Topical Area: Dietary Bioactive Components
Objectives : Cranberry (Vaccinium spp.) has been advocated for maintaining healthy urinary tract function in women; however, the effect in other populations is controversial. The aim of this meta-analysis was to evaluate cranberry intake and the risk of uncomplicated urinary tract infection (UTI) and some categories of complicated UTI in otherwise healthy populations.
Methods : MEDLINE, EMBASE, Cochrane, and Web of Science were systematically searched, and studies screened and extracted using a predefined strategy by two independent investigators. Discrepancies were resolved by discussion with a third investigator. Meta-analysis was performed using RevMan (version 5.3.5, Cochrane, UK). Heterogeneity was assessed with both I2 and the chi-square tests. A low to moderate (I2 < 50%) heterogeneity was found; thus, fixed-effect model using the Mantel-Haenszel method were used to estimate the risk ratio (RR).
Results : A total of 16 studies were included in the quantitative analysis. Pooled RR estimates for the seven studies on healthy, non-pregnant women (RR = 0.76 [95% CI: 0.63-0.91]) suggest that cranberry may reduce the risk for UTI recurrence in this population, consistent with previous meta-analyses. Meta-analysis also suggests lower UTI risk with cranberries in children based on four studies (RR = 0.58 [95% CI: 0.41-0.83]). Only two studies in pregnant women were identified and these were both performed by the same research group. RR estimates obtained for healthy, pregnant women (RR = 0.87 [95% CI: 0.37-2.04]) were not significant. The RR estimate for elderly/institutionalized adults was also not significant (RR = 0.81 [95% CI: 0.48-1.35]), but the three studies in this evaluation included data combined from heterogeneous populations having immune, neurological, and /or physical dysfunction with data from healthy people. Therefore, these findings do not reflect data in the generally healthy elderly population.
Conclusions : Meta-analysis of studies investigating cranberry and UTI risk suggests that cranberries may be useful in reducing the risk of uncomplicated UTI recurrence in healthy, non-pregnant women and children. More research is needed on the effect of cranberry on UTI risk in pregnant women and generally healthy elderly/institutionalized adults before firm conclusions can be made.
Funding Sources : Ocean Spray