The present study aims to investigate the effects of duration and complications of type 2 diabetes mellitus on diabetic related parameters, adipocytokines and calcium regulating hormones. This study was conducted on eighty diabetic patients (41 male and 39 female) in Iraq, with an age range of 20-60 years and a disease duration range of 1-180 months. Blood samples were collected from the patients to determine three main types of biomarkers: diabetic-related parameters [Fasting blood sugar is FBS glycated hemoglobin (HbA1c), insulin, and insulin resistance (IR)], adipocytokines [adiponectin and tumor necrosis factor-α (TNF-α), and calcium regulating hormones [parathyroid hormone (PTH), calcitonin, and vitamin D].

     The result showed increased levels of some parameters with the increase in duration of disease. Levels of FBS and HbA1c increased significantly (probability <0.05) in the second and the third categories of duration of disease (61-120 and 121-180 month) compared with the first category (1-60 month). Levels of insulin and IR were increased with the increase in duration of disease; this increase was found to be significant (p<0.05) when a comparison was made between the second and the third categories with the first category. Also, a similar trend was observed when a comparison was made between the third category and the second category. There was a significant (P<0.05) increase in the levels of TNF-α and calcitonin in the last category compared with the other categories, and a significant (P<0.05) increase in vitamin D levels in the last category compared with the first category. Non-significant (P>0.05) differences were found in the levels of adiponectin and PTH among all categories of duration of disease.

     When a comparison was made between the two groups of patients (with complications and without complications), a significant (P<0.05) increase was found in the levels of FBG, HbA1c, insulin, and IR in patients with complications as compared with patients without complications. A significant (P<0.05) decrease was found in calcitonin levels in patients with complications as compared with patients without complications. Non-significant (P>0.05) differences were found in the levels of the other parameters (adiponectin, TNF-α, PTH and vitamin D) between the two groups of patients.

     It can be concluded from the present study that duration of disease affects diabetic related parameters, TNF-α and some calcium regulating hormones (calcitonin and vitamin D), while complications of disease affect diabetic related parameters and calcitonin. It can be suggested that the duration of diabetes is one of the strongest determinants of complication risk.