Obesity and Chronic Pain

Many chronic conditions that cause pain are more common in people who are overweight or obese — arthritis, depression, fibromyalgia, hypertension, asthma, type 2 diabetes, and back pain. Because of this, the assumption is that being obese increases the likelihood of having multiple medical problems, and many of these conditions may cause pain. Obesity and pain often go hand in hand, even if the obese person is otherwise healthy.

The study looked at the connection between obesity and chronic pain caused by many conditions, including osteoarthritis, migraines, lower-back pain, and vitamin D deficiency.

Researchers recognize that the relationship between obesity and chronic pain is complex. For example, for someone with arthritis, a chronic health problem, they may not feel well enough to exercise or move around much. This can contribute to weight gain and other problems down the road. On the other hand, it may be that someone starts out overweight, which puts strain on the joints, leading to joint problems that cause pain.

In fact, one of the factors leading to increased incidence of chronic pain in obese patients is the increased weight on joints and the spine. Higher body mass index is associated in arthritis research with greater defective change in knee cartilage and joint space widths.

Studies also look at the role of vitamin D in the relationship between obesity and chronic pain. Low levels of vitamin D appear to be more common in obese people. Poor skeletal mineralization due to vitamin D deficiency may lead to aches in the joints and muscles, including knee osteoarthritis.

Obesity is a major risk factor for chronic pain that needs to be discussed, especially as the prevalence of obesity worldwide and in the U.S. continues to grow. While progress has been made and research continues, a better understanding of this connection could potentially benefit both practitioners and patients.

Obesity is one of the most prevalent co-morbidities associated with chronic pain, which can severely interfere with daily living and increase utilization of clinical resources. A higher level of obesity, measured by BMI, would be associated with increased pain severity, or intensity, and interference, a pain related disability. Essentially, obesity is associated with increased pain severity and pain interference.

Since the relationship between obesity and chronic pain is not random, understanding this relationship can contribute to effectively managing both conditions. Examining the specifics of both pain management techniques for obese patients and interventional approaches for weight reduction in obese individuals is necessary in an approach to treatment. The infrastructure for the treatment of chronic pain and obesity is present in pain medicine — medications, physical and psychological rehabilitation, and interventional management.

Obesity, defined by the WHO as a BMI of >30, affects more than half a billion individuals worldwide, and being overweight, defined as having a BMI of 25–29.9, affects almost three-times more adults. Obesity is associated with cardiovascular disease, hypertension and diabetes, and, according to the WHO, millions of people die annually as a result of it. Furthermore, a significant portion of healthcare spending is allocated to the treatment of obesity co-morbidities. Impaired health-related quality of life, social stigma, mood changes and chronic pain are other well-recognized problems related to obesity.

In one study almost four out of ten obese individuals reported chronic pain, and 90% of them suffered from moderate-to-severe pain. A survey of more than 1 million people demonstrated that individuals with BMIs 25–29.9 had about 1/5 more pain compared with normal-weight people, those whose BMIs were 30–34 reported about 68% more pain, those with BMIs of 35–39 had 136% more pain and those whose BMIs were more than 40 reported 254% more pain.

Chronic pain compounds the already enormous clinical, psychological, societal and economical burdens of obesity. The nature of the chronic pain–obesity relationship is multifaceted, and includes the interfaces of cultural, social, behavioral, environmental, biomechanical, metabolic and genetic factors.

Lifestyle reformation is considered to be a fundamental instrument in effective rehabilitation of obese individuals. The same strategy is applied to a multitude of chronic pain states. Patient education, behavior modification, an increased level of physical activity, including specific exercises, are common tools for both obesity and pain management. Alternative treatment strategies may include acupuncture, chiropractic or osteopathic interventions, or other approaches.

Pharmacotherapy of obesity has been increasingly popular. The drugs approved for the treatment of obesity are typically quite expensive and are generally not supported by most insurances: the weight reduction is generally modest, and there are concerns about their safety. In addition, data regarding the effects of these medications on chronic pain are very limited.

Obesity significantly alters drug absorption, binding, distribution and elimination through a variety of physiologic and pathophysiologic mechanisms. Such commonly occurring deviations, which could have a profound effect on medications prescribed for chronic pain, may be initially undetected but ultimately dangerous. Some medications, such as gabapentin or pregabalin, commonly used in pain management, are associated with weight gain. Some others, such as topiramate or zonisamide, may actually help to reduce weight. But, since obesity and dependency share some mechanisms, chronic opioid therapy for obese patients who have non-cancer pain probably should be discouraged, especially in high doses. 

Challenges: Acute radicular pain, commonly encountered in obese individuals, is frequently treated using epidural injections. However, the procedure can be challenging in these individuals in terms of both access to, and visualization of, injection targets. The imaging technique used for interventional procedures must ensure adequate views during the procedure to see the target structure because the anatomy of the epidural space differs in obese and normal-weight patients. Similar challenges were illustrated when ultrasonography was used for lumbar medial branch blocks and facet injections in obese individuals. Thus, special modifications are required for some commonly performed nerve blocks in patients.

Options: Obese patients commonly have diabetes mellitus or records of rapid weight gain associated with corticosteroid use. Therefore, corticosteroids should be used with a great caution. There are now newer treatment options, such as autologous conditioned plasma, platelet rich plasma and others, which may incite tissue regeneration in obese individuals. Novel biologic strategies, including gene therapy and stem cell treatments, that target impaired intervertebral discs are being explored. Pain management physicians are equipped with the knowledge and technology of delivering the newer agents to the targeted structures in obese individuals. In addition, newer, implantable devices have become available for treating obesity.

If you suffer from chronic pain and obesity, talk to your physician about options and alternatives for your care. Look at treatments that are co-productive, rather than counterproductive.

Additional reading - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4590160/