Effects of Obesity, Physical Activity, and Nutrient Intake on Knee Osteoarthritis

  • Author / Creator
    Fatemeh Baghbaninaghadehi
  • Osteoarthritis (OA) is a highly prevalent, disabling, and costly disease that affects 1 in 8 (13%) Canadians. In all stages of knee OA, identifying and addressing modifiable risk factors is essential in managing OA, including the recovery trajectory following total knee arthroplasty (TKA). Obesity is the greatest modifiable risk factor for both the development and progression of knee OA, and it is one of the most important predictors for the risk of TKA. Studies to date report conflicting results related to the effectiveness of TKA for patients with obesity. Along with obesity management, diet and physical activity are also repeatedly recommended by the guidelines as modifiable risk factors, yet there are few studies examining the nutritional and activity status of patients with OA in relation to the disease outcomes. Therefore, the assessments and monitoring of physical activity during daily life circumstances and the nutritional status of patients with OA is warranted. This thesis consists of three studies. In the first study, the association between obesity (defined by the World Health Organization (WHO) classification of Body Mass Index (BMI) to normal weight (BMI≤24.99 kg/m2), overweight (25≤BMI≤29.99 kg/m2), obese class I (30≤BMI≤34.99 kg/m2), obese class II (35≤BMI≤39.99 kg/m2), or obese class III (BMI≥40 kg/m2) and comorbidities with complication rates in patients who underwent TKA was examined. Data were extracted from a provincial database of patients who underwent TKA (N=15151) between 2012 and 2016. Results showed that patients in obese class I and II groups were more likely to have pulmonary embolism (p<.001; OR: 2.75 and 2.77, respectively) whereas the patients in obese class III group were more likely to have pulmonary embolism (p<.001; OR: 3.46), deep wound infection (P=.04; OR: 2.25) as well as a trend towards increased risk of readmission (p=.10; OR: 1.32) compared to patients in the normal BMI group. Patients with diabetes, cardiac disease, and circulatory/blood clotting disorders were more likely to have undergone postoperative blood transfusion (p<.001; OR: 1.71, 3.01, and 7.01, respectively), compared to patients without comorbidities. Patients with diabetes and poor mental health were more likely to be readmitted (p<.001; OR: 1.6 and 2.17, respectively), compared to patients without comorbidities. In the second study, we used the same data from the Alberta Bone and Joint Health Institute (ABJHI) repository to investigate the impact of the degree of obesity on patient-reported outcome measures following TKA. Patients who completed the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index (N=7748), as well as the EuroQol-5D (EQ-5D; N=3848) quality of life questionnaire were included in this study. By 12 months postoperatively, there were no differences among BMI groups in terms of WOMAC subscales as well as EQ-5D-5L, and all patients, regardless of BMI group, received similar benefits from surgery (p<.001). In the third study, we used a cross-sectional study design to compare nutrient intake, including the amount of fat and saturated fatty acids (SFA) intakes, and daily physical activity between patients with knee OA (N=57) and healthy controls (N=49). We also examined the association between nutrient intake as well as the amount of daily physical activity with self-reported and performance-based measures. Results revealed that patients with OA had less steps/day compared to the control group (5319±432 versus 6839±483 steps/day, p=.04) after adjusting for sex, age, and BMI. Compared to the control group, patients with OA had significantly higher energy-adjusted SFA (p=.04; 250±13.1 and 204±14.8 gr/day, respectively) and trans fatty acids (TFA) intake (p=.05; 1.43±0.15 and 0.91±0.20 gr/day, respectively). Increased SFA intake was associated with greater pain and worse physical function measured using both self report WOMAC (pain and function subscales) and Lower Extremity Function Score (LEFS), as well as a performance-based 6-minute walk test (6MWT) distance. Increased TFA intake was associated with worse WOMAC pain and function, total, and shorter 6MWT distance. However, increased steps/day was associated with better scores in all WOMAC subscales, LEFS, 6MWT, and stair test scores. Overall, findings from this dissertation support the following: 1) obesity appears to be an independent risk factor for adverse events following TKA; 2) patients with higher BMI reported similar benefits from TKA compared to the normal BMI group in terms of OA symptoms and quality of life measures; 3) patients with knee OA walked significantly fewer steps than healthy controls. In terms of nutrient intake, patients also had significantly higher levels of energy, SFA, and TFA intake compared to the healthy control group. More walking was associated with better performance in WOMAC subscales, stair test, LEFS, and 6MWT. Higher consumption of SFA and TFA were associated with worse WOMAC subscales, LEFS, and 6MWT. These findings may be used by patients and care providers to inform the risks and benefits of an elective TKA procedure, and by care providers to emphasize the importance of dietary intake and daily physical activity to manage symptoms in patients with OA.

  • Subjects / Keywords
  • Graduation date
    Spring 2021
  • Type of Item
  • Degree
    Doctor of Philosophy
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.