Vegetarian Women Have a Higher Risk of Hip Fracture

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A study of more than 26,000 middle-aged British women reveals that those with a vegetarian diet had a 33% increased risk of hip fracture compared to regular carnivores.

The University of Leeds research, published in the journal BMC Medicine , investigated the risk of hip fracture in casual carnivores; Pescatarians, people who eat fish but not meat; and vegetarians compared to usual carnivores.

Among 26,318 women, 822 cases of hip fracture were observed over approximately 20 years , which represented just over 3% of the sample population. After adjustment for factors such as smoking and age, vegetarians were the only diet group with an elevated risk of hip fracture.

This study is one of the few studies comparing the risk of hip fracture in vegetarians and carnivores in which the occurrence of hip fracture was confirmed from hospital records.

Scientists emphasize the need for more research into the exact causes of why vegetarians had a higher risk of hip fracture.

Main findings

Vegetarians, but not occasional carnivores or pescetarians, had a higher risk of hip fracture than regular carnivores in this cohort of UK women. There was no clear evidence of effect modification by BMI between diet groups. The risk differences remained after accounting for confounding factors and were not explained by differences in intake of key nutrients related to bone health between vegetarians and regular meat-eaters, implying the potential importance of other unaccounted factors. .

Vegetarian diets can be "healthy or unhealthy"

Lead author of the study, James Webster, a doctoral researcher at the Leeds School of Food Sciences and Nutrition, said: “Our study highlights potential concerns about the risk of hip fracture in women who eat a vegetarian diet. However, it does not warn people to abandon vegetarian diets. As with any diet, it is important to understand your personal circumstances and what nutrients are needed for a healthy, balanced lifestyle.

“Vegetarian diets can vary greatly from person to person and may or may not be healthy, as can diets that include animal products. Worryingly, however, vegetarian diets often have lower intakes of nutrients that are linked to bone and muscle health. “These types of nutrients are generally more abundant in meat and other animal products than in plants, such as protein, calcium, and other micronutrients.”

“Low intake of these nutrients can lead to lower bone mineral density and muscle mass , which can make you more susceptible to the risk of hip fracture. “This makes it especially important for future research to better understand the factors driving increased risk in vegetarians, whether deficiencies of particular nutrients or weight control, so we can help people make healthy choices.”

Plant-based diets are growing in popularity

Vegetarian diets have grown in popularity in recent years, with a 2021 YouGov survey putting the size of the UK’s vegetarian population at approximately 5-7%. It is often perceived as a healthier dietary choice, with previous evidence showing that a vegetarian diet can reduce the risks of several chronic diseases, such as diabetes, heart disease and cancer compared to omnivorous diets.

There is also a global call to reduce the consumption of animal products in an effort to address climate change. Therefore, understanding the risk of hip fracture in vegetarians is increasingly important for public health.

Study co-author Professor Janet Cade, leader of the Nutritional Epidemiology Group at Leeds School of Food and Nutrition Sciences, said: "Hip fracture is a global health problem with high economic costs causing loss of independence, reduces quality of life, and increases the risk of other health problems.

“Plant-based diets have been linked to poor bone health , but evidence on links to hip fracture risk has been lacking. “This study is an important step in understanding the potential risk that plant-based diets could pose in the long term and what can be done to mitigate those risks.”

The team used data from the UK Women’s Cohort Study to investigate possible links between diet and hip fracture risk. The National Cohort of Midlife Women was established at the University of Leeds to explore the links between diet and chronic disease, covering a wide range of different eating patterns. Dietary information was collected using a food frequency questionnaire and validated using a 4-day food diary in a subsample of women.

At the time they were recruited for the cohort study, the women were between 35 and 69 years of age.

Effect of low BMI

The research team found that the average BMI among vegetarians was slightly lower than the average among regular meat-eaters. Previous research has shown a relationship between low BMI and high risk of hip fracture.

A lower BMI may indicate that people are underweight , which can mean poorer bone and muscle health and a higher risk of hip fracture. More research is needed to determine whether low BMI is the reason for the increased risk seen in vegetarians.

Study co-author Dr Darren Greenwood, a biostatistician at Leeds Medical School, said: “This study is just one part of the bigger picture of diet and healthy bones and muscles in old age.

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