Association between Fasting Glucose Levels and Frozen Shoulder in a Normoglycemic Population: A Case-Control Study

Abstract Background Hyperglycemia is the most commonly cited risk factor for adhesive capsulitis. However, no study has established whether fasting glucose levels within the normoglycemic range are associated with idiopathic adhesive capsulitis (IAC). This study hypothesized that increments of fasting glucose levels within the normoglycemic range are linked to IAC. This study investigated any association between normoglycemic fasting glucose levels and IAC. Methods This case-control study comprised a group of 151 IAC patients without intrinsic shoulder lesions, extrinsic causes, or known metabolic risk factors such as diabetes, dyslipidemia, and thyroid dysfunction. The control group comprised 453 age- and sex-matched persons seeking general check-ups at the authors’ health promotion center during the same period as the case group. Control subjects had normal shoulder function, no previous diagnosis of adhesive capsulitis or of metabolic disease, and no history of trauma or of shoulder surgery. The studied variables were body mass index (BMI), serum lipid profiles, thyroid hormone levels, fasting glucose levels, glycosylated hemoglobin A1c, and high-sensitivity C-reactive protein (hs-CRP). Fasting glucose levels were studied as scale data and categorical data ( Results Fasting glucose level, hyper-cholesterolemia, and hs-CRP were significantly associated with IAC (P ≤ .030). Fasting glucose levels in the Conclusion IAC is positively associated with fasting glucose levels of 90-99 mg/dl, which are currently considered normoglycemic.