Table 3.

Estimates and 95% confidence intervals (CI) for multivariable regression analysis of two-year areal bone mineral density (BMD) change at the lumbar spine (L2-4), femoral neck (FN) and total hip (TH) for: A. never (N-CHC) versus ever (E-CHC) use of combined hormonal contraceptives (CHC); and B. age at first CHC use, in all women in the Canadian Multicentre Osteoporosis Study (CaMos) Youth Cohort (ages 16-24 years) and in Adolescent (ages 16-19 years) and Young Adult (aged 20-24 years) sub-cohorts with 95 percent confidence intervals (95% CI). Results in bold are statistically significant.

A. +Adjusted 2-y BMD change estimates (95% CI) for N-CHC users versus E-CHC users
	CaMos Youth Cohort 16-24 years		Adolescent 16-19 years		Young Adult 20-24 years
	estimate	95% CI	estimate	95% CI	estimate	95% CI
L1-L4	0.002	(-0.104; 0.091)	0.004	(-0.008; 0.015)	-0.007	(-0.020; 0.006)
FN	-0.001	(-0.010; 0.008)	0.009	(-0.002; 0.021)	-0.021	(-0.036; -0.006)
TH	-0.001	(-0.009; 0.006)	0.002	(-0.008; 0.012)	-0.013	(-0.026; 0.000)
B. +Adjusted 2-year BMD change estimates (95% CI) for age CHC started among CHC users
	CaMos Youth Cohort 16-24 years		Adolescent 16-19 years		Young Adult 16-24 years
	estimate	95% CI	estimate	95% CI	estimate	95% CI
L1-L4	0.001	(-0.001; 0.003)	-0.001	(-0.005; 0.004)	-0.007	(-0.020; 0.006)
FN	0.000	(-0.002; 0.002)	-0.001	(-0.005; 0.003)	0.000	(-0.002; 0.003)
TH	0.000	(-0.002; 0.002)	0.000	(-0.004; 0.004)	0.000	(-0.002; 0.002)

⁺ Adjusted for baseline age, height, BMI, menarche age, total calcium intake, 24 hour physical activity (kcal/d), alcohol consumption, current smoking, BMD and Body Mass Index change over 2-years.