Table 4.
Association of Baseline Urinary Cotinine Levels with Pubertal Onseta; Crude and Adjusted Time Ratios (TRs) with 95% Confidence Intervals (CI)
| Smoke exposure | Crude model
|
Adjustedb model
|
||
|---|---|---|---|---|
| Breast Onset TR (95% CI) |
Pubic Hair Onset TR (95% CI) |
Breast Onset Adjusted TR (95% CI) |
Pubic Hair Onset Adjusted TR (95% CI) |
|
| Cotinine quartile (creatinine-adjusted) | ||||
| Q4: ≥2.25ug/g | 0.94 (0.92–0.97) | 0.95 (0.92–0.98) | 0.99 (0.96–1.01) | 1.00 (0.97–1.03) |
| Q3: 0.62–2.24ug/g | 0.95 (0.93–0.97) | 0.98 (0.95–1.00) | 0.98 (0.96–1.01) | 1.02 (0.99–1.05) |
| Q2: 0.26–0.61ug/g | 0.97 (0.95–1.00) | 0.99 (0.97–1.02) | 0.99 (0.97–1.02) | 1.02 (0.99–1.04) |
| Q1: ≤0.25ug/g | ref | ref | ref | ref |
a
Pubertal onset defined (separately) as breast or pubic hair development at Tanner stage 2 or higher (B2+ or PH2+).
b
Adjusted model includes: child race, study site, household income, primary caregiver’s education, maternal age at delivery, child BMI (baseline) and birth weight.