In addition, BMI is also an important factor for fracture risk, and a recent study suggested that the lower BMD observed in US vegetarians might be largely explained by their lower BMI and waist circumference. For protein, while older studies suggested that high protein intake might lead to higher calcium excretion and therefore weaker bones, more recent evidence has suggested a positive association between protein and bone health, although this might not translate to differences in fracture risk. However, a recent meta-analysis of randomised trials showed that combined vitamin D and calcium supplementation, but not vitamin D supplementation alone, was effective in fracture prevention, therefore supporting the importance of calcium. For calcium, although previous meta-analyses have found that calcium supplements are effective in producing small increases in BMD, it is less clear whether this degree of improvement would be sufficient to reduce fracture risks.
Prior studies have linked both calcium and protein intakes to bone health, but their relationships with fracture risks are nuanced. Potential risk differences are plausible however, owing to differences in several dietary factors, such as the substantially lower intakes of calcium in vegans, lower intakes of dietary protein in both vegetarians and vegans, and the lower body mass index (BMI) of non-meat eaters. Previous epidemiological studies have shown that vegetarians had lower bone mineral density (BMD) than non-vegetarians, but the associations of vegetarian diets with fracture risks are unclear. This is the first prospective study of diet group with both total and multiple specific fracture sites in vegetarians and vegans, and the findings suggest that bone health in vegans requires further research.įractures in adulthood and older ages are a common occurrence which pose a significant burden to health systems worldwide. Non-meat eaters, especially vegans, had higher risks of either total or some site-specific fractures, particularly hip fractures. No significant differences were observed in risks of wrist or ankle fractures by diet group with or without BMI adjustment, nor for arm fractures after BMI adjustment. Overall, the significant associations appeared to be stronger without adjustment for BMI and were slightly attenuated but remained significant with additional adjustment for dietary calcium and/or total protein. ResultsĬompared with meat eaters and after adjustment for socio-economic factors, lifestyle confounders, and body mass index (BMI), the risks of hip fracture were higher in fish eaters (hazard ratio 1.26 95% CI 1.02–1.54), vegetarians (1.25 1.04–1.50), and vegans (2.31 1.66–3.22), equivalent to rate differences of 2.9 (0.6–5.7), 2.9 (0.9–5.2), and 14.9 (7.9–24.5) more cases for every 1000 people over 10 years, respectively. clavicle, rib, and vertebra, n = 467) by diet group over an average of 17.6 years of follow-up. Using multivariable Cox regression, we estimated the risks of total ( n = 3941) and site-specific fractures (arm, n = 566 wrist, n = 889 hip, n = 945 leg, n = 366 ankle, n = 520 other main sites, i.e. Outcomes were identified through linkage to hospital records or death certificates until mid-2016. Participants were categorised into four diet groups at both time points (with 29,380 meat eaters, 8037 fish eaters, 15,499 vegetarians, and 1982 vegans at baseline in analyses of total fractures). In EPIC-Oxford, dietary information was collected at baseline (1993–2001) and at follow-up (≈ 2010).
We aimed to study this in a prospective cohort with a large proportion of non-meat eaters. There is limited prospective evidence on possible differences in fracture risks between vegetarians, vegans, and non-vegetarians.