Alkaline-earth elements of scalp hair and presence of hypertension in housewives: A perspective of chronic effect

Analysis of the association between mixed exposure to multiple metals and comorbidity of hypertension and abnormal bone mass: Baseline data from the Chinese multi-ethnic cohort study (CMEC)

Comorbidity represents an increasingly significant public health challenge. While numerous studies have confirmed the association between metals and both hypertension and osteopenia, the relationship between the multi-faceted effects of mixed metal exposure and the comorbidity of hypertension with abnormal bone mass, as well as age-specific associations, remains unclear. This study utilized baseline data from the China Multi-Ethnic Cohort Study, investigating 9870 Chinese ethnic minorities (Dong and Miao) aged 30-79 years. We measured 17 urinary metal levels using inductively coupled plasma mass spectrometry. The study employed Least Absolute Shrinkage and Selection Operator (LASSO) penalized regression and Bayesian Kernel Machine Regression (BKMR) models to explore the association between urinary metals and comorbidity of hypertension and abnormal bone mass risk. In single-metal models, urinary nickel and zinc levels showed positive correlations with hypertension-related bone mass reduction risk, with ORs and 95 % CIs of 1.23 (1.01, 1.50) and 1.56 (1.27, 1.90), respectively. LASSO regression identified 11 urinary metals (aluminum, cobalt, chromium, copper, iron, manganese, lithium, lead, strontium, vanadium, and zinc) associated with hypertension and abnormal bone mass comorbidity. These selected metals were incorporated into subsequent analyses. BKMR analysis revealed an overall negative effect of metal mixtures on hypertension and abnormal bone mass comorbidity when all metals were fixed at their 50th percentiles. Vanadium and lithium showed negative correlations with the comorbidity. In subgroup analyses, age-stratified groups demonstrated consistent overall negative effects of metal mixtures on the comorbidity. Notably, in individuals over 60 years old, aluminum additionally exhibited a negative association alongside vanadium. Interactions were observed among metals in mixed exposures. Increasing urinary aluminum concentrations attenuated the negative correlation between manganese and hypertension-bone mass abnormality comorbidity. Similarly, increasing manganese concentrations weakened the positive association between urinary zinc and the comorbidity. In individuals under 60 years old, consistent with the general population, increasing urinary aluminum concentrations at P50 levels of other metals diminished the protective effect of manganese against hypertension-bone mass abnormality comorbidity. Interactions were identified between aluminum and lithium, and between manganese and zinc. This study provides substantial evidence linking mixed urinary metal exposure to hypertension and bone mass comorbidity, exploring the multifaceted effects of mixed metal exposure. These findings contribute to a deeper understanding of the role of metal exposure in chronic disease comorbidity, offering a scientific foundation and new directions for preventing and controlling hypertension and bone mass comorbidity, as well as informing public health policy formulation from an environmental metal perspective.

Increased hypertension risk for the elderly with high blood levels of strontium and lead

Hypertension has long been recognized as the global health burden. Heavy metal pollution may be one of the environmental risk factors of hypertension. However, the association remains unclear. We studied the levels of aluminum (Al), vanadium (V), manganese (Mn), arsenic (As), selenium (Se), strontium (Sr), barium (Ba), titanium (Ti), lead (Pb) and cobalt (Co) in whole blood, and the relationship between trace element exposure and hypertension in the elderly community-based Chinese population. A total of 1013 participants from the west of Anhui Province in China were consecutively enrolled in this study in 2016. The general sociodemographic characteristics, lifestyles, disease history and physical examination information were collected by face-to-face survey and physical examination. The levels of ten trace elements were determined by inductively coupled plasma mass spectrometry (ICP-MS). Multivariable logistic regression model was used to assess the association of trace element exposure with the risk of hypertension. Results showed that the odds ratio of hypertension in the highest quartile was 1.811 (95% CI 1.175-2.790, P trend = 0.005) and 1.772 (95% CI 1.121-2.800, P trend = 0.022), respectively, after adjusting for potential confounders, as compared with the lowest quartile of blood Pb and Sr levels.

Association of alkali metals and Alkaline-earth metals with the risk of schizophrenia in a Chinese population: A Case-Control study

Alkali metals (AMs) and alkali earth metals (AEMs) affect levels and signaling of neurotransmitters, which potentially play a role in the etiology of schizophrenia (SCZ). The current case-control study aims to explore how AMs [i.e. Potassium (K), sodium (Na), rubidium (Rb), cesium (Cs)] and AEMs [i.e. magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba)] in serum could associate with SCZ. One hundred and five inpatients with SCZ and 106 age- and sex-matched healthy controls (HCs) were recruited from Weifang, China. Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) was used to evaluate serum concentrations of Na, K, Ca, Mg and Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was for Rb, Cs, Sr, Ba. Subjects with SCZ had significantly higher Mg and Sr serum concentrations than HCs (20.86 vs. 19.73 μg/mL of Mg, p < 0.001; 53.14 vs. 42.26 ng/mL of Sr, p < 0.001). After adjusting for confounders, the odds ratio of Mg and Sr remain significantly higher in the SCZ group (Mg: OR = 2.538, 95 % CI: 1.254-5.136, p=0.010; Sr: OR = 3.798, 95 % CI: 1.769-8.153, p = 0.001). No significant differences between SCZ subjects and HCs were observed for other AMs and AEMs. Higher serum concentrations of Mg and Sr were associated with SCZ. Studies are suggested to find the related mechanisms and provide clues for pathogenesis of SCZ, which would impact prevention and treatments of SCZ.

Environmental complex exposure and the risk of influenza-like illness among housewives: A case study in Shanxi Province, China

The association between environmental pollution and risk of influenza-like illness (ILI) among general population has been reported. However, the relationships between the individual pollutants and ILI risk are still under discussion. Our study aimed to explore the associations of the typical environmental polycyclic aromatic hydrocarbons (PAHs) and metal(loid)s with ILI risk among women population. We carried out a cross-sectional study and included a total of 396 housewives in Shanxi Province, China. The information on their general characteristics and ILI frequency was collected by questionnaire. We collected their hair samples and analyzed the concentrations of PAHs and various metal(loid)s. The results indicated that only acenaphthylene concentration of the nine detected PAH congeners in the hair was significantly associated with ILI risk with adjusted odds ratio (AOR) and 95% confidence interval (95% CI) of 0.58 (0.38 - 0.91). Among the concerned 4 toxic metal(loid)s and 15 rare earth elements, only the hair concentration of arsenic had a positive dose-response relationship with ILI risk. In addition, we found that there were negative dose-response associations of the three essential trace elements (i.e. chromium, cobalt, and nickel), and four essential alkaline earth elements (i.e. magnesium, calcium, strontium, barium) with ILI risk. It was concluded that the environmental exposure to certain compounds of housewives may contribute to their ILI development.

External interference from ambient air pollution on using hair metal(loid)s for biomarker-based exposure assessment

Hair metal(loid)s are often measured as biomarkers to evaluate population internal exposure, however, hair samples could be easily contaminated by ambient particulate matter (PM) pollution. Here, we evaluated the potential external interference from ambient PM pollution on using hair metal(loid)s for population biomarker-based exposure assessment. The raw hair samples were strictly washed and placed under various indoor and outdoor scenarios for ~6 months at sites with high PM pollution. The contaminated hair was then washed using the same method. A total of 33 hair elements were quantified by inductively coupled plasma-mass spectrometry. The surface residual PM on hair after washing was observed by scanning electron microscopy. In addition, we chose a practical exposure scenario including 77 housewives in Shanxi Province, China for validation. The results for the hair exposure experiment revealed that external contamination of some elements that had relatively high concentrations in hair was generally mild in both indoor and outdoor exposure scenarios (i.e., Zn, Mg, Se, Fe, Sr, Ti, Mn, Sn, Ge, U, Co, Mo, and As). A relatively higher external contamination of other elements (e.g., Al, Cr, Pb, Cd, Li, and most rare earth elements (REEs)) was observed, especially for those elements with relatively low hair concentrations (e.g., Cd, and REEs) in the outdoor environment. This finding was due mainly to some small ambient PM not being fully removed by the current washing strategy when the hair sample was heavily contaminated. However, results from practical exposure scenario of the housewives showed that there were overall no significant differences of hair metal(loid)s between the housewives using coal and clean energy for cooking. We concluded that the external interference on hair internal metal(loid) analysis could be negligible when hair was efficiently washed, especially for population with relatively longer indoor activities. It is therefore promising to use hair analysis for their population exposure assessment.

A disadvantageous effect of adsorption of barium by melanin on transforming activity

At present, beneficial effects of melanin and harmful effects of barium have been reported. However, little is known about the adsorption of barium, and even less is known about the biological significance of adsorption of barium by melanin. In this study, we showed that there was a strong correlation between the digitalized level of skin pigmentation and barium level in murine skin compared to the correlations between skin pigmentation level and levels of homologous elements of barium (magnesium, calcium and strontium). The concentration of subcutaneously injected barium in skin with a high level of pigmentation was higher than that in skin with a low level of pigmentation. Our cell-free experiment using the Langmuir isotherm for adsorption of barium in synthetic melanin also provided direct evidence of adsorption of barium by melanin. We then investigated the biological significance of melanin-mediated barium adsorption. We found barium-mediated increase in transforming activity in pigmented melanocytes (melan-a) but not in unpigmented melanocytes (melan-c) after confirming that the barium level in melan-a melanocytes was 3.4-fold higher than that in melan-c melanocytes after culture of 5 μM barium for 24 h. Taken together, our results not only indicate adsorption of barium by melanin in mice, cells and cell-free systems but also suggest a disadvantageous effect of adsorption of barium by melanin on transforming activity in cultured cells.

Indoor air pollution affects hypertension risk in rural women in Northern China by interfering with the uptake of metal elements: A preliminary cross-sectional study

Coal combustion and passive smoking are two important contributors to indoor air pollution (IAP) in rural areas of northern China. Although the association between outdoor air pollutants and hypertension risk had been widely reported, fewer studies have examined the relationship between IAP and hypertension risk. This study evaluated the association between IAP and hypertension risk in housewives in rural areas of northern China and the potential mediation pathway of metal elements. Our cross-sectional study, conducted in Shanxi Province, China, enrolled 367 subjects without taking anti-hypertensive drugs, including 142 subjects with hypertension (case group) and 225 subjects without hypertension (control group). We collected information on energy use characteristics and lifestyle using questionnaires. An IAP exposure index was developed to indicate the population exposure to coal combustion and passive smoking. Scalp hair samples were collected from the housewives and various trace and major metal elements were measured. Our results revealed that the IAP index was positively correlated with systolic and diastolic blood pressure. A significant association between the IAP index and hypertension risk was found both without [odds ratio (95% confidence interval, CI) = 2.08 (1.30-3.31)] and with [OR (95% CI) = 2.52 (1.46-4.36)] adjustment for confounders. We also observed that the IAP index was positively correlated with the arsenic, lead, and rare earth element levels in hair samples, and negatively correlated with the levels of some other trace elements (i.e., chromium, cobalt, nickel, and tin) and alkaline earth elements (i.e., calcium, magnesium, and barium) with an overall p value of <0.01. We concluded that IAP may contribute to the development of hypertension in rural housewives in northern China, possibly by interfering with the uptake of metal elements.