Peer-reviewed and published studies may not provide reliable estimates of effect.
Even though a study has been published in a prestigious journal, the results may not be reliable. Peer review (assessment of a study by others working in the same field) does not guarantee that published studies are reliable. Assessments vary and may not be systematic. Similarly, just because a study is widely publicised does not mean that it is trustworthy.
BEWARE of claims based on where they are reported or how widely publicised they are alone.
REMEMBER: Always consider whether an estimate of effects is fair and whether the results are reliable. Peer-review is a poor indicator of reliability.