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Table 1 Sample characteristics

From: Novel DNA methylation signatures of tobacco smoking with trans-ethnic effects

Cohorta Sample size Smoking statusb Sex Age (years) BMI Ethnicityc
S (n) F (n) NS (n) F (%) M (%)
Discovery stage
TwinsUK 407 23 237 147 100 0 64 ± 8 26.8 ± 5.0 White British
NSHD 236 23 75 138 60 40 63 ± 0.5 27.9 ± 4.7 White British
NCDS1 235 53 118 64 53 47 45 25.6 ± 4.3 White British
NCDS2 294 125 87 82 51 49 45 25.8 ± 4.3 White British
BCS70 235 45 126 64 57 43 46 26.6 ± 5.0 White British
Replication stage
SHS 2325 893 648 748 59 41 55 ± 6 29.6 ± 3.0 American Indian
GENOA 1100 179 255 666 71 29 56 ± 10 31 ± 6.6 African-American
  1. aCohort abbreviations: TwinsUK: https://twinsuk.ac.uk/, NSHD: MRC National Survey of Health and Development, NCDS: National Child Development Study (NCDS1 = selected to minimize data missingness, but not selected for specific exposures and trait outcomes. NCDS2 = selected for extremes of child and adulthood adversity), BCS70: 1970 British Cohort Study, SHS: Strong Heart Study. GENOA: Genetic Epidemiology Network of Arteriopathy
  2. bSmoking status, age and BMI are obtained at the date of blood draw for DNA methylation profiling. Smoking status (S = smoker, F = former smoker, NS = never smoker) is determined through questionnaires
  3. cParticipants from the UK population cohorts are predominantly “White British.” NCDS2 includes one individual who did not identify as “White British” (“Mixed”). BCS70 includes three individuals who did not identify as “White British” (one “White Other”, one “White and Asian” and one “Other Ethnic Group”)
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