Meta‐analysis: formulating, evaluating, combining, and reporting

Normand, Sharon‐Lise T.

doi:10.1002/(sici)1097-0258(19990215)18:3<321::aid-sim28>3.3.co;2-g

Cited by 317 publications

(439 citation statements)

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“…As we assumed variability to be due to both sampling error and random differences across studies, to combine study-to-study variations data were fitted to a random effects model as described by Fleiss (Fleiss, 1993), which provides more conservative estimates than a fixed effects model. Random effects are also more appropriate when heterogeneity is present in the results (Normand, 1999).…”

Section: Discussionmentioning

confidence: 99%

Rapid effects of aromatase inhibition on male reproductive behaviors in Japanese quail

Cornil

Taziaux

Baillien

et al. 2006

Hormones and Behavior

101

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Non-genomic effects of steroid hormones on cell physiology have been reported in the brain. However, relatively little is known about the behavioral significance of these actions. Male sexual behavior is activated by testosterone partly through its conversion to estradiol via the enzyme aromatase in the preoptic area (POA). Brain aromatase activity (AA) changes rapidly which might in turn be important for the rapid regulation of behavior. Here, acute effects of Vorozole ™ , an aromatase inhibitor, injected IP at different doses and times before testing (between 15 and 60 min), were assessed on male sexual behavior in quail. To limit the risk of committing both types of statistical errors (I and II), data of all experiments were entered into a meta-analysis. Vorozole ™ significantly inhibited mount attempts (p<0.05, size effect [g]=0.527) and increased the latency to first copulation (p<0.05, g=0.251). The treatment had no effect on the other measures of copulatory behavior. Vorozole ™ also inhibited appetitive sexual behavior measured by the social proximity response (p<0.05, g=0.534) or rhythmic cloacal sphincter movements (p<0.001, g=0.408). Behavioral inhibitions always reached a maximum at 30 min. Another aromatase inhibitor, androstatrienedione, induced a similar rapid inhibition of sphincter movements. Radioenzyme assays demonstrated that within 30 min Vorozole ™ had reached the POA and completely blocked AA measured in homogenates. When added to the extracellular milieu, Vorozole ™ also blocked within 5 min the AA in POA explants maintained in vitro. Together, these data demonstrate that aromatase inhibition rapidly decreases both consummatory and appetitive aspects of male sexual behavior.

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Section: Discussionmentioning

confidence: 99%

Rapid effects of aromatase inhibition on male reproductive behaviors in Japanese quail

Cornil

Taziaux

Baillien

et al. 2006

Hormones and Behavior

101

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“…A SIR adjusted for study was then calculated, using either a fixed or a random-effects model, according to the results of the Cochran's test (Normand, 1999).…”

Section: Discussionmentioning

confidence: 99%

Meta-analysis of cancer incidence in children born after assisted reproductive technologies

2005

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A meta-analysis was performed on 11 cohort studies of Assisted Reproductive Technologies (ART) and subsequent childhood cancer, published up to February 2005, which reported comparable, nonoverlapping data, and then restricted to eight studies which presented a similar research design. The overall Standardised Incidence Ratio was 1.33 (95% CI 0.62 -2.85), and 0.77 (95% CI 0.41 -1.42) when the analysis was restricted to eight studies. No evidence of publication bias was observed for the overall analysis. The data are consistent with a lack of increase in risk of childhood cancer, though the amount of data on ART and cancer is still limited; larger multicentric studies as well as a pooled analysis on the available data are warranted.

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“…The standard deviation of the difference in plasma cholesterol changes between groups I and C was estimated by standard equations from the reported standard error, standard deviations or 95% CIs of the changes within the groups and differences between the groups. Standard methods of meta-analysis (Normand, 1999) were used to carry out a chi-square test of homogeneity of study means, a ®xed effects estimate, standard error and test of the difference in cholesterol change between intervention and control treatment, and a random effects estimate and standard error. In either case, the studies are combined to obtain an overall estimate, with individual studies weighted according to their sample size and the variance of their estimated effects.…”

Section: Discussionmentioning

confidence: 99%

The effect of a probiotic milk product on plasma cholesterol: a meta-analysis of short-term intervention studies

Agerholm-Larsen¹,

et al. 2000

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Introduction: Certain fermented dairy milk products may have bene®cial effects on plasma cholesterol levels. However, a number of studies have produced con¯icting results as to whether dietary supplementation by a probiotic dairy product containing the bacteria culture Causido 1 reduces plasma cholesterol. Objective: To conduct a meta-analysis of intervention studies to evaluate the effect of the Causido 1 culture on plasma total cholesterol and low-density lipoprotein (LDL)-cholesterol. The probiotic milk product: The yoghurt product Gaio 1 is fermented with Causido 1 , composed of one strain of Enterococcus faecium (human species) with the proposed cholesterol-lowering effect, and two strains of Streptococcus thermophilus. Study inclusion and data extraction: Six studies were identi®ed from a literature search and from the yoghurt producer. All studies met the inclusion criteria. Summary data for plasma concentrations of total cholesterol and LDL-cholesterol were extracted from the original publications or by personal request to the authors. Data from 4 ± 8 weeks of treatment duration was used. Statistical analysis: We performed a traditional meta-analysis where mean differences between intervention and control of the pre ± post changes in total cholesterol and LDL-cholesterol were calculated, as well as 95% con®dence intervals (CIs). Results: In the six studies included in the meta-analysis, the Gaio 1 interventions produced changes in total cholesterol above those of the control groups ranging from À0.02 to À1.02 mmolal and in LDL-cholesterol ranging from À0.02 to À1.15 mmolal. After inclusion of an open-label study, the meta-analysis of the doubleblind studies showed that Gaio 1 as compared to the control group changed total cholesterol by À0.22 mmolal (95% CI: À0.35 to À0.08, P`0.01) and LDL-cholesterol by À0.20 mmolal (95% CI: À0.33 to À0.06, P`0.005). The outcome was essentially the same if all studies were included. Conclusions: The present meta-analysis of controlled short-term intervention studies shows that the fermented yoghurt product produced a 4% decrease in total cholesterol and a 5% decrease in LDL-cholesterol when the open-label study is excluded. To demonstrate sustained effects on blood lipids, long-term studies are required. Sponsorship: MD Foods AaS, Denmark. Descriptors: probiotic milk product; plasma cholesterol; meta-analysis

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Meta‐analysis: formulating, evaluating, combining, and reporting

Cited by 317 publications

References 0 publications

Rapid effects of aromatase inhibition on male reproductive behaviors in Japanese quail

Rapid effects of aromatase inhibition on male reproductive behaviors in Japanese quail

Meta-analysis of cancer incidence in children born after assisted reproductive technologies

The effect of a probiotic milk product on plasma cholesterol: a meta-analysis of short-term intervention studies

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