There is a growing awareness about the need to comprehensively integrate sex and gender into health research in order to enhance the validity and significance of research results. An in-depth consideration of differential exposures and vulnerability is lacking, especially within environmental risk assessment. Thus, the interdisciplinary team of the collaborative research project INGER (integrating gender into environmental health research) aimed to develop a multidimensional sex/gender concept as a theoretically grounded starting point for the operationalization of sex and gender in quantitative (environmental) health research. The iterative development process was based on gender theoretical and health science approaches and was inspired by previously published concepts or models of sex- and gender-related dimensions. The INGER sex/gender concept fulfills the four theoretically established prerequisites for comprehensively investigating sex and gender aspects in population health research: multidimensionality, variety, embodiment, and intersectionality. The theoretical foundation of INGER’s multidimensional sex/gender concept will be laid out, as well as recent sex/gender conceptualization developments in health sciences. In conclusion, by building upon the latest state of research of several disciplines, the conceptual framework will significantly contribute to integrating gender theoretical concepts into (environmental) health research, improving the validity of research and, thus, supporting the promotion of health equity in the long term.

When assessing the association between air pollution and cardiovascular mortality, it remains unclear whether females or males are more susceptible and whether and to what extent the pre-existing studies have accounted for different sex/gender dimensions. We searched three databases to identify short-term and long-term studies on the association between air pollution and cardiovascular mortality published 2000-2023 to assess their integration of sex/gender. We further evaluated whether sex/gender was a source of heterogeneity within these through a moderator analysis using random effects models. We examined sex/gender differences through random effects pooling of the female-to-male-ratio (FMR) of each study. We identified 106 studies, all of which operationalised sex/gender in binary terms and lacked a sex/gender-theoretical concept. However, the biological and social dimensions of sex/gender were indirectly included in the discussions. Meta-analyses did not identify sex/gender as a source of heterogeneity (e.g. short-term particulate matter with a diameter <10μm (PM₁₀): p-value of moderator test= 0.85; long-term: 0.34). The pooled FMR showed no sex/gender differences for short-term associations (1.0[CI: 0.0;0.0] for each air pollutant) and a trend towards higher effect estimates for males than females in long-term studies with a pooled FMR ranging from 0.93 to 0.99. Binary categorisation without conceptualisation does not appear to be sufficient to identify vulnerable sex/gender groups, if any, in the association between air pollution and cardiovascular mortality. Considering the multiple biological and sociocultural dimensions of sex/gender from the very beginning of study planning will help to move beyond speculative discussions and derive meaningful action for prevention and health care.

Recently, attention has been drawn to the need to integrate sex/gender more comprehensively into environmental health research. Considering theoretical approaches, we define sex/gender as a multidimensional concept based on intersectionality. However, operationalizing sex/gender through multiple covariates requires the usage of statistical methods that are suitable for handling such complex data. We therefore applied two different decision tree approaches: classification and regression trees (CART) and conditional inference trees (CIT). We explored the relevance of multiple sex/gender covariates for the exposure to green spaces, measured both subjectively and objectively. Data from 3742 participants from the Cooperative Health Research in the Region of Augsburg (KORA) study were analyzed within the INGER (Integrating gender into environmental health research) project. We observed that the participants’ financial situation and discrimination experience was relevant for their access to high quality public green spaces, while the urban/rural context was most relevant for the general greenness in the residential environment. None of the covariates operationalizing the individual sex/gender self-concept were relevant for differences in exposure to green spaces. Results were largely consistent for both CART and CIT. Most importantly we showed that decision tree analyses are useful for exploring the relevance of multiple sex/gender dimensions and their interactions for environmental exposures. Further investigations in larger urban areas with less access to public green spaces and with a study population more heterogeneous with respect to age and social disparities may add more information about the relevance of multiple sex/gender dimensions for the exposure to green spaces.

Exposure to green space has a positive impact on health. Whether sex/gender modifies the green space–health association has so far only been studied through the use of a binary sex/gender category; however, sex/gender should be considered more comprehensively as a multidimensional concept based on theoretical approaches. We therefore explored whether sex/gender, operationalized through multiple sex/gender- and intersectionality-related covariates, modifies the green space–self-rated health association. We collected data from participants involved in the German KORA study (Cooperative Health Research in the Region of Augsburg) in 2019. Self-rated health was assessed as a one-question item. The availability of green spaces was measured subjectively as well as objectively. The multiple sex/gender- and intersectionality-related covariates were measured via self-assessment. To analyze the data, we used model-based recursive partitioning, a decision tree method that can handle complex data, considering both multiple covariates and their possible interactions. We showed that none of the covariates operationalizing an individual sex/gender self-concept led to subgroups with heterogeneous effects in the model-based tree analyses; however, we found effect heterogeneity based on covariates representing structural aspects from an intersectionality perspective, although they did not show the intersectional structuring of sex/gender dimensions. In one identified subgroup, those with a lower education level or a feeling of discrimination based on social position showed a positive green space–self-rated health association, while participants with a higher education level or no feeling of discrimination based on social position had a high level of self-rated health regardless of the availability of green spaces. Model-based recursive partitioning has the potential to detect subgroups exhibiting different exposure–outcome associations, with the possibility of integrating multiple sex/gender- and intersectionality-related covariates as potential effect modifiers. A comprehensive assessment of the relevance of sex/gender showed effect heterogeneity based on covariates representing structural aspects from an intersectionality perspective.

Cannabis use can have detrimental effects on adolescents’ mental health, often co-occurring with child and adolescent psychiatric disorders (CAPD). This study assessed diagnostic prevalence trends in cannabis-related disorders and co-occurring diagnosed CAPD in adolescents receiving outpatient treatment in Germany. Outpatient claims data from the national public health insurance system, covering almost 4 million children and adolescents, were assessed for diagnostic prevalence of cannabis-related disorders (ICD-10 diagnoses F12.X) in insurees aged 12 to 17 years for the years 2013–22, stratified by age group and sex. In addition, the diagnostic prevalence of co-occurring CAPD during the year 2022 was evaluated. From 2013 to 2022, the diagnostic prevalence of cannabis-related disorders among German adolescents utilizing outpatient services increased from 0.08% to 0.10% (+22.4%), with a decline during the COVID-19 pandemic and a higher diagnostic prevalence in older adolescents. Up to 14 years of age, the diagnostic prevalence of cannabis-related disorders was distributed evenly among males and females, while from age 15 onwards, the diagnostic prevalence was higher in males. Overall, 78.3% of adolescents diagnosed with cannabis-related disorders had at least one co-occurring CAPD diagnosis in 2022. Most common co-occurring conditions were depressive disorders, conduct disorders, adjustment disorders, attention-deficit/hyperactivity disorders, and anxiety disorders. Co-occurring depression was particularly often diagnosed, underscoring the urgent need for integrated treatment approaches addressing both disorders simultaneously in this age group.