Dietary Patterns and Hip Fracture Risk in the UK Biobank

Risk of Hip Fracture in Meat-eaters, Pescatarians, and Vegetarians in the UK Biobank

Hip fracture is a common serious injury in older adults that reduces mobility, independence, and quality of life, and can lead to premature death. Around 1.6 million cases occur globally per year, and continual increases in the number of older adults worldwide suggests that cases could reach 4.5 million by 2050. Diet can affect bone health and risk of hip fracture, with varying risks in adults on specific diets. There is some evidence that vegetarians may have poorer bone health and higher risks of fractures than meat-eaters, but prospective evidence for hip fractures is limited, and the influence of factors including diet quality and body mass index (BMI) are unclear.

The main aim of this research is to investigate risk of hip fracture in occasional meat-eaters, pescatarians, and vegetarians compared to regular meat-eaters. A secondary aim is to determine if risk of hip fracture in these diet groups depends on age, sex, diet quality, body mass index, and diet-gene interactions. Thirdly, we will explore the role of potential factors underpinning any risk differences, such as BMI, bone mineral density, and intake of nutrients that are mostly found in animal-sourced foods. The purpose of this study is to better understand hip fracture risk in vegetarian UK adults. The proposed project will use existing diet and lifestyle data from the UK Biobank resource, and hospital records of hip fractures.

Study Overview

• Status: Completed
• Conditions: Hip Fractures
• Intervention / Treatment: Other: Dietary pattern observed

Detailed Description

Background:

Hip fracture is an increasingly prevalent health problem in the UK and worldwide that increases morbidity and mortality. Previous epidemiological evidence suggests that compared to meat-eaters, people following plant-based diets have lower bone mineral density (BMD) and a higher risk of fractures. Emerging evidence suggests a higher risk of hip fracture in vegetarian women, but prospective evidence of hip fracture risk in these diet groups is scarce and limited, particularly in men. Risk differences between diet groups are plausible in men and women, for example due to bone or muscle-related nutrient deficiencies or low BMI in vegetarians, but underlying mechanisms explaining potential risk differences require further investigation.

This study aims to investigate risk of hip fracture in occasional meat-eaters, pescatarians, and vegetarians compared to regular meat-eaters in the UK Biobank cohort. A secondary aim is to determine the role of potential modifying factors on associations between each diet group and hip fracture risk, including diet quality (determined by adherence to the Alternative Healthy Eating Index, AHEI), age, sex, and BMI, as well as investigating interactions between diet groups and genotypes on BMD and hip fracture risk. Thirdly, we aim to determine the role of potential mediating factors on any observed associations, including BMI, BMD, and intake of dietary nutrients abundant in animal products.

Research plan and methods:

The investigators will utilise dietary and lifestyle data from the UK Biobank cohort, which recruited over 500,000 adults between 2006-2010, and linked hospital records of UK Biobank participants to identify hip fracture cases.

A Cox regression model will be applied to investigate risk of hip fracture in each diet group compared to regular meat-eaters, and will be adjusted for relevant confounders. The roles of age, sex, AHEI score, BMI, and diet-gene interactions as potential effect modifiers will be explored by adding each variable to Cox regression models as interaction terms. Causal mediation analysis will be used to determine the role of potential mediators.

• Study Type: Observational
• Enrollment (Actual): 500000

Contacts and Locations

Study Locations

• United Kingdom
  • West Yorkshire
    • Leeds, West Yorkshire, United Kingdom, LS2 9JT
      • University of Leeds

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 40 years to 70 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

• Sampling Method: Non-Probability Sample

Study Population

Information on the UK Biobank cohort profile is available here: https://www.ukbiobank.ac.uk/

Description

Inclusion Criteria:

• Male or female
• Ages 40 to 70 years at time of recruitment
• Able to provide informed consent

Exclusion Criteria:

• Unable to link dietary and lifestyle data with hospital episode statistics
• Had a hip fracture or osteoporosis before or no the date of recruitment
• Withdrew consent during the study period
• Genetic sex differs to reported sex
• Outlier diet or anthropometric data (energy intake <500 or >5000 kcal/day or body mass index <10 or >60 kg/m2

Study Plan

How is the study designed?

Design Details

• Observational Models: Cohort
• Time Perspectives: Prospective

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
UK Biobank; UK Biobank. There are no interventions in this observational cohort study.	Other: Dietary pattern observed; Dietary pattern: regular meat-eater, occasional meat-eater, pescatarian, and vegetarian. There are no interventions in this observational cohort.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Hip fracture incidence (first)	First incidence of hip fracture, identified from all relevant ICD diagnosis codes and treatment codes identified through linked HES data.	Age when the completed questionnaire was returned (2006-2010) until age at event, death, or end of study period (2021).

Collaborators and Investigators

• Sponsor: University of Leeds

Publications and helpful links

General Publications

• Webster J, Greenwood DC, Cade JE. Risk of hip fracture in meat-eaters, pescatarians, and vegetarians: a prospective cohort study of 413,914 UK Biobank participants. BMC Med. 2023 Jul 27;21(1):278. doi: 10.1186/s12916-023-02993-6.

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2006
• Primary Completion (Actual): September 30, 2021
• Study Completion (Actual): July 31, 2023

Study Registration Dates

• First Submitted: September 21, 2022
• First Submitted That Met QC Criteria: September 21, 2022
• First Posted (Actual): September 26, 2022

Study Record Updates

• Last Update Posted (Estimated): December 6, 2023
• Last Update Submitted That Met QC Criteria: November 29, 2023
• Last Verified: November 1, 2023

More Information

Terms related to this study

• Keywords: Cohort study; Nutrition; Epidemiology; Osteoporosis; Fracture; Vegetarian
• Additional Relevant MeSH Terms: Wounds and Injuries; Leg Injuries; Femoral Fractures; Hip Injuries; Fractures, Bone; Hip Fractures
• Other Study ID Numbers: 88995

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: IPD from UK Biobank is available to genuine researchers on application (https://www.ukbiobank.ac.uk/enable-your-research/apply-for-access).

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No