Poster Presentation GENEMAPPERS 2024

Associations between DNA methylation and cigarette smoking in Pacific Peoples living in Aotearoa New Zealand (#100)

Sam FP Gibbs 1 , Gregory T Jones 2 , Vicky A Cameron 1 , Tony Fakahau 3 , Chris Frampton 1 , Nikki J Earle 4 , Katrina K Poppe 4 , Anna Rolleston 5 , Malcolm E Legget 4 , Rob Doughty 4 6 , Richard Troughton 1 , Anna P Pilbrow 1 , Allamanda F Faatoese 1
  1. Christchurch Heart Institute, University of Otago, Christchurch, New Zealand
  2. Department of Surgical Sciences, University of Otago, Dunedin, New Zealand
  3. Analytical Intel Limited, Auckland, New Zealand
  4. Department of Medicine, University of Auckland, Auckland, New Zealand
  5. Centre for Health, Tauranga, New Zealand
  6. Greenlane Cardiovascular Service, Te Toka Tumai Auckland Hospital, Auckland, New Zealand

Background: Specific DNA methylation sites have been proposed as novel markers of smoking related disease but have not been validated in NZ’s Pacific populations, who are underrepresented in epigenetic research. We examined associations between DNA methylation and cigarette smoking across two cohorts of Pacific Peoples living in NZ.

Methods: Whole blood DNA methylation was measured using Illumina MethylationEPIC arrays for 289 Pacific participants from the Pasifika Heart Study (PHS, n=191) and the Multi-Ethnic NZ Study of Acute Coronary Syndromes (MENZACS, n=98). Epigenome-wide association study (EWAS) analyses were adjusted for age, sex and blood cell composition.

Results: Participants were of Samoan (n=117, 40%), Tongan (n=66, 23%), Fijian (n=61, 21%), Cook Island Māori (n=22, 8%), Niuean (n=9, 3%) and Other/Multiple Pacific (n=14, 5%) self-identified ethnicity. PHS participants had a mean age of 42 years, 98 were female (51%), 31 were current smokers (16%), and ever smokers had a median cigarette consumption of 6 pack-years. MENZACS participants had a mean age of 52 years, 18 were female (19%), 32 were current smokers (33%) and ever smokers had a median cigarette consumption of 11 pack-years. At a false discovery rate of <0.05, Current to never smoker EWAS identified 30 differentially methylated loci in PHS, 176 in MENZACS and 16 in the combined meta-analysis. Our findings are consistent with previously reported associations at these 16 loci in non-Pacific populations[1]. In PHS ex-smokers, eight of the 16 validated loci were correlated with years since quitting, consistent directionally with return to never smoker levels.

Conclusion: Our data identify associations between DNA methylation and cigarette smoking in Pacific Peoples living in NZ. Although we found no novel loci associated with cigarette smoking, the consistency between our observations and previous reports indicates that these sites may have clinical utility as equitable markers of smoking and smoking related disease risk.

  1. Hoang TT, Lee Y, McCartney DL, Kersten ETG, Page CM, Hulls PM, et al. Comprehensive evaluation of smoking exposures and their interactions on DNA methylation. EBioMedicine. 2024;100:104956.