such databases as MEDLINE (1950 to April 2011), EMbase (1989 to April 2011), VIP (1989 to April 2011), WANFANG (1977 to April 2011), CBM (1978 to April 2011) and CNKI (1979 to April 2011) were searched to collect literatures about the correlation between OSAHS and hypertension. The literatures in conference proceedings and some unpublicized articles were also retrieved. All cohort studies and case control studies were included. Two reviewers independently collected the data, assessed the quality, and conducted the Meta-analysis by using RevMan5.1 software. Results Among the total 11 studies involving 4 019 participants were included, 1 was prospective cohort study and the other 10 were case control studies. The results of Meta-analyses showed that: a) the OSAHS was correlated with hypertension (P=0.16, RR=2.52, 95%CI 2.21 to 2.87); and b) the correlation between OSAHS and hypertension was related with the different grades of OSHAS (P=0.83, RR=1.84, 95%CI 1.53 to 2.22). The more severe grade the OSAHS, the greater possibility the hypertension. Conclusion OSAHS is significantly related with hypertension, and they may be the mutual risk factor for each other. The correlation between OSAHS and hypertension may be related with different grades of OSAHS.
Objective To assess the effectiveness and safety of different dual antiplatelet therapies in patients undergoing percutaneous coronary intervention. Methods Such databases as The Cochrane Library, MEDLINE, EMbase, CBM, CNKI and WanFang Data were searched to collect the randomized controlled trials (RCTs) and observational studies on the effectiveness and safety of dual antiplatelet therapies both short-duration (≤6 months) and long-duration (gt;6 months) after percutaneous coronary intervention. The literature was screened according to the inclusive and exclusive criteria by two reviewers independently, the quality was evaluated, the data were extracted, and meta-analyses were performed by using RevMan 5.1 software. Results Eight trials were included, of which 3 were RCTs involving 7 475 patients, and 5 were observational studies involving 12 744 patients. Meta-analyses on RCTs showed that the incidence of death or myocardial infarction in the long-duration treatment group was lower than that of the short-duration treatment group (OR=0.74, 95%CI 0.56 to 0.98, Plt;0.000 1), while meta-analyses on observation studies showed the similar result (OR=0.7, 95%CI 0.45 to 1.08, P=0.11). With the variables of published year and follow-up time, the heterogeneity of cohort studies was discussed through meta-regression (Z=3.61, P=0.000) which indicated that both published year and follow-up time might be the source of heterogeneity due to their contribution. For RCTs, the incidence of severe bleeding events in the short-duration treatment group was lower than that in the long-duration treatment group (OR=1.29, 95%CI 0.99 to 1.69, P=0.06). For observational studies, the incidence of late stent thrombosis in the long-duration treatment group was lower than that in the short-duration treatment group (OR=0.40, 95%CI 0.15 to 1.07, P=0.07). Conclusion The long duration (gt;6months) of dual antiplatelet therapy in patients undergoing percutaneous coronary intervention can reduce the incidence of death or myocardial infarction and decrease the tendency of late stent thrombosis, but cannot obviously increase the incidence rate of severe bleeding events. The current evidence shows no marked superiority in longer duration (gt;12months) of dual antiplatelet therapy.
Objective To systematically evaluate posterior fossa decompression with duraplasty (PFDD) and posterior fossa decompression without duraplasty (PFD) for Chiari malformation type I (CM-I). Methods A meta-analysis was performed according to the guideline of the MOOSE statement. Relevant literature and references were electronically searched in CENTRAL, Science Citation Index Expanded, MEDLINE (Ovid), PubMed, CBM, CNKI and WanFang Data from 1993 to September 2011. Two reviewers independently identified literature according to inclusion and exclusion criteria. The included studies were evaluated using the Newcastle-Ottawa Scale. Original data were extracted and analyzed using RevMan 5.1 software. Besides, the level of evidence was assessed using the GRADE system. Results Ten studies involving 829 patients were included. The results of meta-analyses showed that: a) compared with patients undergoing PFD, patients undergoing PFDD had a significantly lower reoperation rate (RR=0.41, 95%CI 0.23 to 0.74, P=0.003), and a higher rate of syringomyelia decrease (RR=1.27, 95%CI 1.03 to 1.56, P=0.02). But there was no significant difference in clinical improvement (RR=1.11, 95%CI 0.95 to 1.28, P=0.18). b) compared with PFD, patients undergoing PFDD had a higher rate of cerebrospinal fluid–related complications (RR=6.3, 95%CI 2.71 to 14.67, Plt;0.000 1). There were no significant differences in the complication of occipital neuralgia and wound infection (Pgt;0.05). Based on GRADE system, the evidence was at Level C and we made a weak recommendation. Conclusion Posterior fossa decompression with duraplasty is associated with a lower risk of reoperation, a better effect of syringomyelia decrease and a greater risk for cerebrospinal fluid–related complications, compared with PFD. Due to the influencing factors of lower-quality included studies, a prudent choice is suggested, and also more high-quality, large-sample studies are need.
Objective To systematically assess literature regarding the relationship between ovulation induction and the risk of ovarian cancer. Methods We searched MEDLINE, EMbase, The Cochrane Library, CBM and CNKI (from inception to Feb, 2012). Cohort or case-control studies were identified according to the inclusion and exclusion criteria. Then the quality of the included studies was assessed, and the data was extracted. Meta-analysis was performed by RevMan 5.0 software. The incorporated RR (relative risk) and 95%CI (confidence interval) of the included cohort studies and incorporated OR (odds ratio) and 95%CI of case-control studies were calculated, respectively. Results Four cohort studies and four case-control studies were included. Result of meta-analysis on cohort studies showed ovulation induction didn’t increase the risk of ovarian cancer (RR=1.07, 95%CI 0.81 to 1.42, P=0.63). Besides, result of meta-analysis on case-control studies showed ovulation induction was not associated with the incidence of ovarian cancer (OR=1.28, 95%CI 0.78 to 2.08, P=0.33). But the risk of borderline ovarian tumors increased when compared with general population controls (OR=1.71, 95%CI 1.05 to 2.79, P=0.03). Conclusion Ovulation induction does not increase the risk of ovarian cancer, but may relate to the incidence of borderline ovarian cancer. However, more high-quality studies, especially perspective cohort studies are required because of the limited quantity of the included studies.
Objective To systematically review the evidence of the factors associated with self-rated health (SRH) and estimating the population attributable risk proportion (PARP) of interests in the elderly. Methods MEDLINE, EMbase, CBM, CNKI, VIP and WanFang Data were searched (from January 1960 to April 2011) for relevant literature. The combined effect on each factor associated with poor SRH was expressed as RR or OR (95%CI). The contribution of each factor to poor SRH in the elderly population was estimated with PARP. Meta-analysis was performed using RevMan 5.1 software. Results Twelve studies involving a total of 35 349 participants aged 60 or above were eligible in this systematic review. Ten studies were conducted in China and the rest two studies were from the USA and Brazil. Of them, only one was prospective cohort study and 11 studies were cross-sectional. The results of meta-analysis showed that the main factors associated with poor SRH in the elderly were dependency, diabetes and coronary heart disease with the corresponding OR and 95%CI as 12.10 (6.31, 23.20), 6.49 (3.21, 13.09) and 5.60 (1.07, 29.42), respectively. However, the top three factors contributing to poor SRH in the elderly population were coronary heart disease, having illness half one year ago and chronic disorders with the corresponding PARP as 53.91%, 52.56%, and 50.09%, respectively. It was not possible to perform sub-group analysis because of the limited quantity of studies on each factor associated with poor SRH. Conclusion Based on the current available evidence, it appears that chronic disorders are closely related to poor SRH and contribute most in the elderly population. However, due to the limitation of the included predominantly cross sectional studies which are not enough for causal argument, it is insufficient to determine the association of many factors with poor SRH. Further high-quality prospective cohort studies are needed.