Earlier studies have shown: (i) an association between obesity and reduced lung function [12-15,23,24]; (ii) metabolic syndrome and impaired lung function [16,17]; (iii) no association between TLR4 polymorphism and metabolic syndrome and diabetes [10,11]; and (iv) controversial relationship between TLR4 polymorphism and lung function [2-7,9,25]. Here, TLR4 is linked to metabolic syndrome.