Table 3.

Estimates of the intention-to-treat effect of initiation of estrogen/progestin therapy on the incidence of CHD events in the NHS “trials”

		Follow-up Period
	All	0–24 mo	>24 mo
Initiators
Total no.	7,258	7,258	7,221
No. CHD events	98	22	76
Noninitiators
Total no.	141,002	141,002	139,599
No. CHD events	3,606	512	3,094
	HR (95% CI)	HR (95% CI)	HR (95% CI)
All women	0.96 (0.78 – 1.18)	1.42 (0.92 – 2.20)	0.88 (0.69 – 1.12)
By time after menopause (years)
< 10	0.84 (0.61 – 1.14)	1.33 (0.66 – 2.64)	0.77 (0.54 – 1.09)
≥10	1.12 (0.84 – 1.48)	1.48 (0.83 – 2.64)	1.05 (0.77 – 1.43)
P for interaction	0.08	0.90	0.07
By age (years)
< 60	0.86 (0.65 – 1.14)	1.36 (0.73 – 2.52)	0.78 (0.57 – 1.07)
≥60	1.15 (0.85 – 1.57)	1.49 (0.79 – 2.80)	1.08 (0.76 – 1.54)
P for interaction	0.05	0.72	0.06

Adjusted for the following baseline variables: age, parental history of myocardial infarction before age 60, education, husband’s education, ethnicity, age at menopause, calendar month, high cholesterol, high blood pressure, diabetes, angina, stroke, coronary revascularization, osteoporosis, body mass index, cigarette smoking, aspirin use, alcohol intake, physical activity, diet score, multivitamin use, fruits and vegetables intake, and previous use of hormone therapy. The last column is restricted to women who were not censored by the first 2 years of follow-up of the corresponding trial.