Researchers from Stony Brook University, New York, have associated obesity with pain stating that people who are overweight suffer from higher incidences of pain.      

In a study of more than one million Americans published online in the latest edition of Obesity, lead researchers Arthur A. Stone and Joan E. Broderick based their analysis on a telephone survey of 1,010,762 respondents as interviewed by the Gallop Organization between 2008 and 2010.

Although, past studies did look at the association between obesity and pain, the current study was based on a very large sample size of American men and women who answered health survey questions.

In the new study, researchers indicated that as people age, excess weight is associated with even more pain, as part of the developmental process.

The study findings note that 63 percent of the 1,010,762 people who responded to the survey were either overweight or obese. Thirty eight percent were seen as overweight while 25 percent were obese.

The study, published in the online edition of Obesity, found that in comparison to individuals with low to normal weight, the overweight group reported 20 percent higher rates of pain. The more the weight, the higher the levels of pain.

We wanted to explore this relationship further by checking to see if it was due to painful diseases that cause reduced activity, which in turn causes increased weight, said lead investigator Broderick, Associate Professor in the Department of Psychiatry and Behavioral Science and School of Public Health at Stony Brook University.

We found that 'pain yesterday' was definitely more common among people with diseases that cause bodily pain. Even so, when we controlled for these specific diseases, the weight-pain relationship held up. This finding suggests that obesity alone may cause pain, aside from the presence of painful diseases, Broderick explained.

The researchers investigated and calculated respondents' body mass index (BMI) based on questions on height and weight. Respondents answered questions about pain, including if they experienced pain yesterday.

Our findings confirm and extend earlier studies about the link between obesity and pain. These findings hold true after we accounted for several common pain conditions and across gender and age, said Stone, an expert on patient reported measures of health, pain and well-being from the Department of Psychiatry and Behavioral Science, Stony Brook University School of Medicine.

According to the study findings, the obese respondents were further classified into one of three obesity levels as defined by the World Health Organization.

In comparison to individuals with low to normal weight, the overweight group reported 20 percent higher rates of pain. The percent increase of reported pain in comparison to the normal weight group grew rapidly in the obese groups: 68 percent higher for Obese 1 group, 136 percent higher for Obese 2 group, and 254 percent higher for Obese 3 group, the report stated.

The authors explained that the pain quotient experienced by obese individuals was not necessarily caused due to musculoskeletal pain, the type of pain that is associated by those carrying excess weight.

Broderick and Stone suggested that the relation between obesity and pain could also be a result of excess fat in the body that triggers complex physiological processes, resulting in inflammation and pain.

The authors explained that sometimes this change could lead to depression, the other side-effect of being obese. Medical conditions such as arthritis that cause pain could also be one of the causes of weight-gain that could limit exercise levels in obese individuals.

Broderick and Stone infer that that the study findings could help understand the importance of metabolic investigations that cause pain. In addition, there is need for further investigation into studying the obesity-pain linkages within the U.S. populations, they suggested.