Vegetarian women have a 33 percent higher risk of hip fracture, 20-year study findings

X-ray of the pelvic bone of a woman.

Here’s the problem ma’am, it’s all that broccoli you’re eating. Image credit: Alona Siniehina/Shutterstock

There are many good reasons to become a vegetarian or vegan: some do it for ethical reasons; others for health benefits; and some as a way to help mitigate the climate crisis. But even the most die-hard plant eaters will rarely point to the diet’s effect on bone and muscle density as motivation. According to a new study, published today in the journal BMC Medicine, vegetarian women have a 33 percent higher risk of hip fracture than meat eaters – but are the results as clear cut as they sound?

“Our study highlights potential concerns regarding hip fracture risk in women on a vegetarian diet. However, it does not warn people to abandon vegetarian diets,” explained James Webster, a PhD researcher from the School of Food Science and Nutrition at the University of Leeds and lead author of study, in a statement.

“As with any diet, it’s important to understand personal circumstances and what nutrients are needed for a balanced healthy lifestyle,” he said. “Vegetarian diets can vary greatly from person to person and can be healthy or unhealthy, just like diets that include animal products.”

The study followed 26,318 women over a period of around 20 years. All had filled out a food frequency questionnaire originally sent out by the World Cancer Research Fund in the mid-90s, allowing the researchers to sort them into three groups: meat eaters, pescatarians and vegetarians.

Over the entire period, 822 hip fractures were registered in the study cohort – approximately three percent of the total group. After accounting for variables such as age, physical activity level, socio-economic status, lifestyle factors such as smoking and so on, one group stood out above the rest as uniquely likely to suffer from hip fractures: the vegetarians.

“Hip fractures are a global health problem with high economic costs that cause loss of independence, reduce quality of life and increase the risk of other health problems,” said study co-author Janet Cade, professor in the Nutritional Epidemiology Group at the University of Leeds.

“Plant-based diets have been linked to poor bone health, but there has been a lack of evidence on the links to hip fracture risk. This study is an important step in understanding the potential long-term risks of plant-based diets and what can be done to to reduce these risks.”

An infographic about the results

Image credit: University of Leeds

So the correlation was certainly there – but what about causation? Well, here’s where things get a little tricky. While it is true that vegetarian diets often have lower levels of nutrients such as protein, calcium, and other micronutrients linked to bone and muscle health, the study notes that the differences in risk between meat eaters and vegetarians “were not explained by differences in key nutrient-related intakes.” to bone health between vegetarians and regular meat eaters, suggesting the potential importance of other obscure factors.”

One of these factors may be the difference in BMI between the two groups: vegetarians have, on average, a lower BMI than meat eaters, and this has been shown to increase a person’s risk of hip fracture.

Then there are the factors that were beyond the scope of the study: “supplementary sources of specific nutrients and circulating vitamin D concentrations may differ between vegetarians and non-vegetarians and may influence hip fracture risk,” the study notes, “but cannot be accounted for in this the analysis due to lack of data.”

The same is true for certain hormones associated with hip fracture risk – they may have been a factor between the groups, but the researchers simply did not have the information to assess them.

“This study is only part of the broader picture of diet and healthy bones and muscles in old age,” pointed out biostatistician and study co-author Darren Greenwood.

“Further research is needed to confirm whether there may be similar results in men, to explore the role of body weight, and to identify the reasons for different outcomes in vegetarians and meat eaters.”

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