Amanda L Brennan1, Scott M Blackman2. 1. Manchester Adult Cystic Fibrosis Centre, Manchester University NHS Foundation Trust, Manchester, United Kingdom. Electronic address: amanda.brennan@mft.nhs.uk. 2. Division of Pediatric Endocrinology and Diabetes, Johns Hopkins University School of Medicine, Baltimore, MD, USA. Electronic address: sblackman@jhmi.edu.