Nickel and cobalt release from beauty tools: a field study in the German cosmetics trade

Maternal cobalt concentration and risk of spontaneous preterm birth: the role of fasting blood glucose and lipid profiles

Introduction

Spontaneous preterm birth (SPB) is a significant cause of neonatal mortality, yet its etiology remains unclear. Cobalt, an essential trace element, might be a risk factor for SPB. This study aims to investigate the relationship between maternal serum cobalt concentration and SPB, and to clarify the role of blood lipids and fasting blood glucose (FBG) in this relationship.

Methods

We conducted a nested case-control study within the Beijing Birth Cohort Study. Serum samples were obtained from 222 pregnant women with SPB and 224 controls during the first (7-13 weeks of pregnancy) and third trimesters (32-42 weeks of pregnancy). Serum cobalt concentration was determined using inductively coupled plasma mass spectrometry (ICP-MS). Fasting blood glucose and lipids levels were detected using a fully automated biochemical immunoassay instrument. Logistic regression models and linear regression models were established to explore the association between serum cobalt concentration and the risk of SPB in pregnant women, and to test the mediating effect of fasting blood glucose (FBG) and lipids.

Results

We found that the serum cobalt concentration in mothers with SPB and controls was similar in the first trimester, with values of 0.79 (0.58-1.10) ng/mL and 0.75 (0.51-1.07) ng/mL, respectively. However, in the third trimester, the cobalt concentration increased to 0.88 (0.59-1.14) ng/mL and 0.84 (0.52-1.19) ng/mL, respectively. In the logistic regression model, when considering the third trimester of pregnancy, after adjusting for ethnicity, pre-pregnancy body mass index (BMI), maternal age, education, income, and parity, it was observed that the medium level of cobalt concentration (0.63-1.07 ng/ml) had a negative correlation with the risk of SPB. The odds ratio (OR) was 0.56, with a 95% confidence interval of 0.34-0.90 ng/mL and a p-value of 0.02. This suggests that cobalt in this concentration range played a protective role against SPB. Additionally, it was found that FBG in the third trimester of pregnancy had a partial intermediary role, accounting for 9.12% of the association. However, no relationship between cobalt and SPB risk was found in the first trimester.

Conclusion

During the third trimester, intermediate levels of maternal cobalt appear to offer protection against SPB, with FBG playing a partial mediating role. To further clarify the optimal cobalt concentrations during pregnancy for different populations, a multi-center study with a larger sample size is necessary. Additionally, exploring the specific mechanism of FBG's mediating role could provide valuable insights for improving the prevention of SPB.

Nickel release from hairdressing tools in the United States

BACKGROUND

Hairdressers have a high prevalence of contact dermatitis, especially to nickel. The presence of nickel in hairdressing tools has been evaluated in the European Union, where the government limits nickel release levels from objects.

OBJECTIVES

The aim of this study is to qualitatively investigate nickel release in hairdresser tools in both rural and urban United States, a country without nickel release legislation.

METHODS

Hairdressers and individuals with hairdressing tools were invited to participate. Metallic parts of each tool were tested with dimethylglyoxime (DMG), which detects nickel release. Data on tool cost were recorded.

RESULTS

A total of 89 tools from 9 salons and 2 over-the-counter sets were tested. Twenty-four (27%) tested positive: trimmers (100%), curling irons (100%), clippers (50%), hair clips (36%), texturizing shears (26%), and trimming shears (4%). Nickel was detected in both salon and over-the-counter tools, and rural and urban salons. Nickel-releasing tools were cheaper than DMG-negative tools of the same type.

CONCLUSIONS

Our findings help explain the high prevalence of contact dermatitis among hairdressers, alert clinicians to consider occult occupational nickel when assessing patients with allergic contact dermatitis, reinforces the importance of using barrier protection including gloves when handling hairdressing tools including at home, and augments impetus for more legislation regulating common allergens.

Metal Allergy: State-of-the-Art Mechanisms, Biomarkers, Hypersensitivity to Implants

Metal allergy is mainly an environmental disorder which can cause allergic contact dermatitis. Environmental metal exposures include jewelry, everyday metal items, mobile phones, leather, metal-rich food and implants, including stents or anchors. While consumer exposure is liable for the majority of metal hypersensitivity cases, the significance of occupational exposure to metals remains relevant. Although the most common metal allergens are nickel, chromium, and cobalt; however, lately, gold, palladium, titanium, and some others have also attracted attention. This review highlights advances in metal allergy mechanisms, biomarkers for potential patients' stratification as well as biological treatments. The most recent evidence of human exposure to metal for risk assessment is discussed, as well as the relationship between the occurrence of metal hypersensitivity and implanted devices, including non-characteristic symptoms. The latest data on the diagnosis of metal hypersensitivity are also reported.