Associations Between Serum Zinc Levels and Mental Health: Findings from the 2010 Korean National Health and Nutrition Examination Survey

Association between serum zinc levels and suicidal ideation in US adults: A population-based cross-sectional study

BACKGROUND

Evidence suggests that the homeostatic disruption of zinc, copper, and selenium might contribute to the pathophysiology of mental disorders. However, the specific relationship between the serum levels of these trace elements with suicidal ideation remains poorly understood. This study aimed to investigated the association among suicidal ideation on serum levels of zinc, copper, and selenium.

METHODS

The cross-sectional study was conducted using data from a nationally representative sample of the National Health and Nutrition Examination Survey (NHANES) 2011-2016. Suicidal ideation was assessed using Item #9 of the Patient Health Questionnaire-9 Items. Multivariate regression models and restricted cubic splines were performed and E-value was calculated.

RESULTS

A total of 4561 participants aged 20 years and older were analyzed, of whom 4.08 % had suicidal ideation. The serum zinc levels were lower in the suicidal ideation group than in the non-suicidal ideation group (P = 0.021). In Crude Model, the serum zinc levels were associated with a higher suicidal ideation risk in the second quartile compared with the highest quartile [odds ratio (OR) = 2.63; 95 % confidence interval (CI): 1.53-4.53]. The association persisted (OR = 2.35; 95 % CI: 1.20-4.58) after full adjustment, with E-value 2.44. A nonlinear relationship was observed between serum zinc levels and suicidal ideation (P = 0.028). No relationship was observed between suicidal ideation and serum copper or selenium levels (all P > 0.05).

CONCLUSIONS

Decreased serum zinc levels may increase susceptibility to suicidal ideation. Future studies are needed to validate the findings of this study.

Associations of Multiple Serum Trace Elements with Abnormal Sleep Duration Patterns in Hospitalized Patient with Cirrhosis

The associations of circulating trace elements with sleep health have attracted increasing attention given their potential link. However, there is scant data on the relationship between serum trace elements and abnormal sleep duration patterns in cirrhosis. We aimed to investigate these associations with the purpose of identifying modifiable risk factors. The blood samples were collected from inpatients with cirrhosis, and serum levels of several trace elements were assessed by inductively coupled plasma mass spectrometry. Self-reported sleep duration was categorized to short- (< 7 h/night), optimal (7-8 h/night), and long-sleep duration (> 8 h/night). The dose-response trends and associations of trace elements levels with sleep duration were determined by restricted cubic splines (RCS) and logistic regression, respectively. Cirrhotic patients with optimal sleep duration experienced the highest levels of serum Zinc (Zn) and the lowest values of copper to zinc ratio (CZr). RCS model corroborated non-linear associations of serum Zn and CZr against sleep duration. Multiple regression analysis showed that both CZr (short vs optimal sleep duration: OR 4.785, P < 0.001; long vs optimal sleep duration: OR 4.150, P = 0.019) and serum Zn levels (short vs optimal sleep duration: OR 0.985, P = 0.040; long vs optimal sleep duration: OR 0.956, P = 0.008) serve as independent risk factors for sleep duration abnormalities. In conclusion, our findings unraveled a close relationship of serum Zn and CZr with sleep duration in cirrhosis. Further trace element-based therapy such as Zn supplementation may be novel approach to reverse this sleep problem.

Associations of Serum Zinc, Copper, and Zinc/Copper Ratio with Sleep Duration in Adults

The existing evidence on the relationships of serum zinc, copper, and zinc/copper ratio with sleep duration is limited and conflicting. The present cross-sectional study aimed to investigate these associations in general adults by utilizing data from the 2011-2016 National Health and Nutrition Examination Survey. The concentrations of zinc and copper were measured in serum samples. Sleep duration (self-reported usual sleep duration) was categorized as < 7 h/night (short sleep duration), 7-8 h/night (optimal sleep duration), and > 8 h/night (long sleep duration). Multinomial logistic regression models and restricted cubic splines were constructed to examine the associations of serum zinc, copper, and zinc/copper ratio with sleep duration. A total of 5067 adults were included. After multivariate adjustment, compared with the optimal sleep duration group, the odds ratios (ORs) (95% confidence intervals, CIs) in the long sleep duration group for the highest versus lowest quartile of serum zinc concentration and zinc/copper ratio were 0.61 (0.39-0.96) and 0.58 (0.38-0.89), respectively. Furthermore, among males, the OR (95% CI) of long sleep duration for the highest versus lowest quartile of serum copper concentration was 2.23 (1.15-4.32). Finally, the dose-response trends suggested that participants with optimal sleep duration had the highest serum zinc concentration and zinc/copper ratio and a slightly lower serum copper concentration. No significant association was found between serum zinc, copper concentrations and the zinc/copper ratio and short sleep duration. In conclusion, serum zinc and zinc/copper ratio were inversely related to long sleep duration in adults, while serum copper was positively associated with long sleep duration in males.

Serum Zinc Status and Its Association with Allergic Sensitization: The Fifth Korea National Health and Nutrition Examination Survey

Zinc (Zn) is an essential trace element that plays important roles in the immune system. There is little known about the role of trace elements in allergic diseases, and previous reports have shown conflicting results. The aim of this study was to investigate the relationship between serum Zn levels and total or allergen-specific immunoglobulin E (IgE) levels. The initial candidates for this study were those who participated in the 5^th Korean National Health and Nutrition Examination Survey 2010 (n = 8,958), and 1,867 adults who had serum total and allergen specific-IgE levels measured were included. Upon adjusting for covariates, mean total IgE, Dermatophagoides farinae and dog-specific IgE levels increased significantly as the Zn levels decrease from the highest to the lowest quartile (p = 0.009, 0.004, and < 0.001, respectively). The multiple logistic regression analyses showed significant negative linear correlations between serum Zn levels and total, D. farinae-, cockroach-, and dog-specific IgE levels (p-value for linear trend = 0.004, 0.006, 0.027, and < 0.001, respectively). This study demonstrated that total/allergen specific IgE and Zn levels are significantly inversely related.