Pamela Cruz. Peninsula 360 Press
Compared to meat eaters, vegans have an increased risk of total, hip, leg and vertebral fractures, while fish eaters and vegetarians only have an increased risk of hip fractures, according to the prospective EPIC-Oxford study.
The paper, published Sunday in the journal BMC Medicine, reports that these risk differences were probably due, in part, to their lower Body Mass Index (BMI) and possibly lower calcium and protein intake.
Previously, according to epidemiological studies, it was known that vegetarians had lower bone mineral density - BMD - than non-vegetarians, but the associations of vegetarian diets with fracture risks were unclear.
For the study, 54,898 men and women from across the UK were recruited between 1993 and 2001, through general practice or a postal questionnaire; of these, 30,391 maintained the same type of diet for 14 years.
Thus, the study, which concluded in 2010 and obtained results during 17.6 years of the participants' lives, was divided into four diet groups: 29,380 meat eaters, 8,377 fish eaters, 15,499 vegetarians and 1,982 vegans.
Compared to meat eaters, and after adjustment for socioeconomic factors, lifestyle confounders, and BMI, hip fracture risks were higher in fish eaters, vegetarians, and vegans.
Vegans also had higher risks of total, leg and other fractures compared to meat eaters. Overall, he notes, the significant associations appeared to be stronger without an adjustment for BMI and attenuated slightly, but remained significant, with an additional adjustment for dietary calcium or total protein.
Apart from this, no significant differences were observed in the risks of wrist or ankle fractures by diet group with or without BMI adjustment, nor for arm fractures after BMI adjustment.
In that sense, the study concludes that people who do not eat meat, especially vegans, had a higher risk of total fractures or fractures in specific areas, particularly in the hip.
Similarly, he explains that more studies are needed, especially of non-European and contemporary populations, to examine the generality of the findings and explore possible heterogeneity by factors including age, sex, menopausal status, and BMI.
"Future work could benefit from examining possible biological pathways by investigating serum levels of vitamin D, B12 or Insulin-like Growth Factor-1 -IGF-1-, or by assessing the possible roles of other nutrients that are abundant in animal foods," he says.
This is the first prospective study of a diet group with specific total and multiple fractures in vegetarians and vegans, and the findings suggest that bone health in vegans requires further investigation.
