High-Dose Aspirin Consumption Contributes to Decreased Risk for Pancreatic Cancer in a Systematic Review and Meta-analysis.
ABSTRACT The aim of this study was to analyze the association between aspirin intake and its effect for chemoprevention of pancreatic cancer incidence by using a meta-analysis method.
The databases of MEDLINE, EMBASE, and Wangfang (Chinese database) were retrieved to identify eligible studies. Odds ratio (OR) and 95% confidence interval (CI) were calculated using a random-effects model.
A total of 10 studies (4 case-control studies, 5 prospective cohort studies, and 1 randomized controlled trial) with 7,252 cases of pancreatic cancer and more than 120,0000 healthy control subjects were enrolled in the studies. Pooled analyses showed that high-dose aspirin intake was marginally associated with decreased risk for pancreatic cancer for overall analysis (OR, 0.88; 95% CI, 0.76-1.01) as well as for both cohort and case-control studies (OR, 0.70; 95% CI, 0.54-1.16, for the cohort studies; OR, 0.82; 95% CI, 0.62-1.02, for the case-control studies), without between-study heterogeneity. Stratified analysis for Americans showed a similar result (OR, 0.82; 95% CI, 0.65-1.02). In contrast, our study inferred that low-dose aspirin intake was not associated with risk for pancreatic cancer for the total and subgroup analyses.
In summary, our study indicated that high-dose aspirin, rather than low-dose aspirin, might be associated with decreased risk for pancreatic cancer, especially for Americans.
- Epidemiologic Reviews 02/1987; 9:1-30. · 9.27 Impact Factor
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ABSTRACT: ADVANTAGES OF META-ANALYSIS: Literature reviews have traditionally been largely narrative. Meta-analysis now offers the opportunity to critically evaluate and statistically combine results of comparable studies or trials. Its major purposes are to increase the numbers of observations and the statistical power, and to improve the estimates of the effect size of an intervention or an association. METHODS: There is, as yet, no unanimously accepted strategy for performing a meta-analysis but researchers agree that each meta-analysis should be conducted like a scientific experiment and begin with a protocol, which clearly states its aim and methodology. Meta-analysts disagree on the criteria for inclusion or exclusion of primary studies, with relation to publication status, comparability and required scientific quality, but sensitivity analyses make it possible to assess the impact of various selection criteria on the results. Several statistical methods have been developed to analyse data extracted from the literature; more recently, meta-analyses have also been performed on individual subject data. CONCLUSIONS: Meta-analysis is superior to narrative reports for systematic reviews of the literature, but its quantitative results should be interpreted with caution even when the analysis is performed according to rigorous rules.Journal of hypertension. Supplement: official journal of the International Society of Hypertension 10/1996; 14(2):S9-12; discussion S13.
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ABSTRACT: Funnel plots (plots of effect estimates against sample size) may be useful to detect bias in meta-analyses that were later contradicted by large trials. We examined whether a simple test of asymmetry of funnel plots predicts discordance of results when meta-analyses are compared to large trials, and we assessed the prevalence of bias in published meta-analyses. Medline search to identify pairs consisting of a meta-analysis and a single large trial (concordance of results was assumed if effects were in the same direction and the meta-analytic estimate was within 30% of the trial); analysis of funnel plots from 37 meta-analyses identified from a hand search of four leading general medicine journals 1993-6 and 38 meta-analyses from the second 1996 issue of the Cochrane Database of Systematic Reviews. Degree of funnel plot asymmetry as measured by the intercept from regression of standard normal deviates against precision. In the eight pairs of meta-analysis and large trial that were identified (five from cardiovascular medicine, one from diabetic medicine, one from geriatric medicine, one from perinatal medicine) there were four concordant and four discordant pairs. In all cases discordance was due to meta-analyses showing larger effects. Funnel plot asymmetry was present in three out of four discordant pairs but in none of concordant pairs. In 14 (38%) journal meta-analyses and 5 (13%) Cochrane reviews, funnel plot asymmetry indicated that there was bias. A simple analysis of funnel plots provides a useful test for the likely presence of bias in meta-analyses, but as the capacity to detect bias will be limited when meta-analyses are based on a limited number of small trials the results from such analyses should be treated with considerable caution.BMJ Clinical Research 10/1997; 315(7109):629-34. · 14.09 Impact Factor