Inclusion Criteria:  Aged 18 - 75 years Male or female Participants who are otherwise healthy enough to participate, as determined by pre-study medical history Participants who are able and willing to give written informed consent to participate in the study Group A only: Patients requiring acute (<5 days) high dose (minimum 30mg) oral prednisolone therapy for antiinflammatory purposes in either an inpatient or outpatient setting. Group B only: Minimum of 1 month duration of high dose prednisolone (>30mg) if in the chronic use group. Group C only: Patients started on high dose methylprednisolone (>3 day course) or prolonged courses of dexamethasone.  Exclusion Criteria:  Participants with a diagnosis of Type 1 or Type 2 diabetes mellitus. Unable to give informed consent. Taking supplements or herbal medications that the participant is unwilling or unable to stop prior to and during the study period e.g. St John's Wort (may decrease prednisolone levels), Cat's claw, Echinacea (immunomodulatory properties). Currently taking medications that alter CYP3A4 metabolism of glucocorticoids that the participant is unwilling or unable to stop prior to and during the study period e.g. phenytoin, phenobarbital, rifampicin, rifabutin, carbamazepine, primidone, aminogluethimide, itraconazole, ketoconazole, ciclosporin or ritonavir. Pregnancy. Females of child-bearing age will be asked to provide a urine sample for a pregnancy test at each visit. History of any medical, psychological or other condition, or use of any medications, including over-the-counter products, which, in the opinion of the investigators, would either interfere with the study or compromise the safety of the participant.