Secondhand smoke is associated with heavy metal concentrations in children

Associations of urinary heavy metals with age at menarche, age at menopause, and reproductive lifespan: A cross-sectional study in U.S. women

Female reproductive timing and lifespan, with a close relation to long-term health outcomes, have been altered in U.S. women over the past decades. However, epidemiologic evidence of the potential causes was lacking. On the basis of 1981 naturally postmenopausal women from the National Health and Nutrition Examination Survey 1999-2020, this study aimed to investigate the associations of urinary heavy metals with age at menarche, age at menopause, and reproductive lifespan. Multivariate generalized linear regression and addictive models were used for single metal exposure analysis, and weighted quantile sum (WQS) and Bayesian kernel machine regression (BKMR) models were employed for mixed exposures. In the fully adjusted model, higher urinary antimony concentration was associated with earlier age at menarche of 0.137 years, while higher concentrations of cadmium, cesium, lead, antimony, and thallium were associated with delayed age at menopause of 0.396-0.687 years. Additionally, urinary barium, cesium, lead, antimony, and thallium levels were associated with longer reproductive lifespan ranging between 0.277 and 0.713 years. Both WQS and BKMR models showed significantly positive associations of metal mixtures with age at menopause (β: 0.667, 95 % CI: 0.120-1.213) and reproductive lifespan (β: 0.686, 95 % CI: 0.092-1.280), with cadmium and lead identified as principal contributors. In conclusion, heavy metal exposures were associated with reproductive timing and lifespan of U.S. women, highlighting the need for further prevention and intervention strategies.

Association of environmental tobacco smoke (ETS) with lead and cadmium concentrations in biological samples of children and women: systematic review and meta-analysis

OBJECTIVES

Previous literature has shown that heavy metals (HMs) in cigarette smoke have been overestimated, and second-hand smoke (SHS) has recently raised public concern. This study aimed to review the effects of passive tobacco exposure on lead (Pb) and cadmium (Cd) concentrations of children and women in different biological samples.

CONTENT

In this systematic review, two independent researchers assessed different databases/search engines including PubMed, Web of Science, Scopus, and Google Scholar using Mesh terms and Text Words. Studies between January 2000 and May 2022 were included. After quality assessment, studies with sufficient data were included in the meta-analysis. A fixed or random model was used to pool the results in a meta-analysis. Heterogeneity between the studies was assessed by using I-square and Q tests. Forest plots demonstrating the point and pooled estimates were provided.

SUMMARY

A total of 976 studies were obtained from different databases and finally 17 studies meet our criteria and were included in our systematic review. Out of 17 studies, six studies had sufficient data for analysis and were included in the meta-analysis. The results of the meta-analysis showed a significant difference in blood lead concentrations (BLC) between the children with SHS exposure and the control group (Hedges' g: 2.44, 95% CI: 1.01-3.86, p<0.05). Also, there were significant differences in hair levels of Cd (Hedges' g: 0.66, 95% CI: 0.04, 1.28, p<0.05) and Pb (Hedges' g: 0.94, 95% CI: 0.05, 1.83, p<0.05) between children with SHS exposure compared to the control group.

OUTLOOK

The results of the present meta-analysis showed that passive smokers had higher Pb and Cd concentrations than those who were not exposed to cigarette smoke.

Covariation between serum cotinine and blood lead levels among US pediatric populations: Trends from 1999 to 2018

BACKGROUND

Tobacco smoke, including both active and passive smoke, can be an important source of lead exposure. However, the relationship between passive tobacco smoke exposure (PTSE) and blood lead levels (BLL), especially in vulnerable populations, needs to be further explored. The present study was to assess the covariation between serum cotinine, a measure of PTSE, and BLL in a pediatric population during 1999-2018.

METHODS

Data on 21,817 children, aged 3-19 years, was extracted from the biennial nationally representative surveys. The trends of the prevalence of lead exposure (BLL ≥ 3.5 µg/dL) and PTSE (cotinine ≥ 1 ng/mL but < 10 ng/mL) were determined, and the covariation between BLL and cotinine was assessed. The population attributable fraction (PAF) of PTSE to the BLL was proxied using the partial R2 of the hierarchical linear regression. The association between PTSE and lead exposure was estimated using multivariate logistic regression.

RESULTS

A parallel decreasing trend in the prevalence of lead exposure and PTSE was observed. Similarly, the means of both BLL and cotinine declined simultaneously. Overall, the PAF from PTSE towards blood lead was 7 %, doubling the PAF from race/ethnicity and family income combined. Stratified by race/ethnicity, PAF from PTSE was 8 % in Blacks and Whites and 4 % for Hispanics. The odds ratio of PTSE with lead exposure was 2.45 (95 % CI, 1.75, 3.44), 2.00 (1.21, 3.33), and 1.16 (0.64, 2.13) for Black, White, and Hispanic children, respectively. Cotinine mean remained two times higher in Blacks than non-Black children at the end of the study period.

CONCLUSION

Serum cotinine and BLL may have a significant association in children that persists even as both have been steadily declining in recent years. The contribution from PTSE to blood lead variations could be greater than that from socioeconomic factors. Further reducing lead exposure might be achieved by eliminating PTSE, particularly for the Black pediatric population.

Passive Smoking Is Associated with Multiple Heavy Metal Concentrations among Housewives in Shanxi Province, China

Background: Passive smoking may increase the content of heavy metals in housewives. However, this association remains a subject of debate. Female passive smoking is widespread, particularly in Chinese rural areas. Objective: This study aimed to assess the association between heavy metal accumulation and passive smoking status among rural housewives. Methods: 405 women were recruited in Shanxi Province of Northern China, and 384 (94.8%, 384/405) participants were included in the final study, of whom 117 women were exposed to passive smoking. The information on their basic characteristics was collected via a structured questionnaire. We used inductively coupled plasma mass spectrometry (ICP-MS) to analyze the concentrations of nine heavy metals, including cadmium (Cd), germanium (Ge), arsenic (As), lead (Pb), titanium (Ti), copper (Cu), iron (Fe), cobalt (Co), and chromium (Cr), in hair samples. Results: The results indicated that higher As, Ge, Ti, and Fe concentrations were significantly associated with passive smoking. After adjusting for potential confounders, the adjusted odds ratios and the 95% confidence intervals of As, Ge, Ti, and Fe were (1.80 (1.13–2.90),p = 0.028), (1.78 (1.14–2.80), p = 0.007), (1.70 (1.09–2.67), p = 0.019), and (1.67 (1.07–2.63), p = 0.035), respectively. The statistically significant linear trend of the adjusted odds ratios at different levels further supported their association. Conclusion: Our research concluded that exposure to environmental tobacco smoke might contribute to As, Ge, Ti, and Fe accumulation among housewives.

Prenatal environmental tobacco smoke exposure alters children's cognitive control circuitry: A preliminary study

BACKGROUND AND OBJECTIVES

Prenatal exposure to environmental tobacco smoke (ETS) is associated with increased attention problems in children, however, the effects of such exposure on children's brain structure and function have not been studied. Herein, we probed effects of prenatal ETS on children's cognitive control circuitry and behavior.

METHODS

Forty-one children (7-9 years) recruited from a prospective longitudinal birth cohort of non-smoking mothers completed structural and task-functional magnetic resonance imaging to evaluate effects of maternal ETS exposure, measured by maternal prenatal urinary cotinine. Attention problems and externalizing behaviors were measured by parent report on the Child Behavior Checklist.

RESULTS

Compared to non-exposed children, exposed children had smaller left and right thalamic and inferior frontal gyrus (IFG) volumes, with large effect sizes (p-FDR < .05, Cohen's D range from 0.79 to 1.07), and increased activation in IFG during the resolution of cognitive conflict measured with the Simon Spatial Incompatibility Task (38 voxels; peak t(25) = 5.25, p-FWE = .005). Reduced thalamic volume was associated with increased IFG activation and attention problems, reflecting poor cognitive control. Mediation analyses showed a trend toward left thalamic volume mediating the association between exposure and attention problems (p = .05).

CONCLUSIONS

Our findings suggest that maternal ETS exposure during pregnancy has deleterious effects on the structure and function of cognitive control circuitry which in turn affects attentional capacity in school-age children. These findings are consistent with prior findings documenting the effects of active maternal smoking on chidlren's neurodevleoment, pointing to the neurotixicity of nicotine regardless of exposure pathway.

Urinary Metal Levels with Relation to Age, Occupation, and Smoking Habits of Male Inhabitants of Eastern Iran

In low-income and middle-income countries such as Iran, smoking is becoming increasingly popular, especially among young people. This has led to additional exposure to a variety of substances, including metals which may exert a toxic influence and lead to severe diseases. In order to evaluate the influence of smoking on metal concentrations, a case-control study of levels of metal in urine was carried out in smokers (n = 64) and non-smokers (n = 35) from the city of Birjand (Iran). They were divided according to their age and socioeconomic status. Concentrations of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), nickel (Ni), lead (Pb), and zinc (Zn) were measured using ET-AAS. We found higher concentrations of Cd (0.03 vs. 0.12 μg/L), Co (0.6 vs. 1.22 μg/L), and Cr (14.00 vs. 18.17 μg/L) in the urine of smokers. Age and occupation are factors that also influence the levels of metals. Young smokers demonstrate higher Cd and Pb levels than other age groups. It would also appear that public sector workers and self-employed are the sectors most susceptible to high levels of metals.

Secondhand smoke exposure and higher blood pressure in children and adolescents participating in NHANES

We assessed the relationship between acute and intermittent secondhand tobacco smoke (SHS) exposure with child and adolescent blood pressure (BP). We analyzed cross-sectional data from 3579 children and adolescents aged 8-17 years participating in the National Health and Nutrition Examination Survey (NHANES) collected between 2007 and 2012, with SHS exposure assessed via serum cotinine (a biomarker for acute exposures) and urine NNAL (4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol, a biomarker for intermittent exposures). BP percentiles and z-scores were calculated according to the 2017 guidelines established by the American Academy of Pediatrics. We used weighted linear regression accounting for the complex sampling weights from NHANES and adjusting for socio-demographic and clinical characteristics. Overall, 56% of the children were non-Hispanic white with a mean age of 12.6 years. There was approximately equal representation of boys and girls. Approximately 15.9% of participants lived in homes where smoking was present. In adjusted models, an interquartile range (IQR) increase in urinary NNAL was associated with 0.099 (95% CI: 0.033, 0.16) higher diastolic blood pressure (DBP) z-score, and with a 0.094 (95% CI: 0.011, 0.18) higher systolic blood pressure (SBP) z-score. The odds of being in the hypertensive range was 1.966 (95% CI: 1.31, 2.951) times greater among children with high NNAL exposures compared to those with undetectable NNAL. For serum cotinine, an IQR increase was associated with 0.097 (95% CI: 0.020, 0.17) higher DBP z-scores, but was not significantly associated with SBP z-scores. The associations of cotinine and NNAL with BP also differed by sex. Our findings provide the first characterization of the relationship between a major tobacco-specific metabolite, NNAL, and BP z-scores in a nationally representative population of US children.

Presence of Toxic Heavy Metals in Platelet-Rich Fibrin: a Pilot Study

Platelet-rich fibrin (PRF) is widely used blood-derived biomaterial which is directly applied to the surgical wounds. Depending on its autologous origin, PRF is thought as a safe material. However, it is not known to what extent the blood-derived toxins can be found in the PRF by considering the systemic exposure rates of the individuals to the toxins. The aim of this pilot study was to test the hypothesis whether PRF contains any blood-origin heavy metals (HMs) and smoking increases their concentrations as an environmental HM source. PRF samples were obtained from systemically healthy 30 non-smoker and 30 smoker volunteers. All liquid and dry fibrin parts of the PRF samples were analyzed in terms of 15 toxic elements using inductively coupled plasma mass spectrometry. All analyzed HMs were detected in all investigated PRF samples within various concentrations in both groups. In addition, significantly high levels of cadmium, arsenic, lead, manganese, nickel, chromium, and vanadium were detected in dry fibrin matrices of PRF samples of smokers comparing with non-smokers (p < 0.05). Only cadmium was at significantly high levels in the liquid part of PRF samples of smokers (p < 0.05). This is the first study evaluating toxic ingredients of PRF. The results revealed that PRF contains various toxic HMs. Additionally, systemic exposure to environmental HM sources such as smoking may significantly increase HM concentrations in PRF. Further studies are required to investigate the transmission potentials of HMs to the applied tissues and biological importance of PRF-origin HMs.

Linking Cigarette Smoking/Tobacco Exposure and Cluster Headache: A Pathogenesis Theory

INTRODUCTION

To propose a hypothesis theory to establish a linkage between cigarette smoking and cluster headache pathogenesis.

BACKGROUND

Cluster headache is a primary headache syndrome grouped under the trigeminal autonomic cephalalgias. What distinguishes cluster headache from all other primary headache conditions is its inherent connection to cigarette smoking. It is undeniable that tobacco exposure is in some manner related to cluster headache. The connection to tobacco exposure for cluster headache is so strong that even if an individual sufferer never smoked, then that individual typically had significant secondary smoke exposure as a child from parental smoking behavior and in many instances both scenarios exist. The manner by which cigarette smoking is connected to cluster headache pathogenesis is unknown at present. If this could be determined this may contribute to advancing our understanding of cluster headache pathophysiology.

METHODS/RESULTS

Hypothesis statement.

CONCLUSION

The hypothesis theory will include several principles: (1) the need of double lifetime tobacco exposure, (2) that cadmium is possibly the primary agent in cigarette smoke that leads to hypothalamic-pituitary-gonadal axis toxicity promoting cluster headache, (3) that the estrogenization of the brain and its specific sexually dimorphic nuclei is necessary to develop cluster headache with tobacco exposure, and (4) that the chronic effects of smoking and its toxic metabolites including cadmium and nicotine on the cortex are contributing to the morphometric and orexin alterations that have been previously attributed to the primary headache disorder itself.