Obesity has been widely recognized as a risk factor for osteoarthritis (OA). While the elderly population continues to multiply here in the US, so does the epidemic of obesity. This surge has also caused incidences of OA to rise, as well. Today, approximately 70% of people over 65 are affected by OA, with knee OA being the most prevalent.
Why Does Obesity Cause OA?
Obesity causes OA in three ways. First, the added pressure placed on the joints, resulting from excess body weight, causes significant articular cartilage deterioration. Obese individuals experience an increased amount of strain from the load they are carrying, which eventually wears down their joints. The weight-bearing joint of the knee, primarily, and the hip, secondarily, may be the most affected. But how can one explain the high incidence of OA in the non-weight bearing hand joint of obese people?
This can only be explained on the basis of a systemic factor. Scientists now believe that obese people have a factor that circulates in their blood affecting all joints. Adipose (fat) tissue is the source of this factor. Fat tissue is a part of the integumentary system, including the skin, and is used to store energy, provide insulation against heat or cold, and protect the internal organs. It also acts as a nutrient reservoir.
However, apart from its classical role, adipose tissue has been recognized as major endocrine organ. It secretes factors whose levels are determined by the degree of adiposity . Factors such as TNF-alpha and leptin, have been implicated in the initiation of inflammatory processes. Inflammation, a chronic condition in obese people, accelerates cartilage degeneration, which may explain some of the mystery and intrigue in the progression of hand OA, a non-weight bearing joint.
Finally, obese individuals ordinarily have a higher bone mineral density, the opposite of osteoporosis, which may also be a risk factor for OA .
Can Weight Loss Alleviate Pain caused by OA?
A meta-analysis that synthesized all findings from previously published relevant studies, measured the effect of weight loss in improving pain and functional disability, among patients with knee OA. The findings indicated that “physical disability of patients with knee OA and overweight diminished after a moderate reduction regime”. Specifically, individuals who reduced their body weight by 5-10% at a progressive rate of 1.1-3.3 pounds per week experienced a significant reduction in knee OA symptoms .
Clinically studied weight loss programs, such as Nutrisystem or Medifast, combined with high quality arthritis supplements, like Arthrit-Eze, may be effective in mitigating the risk of developing OA and minimizing its effect among the population who has it.
How Effective is Weight Loss in Preventing OA?
The Framingham OA study revealed that if men in the overweight or obese BMI categories would lose weight and drop into the lower category they would reduce their chances of developing OA by 21.4%. Women would reduce their risk by 33%.
The challenge is in identifying the specific amount of weight to lose, which will differ for each individual. The problem is that only 5% of the people who want to lose weight and keep it off, actually do. Individualized coaching and completing a multiple behavior lifestyle intervention program, addressing diet, physical activity, and the elimination of at-risk behaviors (smoking, alcohol, drugs, etc.) has shown to provide the most sustainable benefit.
Food for thought
In conclusion, while many studies reveal that there is a direct correlation between obesity, weight loss, and OA—it is unclear as to how they relate at a physiological level. Obesity has, in fact, been identified as a causal factor in the development and progression of OA, especially in the knees, hips, and hands. However, more research is needed to determine if it is the result of mechanical stress or adipose tissue secretions occurring within the human body.
Weight management is an effective treatment option, since obesity has been known to exacerbate OA symptomology, among chronic sufferers. Improved dietary habits and micronutrient supplementation in conjunction with a healthy amount of physical activity will aid in reducing pain and stiffness, while increasing functionality and mobility. Likewise, taking the necessary, preventative steps now, at an earlier age, will assist individuals to develop a solid work ethic in combating obesity and in living an improved, healthier lifestyle with the aim of reducing incidences of OA.
About the Author
Matthew Papaconstantinou, PhD, a biology researcher, closely follows the scientific studies related to obesity and associated chronic diseases, such as osteoarthritis. In his blog, he discusses issues in the area of obesity, weight loss programs, and nutrition and offers a Medifast coupon and Nutrisystem diet promotion codes.
- TNF-alpha and Obesity. Tzanavari T, Giannogonas P, Karalis KP. Curr Dir Autoimmun. 2010;11:145-156. Epub 2010 Feb 18.
- Bone mineral density and risk of incident and progressive radiographic knee osteoarthritis in women: the Framingham Study. Zhang Y, Hannan MT, Chaisson CE, McAlindon TE, Evans SR, Aliabadi P, Levy D, Felson DT. J Rheumatol. 2000 Apr;27(4):1032-7.
- Ann Rheum Dis. 2007 Apr;66(4):433-9. Epub 2007 Jan 4. Effect of weight reduction in obese patients diagnosed with knee osteoarthritis: a systematic review and meta-analysis. Christensen R, Bartels EM, Astrup A, Bliddal H.