Serum ferritin level as an early indicator of metabolic dysregulation in young obese adults - a cross-sectional study

Ferritin is a potential marker of cardiometabolic risk in adolescents and young adults with sleep-disordered breathing

Objective

To explore markers that reflect sleep-disordered breathing (SDB) severity and investigate their associations with cardiometabolic risk factors in adolescents and young adults.

Methods

Participants were recruited from our SDB epidemiological cohort. They underwent overnight polysomnography and ambulatory blood pressure (BP) monitoring. Complete blood count, ferritin, high-sensitivity C-reactive protein (hs-CRP), fasting blood glucose, and lipid profile were measured. Multiple linear regression was used to examine the association between red cell indices (RCIs), ferritin, and obstructive apnea-hypopnea index (OAHI). Subgroup analyses on participants with SDB were performed for the association of RCIs and ferritin with lipid profile, hs-CRP, and BP.

Results

There were 88 participants with SDB and 155 healthy controls aged 16-25 years. Hemoglobin (Hb; p < .001), hematocrit (HCT; p < .001), and ferritin (p < .001) were elevated with increasing SDB severity and were independently associated with OAHI (β=1.06, p < .001; β=40.2, p < .001; β=4.89 × 10-3, p = .024, respectively). In participants with SDB, after adjusting for age, sex, and BMI, significant associations were found between ferritin with low-density lipoprotein (LDL; β=0.936 × 10-3, p = .008) and triglyceride (TG; β =1.08 × 10-3, p < .001), as well as between Hb (β=1.40, p = .007), HCT (β=51.5, p = .010) and mean arterial pressure (MAP). Ferritin (β=0.091, p = .002), Hb (β=0.975, p = .005), and HCT (β=38.8, p = .004) were associated with hs-CRP independent of age, sex, BMI, plasma LDL, and MAP. OAHI was not associated with LDL and TG in the multivariable models.

Conclusions

Serum ferritin, but not OAHI, was associated with LDL and TG in participants with SDB, suggesting it is a potential marker of cardiometabolic risk in patients with SDB.

Serum Ferritin Levels Are Associated with Adipose Tissue Dysfunction-Related Indices in Obese Adults

Iron overload is associated with type 2 diabetes and metabolic syndrome. However, little is known about the role of iron status on adipose tissue. We aimed to investigate the association of iron metabolism markers with adipose tissue dysfunction-related indices in obese individuals. A total of 226 obese adults with body mass index (BMI) ≥ 30 kg/m² were recruited into the study. Hemoglobin, serum ferritin, iron, soluble transferrin receptor (sTfR), total iron-binding capacity (TIBC), transferrin saturation (TSAT), and other clinical parameters were measured. Adipose tissue dysfunction was assessed by adipose tissue insulin resistance (adipose-IR), visceral adiposity index (VAI), and lipid accumulation product (LAP) index. Serum ferritin levels, adipose-IR, and VAI progressively increased from class I to class III obesity and significantly higher in class III obesity. Correlation analysis suggested that only serum ferritin levels were positively correlated with adipose-IR (r = 0.284, P < 0.001), VAI (r = 0.209, P = 0.002), and LAP (r = 0.324, P < 0.001). Moreover, further logistic regression analysis revealed serum ferritin was significantly associated with elevated adipose-IR, VAI, and LAP. After adjustment for potential confounders, serum ferritin levels remained independently associated with elevated adipose-IR (OR = 1.004, 95% CI 1.000-1.009, P < 0.05) and VAI (OR = 1.005, 95% CI 1.001-1.009, P < 0.05). Serum ferritin was associated with elevated adipose-IR, VAI, and LAP, suggesting that ferritin could be an important early indicator for the risk of developing adipose tissue dysfunction in obese individuals.

The association between vitamin C dietary intake and its serum levels with anthropometric indices: A systematic review and meta-analysis

BACKGROUND

studies showed inflammatory background of overweight and obesity. Prevalence of weight disorders has dramatically increased over the past few decades. Vitamin C is an antioxidant and may be associated with weight disorders. This study aims to systematically review the relationship between dietary and serum vitamin C levels with anthropometric indices.

METHODS

A systematic search was conducted in Medline database (PubMed), Scopus, Embase, Web of Science, Cochrane library and Google Scholar up to the end of August 2021. All observational studies that assessed the relationship between dietary or circulating vitamin C levels and body mass index (BMI) and waist circumference (WC) on adults were included. The quality of included studies was assessed using the National Institute of Health quality assessment tool.

RESULTS

Among 11,689 studies, 47 and 37 articles were included in the systematic review and meta-analysis, respectively. There was an inverse significant correlation between WC and serum vitamin C levels (r = -0.28, 95% CI: -0.35,-0.21, I² = 14.2%) and between BMI and serum vitamin C levels (r = -0.17, 95% CI: -0.25, -0.09, I² = 72.8%). Higher vitamin C consumption was significantly associated with lower BMI. There were no significant differences in serum vitamin C levels between normal-weight and overweight subjects, but serum vitamin C levels were significantly higher in obese subjects in comparison with normal-weight subjects.

CONCLUSION

Results showed that both dietary and serum vitamin C levels were inversely associated with BMI and WC. More well-designed clinical trials are needed to assess the effect of vitamin C supplementation in prevention and treatment of obesity.

Correlation between Central Obesity and Liver Function in Young Adults—A Cross-Sectional Study

Background Visceral fat is a more accurate predictor of metabolic and cardiovascular disease risk than body fat alone. Although the liver function is associated with waist-to-hip ratio (WHR) in studies, this correlation is not well established in young central obese individuals. In this study, we examined the correlation between liver function parameters and central obesity in young obese subjects.

Methods Subjects with central obesity among the student and staff community between 18 and 40 years were recruited for the study after their written and informed consent. Male subjects whose WHR is above 0.90 and females above 0.85 were included. The liver function was assessed by estimating alanine transaminase (ALT), aspartate transaminase (AST), albumin, globulin, albumin:globulin ratio (A:G ratio), total bilirubin, direct bilirubin, and Gamma-glutamyl transferase (GGT). The data were analyzed using Pearson correlation to find the statistical significance between lung function parameters in centrally obese individuals with their WHR using SPSS version-16. A p-value less than 0.05 was considered the level of significance.

Results The results showed an insignificant correlation between the liver function parameters (p > 0.05) and WHR except for serum albumin (p < 0.021). The level of AST, ALT, total protein, globulin, A:G ratio, GGT, total Bilirubin, and direct bilirubin in young male and female central obese subjects have not deviated from the normal physiological range.

Conclusion The serum albumin level estimation will be considered an early indicator of metabolic disorder due to central obesity.

Obstructive sleep apnea and metabolic disorders in morbidly obese adolescents

BACKGROUND

Little known about the prevalence of obstructive sleep apnea (OSA) in morbid obese adolescents and the association between OSA and comorbid factors.

AIM

To examine the association between apnea-hypopnea index (AHI, a measure for OSA severity) and metabolic morbidity among morbidly obese adolescents.

METHODS

We performed a population-based retrospective cohort study by reviewing sleep study, metabolic indices, and comorbidity-related data of a cohort (n = 106) of adolescents referred to a bariatric surgery clinic. We compared subjects with moderate/severe OSA (AHI ≥ 5) versus no/mild OSA (AHI < 5) OSA and three groups of subjects with increasing body mass index (BMI) concerning sleep-study and metabolic indices using univariate analyses. To assess the link between AHI and ferritin levels a multivariate linear regression (adjusted for BMI and mean cell volume) was preformed.

RESULTS

A total of 71 patients met the inclusion criteria. Subjects with moderate/severe OSA (n = 32, 45%) had higher BMI, cholesterol, cholesterol/high-density lipoprotein (HDL) ratio, hemoglobin A1c, and serum ferritin levels (p < .05). AHI significantly increased across BMI strata (p = .02). Multivariate linear regression indicated that moderate/severe OSA was associated with higher levels of ferritin, unstandardized β = 49.1 (nIU/ml) (p = .025).

CONCLUSIONS

Morbidly obese adolescents with moderate/severe OSA versus no/mild OSA have a higher risk for metabolic complications. Therefore, OSA management should be considered in adolescents with morbid obesity, in addition to weight loss.

Higher Hepcidin Levels in Adolescents with Obesity Are Associated with Metabolic Syndrome Dyslipidemia and Visceral Fat

Tightly regulated iron metabolism prevents oxidative stress. Hepcidin is a hormone that regulates iron flow in plasma; its production is induced by an iron overload and by inflammation. It inhibits iron entry into the circulation by blocking dietary absorption in the duodenum, the release of recycled iron from macrophages and the exit of stored iron from hepatocytes. Varied signals responding to iron stores, erythropoietic activity and host defense converge to regulate hepcidin production and thereby affect iron homeostasis. Although it is known that hepcidin increases when interleukin 6 (IL-6) increases, the relationship between hepcidin, dyslipidemia, insulin resistance (IR) and visceral adiposity index (VAI) in adolescents with obesity is unclear. In this cross-sectional study of 29 obese adolescents and 30 control subjects, we explored the difference of hepcidin, iron metabolism markers and IL-6 between obese and non-obese adolescents, and identified associations with inflammation, atherogenic dyslipidemia and IR. As compared to lean controls, obese participants showed 67% higher hepcidin: 14,070.8 ± 7213.5 vs. 8419.1 ± 4826.1 pg/mL^c; 70% higher ferritin: 94.4 ± 82.4 vs. 55.1 ± 39.6 pg/mL^a and 120% higher IL-6: 2.0 (1.1–4.9) vs. 0.9 (0.5–1.3) pg/mL^d. Transferrin, soluble transferrin receptor and total body iron (as measured by sTFR/ferritin, log10 sTFR/ferritin ratio and sTFR/log ferritin ratios) were not different between the two cohorts. In the whole cohort, hepcidin correlated with VAI (r = 0.29^a), sd-LDL (r = 0.31^b), HOMA-IR (r = 0.29^a) and IL-6 (r = 0.35^c). In obese adolescents hepcidin correlated with TG (r = 0.47^b), VLDL-C (r = 0.43^b) and smaller LDL2 (r = 0.39^a). Hepcidin elevation in adolescents with obesity is linked more to inflammation and metabolic alterations than to iron metabolism since the other markers of iron metabolism were not different between groups, except for ferritin. Studies addressing the long-term effects of higher hepcidin levels and their impact on subclinical anemia and iron status are warranted. ^a p < 0.05; ^b p < 0.01, ^c p < 0.001 ^dp < 0.0001.

Serum Trace Elements in Patients With Polycystic Ovary Syndrome: A Systematic Review and Meta-Analysis

Polycystic ovary syndrome (PCOS) is reported to be associated with certain trace elements. However, previous data are inconsistent and potentially biased due to small sample sizes. The potential utility of trace element levels for screening of PCOS remains to be established. The aim of this meta-analysis was to investigate the potential relationships between PCOS and serum levels of zinc (Zn), copper (Cu), magnesium (Mg), iron (Fe) and ferritin. We carried out a literature search of PubMed, EMBASE, and Web of Science for relevant cross-sectional/case-control studies published prior to October 2019. Random-effect models were used to estimate the overall standard mean differences (SMDs) between PCOS and healthy control subjects. The screening value of potential microelement biomarkers for PCOS was assessed using the receiver operating characteristic (ROC) curve. Twenty-one studies featuring 2,173 women with PCOS and 1,897 healthy women were selected for analysis. Our results showed that Cu and ferritin levels were significantly higher in women with PCOS than healthy controls, with SMDs of 0.52 [95% confidence interval (CI): 0.38-0.67, I2 = 47.6%] and 1.05 (95% CI: 0.25-1.86, I2 = 97.0%), respectively. The serum ferritin concentration was distinguished as a potential biomarker for PCOS based on the high area under ROC curve value of 0.71 (95% CI: 0.57-0.86). Although we did not identify a statistical association between serum Zn concentration and PCOS overall, the concentration of Zn in PCOS women with insulin resistance (IR) was lower than that in healthy women (SMD = -0.89, 95% CI: -1.73 to -0.06). Furthermore, the concentrations of Mg (SMD = 0.31, 95% CI: -0.32-0.94, I2 = 95.4%) and Fe (SMD = -0.59, 95% CI: -1.29-0.12, I2 = 97.2%) were not statistically significant between the PCOS and control groups. We generated hypothetical pathways for associations among serum Cu, ferritin and PCOS. The serum concentrations of both Cu and ferritin were significantly higher in women with PCOS, and ferritin was identified as a potential early indicator for PCOS screening. Further studies are essential to determine the specific underlying mechanisms.