OBJECTIVE: This systematic review aims to examine the relationship between serum folate level and folic acid supplements with glycemic control parameters (fasting blood glucose (FBG), insulin level, Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), and Hemoglobin A1C (HbA1c)) in adult individuals with current studies.
METHODS: In this study, which was designed as a systematic review, the searches were performed on Web of Science, Science Direct, Medline, Wiley, and Cochrane Library databases between April 10, 2023, and May 10, 2023, and the searches were updated between October 16, 2023, and November 14, 2023. Of the 1855 studies obtained from the screening, 17 met the criteria and were included in the systematic review. The PROSPERO system registered the study protocol (ID: CRD42023472434).
RESULTS: Although no significant correlation was found between serum folate levels and glycemic control parameters in most of the cross-sectional studies included in this systematic review, most of the randomized controlled trials showed that glycemic control parameters (FBG, insulin, HOMA-IR) decreased significantly in the intervention group receiving folic acid supplementation compared to the control group. However, study durations were short, and HbA1c needed to be evaluated in most studies. This makes it difficult to get information about the long-term effects of folic acid supplementation. More comprehensive studies should be conducted to draw more precise conclusions about the relationship between folic acid levels and folic acid supplementation with glycemic control parameters.

UNASSIGNED: The correlation between various insulin resistance surrogates and frailty remains under investigation in the scientific community.
UNASSIGNED: Data from NHANES (1999-2018) were used. We utilized weighted binary logistic regression, trend tests, RCS analysis, and subgroup analysis to comprehensively assess the link between METS-IR, HOMA-IR, and TyG, and frailty risk.
UNASSIGNED: The results revealed a significant positive association between high levels of METS-IR, HOMA-IR, and TyG with the risk of frailty in all models. Notably, in model 4, the highest quintile of METS-IR showed the strongest link (OR: 2.960, 95% CI: 2.219-3.949), with HOMA-IR (OR: 2.522, 95% CI: 1.927-3.301) following closely behind. Trend tests revealed a positive trend between METS-IR, HOMA-IR, and TyG with the risk of frailty (P for trend < 0.05). RCS analysis showed a linear relationship between METS-IR and the risk of frailty (P for nonlinearity > 0.05). In contrast, HOMA-IR and TyG exhibited a U-shaped nonlinear relationship (P for nonlinearity < 0.05).
UNASSIGNED: The research identified a linear association between METS-IR and frailty risk, whereas HOMA-IR and TyG displayed a U-shaped, nonlinear relationship pattern with the risk of frailty. Among the varying levels examined, the linkage between METS-IR and frailty was most pronounced in the top quintile.

BACKGROUND: Insulin resistance (IR) is related with adverse outcomes of in vitro fertilization (IVF) in women with obesity, but little is known about the relationship between IR and unexpected poor ovarian response (uPOR) in non-obese subjects with sufficient ovarian parameters (classified as POSEIDON group 1). This research aims to explore the association between the homeostasis model assessment of insulin resistance (HOMA-IR) and uPOR in non-obese women with normal biomarkers of ovarian reserve.
METHODS: The retrospective cohort study was conducted at a fertility center. The main inclusion criteria were age < 35 years, body mass index (BMI) < 28 kg/m2, normal ovarian reserve (anti-Mullerian hormone ≥ 1.2 ng/ml, antral follicle count ≥ 5). Women undergoing the first oocyte retrieval cycle were included consecutively between 2018 until 2023. Patients who have ≤ 9 oocytes retrieved were defined as uPOR. The multivariable logistic model and subgroup analysis were conducted after adjusting confounders.
RESULTS: A total of 6977 cycles were included. The adjusted odds ratio was 1.25 (95% confidence interval [CI], 1.12-1.39) for the increment of Ln HOMA-IR which was taken as a continuous variable. Meanwhile, as a sensitivity analysis, elevated tertile of HOMA-IR exhibited an increase in risk of uPOR for the third tertile (≥ 2.75) when compared with the first tertile (< 1.75) with OR of 1.33 (95%CI, 1.15-1.54). In the subgroup analysis, the positive association remained consistent.
CONCLUSIONS: Elevated HOMA-IR values is significantly associated with increased risk of uPOR in non-obese women classified as POSEIDON group 1. Our study provided evidence for the adverse influence of IR on the ovarian response during IVF and shed light on the importance of IR measurement at the time of pre-stimulation among non-obese women.

OBJECTIVE: Myo-inositol (MI) is an insulin-sensitizing dietary supplement, enhancing the transfer of glucose into the cell. Gestational diabetes mellitus (GDM) is characterized by abnormal glucose tolerance, which is associated with elevated insulin resistance. The present study aimed to assess the effect of MI supplementation during pregnancy on the incidence of GDM.
METHODS: We performed a single-center, open-label, randomized controlled trial. A cohort of 200 pregnant women at 11-13+6 weeks of gestation were randomly assigned in two groups: MI group (n = 100) and control group (n = 100). The MI group received MI and folic acid (4000 mg MI and 400 mcg folic acid daily), while the control group received folic acid alone (400 mcg folic acid daily) until 26-28 weeks of gestation, when the 75 g Oral Glucose Tolerance Test (OGTT) was performed for the diagnosis of GDM. Clinical and metabolic outcomes were assessed.
RESULTS: The incidence of GDM was significantly higher in the MI group (14.9%) compared to the control group (28.5%) (P = 0.024). Women treated with MI had significantly lower OGTT glucose values, than those not treated with MI (P < 0.001). The insulin resistance as assessed by HOMA-IR was significantly lower in the MI group versus control (P = 0.045). Furthermore, MI group had significantly higher insulin sensitivity as measured by the Matsuda Index, compared to the control group (P = 0.037).
CONCLUSIONS: MI supplementation seems to be an effective option to improve the glycemic control of pregnant women and prevent the onset of GDM.
BACKGROUND: ISRCTN registry: ISRCTN16142533. Registered 09 March 2017.

Prosthechea karwinskii is an endemic orchid of Mexico with cultural significance for its ornamental, food, religious, and medicinal uses. In traditional medicine, diabetic patients use the leaves of this plant to lower glucose levels. The present study evaluated the effect of P. karwinskii leaves extract on the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) in a model of obese rats with insulin resistance for its nutraceutical potential to reduce insulin resistance and oxidative stress. Obesity and insulin resistance were induced with 40% sucrose in water for 20 weeks. Four groups (control rats, obese rats, obese rats administered the extract, and obese rats administered metformin) were evaluated. Extract compounds were identified by UHPLC-ESI-qTOF-MS/MS. Glucose, insulin, triglyceride, and insulin resistance indices (HOMA-IR and TyG), as well as the activity of the antioxidant enzymes, increased in rats in the obese group. Administration of P. karwinskii extract and metformin reduced glucose, insulin, triglyceride, and insulin resistance indices and antioxidant enzyme activity to values similar to those of the control group. Therefore, this study shows the nutraceutical potential of P. karwinskii extract as an ingredient in the formulation of dietary supplements or functional foods to help treat diseases whose pathophysiology is related to oxidative stress and insulin resistance.

There is a relative scarcity of large-scale population studies investigating the relationship between the insulin resistance index of homeostasis model assessment (HOMA-IR) and vascular damage. Therefore, we assessed the association between HOMA-IR and vascular damage in adults aged 18 years and older in China. A total of 17,985 research subjects were included. Vascular damage markers and relevant laboratory tests were measured. HOMA-IR was calculated as (fasting insulin * fasting blood glucose)/22.5. Vascular damage included arteriosclerosis (ba-PWV > 1800 cm/s), peripheral artery disease (ABI < 0.9), and microalbuminuria (UACR > 30 mg/g). The relationship between HOMA-IR and vascular damage was analyzed using the RCS. The restricted cubic spline (RCS) analysis suggested that HOMA-IR was nonlinearly associated with arteriosclerosis (P for no-liner < 0.01), peripheral artery disease (P for no-liner < 0.01), and microalbuminuria (P for no-liner < 0.01). Further segmented regression analyses revealed that in study subjects with HOMA-IR < 5, we found that HOMA-IR was associated with an increased OR for arteriosclerosis (OR: 1.36, 95% CI (1.28, 1.45), P < 0.01), peripheral artery disease (OR: 1.33, 95% CI (1.10, 1.60), P < 0.01) and microalbuminuria (OR: 1.59, 95% CI (1.49, 1.70), P < 0.01). HOMA-IR is an independent risk factor for vascular damage, both macrovascular and microvascular. The phenomenon of saturation of HOMA-IR with vascular damage needs further investigation.

OBJECTIVE: To determine how age affects insulin resistance during the menstrual cycle and insulin resistance-associated indices: the Triglyceride-glucose and Triglyceride-glucose-BMI indexes.
METHODS: This prospective observational study used fasting plasma glucose, fasting insulin, triglycerides, body mass index (BMI), and days since the start of the menstrual period collected from the NHANES dataset (1999-2006). Insulin resistance was determined using the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR). The participants were categorized as young (16-34 years) or older (>35 years). Rhythmicity during the menstrual cycle was analyzed using the Cosinor and Cosinor2 packages for R.
METHODS: Cosine fit curves for insulin resistance during the menstrual cycle and age-associated effects on rhythmicity.
RESULTS: Using 1256 participants, rhythmicity was observed for fasting insulin and HOMA-IR (p < 0.05) but not for fasting plasma glucose, the Triglyceride-glucose index, or the Triglyceride-glucose-BMI index. Significant amplitudes for fasting insulin and HOMA-IR were observed when age was considered. Acrophases for fasting insulin and HOMA-IR were significant only for the younger group, and the differences between these groups were significant, suggesting that the changes in scores for insulin resistance for the younger and older groups occur at different times of their menstrual cycle.
CONCLUSIONS: Insulin resistance does fluctuate during the menstrual cycle, and it is at a maximum at different times for younger and older women. Since these results are unadjusted, this study is preliminary and further investigation is required.

BACKGROUND: Insulin resistance (IR), defined as an impaired response to insulin stimulation of target tissues, is a substantial determinant of many metabolic disorders. This study aimed to update the findings of the previous systematic review evidence regarding the effect of melatonin on factors related to IR, including hyperinsulinemia, hyperglycemia, homeostasis model assessment of insulin resistance (HOMA-IR), and quantitative insulin sensitivity check index (QUICKI).
METHODS: We systematically reviewed the evidence on the impact of melatonin supplementation on IR indices, fasting insulin, and fasting plasma glucose. PubMed, ScienceDirect, SCOPUS, and Google Scholar databases were searched until March 2024.
RESULTS: We identified 6114 potentially relevant articles during the search. Eighteen animal studies and 15 randomized clinical trials met the inclusion criteria. The results indicated that melatonin supplementation reduced fasting plasma glucose (FPG, 14 out of 29 studies), fasting insulin (22 out of 28 studies), HOMA-IR (28 out of 33 studies), and increased QUICKI (7 out of 7 studies). According to RCT studies, melatonin treatment at a dosage of 10 mg reduced HOMA-IR levels in individuals with various health conditions.
CONCLUSIONS: According to most evidence, melatonin supplementation may decrease fasting insulin and HOMA-IR and increase QUICKI but may not affect FPG.

The triglyceride-glucose (TyG) index, proven to be a crucial insulin resistance biomarker (better than the Homeostasis Model Assessment for Insulin Resistance), is simple and non-invasive. Recently, indisputable evidence has shown that the TyG index is strongly associated with cardiovascular disease [CVD, including atherosclerosis, heart failure (HF), and hypertension] prognosis and mortality. Nevertheless, the value of the TyG index in HF patients treated with sodium-glucose cotransporter 2 inhibitors (SGLT2is) has not been systematically evaluated. Therefore, in this review, we summarized the value of the TyG index and its related parameters as markers of CVD, especially HF. Furthermore, we addressed the use of SGLT2is and GLP-1 receptor antagonists in HF patients. Finally, we summarized the mechanism of the \"obesity paradox.\"

This study aims to investigate the potential association between serum levels of cytokines, HSP60, HSP70 and IR (HOMA-IR) in postmenopausal women. We conducted a cross-sectional study involving 381 postmenopausal women, including 94 with a breast cancer diagnosis and 278 without. We analyzed anthropometric and laboratory measurements. Immunoassays were used to measure cytokines (TNF-α, IL-10, and IL-6) as well as heat shock proteins (HSP) 60 and 70 in the serum using the ELISA technique. Women diagnosed with breast cancer showed higher levels of HOMA-IR, IL-6, TNF, and HSP60, and lower levels of IL-10 and HSP70 compared to women without cancer. An association was found between HSP70 and HOMA-IR only in women with breast cancer (β = 0.22, p = .030; without cancer: β = 0.04, p = .404), regardless of age, waist circumference, smoking, and physical activity. No associations were observed between cytokines, HSP60, and HOMA-IR in both groups of women. HSP70 is positively associated with IR in women diagnosed with breast cancer.