Researchers at the University of Utah recently published a study entitled “The association between chronic pain and obesity” reviewing the link between these two conditions. The review appeared in the Journal of Pain Research.
Both obesity and pain are considered serious public health concerns that can affect overall quality of life. A correlation between obesity and pain has been reported with pain complaints common among obese individuals and comorbid obesity known to be a common feature in chronic pain conditions.
Obesity causes a systemic inflammatory state in the body and is associated with several chronic diseases such as diabetes, cardiovascular diseases, hypertension and cancer. The population in the United States is estimated to exceed by far the world average in terms of obesity rate.
In this study, the authors reviewed the link between obesity and pain in the general population and also in patients suffering from chronic pain, along with the possible mechanisms behind this association.
Obesity has been reported to be involved in several pain diagnoses including fibromyalgia, a medical disorder characterized by widespread chronic musculoskeletal pain; in addition, fibromyalgia is also linked to incapacitating fatigue, stiffness and numbness in certain parts of the body, painful response to pressure, headaches, unrefreshing sleep (poor sleep quality), anxiety or depression and mood alterations. This condition can affect the ability to conduct simple daily tasks, compromising quality of life. It is estimated that 5 to 15 million Americans are affected by this disorder, especially women.
According to the authors, several studies in women suffering from fibromyalgia have shown a clear tendency for a higher mean body-mass index (BMI) in this patient population while BMI in fibromyalgia patients was found to be significantly related to the number of positive painful tender points upon palpation. In general, it has been reported that when obesity co-occurs with chronic pain, overall health consequences can be further aggravated in chronic pain patients, as is the case in those suffering from fibromyalgia.
Conversely, weight gain may also occur as a result of chronic pain. This phenomenon can be explained by the overeating triggered through the frustration felt by the individual due to their functional limitations, poor sleep quality, sedentary lifestyle and also as side effects of pain medication.
The team suggests several potential mechanisms that may contribute to the link between obesity and pain. They refer possible mechanical/structural factors, such as the increased weight load on the joints and spine, or the altered body mechanics and postures that obese individuals often adopt, which may eventually lead to chronic pain. Chemical mediators are also suggested as a possible mechanism between obesity and pain, namely through the inflammatory state in the body triggered by obesity that can contribute to pain development.
Depression is another suggested link between obesity and pain, with studies reporting that it potentiates both comorbid pain and obesity. Disturbed sleep is also known to promote obesity, and obese fibromyalgia women have been shown to suffer more from disturbed sleep than lean fibromyalgia patients. The authors also suggest that a sedentary lifestyle might be on the basis of the relationship between obesity and pain.
Since obesity can aggravate chronic pain, weight loss might be seen as a therapeutic strategy. Growing evidence supports this reasoning, including studies with fibromyalgia women where weight loss was found to improve disease symptoms, including widespread pain.
Researchers concluded that obesity and pain are comorbidities that negatively impact each other, and suggest that the link between the two conditions is most likely mediated by several factors and mechanisms. The authors believe that weight loss in obese patients might be considered a relevant intervention for pain rehabilitation and improvement of the patient’s quality of life.