Table 6

Estimated number of deaths up to the end of the year 2002 in the Million Women Study cohort and minimum and maximum detectable relative risks for certain common conditions


Current versus never users
 Current users of 5+ years duration versus never users


Cause of death
 Expected number of deaths*
 Minimum detectable RR† > 1
 Maximum detectable RR† < 1
 Minimum detectable RR† > 1
 Maximum detectable RR† < 1
All cancers
 12 600
 1.06
 0.94
 1.08
 0.92
     Colorectal cancer
 1200
 1.20
 0.82
 1.25
 0.77
     Lung cancer
 2000
 1.15
 0.86
 1.19
 0.82
     Breast cancer
 2800
 1.13
 0.88
 1.16
 0.85
     Ovarian cancer
 1100
 1.20
 0.81
 1.26
 0.76
     Endometrial cancer
 250
 1.41
 0.65
 1.53
 0.56
All circulatory disease
 8000
 1.08
 0.93
 1.10
 0.91
     Ischaemic heart disease
 5000
 1.09
 0.91
 1.12
 0.88
     Stroke
 1700
 1.16
 0.85
 1.21
 0.81
All causes of death
 23 200
 1.05
 0.95
 1.06
 0.94

*Based on national mortality rates for 1996 in England and Wales with the assumption that death rates from causes other than breast cancer are 20% lower than the national rate and that breast cancer death rates are 30% lower than the national rate. †Detectable at the 95% significance level with 80% power, assuming that death rates among never users are equivalent to national rates. RR, risk ratio.

The Million Women Study Collaborative Group Breast Cancer Res 1999 1:73   doi:10.1186/bcr16

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