Association between Relative Handgrip Strength and Insulin Resistance in Korean Elderly Men without Diabetes: Findings of the 2015 Korea National Health Nutrition Examination Survey

BACKGROUND

Evidence regarding the association between handgrip strength (HGS) and insulin resistance in a non-diabetic population is scarce. This study aimed to investigate the association between relative HGS and insulin resistance in older men without diabetes, using a representative sample of the Korean male population.

METHODS

The study population comprised 206 participants aged 65-80 years, selected from the 2015 Korea National Health and Nutrition Examination Survey. Insulin resistance was defined as the upper tertile of the homeostatic model assessment of insulin resistance (HOMA-IR). Odds ratios and 95% confidence intervals for insulin resistance were assessed using multiple logistic regression analyses after adjusting for confounding variables.

RESULTS

The prevalence of insulin resistance decreased with increasing relative HGS. The prevalence in the T1, T2, and T3 groups was 46.0%, 32.2%, and 26.4%, respectively. Compared with the individuals in the highest tertile of relative HGS, the odds ratio (95% confidence interval) for insulin resistance in individuals in the lowest quartile was 2.82 (1.10-7.21) after adjusting for age, smoking, alcohol consumption, aerobic exercise, resistance exercise, systolic blood pressure, total cholesterol, residential area, household income, and education level.

CONCLUSION

Lower relative HGS was inversely associated with an increased risk of insulin resistance in older Korean men without diabetes. In clinical practice, relative HGS, which is a simple and inexpensive tool, could be a useful measure for identifying older men with insulin resistance. Moreover, these findings suggest that muscle strengthening exercises should be considered to reduce insulin resistance and increase insulin sensitivity.

Vitamin D Deficiency Is Inversely Associated with Homeostatic Model Assessment of Insulin Resistance

The study was conducted to comprehensively assess the association of the concentration of vitamin D in the blood and insulin resistance in non-diabetic subjects. The objective was to pool the results from all observational studies from the beginning of 1980 to August 2021. PubMed, Medline and Embase were systematically searched for the observational studies. Filters were used for more focused results. A total of 2248 articles were found after raw search which were narrowed down to 32 articles by the systematic selection of related articles. Homeostatic Model Assessment of Insulin Resistance (HOMAIR) was used as the measure of insulin resistance and correlation coefficient was used as a measure of the relationship between vitamin D levels and the insulin resistance. Risk of bias tables and summary plots were built using Revman software version 5.3 while Comprehensive meta-analysis version 3 was used for the construction of forest plot. The results showed an inverse association between the status of vitamin D and insulin resistance (r = -0.217; 95% CI = -0.161 to -0.272; p = 0.000). A supplement of vitamin D can help reduce the risk of insulin resistance; however further studies, like randomized controlled trials are needed to confirm the results.

Anti-hyperglycemic and hypolipidemic effects of Cistanche tubulosa in type 2 diabetic db/db mice

ETHNOPHARMACOLOGICAL RELEVANCE

The dried succulent stem of Cistanche tubulosa (Schenk) R. Wight is one component of traditional Chinese medicine prescriptions for diabetes. However, there have been no modern scientific reports to confirm this traditional claim for the Cistanche species until now. Thus, we investigated the effects of Cistanche tubulosa on glucose homeostasis and serum lipids in male BKS.Cg-Dock7(m) +/+ Lepr(db)/J (db/db) mice, a model of type 2 diabetes.

MATERIALS AND METHODS

The verbascoside and echinacoside contents of Cistanche tubulosa powder were evaluated using HPLC. The total phenolic content, polysaccharide content and antioxidant activity of Cistanche tubulosa powder were also evaluated. Then, different doses of Cistanche tubulosa (equivalent to 120.9, 72.6 or 24.2mg verbascoside/kg) were administered orally once daily for 45 days to male db/db mice. Age matched db/+ mice were used as normal controls. Body weight, fasting blood glucose, postprandial blood glucose and insulin tolerance test were measured during the experiment. At the time of sacrifice, blood was collected for measurement of insulin level, the homeostatic model assessment of insulin resistance (HOMA-IR), and total cholesterol, triglyceride, HDL-c, LDL-c and VLDL-c levels; liver and muscle were harvested for measurement of glycogen levels.

RESULTS

Cistanche tubulosa significantly suppressed the elevated fasting blood glucose and postprandial blood glucose levels, improved insulin resistance and dyslipidemia, and suppressed body weight loss in db/db mice. However, Cistanche tubulosa did not significantly affect serum insulin levels or hepatic and muscle glycogen levels.

CONCLUSION

This study provides scientific evidence for the traditional use of Cistanche tubulosa to treat diabetes, suggesting that Cistanche tubulosa has the potential for development into a functional food ingredient or drug to prevent hyperglycemia and treat hyperlipidemia.