A meta-analysis of coffee intake and risk of urolithiasis.

OBJECTIVE

Epidemiologic studies have reported various results relating coffee to urolithiasis. A meta-analysis of cohort and case-control studies was conducted to pool the relative risk (RR) estimates of the association between coffee and urolithiasis.

METHODS

Eligible studies were retrieved via both computer searches and review of references. We analyzed abstracted data with random effects models to obtain the summary RR estimates. A dose-response meta-analysis was performed for studies reporting categorical RR estimates for a series of exposure levels.

RESULTS

A total of 6 studies (2 cohort and 4 case-control studies) on coffee intake were included in the meta-analysis. The pooled odds ratio (OR) showed a significant influence of the highest coffee consumption (OR = 0.70, 95% confidence interval 0.60-0.82) on the risk of urolithiasis. Coffee exhibited an inverse dose-response relationship with urolithiasis. In stratified analysis, a significant inverse association between coffee and urolithiasis was observed in study design, geographical region and gender subgroup.

CONCLUSIONS

The overall current literature suggests that coffee intake is associated with a decreased risk of urolithiasis. Further efforts should be made to clarify the underlying biological mechanisms.