Objective: High consumption of soft drinks has been associated with lower bone mineral density among postmenopausal women. This study explores the association of soft drink consumption, osteoporosis, and incidental fractures in this population.
Methods: Cross-sectional (at baseline) and cohort combined designs, over 11.9 years of median follow-up for 72,342 postmenopausal women participating in the Women's Health Initiative Observational Study. Multiple linear regression models were used to examine the cross-sectional associations between soft drink consumption and hip and lumbar spine bone mineral density. Cox proportional hazards regression models were used to examine the association of soft drink consumption with incident hip fractures.
Results: There were no associations between soft drink consumption and hip or lumbar spine t scores. During 700,388 person-years of follow-up, 2,578 hip fractures occurred. Adjusted hazard ratios for incident hip fracture for the highest consumption category compared with no consumption were 1.26 (95% confidence interval [CI] 1.01-1.56) for total soda and 1.32 (95% CI 1.00-1.75) for caffeine-free soda. There was no association between caffeinated soda and incident hip fracture (hazard ratio = 1.16; 95% CI 0.86-1.57). There was no apparent linear trend in the risk of hip fracture across categories of soda consumption in the fully adjusted models, suggesting a threshold effect. A sensitivity analysis using adjudicated hip fractures showed significant associations for all three soda exposures in the highest intake groups.
Conclusions: Consuming more than two servings of soft drinks per day on average showed potential associations with higher risk of hip fracture among postmenopausal women.