Table 2. Comparison of age, gender, and trial site of those who did or did not respond to the invitation to participate
CharacteristicInvitedNon-respondersResponders
Agreed to
contact		Declined contactAgreed to take part in telephone interview about reasons for declining
Mean age, years (SD),a n41.5 (16.2)
n = 11 599		40.4 (15.6)
n = 9950		43.1 (15.9)
n = 990		56.7 (18.5)
n = 659		53.7 (17.9)
n = 226
Gender: female,a n (%)7496 (64.2)6377 (63.6)665 (66.9)454 (68.3)157 (68.6)
Trial site: n (%)
Bristol4362 (35.8)3604 (34.7)462 (43.0)296 (40.8)108 (44.4)
London5080 (41.7)4495 (43.3)358 (33.3)227 (31.3)79 (32.5)
York2740 (22.5)2284 (22.0)254 (23.6)202 (27.9)56 (23.0)

  • aData on age and gender were not available for all. n denotes those with available data. SD = standard deviation