Table 5.

Observed number of cases of and deaths from colorectal cancer with expected numbers using the best estimate (plausible range) of risk based on family history

		Best estimate
	Observed	Expected	Standardised risk ratio†	Plausible range of standardised risk ratio‡
Deaths from colorectal cancer		(followed to 31 December 2002)
Moderate risk	2	10.7	0.19**	0.10***-0.38
Group 4§	3	10.9	0.28*	0.20***-0.59
Cases of colorectal cancer
Between first and last colonoscopy (excluding those detected on first colonoscopy)
Moderate risk	1	13.4	0.08***	0.04***-0.15*
Group 4§	8	16.5	0.49*	0.35***-1.04
In individuals followed for at least 3 years (to 31 December 2001)
Moderate risk	4	19.9	0.20***	0.11***-0.41
Group 4§	11	19.2	0.57	0.41***-1.23
In individuals followed for at least 3 years (to 31 December 2003)
Moderate risk	4	26.5	0.15***	0.08***-0.30**
Group 4§	11	26.6	0.41**	0.30***-0.89

^*One sided P<0.025. ^**One sided P<0.005. ^***One sided P<0.0005.

^†Standardised risk ratio: O/E=observed/expected.

^‡O/E based on the expected number of cases when the highest and the lowest reasonable values for the familial risk are used.

^§Families meeting the Amsterdam criteria.