INS and cystic fibrosis-related diabetes: The presence of CFRD has been linked to greater declines in pulmonary function—reflected by lower forced expiratory volume in 1 s (FEV1), and more frequent pulmonary exacerbations—and this deterioration often precedes CFRD diagnosis but improves after insulin treatment, suggesting that the impairment in pulmonary function is a consequence of CFRD rather than its underlying cause [10, 11].