When Obesity and Chronic Pain Co-Occur

Rates of obesity have been increasing steadily. A recent national study found that 42% of US adults met the criteria for obesity (a BMI over 30 kg/m²). Estimates of the prevalence rates increase to 68% when being overweight (a BMI over 25 kg/m²) is included in the general US population, and 77% for individuals within the Veterans Health Administration (VHA).^1-5

Pain that Co-Occurs with Obesity

Complicating obesity management is that the disease is a known risk factor for chronic pain.^6-9 Rates of comorbid pain and overweight/obesity are high, with some estimates ranging from 20% to 45% of overweight/obese individuals reporting pain.¹⁰ One study found that individuals who meet obesity criteria have rates of pain that are 68% greater than individuals who are not overweight.⁸ Further, individuals with abdominal obesity are twice as likely to report chronic pain.⁷

Importantly, co-occurring obesity and chronic pain have been found to cause greater functional impairment compared to those who have one or the other condition.¹¹ The nature of the relationship between obesity and pain, however, is not likely to be direct as many interacting factors appear to contribute. Existing research points to several potential mechanisms that may link obesity and chronic pain, including:¹¹

• mechanical/structural factors

• chemical mediators

• depression

• sleep

• lifestyle

A meta-analysis demonstrated a relationship between obesity and an increase in reported low back pain.¹² Obesity also has been shown to be related to an increase in neck pain,¹³ osteoarthritis,¹⁴ foot pain,¹⁵ shoulder pain,^16,17 fibromyalgia,^9,18 and headaches.^6,9,19 The association between obesity and chronic pain has been found to be higher in females and for those over age 40.⁸

Chronic Pain Management Approaches that Apply to Obesity Care

The infrastructure for the simultaneous treatment of obesity and chronic pain already exists in pain medicine across several different avenues, including:

• patient education

• behavioral medicine approaches

• physical rehabilitation

• medications (ie, support the extension of indications for some drugs in the realm of pain medicine and limit the use of other medicines)

• interventional treatment (ie, incautious use of corticosteroids can impair glucose metabolism)

Screening for obesity, pain-related disability, and behavioral disorders are also methods that are available currently in pain medicine. Monitoring of functional performance should also be routine.²⁰

Weight Loss as an Aspect of Pain Rehabilitation

Weight reduction can help address chronic pain.¹¹ Physical activity is one way to reduce weight.²¹ A meta-analysis across 43 studies (n=3,476) found that exercise had a small weight loss effect compared to no treatment, and that more effective weight loss was achieved when paired with dietary restrictions.²¹ The same study also found that an increase in exercise intensity increased weight loss. Moreover, when physical activity’s calorie expenditure is between 500 calories²² and 700 calories,²³ weight loss is more reliably achievable without dietary restrictions. Further, weight loss through physical activity results in greater total fat loss and visceral fat reduction compared to weight loss through dietary restriction alone.²²

Diet Alone

A nutritional approach involves making changes to a patient’s diet to prevent pain or promote weight loss. A basic principle of nutritional health is to eat food from each of the basic food groups every day. The current recommendations, called MyPlate, were developed by in 2011 First Lady Michelle Obama’s anti-obesity team and federal health officials.²⁴ The plate is split into four slightly different-sized quadrants, with fruits and vegetables taking up half the space, and grains and protein making up the other half. Patients are recommended to fill at least half the grain space with whole grains. A smaller circle sits beside the plate for dairy products.

Patients may have been exposed to any number of diets while surfing the internet. These include the anti-inflammatory diet, the high-protein-intake diet, and assorted vegetarian diets. However, there continues to be no standard guideline for a nutritional health plan to address this comorbidity and one diet does not work for all patients.

Physical Activity

Dose of exercise matters, especially if the exercise program is not paired with dietary restrictions. The Department of Health and Human Services recommends at least 150 minutes of exercise per week. However, research indicates that number should be over 200 minutes a week for reliably achievable weight loss.²⁵ Further, a review of the literature concluded that physical activity should continue after exercise programs to help maintain weight loss.²⁶

Overall, both physical activity and dietary restrictions are generally recommended for weight loss. However, even if patients experience no weight loss, there are still many additional health benefits to physical activity beyond weight loss such as an increase in cardiorespiratory fitness²⁷ and an increase in quality of life.²⁸

Another consideration is that, while exercise programs might not result in weight loss, they can prevent additional weight gain.^29-30 In addition, regular physical activity has been found to lower pain severity, improve sleep, standing, employment, and personal care behaviors.³¹

Barriers to Exercise in People with Obesity and Pain

Starting and maintaining regular physical activity is challenging for most people, and individuals with obesity and chronic pain are no exception. ³² Hamer and colleagues’ review of 34 studies found nine barriers to exercise for obese and overweight individuals, including fear of:³³

• embarrassment

• enacted stigma

• injury

• failing

• worries related to pain

• movement

• cardiac events

• joint damage

• crime

These barriers emphasize the need for behavioral health interventions as a part of a physical activity program to address the cognitive and emotional barriers. Behavioral health interventions can help patients by first cultivating awareness of their cognitive and emotional barriers, and then help to them to develop more adaptive thinking that encourages positive health behaviors, such as physical activity.

How Can Providers Encourage Weight Loss?

Healthcare providers can assess patients’ interest in and ability to lose weight using the transtheoretical model to determine level of motivation to lose weight.³⁴ The transtheoretical model posits that health behavior change involves progress through six stages of change:

• precontemplation: people do not intend to take action in the foreseeable future

• contemplation: people are intending to start the healthy behavior in the foreseeable future

• preparation: people are ready to take action within the next 30 days

• action: people have recently changed their behavior and intend to keep moving forward with that change.

• maintenance: people have sustained their behavior change for a while and intend to maintain the change going forward

• termination: people have no desire to return to their unhealthy behaviors and are sure they will not relapse

Knowing which stage of change the patient is in can help determine initial physical activity recommendations as the stage of change has been found to impact minutes of exercise per week.³⁵ Importantly, providers need to consistently refer patients to weight management programs. These programs should have a multimodal approach: diet modification, exercise, and psychological/ psychoeducation through a motivational interviewing lens. The plans should be individual-specific as opposed to a one-size-fits-all all approach.³⁶

Physical therapists are also a good referral resource. They can gain an understanding of pre-pain activity levels and help patients with the comorbidity set expectations that meet their current level of functioning. They can also help patients not over-exert themselves, which often backfires resulting in increased pain and less physical activity moving forward. Lastly, physical therapists can help develop and monitor a specific plan based on patients’ current levels of functioning.³²

Additionally, family and friends were reported as important motivators to physical activity. ³² Providers can recommend that patients include friends and family in their efforts. Providers can also communicate directly with family about the role they can play in motivating their loved one to begin and maintain physical activity.

The Ultimate Battle: Stigma in the Healthcare System

Healthcare provider stigma is another barrier to physical activity in patients with co-occurring obesity and chronic pain.^37-42 Often, stigmatizing attitudes are unknowingly enacted by healthcare providers and perceived by patients with obesity. A recent study revealed conflicting views between providers and patients with obesity on themes related to responsibility, efforts, knowledge, and motivation which merge to affect the patient and move them to internalize stigma. At times, seemingly appropriate advice may be perceived as patronizing by patients with obesity (see our sample dialogue on patient-first language and shared decision-making). Therefore, healthcare providers should not focus on weight loss to the extent that patients feel that other, even related, medical issues are ignored, resulting in patients feeling unheard and invalidated.^43-44

Further, patients who meet obesity criteria may feel excluded because of the medical system’s lack of consideration of their body type. Finally, patients who experience disrespect from healthcare providers may feel stress, distrust toward the provider, and may avoid the healthcare system. ⁴⁵ Stigma, in turn, obstructs healthy coping and collaboration and creates negative contexts for empowerment, self-efficacy, and weight management. Providers should aim to develop their awareness of potentially stigmatizing attitudes toward vulnerable patient populations.⁴⁶Provider training to reduce obesity stigma is recommended and has been found increasing treatment effectiveness.^47-48

See also, how Dr. Scott Kahan is reshaping the conversation with his patients.

Practical Takeaways

The comorbidity of obesity and chronic pain results in an increase in functional impairment and overall lower quality of life compared to either condition on its own. Patients with this comorbidity face barriers to physical activity and weight loss, such as fear of pain, fear of injury, fear of failing, and obesity stigma. Healthcare provider stigma can be addressed by seeking training to reduce internalized bias towards obesity.

Providers can encourage physical activities that match their patient’s ability and transtheoretical stage of change, suggesting a slow and low start to increase the likelihood of long-term program adherence and weight loss maintenance. Patients can benefit from patient-first communication, shared decision-making, and when, appropriate, healthcare provider referrals to multimodal programs that address physical activity, nutrition, and psychological factors that impact adherence to health behaviors.