Coordination of chemical analyses under the European Human Biomonitoring Initiative (HBM4EU): Concepts, procedures and lessons learnt.

The European Human Biomonitoring Initiative (HBM4EU) ran from 2017 to 2022 with the aim of advancing and harmonizing human biomonitoring in Europe. More than 40,000 analyses were performed on human samples in different human biomonitoring studies in HBM4EU, addressing the chemical exposure of the general population, temporal developments, occupational exposure and a public health intervention on mercury in populations with high fish consumption. The analyses covered 15 priority groups of organic chemicals and metals and were carried out by a network of laboratories meeting the requirements of a comprehensive quality assurance and control system. The coordination of the chemical analyses included establishing contacts between sample owners and qualified laboratories and monitoring the progress of the chemical analyses during the analytical phase, also addressing status and consequences of Covid-19 measures. Other challenges were related to the novelty and complexity of HBM4EU, including administrative and financial matters and implementation of standardized procedures. Many individual contacts were necessary in the initial phase of HBM4EU. However, there is a potential to develop more streamlined and standardized communication and coordination in the analytical phase of a consolidated European HBM programme.

Determinants of Chronic Biological Stress, Measured as Hair Cortisol Concentration, in a General Population of Adolescents: From Individual and Household Characteristics to Neighborhood Urbanicity.

Chronic biological stress may adversely affect adolescents' physical and mental health, but insight in the personal and environmental factors that determine chronic stress is limited. We measured 3-month cumulative hair cortisol concentration (HCC) in 419 adolescents, participating in the Flemish Environment and Health Study. Adolescents' health and lifestyle characteristics, household and neighborhood socio-economic status as well as neighborhood urbanicity were assessed as potential determinants of HCC, using multiple linear regression models. We additionally explored heterogeneity of our results by sex. HCC were significantly higher in boys from densely populated neighborhoods, the association was not significant in girls. Accordingly, boys living outside cities had significantly lower HCC than boys, living in cities. HCC was significantly lower in adolescents with an optimal vitality, a measure of a positive mental health status. In adolescent girls, menarcheal status (pre-/postmenarche) was a significant determinant of HCC. Our findings are the first to suggest that residential urbanicity may have an impact on chronic biological stress in a general population of adolescent boys.