International data suggest that exposure to nature is beneficial for mental health and well-being. The restrictions related to the COVID-19 pandemic have created a setting that allows us to investigate the importance of greenness exposure on mental health during a period of increased isolation and worry. Based on 2060 responses from an online survey in Stockholm County, Sweden, we investigated: (1) whether the COVID-19 pandemic changed peoples’ lifestyle and nature-related habits, and (2) if peoples’ mental health differed depending on their exposure to greenness. Neighborhood greenness levels were quantified by using the average normalized difference vegetation index (NDVI) within 50 m, 100 m, 300 m, and 500 m buffers surrounding the participant’s place of residence. We found that the number of individuals that reported that they visited natural areas “often” was significantly higher during the pandemic than before the pandemic. Higher levels of greenness surrounding one’s location of residence were in general associated with higher mental health/well-being and vitality scores, and less symptoms of depression, anxiety, and perceived and cognitive stress, after adjustments for demographic variables and walkability. In conclusion, the results from the present study provided support to the suggestion that contact with nature may be important for mental health in extreme circumstances.

Background: Allergic rhinitis (AR) is one of the most common chronic diseases worldwide. There are limited prospective long‐term data regarding persistency and remission of AR. The objective of this study was to investigate the natural course of pollen‐induced AR (pollen‐AR) over 20 years, from childhood into early adulthood.Methods: Data from 1137 subjects in the Barn/Children Allergi/Allergy Milieu Stockholm Epidemiologic birth cohort (BAMSE) with a completed questionnaire regarding symptoms, asthma, treatment with allergen immunotherapy (AIT) and results of allergen‐specific IgE for inhalant allergens at 4, 8, 16 and 24 years were analyzed. Pollen‐AR was defined as sneezing, runny, itchy or blocked nose; and itchy or watery eyes when exposed to birch and/or grass pollen in combination with allergen‐specific IgE ≥0.35kU_A/L to birch and/or grass.Results: Approximately 75% of children with pollen‐AR at 4 or 8 years had persistent disease up to 24 years, and 30% developed asthma. The probability of persistency was high already at low levels of pollen‐specific IgE. The highest rate of remission from pollen‐AR was seen between 16 and 24 years (21.5%); however, the majority remained sensitized. This period was also when pollen‐specific IgE‐levels stopped increasing and the average estimated annual incidence of pollen‐AR decreased from 1.5% to 0.8% per year.Conclusion: Children with pollen‐AR are at high risk of persistent disease for at least 20 years. Childhood up to adolescence seems to be the most dynamic period of AR progression. Our findings underline the close cross‐sectional and longitudinal relationship between sensitization, AR and asthma.

Contaminated drinking water (DW) is a major source of exposure to per- and polyfluoroalkyl substances (PFAS) at locations around PFAS production/use facilities and military airports. This study aimed to investigate quantitative relationships between concentrations in DW and serum of nine perfluoroalkyl acids (PFAAs) in Swedish adult populations living near contamination hotspots. Short-chained (PFPeA, PFHxA, PFHpA, and PFBS) and long-chained PFAAs (PFOA, PFNA, PFDA, PFHxS and PFOS) were measured in DW and serum. We matched DW and serum concentrations for a total of 398 subjects living or working in areas receiving contaminated DW and in one non-contaminated area. Thereafter, linear regression analysis with and without adjustments for co-variates was conducted. This enabled to derive (i) serum concentrations at background exposure (C_B) from sources other than local DW exposure (i.e. food, dust and textiles) at 0 ng/L DW concentration, (ii) population-mean PFAA serum:water ratios (SWR) and (iii) PFAA concentrations in DW causing observable elevated serum PFAA concentrations above background variability. Median concentrations of the sum of nine PFAAs ranged between 2.8 and 1790 ng/L in DW and between 7.6 and 96.9 ng/mL in serum. DW concentration was the strongest predictor, resulting in similar unadjusted and adjusted regression coefficients. Mean C_B ranged from <0.1 (PFPeA, PFHpA, PFBS) to 5.1 ng/mL (PFOS). Serum concentrations increased significantly with increasing DW concentrations for all PFAAs except for PFPeA with SWRs ranging from <10 (PFHxA, PFHpA and PFBS) to 111 (PFHxS). Observed elevated serum concentrations above background variability were reached at DW concentrations between 24 (PFOA) and 357 ng/L (PFHxA). The unadjusted linear regression predictions agreed well with serum concentrations previously reported in various populations exposed to low and high DW levels of PFOA, PFHxS and PFOS. The quantitative relationships derived herein should be helpful to translate PFAA concentrations in DW to concentrations in serum at the population level.

Obesity rates are increasing globally, and recent theories suggest that phthalates may contribute to obesity development. This longitudinal study aimed to investigate associations between environmental phthalate exposure during childhood and obesity, utilizing data from 100 participants from a Swedish birth cohort. The participants were followed repeatedly from birth and provided spot urine samples at 4 years. Weight and height were measured at ages 4, 8, 16 and 24 years, as well as additional anthropometric indices at 24 years. Urine samples were analysed for 10 phthalate metabolites using liquid chromatography tandem mass spectrometry. Generalized estimating equation models were performed to assess overall and age-specific associations between urinary phthalate concentrations and BMI groups; thin/normal weight vs overweight/obese. After adjustment for potential confounders, overall associations were observed for diisononyl phthalate (DiNP) metabolites mono(oxo-isononyl) phthalate (MOiNP) (OR per increase ng/ml: 1.18; 95% CI: 1.05, 1.33), mono(carboxy-isooctyl) phthalate (MCiOP) (OR: 1.06; 95% CI: 1.01, 1.11) and ∑DiNP (OR: 1.02; 95% CI:1.00, 1.04) and development of overweight/obesity up to age 24 years. Age-specific associations were observed for the same metabolites at 8, 16 and 24 years. Furthermore, linear regression analysis revealed associations between increased body fat % at age 24 years and MHiNP (β: 2.42; 95% CI: 0.44, 4.39), MOiNP (β: 2.32; 95% CI: 0.46, 4.18), MCiOP (β: 2.65; 95% CI: 0.41, 4.89) and ∑DiNP (β: 2.65; 95% CI: 0.52, 4.77). These findings suggest that DiNP exposure during preschool age may be associated with subsequent obesity, however these findings need to be corroborated by further research.

Aim: To explore how overcrowding affects children’s health, environment and schooling. Methods: A qualitative study was conducted with individual interviews among 20 participants with occupational experience from overcrowded Stockholm areas but diverse in professions, locations and employers. The interviews were recorded, transcribed and analysed with Systematic Text Condensation. Results: Almost all participants expressed that overcrowding has a negative impact on children’s health, environment and schooling – based on perceptions of precarious and different living conditions for children in overcrowded areas, for example, substandard homes, vulnerability, stress, exclusion, limited resources, lack of learning opportunities, gender differences, confinement, shame, insecurity, conflicts, risk of criminality, and bodily impact, both physical and psychological. Conclusions: Our qualitative evidence suggest that overcrowding has a negative impact on children’s health, environment and schooling.

Objectives The aim of this study was to analyse associations between crowded housing and children’s indoor living environment, respiratory and allergic disorders and general health. Design A cross-sectional study. Setting Sweden, using data from the Swedish National Environmental Health Survey 2019. Participants The study sample included 48 512 children (aged 6–10 months, 4 years and 12 years). We also investigated associations in vulnerable subgroups, such as children with asthma and those living under unfavourable socioeconomic conditions. Primary and secondary outcome measures Primary outcomes in the living environment were at least one sign of mould, poor indoor air quality, unpleasant odours, too warm indoors in summer and too cold indoors in winter. Primary outcomes for children’s health were asthma, airway problems, breathing difficulties, rhinitis symptoms, mould and mites allergy, pollen allergy, furred pet allergy and good general health. Results About one in five children lived in an overcrowded home. Factors from the indoor living environment such as perceived poor indoor air quality and mould were significantly associated with crowded housing. Moreover, children who lived in overcrowded conditions were less likely to report good general health than children in non-crowded households (OR 0.64, 95% CI 0.54 to 0.76). This association was even stronger in children with asthma (OR 0.51, 95% CI 0.34 to 0.77). Few significant associations were, however, observed with the respiratory and allergic health outcomes. Conclusions Crowded housing is associated both with a poor indoor environment and with poorer general health in children. Children with asthma may experience even poorer general health.