Endocrine Abstracts

Background: The role of trivalent chromium (Cr³⁺) in improving glucose tolerance, and decreasing insulin resistance is well documented in animals and humans, however supplementation studies gave inconsistent results. Increased urinary excretion of chromium has been reported in type 2 diabetes mellitus (DM). It was not known whether this renal wasting had preceded DM, or was caused by it.

Aim: Our aim was to investigate the relationship between urinary chromium excretion and the degree of insulin resistance (IR) in non-diabetic normotensive Saudi adults; using a known index of insulin resistance; in order to clarify the above point.

Subjects and methods: Of 357 healthy adults aged 18–50 years were recruited randomly from health centers in Jeddah, in a cross-sectional study design. Individuals found to be hypertensive or hyperglycemic were excluded. Anthropometric and demographic information were taken. Insulin, glucose and free fatty acids (FFA) were measured in fasting blood samples. Fasting urinary chromium and creatinine were also determined. Using modified QUICKI (MQUICKI=1/(log(fasting insulin)+log(fasting blood glucose)+log (fasting FFA)) and reported cutoff point, subjects were labeled as high insulin resistant (HIR), or low insulin resistant (LIR). HIR subjects were matched for age and sex to LIR subjects.

Results: Two hundred and nine subjects satisfied the selection criteria. Ninety-seven subjects were found to have HIR. Matching was possible for 90 subjects. This subgroup had higher mean BMI (P=0), and waist circumference (P=0.008). The median urinary chromium (median=2.92 and IQR=1.5–10.28 ng/mg creatinine) was significantly higher than that for LIR subgroup (0.55, and 0.27–1.38 ng/mg creatinine) (P=0).

Conclusion: Higher urinary chromium excretion in studied HIR subgroup indicates a renal lesion leading to chromium deficiency and possibly glucose intolerance and DM eventually. Chromium supplementation might help to protect against the development of DM in this group of HIR non-diabetic Saudi individuals.