Unraveling the role of BMI and blood markers in the relationship between plant-based diets and osteoporosis: A prospective cohort study

Background

The potential adverse effects of plant-based diets on bone health have raised significant concern, while the prospective evidence is limited. This study aimed to evaluate the association between plant-based diet indexes and incident osteoporosis while exploring the underlying mechanisms involved in this relationship.

Methods

The analysis included 202,063 UK Biobank participants conducted between 2006 and 2022. Plant-based diet indexes (hPDI and uPDI) were calculated using the 24-h dietary questionnaire. Cox proportional risk regression and mediation analysis were used to explore the associations of plant-based diet indexes with osteoporosis, estimating the contribution of BMI and blood markers.

Results

We found the highest quintile for hPDI (HR = 1.16; 95% CI: 1.05 to 1.28) and uPDI (HR = 1.15; 95% CI: 1.05 to 1.26) were associated with an increased risk of osteoporosis. BMI was identified as an important mediator in the association between hPDI and osteoporosis, with mediation proportions of 46.17%. For blood markers, the mediating (suppressing) effects of C-reactive protein, alkaline phosphatase, and insulin-like growth factor-1 on the association between uPDI (hPDI) and osteoporosis were significant, ranging from 5.63%–16.87% (4.57%–6.22%).

Conclusion

Adherence to a plant-based diet is associated with a higher risk of osteoporosis, with BMI and blood markers potentially contributing to this relationship. Notably, even a healthy plant-based diet necessitates attention to weight management to mitigate its impact on bone loss. These findings emphasize the importance of personalized dietary recommendations and lifestyle interventions to decrease the risk of osteoporosis.