Studies that attempt to calculate the cost of obesity generally do not control for potentially confounding factors. A 2005 study published in Obesity Research attempted to correct this failing, and concluded that after controlling for health status and socioeconomic factors, "there was no statistically significant relationship between obesity and medical expenditures." The article hypothesized:
"Obese patients may believe that they are at increased risk for health problems that may be prevented or attenuated by more frequent visits to their primary providers. In addition, physicians cognizant of the increased risks associated with obesity, may request more follow-up appointments with interval diagnostic testing and monitoring for their obese patients. This differential care and testing may take place in the absence of actual health status differences, because it is motivated by perceived risk for potential health problems. The difference in the associated costs for this 'extra' care for obese patients may not be of a magnitude high enough to achieve statistical significance."