Long-term plant-based diets did not increase hip fractures for postmenopausal women

Key takeaways:

• Of 70,285 women, 2,038 hip fractures occurred during the study period and throughout 30 years of follow-up.
• Adhering to a plant-based diet long term was not linked to hip fracture risk for postmenopausal women.

Long-term adherence to healthful or unhealthful plant-based diets was not associated with risk for hip fracture among postmenopausal women, according to cohort study results published in JAMA Network Open.

“Plant-based diets, characterized by higher consumption of plant foods and lower or no intake of animal foods, have raised concerns about their potential harmful effect on bone health related to the shortfalls of a vegetarian diet,” Mercedes Sotos-Prieto, PhD, a nutrition epidemiologist at the University Autonomous of Madrid and adjunct professor at the Harvard T.H. Chan School of Public Health, and colleagues wrote. “Previous research supports the benefits of a healthful plant-based diet for different health outcomes. However, evidence is limited about the association between the plant-based diet index and risk of fractures.”

Sotos-Prieto and colleagues conducted a cohort study evaluating data from 70,285 postmenopausal women (mean age, 54.9 years) from the U.S. Nurses’ Health Study from 1984 to 2014. All participants self-reported hip fractures on biennial questionnaires, and researchers assessed diet every 4 years using a validated semiquantitative food frequency questionnaire. Researchers assessed plant-based diet quality with the healthful plant-based diet index (hPDI), which gives positive scores for healthy plant foods and worse scores for less healthy plant foods and animal products, and the unhealthful plant-based diet index (uPDI), which gives positive scores for less healthy plant foods and worse scores for healthy plant foods and animal products.

Overall, 2,038 hip fracture cases occurred during the study period and during follow-up of 30 years. Long-term diet adherence assessed by both the hPDI (HR = 0.97; 95% CI, 0.83-1.14) and the uPDI (HR = 1.02; 95% CI, 0.87-1.2) were not associated with hip fracture risk in this cohort.

In addition, when examining recent intake for the highest vs. lowest quintiles, the hPDI was associated with a 21% lower risk for hip fracture (HR = 0.79; 95% CI, 0.68-0.92; P for trend = .02) and the uPDI was associated with a 28% higher risk for hip fracture (HR = 1.28; 95% CI, 1.09-1.51; P for trend = .008).

“Future research should clarify whether the results for recent dietary intake are associated with the relatively short-term effects of these dietary patterns, reverse causality or both,” the researchers wrote.