Estimates of the prevalence of acromegaly, a condition resulting from excess growth hormone secretion, are as high as 1:1000. If detected late acromegaly increases the risk of joint destruction, heart disease, sleep apnoea, high blood pressure, diabetes, and polyps in the colon. To have a greater effect on long-term outcomes this disease needs to be detected early. By screening a 'high risk' population (sleep apnoea clinic) the investigators may be able to detect these patients earlier and prevent late complications of the disease. At LTHT the referral pathway for new referrals to the sleep apnoea clinic involves initial attendance to pick up a pulse oximeter to wear overnight to measure oxygen levels. These readings show approximately 1:4 patients displays evidence of significant obstructive sleep apnoea to warrant referral to the treatment group for continuous positive airway pressure (CPAP), weight management, and occasionally mandibular adjustment.

Patients attending the sleep apnoea clinic either as new referral or for review will be asked to participate in the proposed study. The study is cross-sectional in design incorporating two sub-populations within the sleep apnoea clinic. The first cohort comprises patients under follow-up known to have sleep apnoea, and the second cohort those patients prospectively attending the sleep apnoea clinic for assessment. If after an explanation of the study they agree to participate blood will be taken for assessment of IGF-I and they will be asked to complete a simple questionnaire.

The aim will to be to screen 1000 consecutive patients. The questionnaire will incorporate five simple questions to be completed with a 'yes' or 'no' answer. Where IGF-I levels are elevated patients will be investigated further for the possibility of acromegaly. The presence of biochemically proven acromegaly will be used to determine if the simple question has sufficient sensitivity to use as a screening tool.

Inclusion Criteria:

• Adults aged 16 and above.
• Referred to the Sleep Apnoea Clinic for assessment of obstructive sleep apnoea
• Have capacity to given informed consent.

Exclusion Criteria:

• Patients under 16 years of age
• Not referred to the Sleep Apnoea Clinic
• Unable to give informed consent

All patients attending the sleep apnoea clinic.