Table 1.

Unadjusted differences and 95% CIs for the association between DNA methylation by prenatal, early life, adolescent, and adult variables (higher values indicate less DNA methylation)

Mean (SD)Range, minimum, maximumDPM/μg ≤ 78,670 (n = 43)DPM/μg > 78,670 (n = 42)log DPM/μg β (95% CI)
Prenatal
Prenatal smoke exposure (cigarettes smoked/d)
    Unexposed122,158 (114,004)(45,872, 660,800)2629
    Exposed96,480 (88,765)(40,032, 536,595)1613−0.17 (−0.41, 0.08)
Race
    White103,917 (81,256)(40,032, 407,086)1514
    Black131,220 (131,296)(64,985, 660,800)11210.17 (−0.11, 0.44)
    Hispanic99,144 (93,132)(45,872, 466,774)177−0.08 (−0.37, 0.21)
Family socioeconomic status−0.005 (−0.01, 0.00)
Early life
Birth weight (kg)
    ≤3.12109,842 (89,544)(45,872, 536,595)2023−0.04 (−0.27, 0.18)
    >3.12115,926 (120,854)(40,032, 660,800)2319
Birth length (cm)
    ≤50125,793 (111,726)(45,872, 536,595)2124−0.05 (−0.10, −0.002)
    >5098,286 (97,549)(40,032, 660,800)2218
Adolescent
Age at menarche (y)
    <13128,563 (126,851)(40,032, 660,800)1822
    ≥13100,348 (82,819)(48,082, 536,595)2320−0.14 (−0.38, 0.10)
Childhood passive smoke exposure
    Unexposed124,461 (140,825)(48,082, 660,800)109
    Exposed109,506 (94,145)(40,032, 536,595)3333−0.04 (−0.32, 0.24)
Adult
Age at interview (y)
    ≤42.28105,210 (107,781)(40,032, 660,800)2517
    >42.28120,310 (104,111)(48,082, 536,595)18250.03 (−0.03, 0.09)
Current BMI (kg/m2)
    <25116,683 (104,058)(45,872, 536,595)1621
    ≥25111,550 (112,165)(40,032, 660,800)2519−0.05 (−0.29, 0.19)
Smoking status
    Never111,913 (96,772)(45,872, 536,595)2022
    Former106,470 (94,724)(40,032, 466,774)1412−0.06 (−0.33, 0.21)
    Current124,914 (142,420)(59,672, 660,800)980.05 (−0.26, 0.36)
Parity
    Parous121,295 (119,662)(45,872, 660,800)2929
    Nulliparous93,660 (65,240)(40,032, 316,790)1412−0.23 (−0.49, 0.02)
    Age at first birth−0.02 (−0.04, −0.004)
  • Abbreviation: DPM, disintegrations per minute.