A study of over 26,000 middle-aged UK women conducted by the University of Leeds reveals those who follow a vegetarian diet had a 33% higher risk of hip fracture compared to meat-eaters.
The study, published in the journal BMC Medicine, compared the hip fracture risk among women who were described as ‘occasional’ meat eaters, pescatarians who eat fish but not meat, vegetarians and ‘regular’ meat eaters who consume meat at least five times a week.
Among 26,318 women, 822 hip fracture cases were observed over roughly 20 years – that 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, the researchers concluded.
“Our study highlights potential concerns regarding risk of hip fracture in women who have a vegetarian diet,” observed lead author James Webster, a doctoral researcher from the School of Food Science and Nutrition at Leeds.
Webster stressed he isn’t ‘warning people to abandon vegetarian diets’ and emphasised that these can be both healthy and unhealthy depending on the choices made by the individual following that diet.
“As with any diet, it is important to understand personal circumstances and what nutrients are needed for a balanced healthy lifestyle,” the nutrition expert said. “Vegetarian diets can vary widely from person to person and can be healthy or unhealthy, just like diets that include animal products.”
Nevertheless, he did note some ‘concerning’ areas that people should be aware of. “It is concerning that vegetarian diets often have lower intakes of nutrients that are linked with bone and muscle health. These types of nutrients generally are more abundant in meat and other animal products than in plants, such as protein, calcium, and other micronutrients.”
What are the health implications of diets that are lower in these nutrients?
“Low intake of these nutrients can lead to lower bone mineral density and muscle mass, which can make you more susceptible to hip fracture risk,” Webster said.
Plant-based popularity and the implications for public health
Vegetarian diets have gained popularity in recent years. In the UK, a 2021 YouGov survey found 5-7% of Brits now identify as vegetarian.
This dietary choice is often viewed as a healthier and more sustainable option. Evidence has linked a vegetarian diet to reduced risk of several chronic diseases, including diabetes, heart disease, and cancer compared to omnivorous diets. Reduced meat consumption has also been linked to efforts to tackle climate change and cut the carbon footprint of food.
The Leeds scientists believe that understanding hip fracture risk in vegetarians is therefore becoming increasingly important to public health.
“Hip fracture is a global health issue with high economic costs that causes loss of independence, reduces quality of life, and increases risk of other health issues,” explained study co-author Professor Janet Cade, leader of the Nutritional Epidemiology Group in the School of Food Science and Nutrition at Leeds.
“Plant-based diets have been linked with 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 risk plant-based diets could present over 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 middle-aged women was established at the University of Leeds to explore links between diet and chronic disease, encompassing a wide range of different eating patterns. Dietary information was collected using a food frequency questionnaire and was validated using a 4-day food diary in a subsample of women.
At the time they were recruited into the cohort study, the women ranged in age from 35 to 69 years.
Vegetarians have lower average BMI
In addition to the higher hip fracture risk, another interesting trend was noted. The research team found that the average BMI among vegetarians was slightly lower than the average among the regular meat eaters. Previous research has shown a link between low BMI and a high risk of hip fracture, they said.
Lower BMI can indicate people are underweight, which can mean poorer bone and muscle health, and higher risk of hip fracture. Further investigation is needed to determine if low BMI is the reason for the observed higher risk in vegetarians.
“This study is just part of the wider picture of diet and healthy bones and muscles in older age,” co-author Dr Darren Greenwood, a biostatistician in the School of Medicine at Leeds, said. “Further research is needed to confirm whether there could 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.”
Webster agreed: “It [is] especially important for further research to better understand factors driving the increased risk in vegetarians, whether it be particular nutrient deficiencies or weight management, so that we can help people to make healthy choices.”
‘Risk of hip fracture in meat-eaters, pescatarians, and vegetarians: results from the UK Women’s Cohort Study’