Obesity And Arthritis: Is There An Association?
The obesity problem facing the Western world has taken vast dimensions causing excess morbidity and mortality in the US and the rest of the world. A variety of musculoskeletal problems originate from obesity leading to locomotor disability and joint pain. Osteoarthritis is one of the major diseases that has been directly linked to obesity.
Two major risks factors for osteoarthritis are aging and obesity, which are rapidly increasing. Osteoarthritis (OA) affects now 70% of people over 65 years of age. This is 27 million Americans, or 12.1% of the adult population of the US [1]. Being the most prevalent joint disorder in the world, OA has been associated with an extremely high economic burden.
The principal symptom of OA, the most common form of arthritis, is joint pain. The pain, which results from loss of articular cartilage, is concentrated mainly in the hips, knees and hands. In the first phase of the disease, pain occurs only when the joint is being used. In later stages of OA, pain is present even during rest and sleep.
Therapy of OA involves surgical and non-surgical procedures. Surgery, as a means for OA treatment, is reserved for people with severe symptoms of the disease who do not get pain relief from medication. Most people, however, can delay or limit their OA symptoms with non-surgical procedures, such as medication, acupuncture, proper diet and lifestyle changes.
On the other hand, the pharmacological approach to OA treatment, which involves the use of analgesic agents (Tylenol) or non-steroidal anti-inflammatory drugs (Advil, Aleve and Orudis), is known to pose serious health hazards, some of the more frequent being adverse gastrointestinal reactions.
It is for this reason that natural pain relief remedies are gaining immense popularity for the treatment of OA, especially after the very promising results of the Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT). Today, at least 5 million people in the United States take glucosamine or chondroitin sulphate as a dietary supplement—main ingredients of the popular Joint Advance natural pain relief formula.
Does Excess Weight Cause Arthritis?
It is well accepted that obesity is a risk factor for OA. Population based studies have consistently shown that overweight persons are at higher risk of suffering from OA than non-overweight subjects.
A 2001 survey of 7500 people in Australia reported that BMI (a measure of overweight and obesity) is an important risk factor for arthritis even after adjusting for age, sex and socioeconomic status [2]. Overweight adults face twice the chance to be diagnosed with OA.
Excess Weight And Knee OA
Large population studies have demonstrated a linear trend in the relative risk of knee OA with increasing BMI. [3]
A Scottish survey, which collected data from 858 people, found a positive relation between obesity and lower limb joint pain. Specifically, obese respondents had twice the frequency of hips, knees, ankles, and feet pain [4]. Another survey of 5000 people in the USA revealed that for every 5-unit increase in BMI, the risk of developing knee OA doubled [5].
In addition, patients selected from lists of people scheduled for joint replacement therapy have been found to be significantly heavier than healthy subjects of the same age and gender.
A strong association between BMI and knee OA was reported in the UK 4-year study of 830 middle aged women. The risk of developing osteophytes—bony projections that develop in deteriorating joints damaged by arthritis—was two times higher in women with a BMI>26.4 than in women with BMI<23.4.
Excess Weight And Hip OA
The hip joint is subject to a lighter mechanical load than the knees where the force is more narrowly distributed. This justifies the observation that the association between obesity and the incidence of OA in the hip is not as strong as that between obesity and knee OA.
In fact, a large cross-sectional study that involved 2358 people found no link between obesity and hip OA. However, other studies have found a positive correlation. Data collected from the USA Nurses study showed that higher BMI at the age of 18 was associated with a 5-fold increased risk of hip replacement due to OA in older age [6].
Large cohort studies have confirmed the positive correlation between BMI and hip OA. The Norwegian study of 1.2 million persons found that the relative risk of undergoing hip arthroplasty later in life was 3.4 times higher among men with BMI>32 versus a BMI of 21.
Obesity And Hand OA
Hands are non-weight-bearing joints. The force exerted across the hand joints is not greater in the overweight people than those of normal weight. Yet, paradoxically overweight people appear to have a higher risk of hand OA than those who are not overweight. The fact that obesity is a risk factor for hand OA implies that the mechanical stress exerted in the joints of obese persons is not the sole cause for developing OA.
Is It Obesity That Causes OA Or The Other Way Around?
The association between obesity and OA raises the question of causality. Is it possible that overweight people have gained the excess weight as a result of their sedentary lifestyle forced by their OA-knee pain?
A number of longitudinal studies have addressed this issue. The Framinham Heart Study followed 1420 initially healthy subjects over a period of 36 years [7]. It found that the participants who were overweight at the age of 37, when OA of the knee is extremely uncommon, had an increased risk of developing the disease in their 70’s. This disproves the notion that OA causes weight gain and points to obesity having a causal effect on OA.
In Summary
Carrying excess weight in the form of adipose tissue is an important risk factor for OA of the knees. Obesity increases the risk of knee OA and has a positive but lesser effect on the risk of hip and hand OA. For this reason, weight reduction is recommended as an important part of treatment for OA, especially OA of the knees.
About The Author
Matthew Denos, PhD, is a biology scientist with a keen interest in the relationship between obesity and OA. He closely follows the current scientific research on obesity treatment, diets and weight loss programs. Matthew maintains a blog at bistro md coupons and discounts diet to go coupon code discount.
References
1. Am J Manag Care. 2009 Sep;15(8 Suppl):S230-5. The economic burden of osteoarthritis. Bitton R.
2. Role of age, sex, and obesity in the higher prevalence of arthritis among lower socioeconomic groups: a population-based survey. Busija L, Hollingsworth B, Buchbinder R, Osborne RH. The University of Melbourne, Melbourne, Victoria, Australia.
3. Coggon D, Reading I, Croft P, McLaren M, Barrett D, Cooper C. Knee osteoarthritis and obesity. Int J Obes Relat Metab Disord 2001;25:622–7
4. Ann Rheum Dis. 2006 Apr;65(4):520-4. Epub 2005 Aug 26. Prevalence and risk factors for joint pain among men and women in the West of Scotland Twenty-07 study. Adamson J, Ebrahim S, Dieppe P, Hunt K.
5. Anderson JJ, Felson DT. Factors associated with osteoarthritis of the knee in the first national Health and Nutrition Examination Survey (HANES I). Evidence for an association with overweight, race, and physical demands of work. Am J Epidemiol
1988;128:179–89
6. Felson DT, Anderson JJ, Naimark A, Walker AM, Meenan RF. Obesity and knee osteoarthritis. The Framingham Study. Ann Intern Med 1988;109:18–24
7. Am J Med. 2003 Feb 1;114(2):93-8. Total hip replacement due to osteoarthritis: the importance of age, obesity, and other modifiable risk factors. Karlson EW, Mandl LA, Aweh GN, Sangha O, Liang MH, Grodstein F.
