Dear Sir,

As I read the study by Patil et al. [1], I noticed that they have not stated several important points; in the methods section, the authors did not state the number of participants they contacted or the method used (telephone or direct interview?). Did they contact all of the study universe? There are 400 participants but as the authors have not estimated the exact number using appropriate epidemiologic formulas we cannot estimate the number required. In a cross-sectional study, sample size is an important part of study design, and without knowing the exact sample size interpretation of the results becomes almost impossible. Furthermore, the facilities or the means participants utilized in order to come and take the diagnostic test (DEX study) was not noted, which precludes ruling out the possibility that disabled participants did not come in for diagnostic tests. The same concern is true of economic status; information regarding the socio-economic status of participants is missing and therefore there is a possibility that participants were wealthier than non-participants. Although cross-sectional studies are not the best type of study for finding causal relationships, in my opinion the points mentioned above should also be considered and included.

As populations get older we must focus on the elderly, keeping in mind that preventing disabilities is a good target. If sarcopenia can be used predict disabilities, by all means we have to find out its social impact. Therefore, research into sarcopenia should take into account epidemiologic methodology.