Table 2.

Associations between age at menarche and lumbar spine BMD

Age at menarche (years)	Beta	SE	P value	95% CI
Model 1
≤ 12	Reference
13–15	− 0.020	0.014	0.160	(− 0.046, 0.007)
≥ 16	− 0.083	0.018	< 0.001	(− 0.117, − 0.048)
Model 2
≤ 12	Reference
13–15	− 0.013	0.014	0.355	(− 0.041, 0.015)
≥ 16	− 0.078	0.018	< 0.001	(− 0.113, − 0.042)
Model 3
≤ 12	Reference
13–15	− 0.014	0.014	0.322	(− 0.041, 0.013)
≥ 16	− 0.065	0.016	< 0.001	(− 0.096, − 0.033)

Model 1: no covariates were adjusted for

Model 2: age, race, and BMI were adjusted for

Model 3: age, race, BMI, education level, family PIR, smoking behavior, alcohol consumption, years since menopause, parity, female hormone use, vigorous activities, moderate activities, total calcium, serum phosphorus, arthritis, thyroid disease, liver disease, kidney disease, and diabetes were adjusted for