Higher soda intake linked to postmenopausal hip fracture risk

Women who consumed high amounts of soda had a higher risk of hip fracture during the postmenopausal period compared with those who did not consume soda, according to a recent study.

Researchers gathered data from the Women’s Health Initiative observational study and analysed 72,342 postmenopausal women (mean age 69.2 years). A total of 2,578 incident cases of hip fracture were reported at 700,388 person-years of follow-up. Food frequency questionnaires were used to assess the consumption of soda, including total, caffeinated, and caffeine-free soda consumption. Hip and lumbar spine T scores and bone mineral density (BMD) measurements were used to assess bone health. [Menopause 2019;26:1234-1241]

At a median follow-up of 11.9 years, women with a higher intake of total soda (>14 servings per week) had an increased risk of hip fracture than those with no intake (adjusted hazard ratio [adjHR], 1.26, 95 percent confidence interval [CI], 1.01–1.56).

An increased risk of hip fracture was also observed among women who had a higher intake of caffeine-free soda (>14 servings per week) compared with no intake (adjHR, 1.32, 95 percent CI, 1.00–1.75).

However, there was no significant association found between caffeinated soda intake and incident hip fracture (HR, 1.16, 95 percent CI, 0.86–1.58), “although the HRs were in the direction of increased [hip fracture] risk,” said the researchers.

When sensitivity analysis was performed on women with adjudicated hip fractures (n=1,275), the risk of hip fractures was strongly, but not statistically significant, associated with high consumption of the three soda drinks, specifically total soda (HR, 1.45, 95 percent CI, 1.07–1.95), caffeinated soda (HR 1.48, 95 percent CI, 1.00-2.26), and caffeine-free soda (HR, 1.43, 95 percent CI, 0.97–2.11).

The findings were consistent with a previous study which showed that increased soda consumption of all types was significantly associated with a higher risk of hip fracture in postmenopausal women, said the researchers. [Am J Clin Nutr 2014;100:953-958]

“[Of note,] our results showed no significant risks if the intake [of soda] was <14 servings per week, suggesting a threshold effect rather than a dose-response relationship,” they said.

The researchers also found no associations between soda intake and reduced BMD, or hip or lumbar spine T scores. “These null findings suggest the need to consider and further investigate whether a reduction in BMD is the causal mechanism in the observed association between high soda consumption and incident hip fracture risk”.

“[In conclusion,] high soda consumption was associated with a modest increased risk of incident hip fracture but no difference in hip or spine T scores,” the researchers noted.

“Future research is needed to quantify risks of soda consumption over adulthood, separate out diet from sugar-containing soda consumption, colas from noncolas, and carbonated from noncarbonated beverages. More research is also needed to identify the biological mechanisms that might be involved in these findings,” they suggested.