Effects of tea consumption on risk of osteoporotic bone fracture in older people: Meta-analysis of observational studies.

There have been several studies published in the medical literature over the past 30 years that address the association between tea consumption and osteoporosis with inconsistent findings. A meta-analysis was undertaken, including 8 studies, to determine the effect of tea consumption on the risk of fracture. This systematic review and meta-analysis conducted on articles published from 1980 to 2010. We searched the following electronic databases: medline, pubmed, ISI, Embase and Chocrane and also reverent journals using mesh search terms including caffeine, tea, coffee, osteoporosis, Bone Mineral Density (BMD) and fracture*. All the relevant English written articles reviewed by two independent researchers. After title and abstract review non-relevant articles were excluded. The full text of accepted publications was obtained and their content reviewed for final inclusion. Using MOOSE (Meta-analysis Of Observational Studies in Epidemiology) criteria, relevant articles with high quality, reporting odds ratio (OR) or risk ratio (RR) for fracture following tea consumption, selected for meta-analysis. Four hundred and twenty one articles found through the primary searches; 78 full text articles evaluated. Only 8 of them fulfilled all the inclusion criteria and their relevant data were extracted included into the analysis. The meta-analysis showed that tea consumption can have a protective effect on the risk of hip fracture which is not significant (RR=0.872; 0.733-1.038). Analysis by type of the studies suggests that according to cohort studies there is a significant decrease in the risk of hip fracture following tea consumption (RR=0.749; 0.603-0.929) while case-control studies do not support this findings (RR=1.157; 0.863-1.553). Tea as a popular drink throughout the world can reduce the risk of osteoporotic bone fractures along with its known antioxidant effects.