Table 1.

Age distribution of women admitted to hospital with BBD in Oxford and England: number and percentage of women in each age group at the time of admission

	Oxford			England
	Number	Percentage	MRa	Number	Percentage	MRa
Age group (years)
Under 25	2709	12.9	15	8627	9.7	17
25–29	2378	11.3	12	7002	7.8	18
30–34	2728	13	10	9370	10.5	14
35–39	3151	15	8	11 852	13.3	11
40–44	3550	16.9	7	12 396	13.9	10
45–49	3012	14.3	8	11 221	12.6	11
50–54	1539	7.3	14	10 947	12.3	12
55–59	667	3.2	23	6229	7	22
60–64	473	2.3	29	4369	4.8	31
65–69	348	1.7	42	2937	3.3	52
70–74	192	0.9	81	1984	2.2	87
75 +	229	1.2	168	2334	2.6	207
Total	20 976	100	14	89 268	100	22

^aMatching ratio (MR) = the number of people in the reference cohort per person with BBD in each age stratum, see the ‘Methods’ section.