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Open Access Highly Accessed Research article

An interaction between Nrf2 polymorphisms and smoking status affects annual decline in FEV1: a longitudinal retrospective cohort study

Hironori Masuko1, Tohru Sakamoto1*, Yoshiko Kaneko1, Hiroaki Iijima2, Takashi Naito2, Emiko Noguchi3, Tomomitsu Hirota4, Mayumi Tamari4 and Nobuyuki Hizawa1

Author Affiliations

1 Division of Respiratory Medicine, Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan

2 Tsukuba Medical Center, Ibaraki, Japan

3 Department of Medical Genetics, Majors of Medical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan

4 Laboratory for Respiratory Diseases, Center for Genomic Medicine, the Institute of Physical and Chemical Research (RIKEN), Kanagawa, Japan

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BMC Medical Genetics 2011, 12:97  doi:10.1186/1471-2350-12-97

Published: 20 July 2011

Abstract

Background

An Nrf2-dependent response is a central protective mechanism against oxidative stress. We propose that particular genetic variants of the Nrf2 gene may be associated with a rapid forced expiratory volume in one second (FEV1) decline induced by cigarette smoking.

Methods

We conducted a retrospective cohort study of 915 Japanese from a general population. Values of annual decline in FEV1 were computed for each individual using a linear mixed-effect model. Multiple clinical characteristics were assessed to identify associations with annual FEV1 decline. Tag single-nucleotide polymorphisms (SNPs) in the Nrf2 gene (rs2001350, rs6726395, rs1962142, rs2364722) and one functional SNP (rs6721961) in the Nrf2 promoter region were genotyped to assess interactions between the Nrf2 polymorphisms and smoking status on annual FEV1 decline.

Results

Annual FEV1 decline was associated with smoking behavior and inversely correlated with FEV1/FVC and FEV1 % predicted. The mean annual FEV1 declines in individuals with rs6726395 G/G, G/A, or A/A were 26.2, 22.3, and 20.8 mL/year, respectively, and differences in these means were statistically significant (pcorr = 0.016). We also found a significant interaction between rs6726395 genotype and smoking status on the FEV1 decline (p for interaction = 0.011). The haplotype rs2001350T/rs6726395A/rs1962142A/rs2364722A/rs6721961T was associated with lower annual decline in FEV1 (p = 0.004).

Conclusions

This study indicated that an Nrf2-dependent response to exogenous stimuli may affect annual FEV1 decline in the general population. It appears that the genetic influence of Nrf2 is modified by smoking status, suggesting the presence of a gene-environment interaction in accelerated decline in FEV1.