Compared with the general population, people with type 1 diabetes (T1D) more often exhibit pathological alterations in musculoskeletal tissue (impairments). Some of these impairments involve the upper extremities, i.e., the shoulders, hands, and fingers. Although present in diabetes, these complications are underdiagnosed and not actively searched for during routine clinical examinations. Furthermore, much is still unclear about these impairments, specifically regarding their etiology, risk factors, and consequences on daily life activities and quality of life. The growth hormone (GH)/insulinlike growth factor (IGF)-system is known to be affected in diabetes, but whether this is involved in upper extremity impairments (UEIs) is unclear. The aim of this thesis was to describe the prevalence of UEIs in patients with diabetes compared with controls. Furthermore, we aimed to search for risk factors of UEIs, and elucidate the impact of UEIs on daily life activities and health-related quality of life (HRQOL). We used two cohorts; the LedIG cohort (papers I-III), a large population-based study in which all patients with a long duration of T1D (>20 years), aged <67 years, living in the southeast region of Sweden were invited to participate, as well as matched controls without diabetes. This study was based on questionnaires as well as blood samples from the participants. The last paper (IV) included a smaller cohort (n=69) of patients with T1D, who both completed a questionnaire and were the subjects of a clinical examination. Paper I: The UEIs were common in diabetes, with a prevalence of up to 48%. Hand paresthesia was the most common impairment, followed by shoulder pain and stiffness. The prevalence of UEIs was 2-4 times higher in patients than in controls and was associated with more activity limitations. Risk factors were heterogeneous for the different UEIs and included female sex, increasing age, longer duration of diabetes, and poor glycemic control. Paper II: The GH-IGF-axis is important for the growth and function of musculoskeletal tissues. We examined differences in the IGF system between patients with T1D on subcutaneous insulin treatment and controls. We found lower levels of IGF-I and insulinlike growth factor-binding protein (IGFBP)-3 and higher levels of GH and IGFBP-1 in patients with T1D than in controls. The largest difference was found in IGFBP-1, and this probably reflected insulin deficiency. The IGF-I levels were increased with increasing insulin doses. However, even at very high insulin doses (>1 U/kg) the IGF-I Z-score was subnormal, indicating that IGF-I cannot be normalized by subcutaneous insulin treatment. Residual endogenous insulin secretion counteracted these alterations. SF-36 Short Form Health Survey T1D Type 1 diabetes UEI(s) Upper extremity impairment(s) Insulin and its impact on the IGF system Under normal physiological conditions, insulin produced by the pancreas reaches the liver directly through the portal vein, thereby exposing the liver to much higher concentrations of insulin ...