Coffee consumption and hip fracture risk: a meta-analysis

To investigate the effect of coffee consumption on hip fracture risk, a meta-analysis was conducted. The PubMed database was screened for all published studies about coffee consumption and hip fracture through to November 2011. Reviews, PubMed option 'related articles' and references of retrieved papers were also searched for potentially relevant papers. Only studies that contained OR with 95 % CI for the association between coffee consumption and hip fracture risk were included. The summary risk estimates were calculated by fixed-and random-effects models. Subgroup analyses were carried out stratified by study designs and participant characteristics, respectively. A total of six prospective cohort studies and six case-control studies were included in the final analysis. The pooled OR displayed increased risk of hip fracture by 29.7 % (95 % CI 0.960, 1.751; P = 0.09) for the highest compared with the lowest coffee consumption by the random-effects model (P for heterogeneity = 0.000; I-2 = 84.0 %), but the result had no statistical significance. Subgroup analyses showed that coffee consumption significantly increased hip fracture risk by 54.7 % (95 % CI 1.152, 2.077; P = 0.004) among women, by 40.1 % (95 % CI 1.015, 1.935; P = 0.040) for elderly participants aged over 70 years, and by 68.3 % for Northern Americans (95 % CI 1.492, 1.899; P = 0.000). Other subgroup analyses according to data published before the year 2000 showed a positive association between coffee and hip fracture risk, and followup duration also positively affected hip fracture risk, especially when the follow-up length was less than 13 years. Although our meta-analysis has provided insufficient evidence that coffee consumption significantly increases hip fracture risk, coffee intake may increase hip fracture risk among women, elderly participants and Northern Americans. No dose-response pattern was observed.