Participants were asked to fill in questionnaires after their clinic visit and return these to the study team using a stamped addressed envelope provided. Participants were sent a reminder if the questionnaires had not been received within 6 weeks of their clinic visit. As the questionnaires were received into the office they were checked for missing or ambiguous answers (e.g. marking two responses instead of one) and corrections sent to the participant. These were generally promptly returned. The LBC1936 Study Questionnaire is a 20-page questionnaire booklet arranged in 5 sections, covering various aspects of the participants' lives.
