Table 2.

Age Difference in Timing of Puberty in Months per 10 Daily Cigarettes in the First Trimester of Gestation for Children in the Puberty Cohort, Danish National Birth Cohort, Denmark, 2012–2017

Pubertal Milestone	No.a	Age Differenceb
		Unadjusted	Adjustedc
		Mean	Mean	95% CI
Sons
Tanner genital stage 2	7,446	−1.3	−1.3	−2.5, 0.0
Tanner genital stage 3	7,446	−2.4	−2.1	−3.3, −1.0
Tanner genital stage 4	7,446	−2.6	−2.3	−3.3, −1.3
Tanner genital stage 5	7,446	−4.0	−3.7	−5.3, −2.0
Tanner pubic hair stage 2	7,450	−1.7	−1.8	−2.9, −0.6
Tanner pubic hair stage 3	7,450	−2.4	−2.2	−3.2, −1.2
Tanner pubic hair stage 4	7,450	−2.3	−2.0	−2.9, −1.2
Tanner pubic hair stage 5	7,450	−3.3	−2.9	−4.2, −1.7
Axillary hair	7,455	−2.5	−2.0	−3.2, −0.8
Acne	7,455	−2.2	−1.9	−3.0, −0.8
Voice break	7,253	−3.1	−2.4	−3.6, −1.3
First ejaculation	7,442	−1.6	−1.7	−2.8, −0.6
Daughters
Tanner breast stage 2	7,866	−4.5	−3.4	−5.3, −1.5
Tanner breast stage 3	7,866	−3.6	−2.6	−3.7, −1.6
Tanner breast stage 4	7,866	−3.6	−2.8	−3.8, −1.8
Tanner breast stage 5	7,866	−5.9	−4.7	−6.5, −2.9
Tanner pubic hair stage 2	7,867	−0.5	−0.1	−1.0, 0.8
Tanner pubic hair stage 3	7,867	−1.3	−0.9	−1.7, −0.1
Tanner pubic hair stage 4	7,867	−1.8	−1.4	−2.5, −0.4
Tanner pubic hair stage 5	7,867	−3.4	−2.5	−4.1, −1.0
Axillary hair	7,872	−1.7	−1.0	−2.1, 0.1
Acne	7,872	−2.8	−2.1	−3.4, −0.9
Menarche	7,864	−4.1	−3.1	−4.0, −2.3

Abbreviation: CI, confidence interval.

^a Some sons and daughters gave information on some but not all pubertal milestones, so different numbers of observations were used for each outcome.

^b Change in age (β) in months at attaining pubertal milestones per 10 daily cigarettes in the first trimester with 95% confidence interval.

^c Adjusted for prepregnancy body mass index, alcohol units per week in the first trimester, time to pregnancy (including assisted reproductive technology), highest social class of parents, maternal age at menarche, maternal age at delivery, parity, and cohabitation of parents during pregnancy.