Citations
Citations
Citations
Previous randomized controlled trials (RCTs) have reported inconsistent findings regarding the association between vitamin C supplementation and the risk of cancer.
We performed a meta-analysis of RCTs to investigate the efficacy of vitamin C supplements for prevention of cancer. We searched the PubMed, EMBASE, and Cochrane Library databases in November 2014 using common keywords related to vitamin C supplements and cancer.
Among 785 articles, a total of seven trials were identified, which included 62,619 participants; 31,326 and 31,293 were randomized to vitamin C supplementation and control or placebo groups, respectively, which were included in the final analysis. A fixed-effects meta-analysis of all seven RCTs revealed no significant association between vitamin C supplementation and cancer (relative risk, 1.00; 95% confidence intervals, 0.95-1.05). Similarly, subgroup meta-analysis by dose of vitamin C administered singly or in combination with other supplements, follow-up period, methodological quality, cancer mortality, gender, smoking status, country, and type of cancer also showed no efficacy of vitamin C supplementation for cancer prevention.
This meta-analysis shows that there is no evidence to support the use of vitamin C supplements for prevention of cancer.
Citations
Because there is no specific treatment for the common cold, many previous studies have focused on prevention of the common cold. There were some studies reporting that regular, moderate-intensity exercise increases immunity and prevents the common cold. We conducted a meta-analysis to determine the effects of exercise on prevention of the common cold.
We searched MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials (CENTRAL), CINAHL for studies released through June 2013. We manually searched the references. Two authors independently extracted the data. To assess the risk of bias of included literature, Cochrane Collaboration's tool for assessing risk of bias was used. Review Manager ver. 5.2 (RevMan, Cochrane Collaboration) was used for statistical analysis.
Four randomized controlled trials were identified. A total of 281 participants, 134 in the exercise group and 147 in the control group, were included. The effect of exercise on the prevention of the common cold had a relative risk (RR) of 0.73 (95% confidence interval [CI], 0.56 to 0.95; I2 = 7%). The mean difference of mean illness days between exercise group and control group was -3.50 (95% CI, -6.06 to -0.94; I2 = 93%). In the subgroup analysis, the RR of under 16 weeks exercise was 0.79 (95% CI, 0.58 to 1.08).
In this meta-analysis, regular, moderate-intensity exercise may have an effect on the prevention of the common cold. But numbers of included studies and participants were too small and quality of included studies was relatively poor. Subsequent well-designed studies with larger sample size are needed to clarify the association.
Citations
Non-steroidal anti-inflammatory drugs (NSAIDs) and acetaminophen are widely used for common cold symptom relief. The objective of this study was to evaluate and compare the efficacy and safety of acetaminophen and NSAIDs in common cold symptom relief using meta-analysis of randomized controlled trial.
We searched MEDLINE (PubMed), Cochrane, EMBASE, CINAHL, KMbase, KoreaMed, National Assembly Library, and Riss4u for studies released through June 2012. Two authors independently extracted the data. To assess the risk of bias, the Cochrane Collaborations risk of bias tool was used. The Review Manager ver. 5.1 (RevMan) was used for statistics.
We identified 5 studies. The relative benefit for participants with pain relief was 1.00 (95% confidence interval [CI], 0.96 to 1.05) and I2 = 0%. The existence of the heterogeneity between studies was not important in this study, thus subgroup analysis was not implemented. The relative benefit for participants with rhinorrhea was 1.02 (95% CI, 0.77 to 1.35) and I2 = 0%, which also indicates the existence of heterogeneity was not important. The relative risk of adverse events was 1.14 (95% CI, 0.93 to 1.40), I2 = 0%. There was no apparent asymmetry in the funnel plot.
There was no difference between NSAIDs and acetaminophen in common cold symptom relief.
Citations
Epidemiologic studies have reported inconsistent findings regarding the association between the use of antidepressants and type 2 diabetes mellitus (DM) risk. We performed a meta-analysis to systematically assess the association between antidepressants and type 2 DM risk.
We searched MEDLINE (PubMed), EMBASE, and the Cochrane Library (through Dec 31, 2011), including references of qualifying articles. Studies concerning the use of tricyclic antidepressants (TCAs), selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs), or other antidepressants and the associated risk of diabetes mellitus were included.
Out of 2,934 screened articles, 3 case-control studies, 9 cohort studies, and no clinical trials were included in the final analyses. When all studies were pooled, use of antidepressants was significantly associated with an increased risk of DM in a random effect model (relative risk [RR], 1.49; 95% confidence interval [CI], 1.29 to 1.71). In subgroup analyses, the risk of DM increased among both SSRI users (RR, 1.35; 95% CI, 1.15 to 1.58) and TCA users (RR, 1.57; 95% CI, 1.26 to 1.96). The subgroup analyses were consistent with overall results regardless of study type, information source, country, duration of medication, or study quality. The subgroup results considering body weight, depression severity, and physical activity also showed a positive association (RR, 1.14; 95% CI, 1.01 to 1.28). A publication bias was observed in the selected studies (Egger's test, P for bias = 0.09).
Our results suggest that the use of antidepressants is associated with an increased risk of DM.
Citations
Probiotics are currently under focus for their immune improvement function. Many studies have been performed to assess the potential efficacy of probiotics in allergic disease, viral disease, respiratory disease, as well as gastrointestinal disease. This study performed a systematic review to determine the effects of probiotics on the prevention of the common cold.
We searched MEDLINE (PubMed), EMBASE, CINAHL, and Cochrane CENTRAL for studies released through June 2011. Two authors independently extracted the data. To assess the risk of bias of included literatures, Cochrane Collaboration's risk of bias tool was used.
We identified 10 studies in 7 articles. A total 2,894 participants, 1,588 in the probiotics group and 1,306 in the control group, were included. The effect of probiotics on the prevention of the common cold had a relative risk (RR) of 0.92 (95% CI, 0.85 to 1.00, I2 = 26%). In the subgroup analysis, the RR of administration of probiotics for 3 months or less was 0.82 (95% CI, 0.70 to 0.97). The RR of administration of probiotics over 3 months was 1.00 (95% CI, 0.92 to 1.09). The RR of administration of probiotics without any active intervention (vitamin and mineral) was 0.87 (95% CI, 0.78 to 0.97).
In this meta-analysis, there was marginal effect of probiotics on the prevention of the common cold. The results implied that probiotics had a modest effect in common cold reduction. The balance of benefit and harms needs to be considered when using probiotics for common cold prevention.
Citations
Coffee is one of the most widely consumed beverages in the world, and contains caffeine and phenolic compounds. Many studies on the association between coffee consumption and risk of stroke have been reported, however, more research is needed to further explore many studies' inconsistent results. Therefore, we conducted a meta-analysis to verify the relationship between coffee consumption and stroke.
We searched MEDLINE (PubMed), EMBASE, and the Cochrane Library, using the keywords "coffee" or "caffeine" for the exposure factors, and "transient ischemic attack" or "stroke" or "acute cerebral infarction" or "cardiovascular events" for the outcome factors. We included prospective cohort and case-control studies published between 2001 and July 2011 in this review. The search was limited to English language.
Among 27 articles identified for this review, only 9 studies met the inclusion criteria, all of which were cohort studies. When using all cohort studies, the pooled relative risk (RR) of stroke for the highest vs. lowest category of coffee consumption was 0.83 (95% confidence interval [CI], 0.76 to 0.91). When subgroup analysis was performed, for Europeans, increased coffee drinking showed a preventive effect on stroke occurrence with RR 0.82 (95% CI, 0.74 to 0.92); RR for women 0.81 (95% CI, 0.70 to 0.93); for ischemic stroke 0.80 (95% CI, 0.71 to 0.90); and for those drinking 4 cups or more per day 0.83 (95% CI, 0.75 to 0.91).
We found that coffee consumption of 4 cups or more per day showed a preventive effect on stroke in this meta-analysis.
Citations
Previous case-control studies have reported inconsistent findings regarding the association between proton pump inhibitor (PPI) use and colorectal cancer (CRC) risk. We investigated these associations using meta-analysis.
We searched MEDLINE (PubMed), EMBASE, and the Cochrane Library in April 2011. Two evaluators independently reviewed and selected articles, based on pre-determined selection criteria.
Out of 737 articles meeting our initial criteria, 5 case-control studies, which involved 120,091 participants (9,514 cases and 110,577 controls), were included in the final analyses. The overall use of PPI (used vs. never or rarely used) was not significantly associated with the risk of CRC in a fixed-effects model meta-analysis of all 5 case-control studies (odds ratio [OR], 1.08; 95% confidence interval [CI], 0.96 to 1.20; I2 = 3.5%). Also, in sensitivity meta-analysis by cumulative duration of PPI use, there was no association between PPI use of 1 year or longer and the risk of colorectal cancer in a fixed-effects meta-analysis (OR, 1.09; 95% CI, 0.98 to 1.22; I2 = 0%).
Although hypergastrinemia could be an important factor in the pathogenesis of some colorectal cancers, our study suggests that this does not lead to significant clinical risk for most PPI users. Further prospective studies or randomized controlled trials related to PPI use and colorectal cancer risk are needed to investigate this association.
Citations
Non-steroidal anti-inflammatory drugs (NSAIDs) and acetaminophen are widely used in the treatment of tension headache. The objective of this study was to evaluate and compare the efficacy and safety of single doses of acetaminophen and NSAIDs using meta-analysis of randomized placebo-controlled trial studies.
We searched MEDLINE, EMBASE, CINAHL, Cochrane, KMbase, KoreaMed, RiCH, National Assembly Library, Riss4u, and DBPIA for studies released through 27th July 2010. Two authors independently extracted the data. To assess the risk of bias, the Cochrane Collaborations risk of bias tool was used. Review Manager 5.0 was used for statistics.
We identified 6 studies. The relative benefit of the NSAIDs group compared to the acetaminophen group for participants with at least 50% pain relief was 1.18 (95% confidence interval [CI], 0.99 to 1.39; I2 = 85%). We did subgroup analysis based on allocation concealment versus non-allocation concealment, and low-dose NSAIDs versus high-dose NSAIDs. The relative benefit of the low-dose NSAIDs subgroup to the acetaminophen group was 0.98 (95% CI, 0.91 to 1.06; I2 = 0%). However, the heterogeneity of other subgroup analysis was not settled. The relative risk for using rescue medication of the NSAIDs group compared to the acetaminophen group was 0.84 (95% CI, 0.64 to 1.12; I2 = 47%). The relative risk for adverse events was 1.31(95% CI, 0.96 to 1.80; I2 = 0%).
In this meta-analysis, there was no difference between low-dose NSAIDs and acetaminophen in the efficacy of the treatment for tension type headache. The results suggested that high-dose NSAIDs have more effect but also have more adverse events. The balance of benefit and harm needs to be considered when using high-dose NSAIDs for tension headache.
Citations
Citations
First
Prev
