See also this paper which is mentioned in the article below and which summarizes results of studies from 2008-2010 (response by authors to criticism). See here for earlier discussion on the overall quality of medical research.
MedConnect: ... Dr. Kausik K. Ray of the University of Cambridge (England) and his associates performed a meta-analysis of 11 randomized controlled trials that assessed the effects on all-cause mortality of statins versus a placebo or control therapies on all-cause mortality. They restricted their analysis to data on high-risk patients with no known cardiovascular disease and included previously unpublished data, “to provide the most robust information to date” on statins as primary prevention in this patient group.
The metaanalysis involved 65,229 men and women in predominantly Western populations, with approximately 244,000 person-years of follow-up. There were 2,793 deaths during an average of 4 years of follow-up.
All-cause mortality was not significantly different between patients taking statins and those taking placebo or control therapies. This suggests that “the all-cause mortality reduction of 20% reported in JUPITER is likely to be an extreme and exaggerated finding, as often occurs when trials are stopped early,” Dr. Ray and his colleagues said (Arch. Intern. Med. 2010;170;1,024-31).
This meta-analysis shows that statin therapy as primary prevention in high-risk patients is less beneficial than is generally perceived, and it can be inferred to be even less helpful in low-risk patients, they added.