From: Breastfeeding and timing of pubertal onset in girls: a multiethnic population-based prospective cohort study
Breastfeeding durationa
N
TR
95% CI
HR
Not breastfed
470
0.98
0.96–1.00
1.24
1.05–1.46
< 6 months
1028
0.99
0.97–1.00
1.14
1.00–1.30
≥6 months
1589
Ref