Vegetarian and vegan diets and risks of total and site-specific fractures: results from the prospective EPIC-Oxford study

Abstract

Background There is limited prospective evidence on possible differences in fracture risks between vegetarians, vegans, and non-vegetarians. We aimed to study this in a prospective cohort with a large proportion of non-meat eaters. Methods In EPIC-Oxford, dietary information was collected at baseline (1993–2001) and at follow-up (≈ 2010). 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). Outcomes were identified through linkage to hospital records or death certificates until mid-2016. 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. clavicle, rib, and vertebra, n = 467) by diet group over an average of 17.6 years of follow-up. Results Compared 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. The vegans also had higher risks of total (1.43; 1.20–1.70), leg (2.05; 1.23–3.41), and other main site fractures (1.59; 1.02–2.50) than meat eaters. 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. 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. Conclusions Non-meat eaters, especially vegans, had higher risks of either total or some site-specific fractures, particularly hip fractures. 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.

Nutrient Intake and Status of German Children and Adolescents Consuming Vegetarian, Vegan or Omnivore Diets: Results of the VeChi Youth Study

“…Mean calcium intake was lowest in the vegan group with intermediate values in the vegetarian subgroup. Studies indicate that vegetarian, including vegan, adults have a lower bone mineral density [ 49 ] and a higher risk for fractures [ 50 ]. Two cross-sectional studies confirmed a lower bone mineral density among vegetarian and/or vegan children [ 12 , 14 ].…”

A Critical Appraisal of the Evidence Supporting Consumer Motivations for Alternative Proteins

“…Several short-term trials are already ongoing [ 161 ] with some raising concerns about changes in bone mineral density [ 65 ] when substituting meat with plant-based foods. A recent prospective study on the EPIC-Oxford cohort found that compared to meat eaters, hip fracture risk was higher in fish eaters, vegetarians and vegans—with vegans carrying the highest risks of total, hip, leg, and vertebral fractures [ 162 ]. This was likely due to lower BMI and lower intakes of calcium and protein, though further studies are needed.…”

NMR Metabolite Profiles in Male Meat-Eaters, Fish-Eaters, Vegetarians and Vegans, and Comparison with MS Metabolite Profiles

“…Prospective epidemiological evidence suggests that individuals excluding some (e.g., fish-eaters and vegetarian) or all animal products (vegans) from their diets may have different risks of some major non-communicable diseases compared to meat-eaters. This includes lower risks of coronary heart disease [ 2 , 3 , 4 ], some cancers [ 5 , 6 , 7 , 8 ], and diabetes [ 9 , 10 ] but possibly an increased risk of stroke [ 4 ] and fractures [ 11 ], in some or all of the non-meat-eating diet groups. Metabolomics has the potential to reveal underlying mechanisms in such diet-disease relationships [ 12 ], because metabolite concentrations reflect dietary, lifestyle, environmental and genetic factors as well as disease states [ 13 ].…”