Tumour necrosis factor and lymphotoxin A polymorphisms and lung function in smokers

Genetic variants in the tumour necrosis factor (TNF) gene have been investigated in chronic obstructive pulmonary disease (COPD). However, there are many instances of nonreplication of these associations due to insufficient power or other factors. In this study, a large number of subjects were examined to elucidate whether genetic variations of TNF and/or lymphotoxin A (LTA), which is clustered with TNF, are associated with variations in lung function among smokers. The present authors designed two nested case-control studies in the National Heart, Lung, and Blood Institute Lung Health Study (LHS), which enrolled 5,887 smokers. The first design included continuous smokers who had the fastest (n=279) and the slowest (n=304) decline of lung function during the 5-yr follow-up period, and the second included the subjects who had the (n=532) post-bronchodilator % predicted forced expiratory rt of the LHS. Within the TNF and LTA region, 10 tagging single-nucleotide polymorphisms were selected and genotyped. Unlike the previous associations between TNF-308 and COPD in Asians, the current study found no association between either of the two phenotypes and the LTA and TNF polymorphisms. In conclusion, these results support the findings of previous studies in late-onset chronic obstructive pulmonary disease in Caucasian populations.