(RxWiki News) If you are overweight, those extra pounds could be adding to the wear and tear on your knee joints. Gaining more weight could make knee pain and function even worse.
According to a recent study, people who gained weight had worse knee pain, more knee stiffness and poorer knee function than those whose weight remained stable.
People who lost weight had improved symptoms. However, the size of that improvement was smaller than the increase in symptoms seen in those who gained weight. In other words, gaining weight seemed to hurt more than losing weight helped.
These findings suggest that avoiding weight gain - which can be easier than losing weight - may be an important part of managing knee symptoms.
"Control your weight to keep knee arthritis from getting worse."
The study was conducted by Flavia M. Cicuttini, PhD, of Monash University and Alfred Hospital in Melbourne, Australia, and colleagues.
The study involved 250 participants. To be included at the start of the study, participants had to be between 25 and 60 years of age and have no history of knee injury or diagnosis of joint disease, including osteoarthritis. A total of 196 participants (78 percent) completed follow-up, which was about two years.
Patients were placed into three groups based on weight change: those who lost 5 percent or more of body weight, those who gained 5 percent or more of body weight and those whose weight remained stable (weight loss or gain of less than 5 percent).
The researchers used the Western Ontario and McMaster Universities Index (WOMAC) to measure knee symptoms. The WOMAC involves a series of questions about knee pain, stiffness and function. Patients answer the questions by pointing to a location on a 100 mm scale. Higher numbers on the scale are signs of worse pain, stiffness and function.
Scores for all the questions are added up to give a total score of 500 mm for pain, 200 mm for stiffness and 1,700 mm for function.
Results showed that weight gain was associated with worsening knee symptoms. Compared to participants whose weight remained stable, those who gained weight had:
- worsening pain, with an increase of 27.1 mm on the visual scale
- worsening stiffness, with an increase of 18.4 mm
- worsening function, with an increase of 99.3 mm
Participants who lost weight had:
- less pain, with a decrease of 22.4 mm
- reduced stiffness, with a decrease of 15.3 mm
- improved function, with a decrease of 73.2 mm
Researchers compared WOMAC results between participants who were obese and those who were not obese. They also compared results between those who had osteoarthritis and those without osteoarthritis.
"The relationship between weight gain and the worsening of knee symptoms seemed particularly important in those who were already obese and who had evidence of osteoarthritis," the authors wrote.
"Although weight loss had a beneficial effect, the magnitude of improvement was less than the increase in symptoms seen in those who gained weight. This study highlights the importance of obesity and weight gain on knee symptoms."
The authors said that worsening of knee symptoms due to weight gain may weaken physical function, which in turn could lead to more weight gain. Therefore, the study "provides an at-risk time when maintaining weight, which is easier to achieve than weight loss, may be important in the management of knee pain," the authors concluded.
The authors pointed out several limitations in their study, including the relatively small number of men. In addition, it was likely that the obese participants were already focused on losing weight, which may not be representative of the obese population as a whole.
The study - which was published December 27 in Arthritis Care & Research - was supported in part by the National Health and Medical Research Council at Monash University, the Shepherd Foundation and the Royal Australian College of Physicians. The authors disclosed no conflicts of interest.