Investigating Racial Differences in Diet Benefits for Knee Osteoarthritis

NCT04343716 | Completed Results

• 2 other identifiers: IRB-3000051455P30AG031054-13
• Study Type: interventional
• Target: 19
• Locations: 1 country
• Sites: 1

Brief Summary

Knee osteoarthritis (OA) is the most prevalent form of arthritis and race is a risk factor for poor outcomes. African-Americans (AAs) report greater OA-related disability and pain severity compared to their Non-Hispanic White (NHW) counterparts. These disparities are reinforced through social and biological mechanisms, ultimately resulting in dramatic racial disparities in pain experience and associated quality of life. Low-carbohydrate diets (LCDs) reduce inflammation and pain independent of weight loss, but significant racial differences exist in metabolism that are rarely addressed in diet interventions. The overall objective of the proposed study is to determine whether the beneficial effects of an LCD for knee OA pain are related to race. The investigators will recruit 20 adult women (65-75) with knee OA with equal representation across racial groups (10 AA, 10 NHW). Following one week of diet and pain self-report, the investigators will assess quality of life, depression, experienced pain and evoked pain. Participants will be placed on a LCD wherein all meals and snacks will be delivered weekly after consult with study personnel. Participants will return every 3 weeks for testing during the 6-week intervention with blood drawn at baseline and at the conclusion of the 6-week diet. Blood will be assayed for oxidative stress markers. This will be the first assessment of racial differences in the efficacy of a LCD to reduce knee OA pain. Objective 1: To determine whether the LCD reduces pain after 6 weeks. Hypothesis: The LCD will significantly reduce evoked and self-reported pain. Objective 2: To determine whether the benefits of the LCD differ based on race. Hypothesis 1: The LCD will reduce evoked and self-reported pain more in AA than in NHW. Hypothesis 2: AAs will experience greater improvements in depression, quality of life, pain interference and show more weight loss than NHWs. Objective 3: To determine whether the LCD has a differential impact on oxidative stress by race. Hypothesis 1: The LCD will significantly reduce oxidative stress over 6 weeks. Hypothesis 2: AAs will show greater reductions in oxidative stress than NHWs. The reduction in oxidative stress will be correlated with reduction in evoked pain.

Conditions

Knee Osteoarthritis

Keywords

diet; chronic pain; knee osteoarthritis; racial differences

Outcome Measures

Primary Outcomes (2)

• WOMAC Pain Change

  The Western Ontario and McMaster Osteoarthritis Index (WOMAC) pain score is a 0-20 score with higher scores reflecting more severe pain. Questions 1-5 are summed to provide a WOMAC pain score. Change scores will be calculated. The week 6 WOMAC pain subscale score was subtracted from the baseline score to obtain a difference score. Numbers closer to zero indicate no change.

  Baseline (week 0), immediately after the intervention (6 weeks)

• BPI Pain Change

  The Brief Pain Inventory (BPI) pain score is a 0-40 score with higher scores reflecting more pain. Questions 3-6 are scored on 0-10 and are summed to provide an overall pain score. The week 6 score was subtracted from the baseline score to obtain a difference score. Numbers closer to zero indicate no change.

  Baseline (week 0), immediately after the intervention (6 weeks)

Secondary Outcomes (5)

• WOMAC Physical Function

  Baseline (week 0), immediately after the intervention (6 weeks)

• BPI Pain Interference Change

  Baseline (week 0), immediately after the intervention (6 weeks)

• TS Pain Intensity Change

  Baseline (week 0), immediately after the intervention (6 weeks)

• RCS Pain Intensity Change

  Baseline (week 0), immediately after the intervention (6 weeks)

• PHQ-9 Depression Change

  Baseline (week 0), immediately after the intervention (6 weeks)

Other Outcomes (5)

• RCS Time to Completion Change

  Baseline (week 0), immediately after the intervention (6 weeks)

• TW Pain Intensity Change

  Baseline (week 0), immediately after the intervention (6 weeks)

• TW Time to Completion Change

  Baseline (week 0), immediately after the intervention (6 weeks)

Study Arms (2)

White women

EXPERIMENTAL

White women aged 65-75 with knee OA

Behavioral: Low-carbohydrate diet

Black women

EXPERIMENTAL

Black women aged 65-75 with knee OA

Behavioral: Low-carbohydrate diet

Interventions

Low-carbohydrate diet BEHAVIORAL

A diet low in daily carbohydrates (\<40 grams/day) provided as prepared meals.

Black women; White women

Eligibility Criteria

• Age: 65 Years - 75 Years
• Sex: female
• Healthy Volunteers: No
• Age Groups: Older Adult (65+)

You may qualify if:

• diagnosis of knee OA
• pain in at least 4/7 days/week for the past 3 months
• age between 65-75
• average daily consumption of \>100 g carbohydrates
• understanding of verbal and written English
• self-identification as either AA or NHW
• BMI between 25 and 40 kg/m2

You may not qualify if:

• diabetes
• unwillingness to follow prescribed diets
• recent weight change (\>4 kg in past month)
• currently on a diet
• history of eating disorders or other psychiatric disorders
• digestive diseases
• difficulty chewing or swallowing
• reliance on others for meal preparation
• cardiovascular or pulmonary disease
• daily opioid pain medications
• use of medications known to alter metabolism or digestion (e.g., proton-pump inhibitors)
• use of anti-hypertensive medications that affect glucose tolerance
• use of tobacco
• participation in extreme exercise
• knee replacement

Sponsors & Collaborators

• University of Alabama at Birmingham: lead
• National Institute on Aging (NIA): collaborator

Study Sites (1)

University of Alabama at Birmingham

Birmingham, Alabama, 35294, United States

Location

Related Publications (2)

• Strath LJ, Jones CD, Philip George A, Lukens SL, Morrison SA, Soleymani T, Locher JL, Gower BA, Sorge RE. The Effect of Low-Carbohydrate and Low-Fat Diets on Pain in Individuals with Knee Osteoarthritis. Pain Med. 2020 Jan 1;21(1):150-160. doi: 10.1093/pm/pnz022.

  PMID: 30865775 RESULT

• Wiggins AM, Strath LJ, McPherson GE, Gower BA, Goss AM, Goodin BR, Sorge RE. The effect of a low-carbohydrate diet on evoked pain and quality of life in Non-Hispanic black women with knee osteoarthritis: a pilot study. BMC Musculoskelet Disord. 2024 Dec 19;25(1):1043. doi: 10.1186/s12891-024-08170-x.

  PMID: 39702235 DERIVED

MeSH Terms

Conditions

Osteoarthritis, Knee; Chronic Pain

Interventions

Diet, Carbohydrate-Restricted

Condition Hierarchy (Ancestors)

Osteoarthritis; Arthritis; Joint Diseases; Musculoskeletal Diseases; Rheumatic Diseases; Pain; Neurologic Manifestations; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Diet Therapy; Nutrition Therapy; Therapeutics; Diet; Nutritional Physiological Phenomena; Diet, Food, and Nutrition; Physiological Phenomena

Limitations and Caveats

This was a pilot study with a small sample size. Due to recruiting issues around the pandemic and after, we were not able to recruit NWH women into the study in numbers to allow for our planned analyses. Thus, the resulting investigation was determined to be focused on NHB women and assessed as pre-post analyses. Blood samples were not taken, so physiological measures were not possible.

Results Point of Contact

• Title: Dr. Robert Sorge
• Organization: University of Alabama at Birmingham

rsorge@uab.edu

2059348563

Study Officials

• Robert E Sorge, PhD

  University of Alabama at Birmingham

  PRINCIPAL INVESTIGATOR

Publication Agreements

• PI is Sponsor Employee: No
• Restrictive Agreement: No

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Associate Professor

Model Details: All participants assigned to a single diet intervention. Between-groups differences and within-group changes will be assessed.

Study Record Dates

• First Submitted: April 6, 2020
• First Posted: April 13, 2020
• Study Start: October 1, 2020
• Primary Completion: September 18, 2023
• Study Completion: September 18, 2023
• Last Updated: January 9, 2025
• Results First Posted: January 9, 2025

Record last verified: 2024-12

Data Sharing

• IPD Sharing: Will share
• Shared Documents: STUDY PROTOCOL, SAP
• Time Frame: For 5 years following final data analysis
• Access Criteria: De-identified data can be made available on encrypted servers for researchers whose research plans do not overlap with the aims of the current project. Requests will be assessed by the PI and Co-Is as needed.

Locations

US (1)