I wish to express my concerns about two aspects of their work. As it has been speculated that sex hormones could affect adiponectin levels, I think they sought more to minimize potential confounders. In his previous study, Sood et al4 showed that in women, but not men, a lower serum adiponectin concentration is associated with asthma. Estrogen and progesterone may affect the adiponectin concentration by controlling adipose tissue metabolism and estrogen, which has been shown to alter the action of lipoprotein lipase and hormone-sensitive lipase in adipocytes. There is also in vitro evidence that estrogen decreased adiponectin expression in adipocytes.5 In the present study, as most of the subjects were women in the premenopausal stage, this phase of their menstrual cycle might also be important.