Breastfeeding and timing of pubertal onset in girls: a multiethnic population-based prospective cohort study

BMC Pediatrics

Table 5 Association between breastfeeding duration and pubertal onset, stratified by maternal race/ethnicity: KPNC puberty study (N = 3331)

Race/Ethnicity	n	Breastfed ≥6 months	Breastfed < 6 months		Not breastfed
Race/Ethnicity	n	HR	HR	95% CI	HR	95% CI
Breast development^a
Non-Hispanic White	1387	Ref	1.15	0.95–1.40	1.19	0.92–1.56
African American	243	Ref	1.63	0.96–2.77	1.92	1.01–3.66
Asian/Pacific Islander	780	Ref	1.00	0.76–1.31	1.32	0.92–1.89
Hispanic	860	Ref	0.99	0.75–1.30	1.21	0.86–1.71
Combined	3270	Ref	1.09	0.97–1.22	1.25	1.07–1.46
Pubic hair development^a
Non-Hispanic White	1311	Ref	1.30	1.06–1.60	1.17	0.88–1.56
African American	227	Ref	0.99	0.48–2.02	1.14	0.51–2.52
Asian/Pacific Islander	740	Ref	1.24	0.94–1.64	1.33	0.93–1.91
Hispanic	809	Ref	0.88	0.67–1.16	1.30	0.93–1.82
Combined	3087	Ref	1.14	1.00–1.30	1.24	1.05–1.46

CI Confidence interval, HR Hazard ratio, KPNC Kaiser Permanente Northern California
^aAdjusted for maternal age at delivery, education, and parity

ISSN: 1471-2431