The following limitations of our study have to be considered. First, the baseline data for the SOS intervention study population and the medication data for the general population were collected during different periods. The introduction and widespread use of new pharmaceuticals, for example, antidepressants and proton pump inhibitors, and new guidelines for the treatment of diabetes mellitus during recent years has probably affected the expenses more in the general population group, which was studied later. Thus, the cost differences between the obese and general populations could be even more pronounced than indicated by our data. On the other hand, data on medication use were available for only approximately 55% of the reference population, and the state of health of nonrespondents is unknown. If more diseased individuals were less likely to participate, the use of medication might be underestimated in the general population. Still, the comparison provides a comprehensive, albeit rough, estimate of various medical costs associated with obesity, particularly because the reference group was randomly selected. Second, the SOS intervention study is based on a selected group of individuals. Participants were self-selected and were recruited by advertisements in public media. Furthermore, several exclusion criteria were used. To be included in the SOS intervention study, the patients had to be operable and also eligible according to the study protocol. Therefore, obese individuals with severe illnesses, abuse, and so on, were not allowed to enter the study. Thus, our study population probably has a better health status than the general obese population. Third, information on the use of medications was self-reported and was collected from dispatched questionnaires, which could affect the reliability of the data. Because we had no access to objective data on drug consumption, we could not validate these questions. However, information on medication use in the reference population was obtained by the same methods as in the intervention study. Finally, we cannot preclude the possibility that participation in the study per se could affect medication use. Participation in the study, with repeated health examinations, could theoretically increase awareness of symptoms and the likelihood of detection of various comorbidities.