Insulin Resistance

Insulin resistance is a clinical condition where insulin becomes less effective at lowering blood sugar. The human body compensates for this by stimulating the pancreas to overproduce insulin and ensure that glucose can leave the bloodstream and enter the cells.

This condition is diagnosed by testing for levels of adiponectin, insulin, proinsulin, and HbA1c. Most of the individuals with insulin resistance report normal blood sugar levels and thus are usually undiagnosed.

Insulin resistance is a major cause of premature aging and mortality. Women in perimenopause or menopause are more likely to have undiagnosed insulin resistance. If this condition is left unchecked it could lead to prediabetes, hyperlipidemia, PCOS, and increased risk of diabetes, cancer, cardiovascular disease.

Nutrition therapy and lifestyle modification under clinical supervision is the primary treatment for insulin resistance.

The National Institute of Health-funded research study, the Diabetes Prevention Program (DPP) suggests that for individuals who are at high risk of developing diabetes, losing 5 to 7 percent of their starting weight reduces the chances of developing the disease¹. The most accurate test for insulin resistance is complicated and used mostly for research. The following tests are generally advised to diagnose insulin resistance.

• The median value for adiponectin was 7.13μg/mL (range 3.14–23.1) in progressors of diabetes and 8.54μg/mL (range 3.18–45.8) in non-progressors².
• Fo proinsulin, the normal ranges are 3.6-22 pmol/L³.
• HbAa1c levels can be used as an early diagnostic tool for insulin resistance. According to a study conducted by Anwar et al HbA1c can be used as a simple and reliable marker of insulin resistance in NGT adults with relatively high insulin sensitivity⁴. Normal ranges for Hb1c are 5.7% to 6.4%

However, the ranges can be lower than normal as Hba1c offers lower sensitivity than other screening tests and individuals have likely developed significant insulin resistance and pancreatic beta-cell dysfunction by the time it rises significantly⁵. In particular insulin, resistance score can be obtained by HOMA -IR values using the following formula proposed by Mathews et al⁶.

HOMA IR = Fasting plasma glucose * Fasting serum insulin/22.5

A Homa value greater than 2.5 is considered an indicator of insulin resistance. Low HOMA -IR values indicate high insulin sensitivity whereas high HOMA-IR values indicate insulin resistance⁷.

REFERENCES:

1. Diabetes Prevention Program Research Group. Long-term effects of lifestyle intervention or metformin on diabetes development and microvascular complications over 15-year follow-up: the Diabetes Prevention Program Outcomes Study. The Lancet: Diabetes & Endocrinology. 2015;3(11):866‒875.

2. Jiang Y, Owei I, Wan J, et al, Adiponectin levels predict prediabetes risk: the Pathobiology of Prediabetes in A Biracial Cohort (POP-ABC) study, BMJ Open Diabetes Research and Care 2016.

3. Proinsulin

4. Borai A, Livingstone C et al, The relationship between glycosylated haemoglobin (HbA1c) and measures of insulin resistance across a range of glucose tolerance, Scand J Clin Lab Invest. 2011 Apr; 71(2):168-72. {:target="_blank"}

5. Kanat M, DeFronzo RA, Abdul-Ghani MA. Treatment of prediabetes. World J Diabetes. 2015;6(12):1207-1222.

6. Matthews DR, Hosker JP, Rudenski AS, Naylor BA, Treacher DF, Turner RC Homeostasis model assessment: insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man, Diabetologia. 1985 Jul;28(7):412-9

7. Bonora E, Targger G, Alberich M, Bonadonna RC, Saggiani F, Zenere MB, Monauni T, Muggeo M: Homeostasis model assessment closely mirrors the glucose clamp technique in the assessment of insulin sensitivity: studies in subjects with various degree of glucose tolerance and insulin sensitivity. Diabetes Care 23:57–63, 2000