Table 1.

Average age and gender of sample at different recruitment stages

Recruitment stage	Mean age (range), years	Female, n (%)	N
Completed online prescreening	25.03 (18–50)	4,503 (71.6)	6,293
Telephone screened	23.22 (18–50)a	120 (70.2)a	173
Attended medical screening	22.98 (18–49)	41 (77.4)	53
Completed trial	23.54 (19–49)	21 (87.5)	24

Note:

^a14 missing data items.