BACKGROUND AND PURPOSE:

• Previous studies have identified a higher risk of fractures associated with plant-based diets although there is limited data regarding the quality of these diets
• Sotos-Prieto et al. (Jama Network Open, 2024) examined the association between the quality of plant-based diets and hip fracture risk among postmenopausal women

METHODS:

• Retrospective cohort study
  • US Nurses’ Health Study
  • Between 1984 to 2014
• Population
  • Postmenopausal women
• Exposures
  • Quality of plant-based diet
• Study design
  • Diet was assessed every 4 years using a validated questionnaire
  • Diet quality was assessed using 2 established indices
    • Healthful Plant-Based Diet Index (hPDI)
      • Positive scores given to healthy plant foods (e.g. whole grains, fruits, vegetables, nuts, legumes, etc.)
      • Negative scores given to less healthy plant foods (fruit juices, sweetened beverages, refined grains, potatoes, and sweets or desserts) and animal foods
    • Unhealthful Plant-Based Diet Index (uPDI)
      • Positive scores given to less healthy plant foods
      • Negative scores given to healthy plant and animal foods
  • Quintile scores of 18 food groups were summed
    • Range for both indices: 18 to 90 (highest adherence)
  • Cox proportional hazards regression with time-varying covariates used to compute hazard ratios (HR)
• Primary outcome
  • Hip fractures

RESULTS:

• 70,285 participants
  • Mean age 54.92 (SD, 4.48) years | White: 100%
• For long-term diet adherence, neither quality measure was associated with hip fracture risk
  • hPDI (higher scores = more healthy)
    • HR (highest vs lowest quintile) 0.97 (95% CI, 0.83 to 1.14)
  • uPDI (higher scores = less healthy)
    • HR 1.02 (95% CI, 0.87 to 1.20)
• However, for recent intake (baseline diet) higher hPDI was associated with a lower risk of hip fracture, and higher uPDI was associated with a higher risk (P_trend=0.008)
  • hPDI
    • HR (highest vs lowest quintile) 0.79 (95% CI, 0.68 to 0.92)
  • uPDI
    • HR 1.28 (95% CI, 1.09 to 1.51)

CONCLUSION:

• Long-term adherence to a healthy plant-based diet by postmenopausal women was not associated with any changes in risk of hip fracture, compared to an unhealthy plant-based diet
• The authors state

The results of this cohort study indicated that long-term adherence to a plant-based diet was not associated with hip fracture risk. 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

Learn More – Primary Sources:

Plant-Based Diets and Risk of Hip Fracture in Postmenopausal Women