Individual and joint associations of co-exposure to multiple plasma metals with telomere length among middle-aged and older Chinese in the Dongfeng-Tongji cohort

Association of multi-metal exposure with hyperuricemia in middle-aged and older adults: A cross-sectional study in rural Guangxi, China

BACKGROUND

Hyperuricemia constitutes a significant global public health concern, particularly among the elderly, and is associated with environmental factors such as metal exposure. In China, the predominant focus of existing research has been on urban populations, which leaves the relationship between hyperuricemia and ecological exposures in rural populations inadequately explored. This study investigates the association between hyperuricemia and exposure to multiple metals among elderly residents in rural China.

METHODS

Cross-sectional survey data were collected from middle-aged and elderly individuals residing in Yao Autonomous County of Gongcheng, Guangxi, China, from 2018 to 2019. The analytical techniques employed included least absolute shrinkage and selection operator (LASSO) regression, binary logistic regression and Bayesian kernel machine regression (BKMR) to examine the association between exposure to multi-metal mixtures and hyperuricemia.

RESULTS

Logistic regression results indicated a negative association between magnesium (OR=0.634, 95 % CI=0.476-0.867, Q3) and hyperuricemia, while iron, nickel, strontium, molybdenum, and tin were positively associated with hyperuricemia (all P < 0.05). The Bayesian kernel machine regression analysis revealed a significant overall positive correlation between hyperuricemia and plasma polymetallic mixtures, with notable contributions from Sr (PIP=0.991) and Fe (PIP=0.749), particularly when all metals were at their respective 50th percentiles. Exposure-response relationships were consistent with the logistic regression results. Plasma Sr was positively correlated with hyperuricemia at different levels of other metals (p25, p50, p75).

CONCLUSION

This study suggests that exposure to multi-metal mixtures is positively associated with hyperuricemia, with Sr and Fe being the most significant contributors.

From severe aplastic anemia with TERT variant to Wilson disease - associations or not

Severe aplastic anemia is a life-threatening ineffective hematopoiesis, arising from inherited or acquired traits. Wilson disease is a rare congenital metabolic disorder with copper accumulation. Here we report a rare case of a 15-year-old boy, who presented with bone marrow failure. Whole exome sequencing revealed several gene mutations in ATP7B and TERT. Based on the phenotypes, telomere lengths and pedigree of his family, the patient was diagnosed with severe aplastic anemia accompanied by Wilson disease. Allogeneic hematopoietic stem cell transplantation and anti-copper therapy helped him achieve transfusion independence and restore relatively normal copper metabolism. We discussed the possible associations between the two rare conditions and optimal management in this situation.

Role of Glucose Metabolism in the Effects of Serum Metals on Telomere Length: Findings in Chinese Diabetic Population

The effects of metal exposure on telomere length have attracted considerable attention, but definitive evidence is still lacking in the diabetic population. Thus, this study was conducted to explore the associations of metal mixture with telomere length and the mediated effects of glucose metabolism among the Chinese diabetic population. Eleven metals in serum and relative telomere length of leucocyte were quantified among 1516 diabetic population based on a large-scale diabetic retinopathy screening program in southern China. Multiple statistical models were used to evaluate the single and joint effects of metal mixture on telomere length. Moreover, to assess the mediating roles of glucose metabolism in the associations between metals and telomere length, mediation analyses were performed. In single-exposure models, serum levels of nickel and thallium were identified to be negatively associated with telomere length, while magnesium showed an inverted U-shaped association with telomere length. Consistent findings from three mixed-exposure analyses indicated that increased serum level of metal mixture was associated with decreased telomere length, with nickel playing a major role in the joint effects of the metals. Mediation analyses further revealed that the associations of nickel and metal mixture with telomere length were partially mediated by glycated hemoglobin, and the mediated proportions were 4.26% and 4.38%, respectively. Moreover, the associations between metals exposure and telomere length were observed to be more prominent in males. Our results indicated that exposure to metal mixture was associated with shortened telomere length, which may be partially mediated by glycated hemoglobin.

Associations of essential trace metals with telomere length in general population: a cross-sectional study

This study investigated the relationship between essential plasma metals (Co, Cr, Cu, Mn, Mo, Se, Zn) and telomere length in 2,194 Chinese adults aged ≥ 30 years. Metal concentrations were measured using ICP-MS, and leukocyte relative telomere length (rTL) was assessed by qPCR. In the elderly, Cr and Mn were significantly positively correlated with rTL, while Mo, Zn, and Cu showed negative correlations. In the 30-59 age group, the overall metal mixture was significantly negatively associated with rTL (estimate = -0.069, P = 0.003), with Zn as the dominant contributor. In the elderly, the metal mixture was positively associated with rTL (estimate = 0.040, P = 0.031), with Cr and Mn as main contributors. The findings highlight the importance of maintaining adequate Cr and Mn levels in older adults, and the potential adverse impact of Cu, Mo, and Zn on telomere length.

Exposure to four typical heavy metals induced telomere shortening of peripheral blood mononuclear cells in relevant with declined urinary aMT6s in rats

Environmental heavy metals pollution have seriously threatened the health of human beings. An increasing number of researches have demonstrated that environmental heavy metals can influence the telomere length of Peripheral Blood Mononuclear Cells (PBMCs), which implicate biological aging as well as predicts diseases. Our previous study has shown that methylmercury (MeHg)-induced telomere shortening in rat brain tissue was associated with urinary melatonin metabolite 6-sulfatoxymelatonin (aMT6s) levels. Here, we aimed to further elucidate the impact of 4 typical heavy metals (As, Hg, Cd and Pb) on telomere length of PBMCs and their association with urinary aMT6s in rats. In this study, eighty-eight male Sprague-Dawley rats were randomized grouped into eleven groups. Among them, forty 3-month-old (young) and forty 12-month-old (middle-aged) rats were divided into young or middle-aged control groups as well as typical heavy metals exposed groups, respectively. Eight 24-month-old rats (old) was divided into aging control group. The results showed that MeHg exposure in young rats while sodium arsenite (iAs), MeHg, cadmium chloride (CdCl2), lead acetate (PbAc) exposure in middle-aged rats for 3 months significantly reduced the levels of and urinary aMT6s, as well as telomere length of PBMCs. In addition, they also induced abnormalities in serum oxidative stress (SOD, MDA and GPx) and inflammatory (IL-1β, IL-6 and TNF-α) indicators. Notably, there was a significant positive correlation between declined level of urinary aMT6s and the shortening of telomere length in PBMCs in rats exposed to 4 typical heavy metals. These results suggested that 4 typical heavy metals exposure could accelerate the reduction of telomere length of PBMCs partially by inducing oxidative stress and inflammatory in rats, while ageing may be an important synergistic factor. Urinary aMT6s detection may be a alternative method to reflect telomere toxic effects induced by heavy metal exposure.

Association Between Combined Polymetallic Exposure and Osteoporosis

Combined polymetallic exposure may be an influential factor in osteoporosis. This study aimed to explore the association between polymetallic combined exposure and osteoporosis. A total of 2115 participants were included. Plasma concentrations of 22 metals were determined by inductively coupled plasma mass spectrometry. Osteoporosis was defined as a T ≤  - 2.5. The least absolute shrinkage and selection operator (LASSO) regression, binary logistics regression, and Bayesian kernel machine regression (BKMR) model were used to explore the association between plasma metals and osteoporosis. LASSO regression showed that 10 metals were associated with osteoporosis in the total population (magnesium, calcium, manganese, nickel, cobalt, arsenic, selenium, rubidium, cadmium, aluminum) and women (magnesium, calcium, molybdenum, nickel, cobalt, arsenic, selenium, rubidium, cadmium, aluminum), and four metals associated with men (magnesium, cobalt, aluminum, iron). Logistics regression showed that in total population, magnesium (ORQ3 = 0.653, 95% CI = 0.446-0.954) was negatively correlated with osteoporosis, while aluminum (ORQ2 = 1.569, 95% CI = 1.095-2.248, ORQ4 = 1.616, 95% CI = 1.109-2.354) and cadmium (ORQ4 = 1.989, 95% CI = 1.379-2.870) were positively correlated; in women, magnesium (ORQ3 = 0.579, 95% CI = 0.379-0.883) was negatively correlated with osteoporosis, while aluminum (ORQ2 = 1.563, 95% CI = 1.051-2.326, ORQ4 = 1.543, 95% CI = 1.024-2.326) and cadmium (ORQ3 = 1.482, 95% CI = 1.003-2.191, ORQ4 = 1.740, 95% CI = 1.167-2.596) were positively correlated. BKMR model showed that combined polymetallic exposure had an overall positive effect on osteoporosis, magnesium was negatively associated with osteoporosis, and cadmium, selenium, and aluminum were positively associated with osteoporosis. Metal mixtures in plasma were associated with osteoporosis risk. Magnesium may reduce the risk of osteoporosis, while cadmium, selenium, and aluminum may increase the risk of osteoporosis. Future studies needed to explore correlations and mechanisms.

Human molybdenum exposure risk in industrial regions of China: New critical effect indicators and reference dose

Evidence increasingly suggests molybdenum exposure at environmental levels is still associated with adverse human health, emphasizing the necessity to establish a more protective reference dose (RfD). Herein, we conducted a study measuring 15 urinary metals and 30 clinical health indicators in 2267 participants residing near chemical enterprises across 11 Chinese provinces to investigate their relationships. The kidney and cystatin-C emerged as the most sensitive organ and critical effect indicator of molybdenum exposure, respectively. Odds of cystatin-C-defined chronic kidney disease (CKD) in the highest quantile of molybdenum exposure significantly increased by 133.5% (odds ratio [OR]: 2.34, 95% CI: 1.78, 3.11) and 75.8% (OR: 1.76, 95% CI: 1.24, 2.49) before and after adjusting for urinary 14 metals, respectively. Intriguingly, cystatin-C significantly mediated 15.9-89.5% of molybdenum's impacts on liver and lung function, suggesting nephrotoxicity from molybdenum exposure may trigger hepatotoxicity and pulmonary toxicity. We derived a new RfD for molybdenum exposure (0.87 μg/kg-day) based on cystatin-C-defined estimated glomerular filtration rate by employing Bayesian Benchmark Dose modeling analysis. This RfD is significantly lower than current exposure guidance values (5-30 μg/kg-day). Remarkably, >90% of participants exceeded the new RfD, underscoring the significant health impacts of environmental molybdenum exposure on populations in industrial regions of China.

Associations between prenatal multiple plasma metal exposure and newborn telomere length: Effect modification by maternal age and infant sex

Exposure to metals during pregnancy may affect maternal and infant health. However, studies on the combined effects of metals on the telomere length (TL) of newborns are limited. A prospective cohort study was conducted among 1313 mother-newborn pairs in the Guangxi Zhuang Birth Cohort. The concentrations of metals in maternal plasma during the first trimester were measured using inductively coupled plasma-mass spectrometry. We explored the associations between nine plasma metals and newborn TL using generalized linear models (GLMs), principal component analysis (PCA), quantile g-computation (qgcomp), and Bayesian kernel machine regression (BKMR). The GLMs revealed the inverse association between plasma arsenic (percent change, -5.56%; 95% CI: -7.69%, -3.38%) and barium concentrations (-9.84%; 95% CI: -13.81%, -5.68%) and newborn TL. Lead levels were related to significant decreases in newborn TL only in females. The PCA revealed a negative association between the PC3 and newborn TL (-4.52%; 95% CI: -6.34%, -2.68%). In the BKMR, the joint effect of metals was negatively associated with newborn TL. Qgcomp indicated that each one-tertile increase in metal mixture levels was associated with shorter newborn TL (-9.39%; 95% CI: -14.32%, -4.18%). The single and joint effects of multiple metals were more pronounced among pregnant women carrying female fetuses and among pregnant women <28 years of age. The finding suggests that prenatal exposure to arsenic, barium, antimony, and lead and mixed metals may shorten newborn TLs. The relationship between metal exposures and newborn TL may exhibit heterogeneities according to infant sex and maternal age.

Single and Combined Associations of Plasma and Urine Essential Trace Elements (Zn, Cu, Se, and Mn) with Cardiovascular Risk Factors in a Mediterranean Population

Trace elements are micronutrients that are required in very small quantities through diet but are crucial for the prevention of acute and chronic diseases. Despite the fact that initial studies demonstrated inverse associations between some of the most important essential trace elements (Zn, Cu, Se, and Mn) and cardiovascular disease, several recent studies have reported a direct association with cardiovascular risk factors due to the fact that these elements can act as both antioxidants and pro-oxidants, depending on several factors. This study aims to investigate the association between plasma and urine concentrations of trace elements and cardiovascular risk factors in a general population from the Mediterranean region, including 484 men and women aged 18−80 years and considering trace elements individually and as joint exposure. Zn, Cu, Se, and Mn were determined in plasma and urine using an inductively coupled plasma mass spectrometer (ICP-MS). Single and combined analysis of trace elements with plasma lipid, blood pressure, diabetes, and anthropometric variables was undertaken. Principal component analysis, quantile-based g-computation, and calculation of trace element risk scores (TERS) were used for the combined analyses. Models were adjusted for covariates. In single trace element models, we found statistically significant associations between plasma Se and increased total cholesterol and systolic blood pressure; plasma Cu and increased triglycerides and body mass index; and urine Zn and increased glucose. Moreover, in the joint exposure analysis using quantile g-computation and TERS, the combined plasma levels of Zn, Cu, Se (directly), and Mn (inversely) were strongly associated with hypercholesterolemia (OR: 2.03; 95%CI: 1.37−2.99; p < 0.001 per quartile increase in the g-computation approach). The analysis of urine mixtures revealed a significant relationship with both fasting glucose and diabetes (OR: 1.91; 95%CI: 1.01−3.04; p = 0.046). In conclusion, in this Mediterranean population, the combined effect of higher plasma trace element levels (primarily Se, Cu, and Zn) was directly associated with elevated plasma lipids, whereas the mixture effect in urine was primarily associated with plasma glucose. Both parameters are relevant cardiovascular risk factors, and increased trace element exposures should be considered with caution.