The metaanalysis by van den Borst et al1 in a recent issue of CHEST (August 2010) importantly provided further indication that, similar to the cardiovascular system, the lung is a target organ in the systemic inflammatory process among subjects with type 2 diabetes. The International Diabetes Association suggests that 80% of these patients are overweight or obese, and because there is already a well-established relationship between obesity and abnormal lung function, the findings reported are not unexpected.2,3 Similarly, the role of inflammation among such patients is already more widely recognized as a part of the metabolic syndrome.4 The evidence to date on lung function, however, has not been entirely consistent, and although studies have generally established subjects who are obese as being more prone to reduced FEV1, FVC, and total lung capacity and, therefore, showing a restrictive pattern, there is also contradicting evidence, with the prevalence of diabetes in individuals who are obese shown to be inversely related to lung restriction rather than obstruction.3,5 Mechanisms contributing to restriction relate more to chest-wall mechanics, with body deposition of fat, reduced diaphragmatic excursion due to increased abdominal adiposity, or increased weight on the chest wall5 providing evidence for additional pleural or interstitial lung disease because a more systematic inflammatory process is not as readily evident. Leptin, which is increased in patients who are obese, may be a potential confounder in determining abnormal lung function, as may smoking, and both of these risk factors for morbidity are frequently found among these adult patients. Clarification, possibly using high-resolution chest CT imaging or full-lung-function tests, including lung volume and gas transfer tests, is needed in this population to establish whether restriction is exclusively due to obesity and altered chest wall mechanics or is possibly an inflammatory process associated with potential pleural or parenchymal lung disease. This is important work because, undetected and untreated, conditions in these patients may, at the extremes, present late and with a disproportionately higher prevalence of right-sided heart failure in the spectrum of sleep apnea and obesity/hypoventilation syndromes.