A Cochrane review included 21 observational studies with nearly 400 000 subjects; 6 of them were cohort studies (n=121 965) and 15 were case-control studies (n=277 397). Two cohort studies appear to involve the same cohort so there were only 5 unique ones. No randomized control trials were found. Meta-analysis of cohort studies showed that thiazide use was associated with a reduction in risk of hip fracture by 24% (RR 0.76, 95% CI 0.64 to 0.89). A pooled summary statistics for case-control studies was not provided because of high heterogeneity ( I2= 62%).