title: Gene-environment interaction between angiotensinogen and chronic exposure to occupational noise contribute to hypertension.
abstract: OBJECTIVE
  Previous studies on the effects of angiotensinogen (AGT) gene polymorphisms and chronic exposure to occupational noise on the risk of hypertension have mainly been cross-sectional or prevalent case-control studies, where temporality constitutes problems. The present study was to assess longitudinally both independent and joint effects of AGT gene polymorphisms and chronic exposure to occupational noise on occurrence of hypertension.
  
  
  METHODS
  The authors conducted a 20-year prospective cohort study of 1301 aviation workers in Taiwan. The study population included 912 workers without hypertension at baseline. The outcome of interest was the development of hypertension during the study period. The studied determinants were three AGT genotypes (TT, TM and MM) and four exposure categories according to the levels of noise representing high (>80 dBA), medium (80-65 dBA), low exposure (64-50 dBA) and the reference level (49-40 dBA).
  
  
  RESULTS
  In Poisson regression adjusting for confounders, AGT (TT vs MM adjusted incidence rate ratio (IRR) 1.77, 95% CI 1.24 to 2.51) and noise exposure (high and medium combined) during 3-15 years (adjusted IRR 2.35, 95% CI 1.42 to 3.88) were independent determinants of hypertension. Furthermore, the risk of hypertension increased with noise exposure (adjusted IRR 3.73, 95% CI 1.84 to 7.56) among TT homozygotes but not among those with at least one M allele (Rothman synergy index=1.05).
  
  
  CONCLUSIONS
  The results evidence further the independent effects of AGT gene polymorphisms and exposure to occupational noise. Our finding also suggests that workers carrying TT variant allele have higher risk of hypertension under chronic exposure to occupational noise.
authors: Department of Occupational Safety and Health, College of Public Health, China Medical University, No 91 Hsueh-Shih Road, Taichung 40402, Taiwan. bfhwang@mail.cmu.edu.tw
authors: Bing-Fang
authors: BF
authors: Hwang
authors: Ta-Yuan
authors: TY
authors: Chang
authors: Kang-Yin
authors: KY
authors: Cheng
authors: Chiu-Shong
authors: CS
authors: Liu
mesh_terms: D000328:Adult; D000401:Aircraft; D000483:Alleles; D000808:Angiotensinogen / Q000235:genetics*; D005260:Female; D059647:Gene-Environment Interaction; D005838:Genotype; D006720:Homozygote; D006801:Humans; D006973:Hypertension / Q000209:etiology* / Q000235:genetics; D015994:Incidence; D007221:Industry; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009623:Noise, Occupational / Q000009:adverse effects*; D016273:Occupational Exposure / Q000009:adverse effects*; D016012:Poisson Distribution; D011110:Polymorphism, Genetic; D012307:Risk Factors
chemical_list: D000808:Angiotensinogen