Does childhood exposure to biodiverse greenspace reduce the risk of developing asthma?

Greenspace Morphology and Preterm Birth: A State-Wide Study in Georgia, United States (2001-2016)

BACKGROUND

Residential greenness is linked to birth outcomes. However, the role of greenspace morphology remains poorly understood. Additionally, evidence is lacking regarding whether these relationships vary by subpopulation.

OBJECTIVE

We examined the association between preterm birth and residential greenspace morphology, including percentage, shape, connectedness, aggregation, closeness, and fragmentation.

METHODS

We analyzed 2,063,444 singleton live births between 2001 to 2016 in Georgia, USA. Thirty-meter resolution landcover data from National Land Cover Databased (2001-2016) were obtained to calculate greenspace morphology metrics for 1,953 census tracts in Georgia. A two-stage logistic regression examined associations between each greenspace morphology metric and preterm birth at individual level. Stratified analysis was conducted by maternal race, ethnicity, education, urbanicity, poverty rate, and greenspace percentage.

RESULTS

Higher greenspace percentage, aggregation, closeness, shape complexity, connectedness, and lower fragmentation were linked to a lower risk of preterm birth. After adjusting for poverty rate, associations with morphology attenuated, except for fragmentation [odds ratio (OR) = 1.014; 95% confidence interval (CI): 1.0001, 1.026] across the entire population. Strongest associations were found among black mothers and in high-poverty areas. Specifically, the odds of preterm birth in the highest quartile of greenspace percentage were 0.962 (95% CI: 0.933, 0.991) times the odds in the lowest quartile. Additionally, a lower risk of preterm birth was associated with higher greenspace aggregation (OR = 0.969; 95% CI: 0.947, 0.992), and a higher risk of preterm birth was associated with higher fragmentation (OR = 1.028; 95% CI: 1.009, 1.047), both in the black mothers group. In tracts with a high poverty rate, a lower risk of preterm birth associate with higher greenspace percentage (OR = 0.953; 95% CI: 0.910, 0.999), aggregation (OR = 0.976; 95% CI: 0.955, 0.997), and lower fragmentation (OR = 0.976; 95% CI: 0.958, 0.994). The association with greenspace morphology was most pronounced in census tracts with a medium level of greenspace percentage.

DISCUSSION

Our study complements other studies by showing the importance and protective effects of greenspace morphology. The observed effects are particularly prominent in census tracts characterized by a moderate level of greenspace percentage, high poverty rates, and among black women. Our findings suggest the need for tailored greenspace planning strategies based on varying levels of greenness in different areas. For locations with low greenness, increasing the greenspace percentage may be prioritized. In areas with a medium level of greenness, strategic enhancement of greenspace morphology is recommended. For areas with high greenness, the focus should be on improving spatial closeness of greenspace. https://doi.org/10.1289/EHP14571.

Residential greenness during pregnancy and early life and development of asthma up to 27 years of age: The Espoo Cohort Study

Previous studies have suggested that living close to green spaces has protective health effects, but potential effects on asthma are contradictory. We investigated the association between the amount of greenness in the residential area during pregnancy and early life and development of asthma in the first 27 years of life. The study population included all 2568 members of the Espoo Cohort Study, Finland. We calculated individual-level exposure to green space measured as cumulative Normalized Difference Vegetation Index (cumNDVI in unit-months) within 300 m of the participant's residence during pregnancy and the first two years of life in both spring and summer seasons. The onset of asthma was assessed using information from the baseline and follow-up surveys. Exposure to residential greenness in the spring season during pregnancy was associated with an increased risk of asthma up to 6 years of age, with an adjusted hazard ratio (aHR) of 3.72 (95% confidence interval (CI): 1.11, 12.47) per 1 unit increase in cumNDVI. Increased greenness in the summer during pregnancy associated with asthma up to 6 years, with an aHR of 1.41 (95% CI: 0.85, 2.32). The effect was found to be related to increased greenness particularly during the third trimester of pregnancy, with an aHR of 2.37 (95% CI: 1.36, 4.14) per 1 unit increase of cumNDVI. These associations were weaker at the ages of 12 and 27 years. No association was found between NDVI in the first two years of life and the development of asthma. Our findings provide novel evidence that exposure to greenness during pregnancy increases the risk of developing asthma. The adverse effects were strongest for the prenatal greenness in the spring season and in the third trimester of pregnancy. Both the season and trimester of exposure to greenness are critical in the development of asthma.

The Role of Biodiversity in the Development of Asthma and Allergic Sensitization: A State-of-the-Science Review

BACKGROUND

Changes in land use and climate change have been reported to reduce biodiversity of both the environment and human microbiota. These reductions in biodiversity may lead to inadequate and unbalanced stimulation of immunoregulatory circuits and, ultimately, to clinical diseases, such as asthma and allergies.

OBJECTIVE

We summarized available empirical evidence on the role of inner (gut, skin, and airways) and outer (air, soil, natural waters, plants, and animals) layers of biodiversity in the development of asthma, wheezing, and allergic sensitization.

METHODS

We conducted a systematic search in SciVerse Scopus, PubMed MEDLINE, and Web of Science up to 5 March 2024 to identify relevant human studies assessing the relationships between inner and outer layers of biodiversity and the risk of asthma, wheezing, or allergic sensitization. The protocol was registered in PROSPERO (CRD42022381725).

RESULTS

A total of 2,419 studies were screened and, after exclusions and a full-text review of 447 studies, 82 studies were included in the comprehensive, final review. Twenty-nine studies reported a protective effect of outer layer biodiversity in the development of asthma, wheezing, or allergic sensitization. There were also 16 studies suggesting an effect of outer layer biodiversity on increasing asthma, wheezing, or allergic sensitization. However, there was no clear evidence on the role of inner layer biodiversity in the development of asthma, wheezing, and allergic sensitization (13 studies reported a protective effect and 15 reported evidence of an increased risk).

CONCLUSIONS

Based on the reviewed literature, a future systematic review could focus more specifically on outer layer biodiversity and asthma. It is unlikely that association with inner layer biodiversity would have enough evidence for systematic review. Based on this comprehensive review, there is a need for population-based longitudinal studies to identify critical periods of exposure in the life course into adulthood and to better understand mechanisms linking environmental exposures and changes in microbiome composition, diversity, and/or function to development of asthma and allergic sensitization. https://doi.org/10.1289/EHP13948.

Association between early life exposure to agriculture, biodiversity, and green space and risk of inflammatory bowel disease: a population-based cohort study

Background

Specific pollutants and environmental exposures are implicated in modulating inflammatory bowel disease (IBD) risk. However, the role of environmental exposures, particularly during the early life period, towards IBD risk, has not been systematically evaluated.

Methods

We conducted a nationwide population-based cohort study during the study period extending from January 1, 1995, to September 1, 2020, using cross-linked Danish registers, maps, and inventories to ascertain the impact of agricultural land use, biodiversity, green space, urban space, blue space, and normalized difference vegetation index during pregnancy and the first two years of life on IBD, Crohn's disease (CD), and ulcerative colitis (UC) risk, using adjusted Cox proportional hazards regression analyses. We adjusted for covariates sex, maternal age at delivery, calendar year of birth, municipal-level socioeconomic status, and first-degree relative with IBD.

Findings

Of 1,438,487 individuals included in the study who were followed from age 2 years until a median (IQR) age of 14 (8-20) years, 3768 individuals were diagnosed with IBD. Exposure to the second, third and highest quartiles of agriculture land use during early life, relative to the lowest quartile, were associated with increased CD risk (aHR 1.12, 95% CI 1.01, 1.26, 1.19, 95% CI 1.05, 1.34 and, 1.24 95% CI 1.06, 1.46, respectively). There was no association of agriculture land use with UC risk. Conversely, exposure to the third quartile of biodiversity in early life, compared to the lowest quartile, were associated with a lower CD risk (aHR 0.86, 95% CI 0.75, 0.98). A protective effect of greenspace was noted in the highest quartile for CD (aHR 0.87, 95% CI 0.78, 0.98).

Interpretation

In a nationwide cohort with long-term follow up data, early life environmental exposures were associated with modulation of CD risk, with a harmful effect of agriculture land use and protective effect of biodiversity and green space.

Funding

Danish National Research Foundation, the International Organization for the Study of Inflammatory Bowel Disease, the National Institute of Diabetes and Digestive and Kidney Diseases.

Environmental microbiome in the home and daycare settings during the COVID-19 pandemic, and potential risk of non-communicable disease in children

An exposure to diverse microbial population early in life is important for the development of immunity against various non-communicable diseases including asthma, childhood leukaemia and other cancers. Social mixing in daycare settings helps with exposure to a variety of microbes. However, social isolation and a high emphasis on workplace hygiene during the COVID pandemic may have affected children's exposure to diverse microbiota. The structure of microbial communities and their role in developing immunity to various diseases are not well understood. In this study, we investigated the structure of microbial communities in daycare and home settings during the pandemic. Interestingly, microbial diversity was relatively higher in dust samples collected from homes, with human-associated taxa being more prevalent compared to those from daycare settings. Environmental microbes were more abundant in dust samples from daycare providers. These results potentially suggest that cleaning practices during the pandemic may have influenced the diversity and microbial abundance of the daycare samples. Several bacterial taxa detected in both the environments are known to induce anti-inflammatory and immunomodulatory responses, conferring protection from various diseases. Therefore, exposure to diverse microbial population in early childhood may play an important role in developing immunity against various non-communicable and infectious diseases.

Mapping wild vascular plant species diversity in urban areas in California using crowdsourcing data by regression kriging: Examining socioeconomic disparities

Biodiversity is crucial for human health, but previous methods of measuring biodiversity require intensive resources and have other limitations. Crowdsourced datasets from citizen scientists offer a cost-effective solution for characterizing biodiversity on a large spatial scale. This study has two aims: 1) to generate fine-resolution plant species diversity maps in California urban areas using crowdsourced data and extrapolation methods; and 2) to examine their associations with sociodemographic factors and identify subpopulations with low biodiversity exposure. We used iNaturalist observations from 2019 to 2022 to calculate species diversity metrics by exploring the sampling completeness in a 5 × 5-km2 grid and then computing species diversity metrics for grid cells with at least 80 % sample completeness (841 out of 4755 grid cells). A generalized additive model with ordinary kriging (GAM OK) provided moderately reliable estimates, with correlations of 0.64-0.66 between observed and extrapolated metrics, relative mean absolute errors of 21 %-23 %, and relative root mean squared errors of 27 %-30 % for grid cells with ≥80 % sample completeness from 10-fold cross-validation. GAM OK was further applied to extrapolate species diversity metrics from saturated grid cells (N = 841) to the remaining grid cells with <80 % sample completeness (N = 3914) and generate diversity maps that cover the grid. Further, generalized linear mixed models were used to examine the associations between species diversity and sociodemographic indicators at census tract level. The wild vascular plant species diversity metrics were inversely associated with neighborhood socioeconomic status (i.e., unemployment, linguistic isolation, educational attainment, and poverty rate). Minority populations (i.e., African American, Asian American, and Hispanic) and children had significantly lower diversity exposure in their neighborhoods. Crowdsourcing data offers a cost-effective solution for characterizing large-scale biodiversity in urban areas.

Higher greenspace exposure is associated with a decreased risk of childhood asthma in Shanghai - A megacity in China

Inconsistent evidence exists about whether exposure to greenspace benefits childhood asthma. Previous studies have only focused on residential or school greenspace, and no research has combined greenspace exposures at both homes and schools to determine their link with childhood asthma. A population-based cross-sectional study was conducted among 16,605 children during 2019 in Shanghai, China. Self-reported questionnaires were used to collect information on childhood asthma and demographic, socioeconomic and behavioural factors. Environmental data including ambient temperature, particulate matter with aerodynamic diameter less than 1 µm (PM₁), enhanced vegetation index (EVI), and normalized difference vegetation index (NDVI) were collected from satellite data. Binomial generalized linear models with a logit link were carried out to evaluate the association between greenspace exposure and children's asthma, as well as the effect modifiers. An interquartile range increment of whole greenspace (NDVI₅₀₀, NDVI₂₅₀, EVI₅₀₀, and EVI₂₅₀) exposure was associated with a reduced odds ratio of children's asthma (0.88, 95% CI: 0.78, 0.99; 0.89, 95% CI: 0.79, 1.01; 0.87, 95% CI: 0.77, 0.99; and 0.88, 95% CI: 0.78, 0.99, respectively) after controlling potential confounders. Low temperature, low PM₁, males, vaginal delivery, suburban/rural area, and without family history of allergy appeared to enhance the greenspace-asthma association. Increased greenspace exposure was associated with a lower risk of childhood asthma, and the association was modified by a range of socio-environmental factors. These findings add to the body of evidence on the benefits of biodiversity and supporting the promotion of urban greenspace to protect children's health.

A short history from Karelia study to biodiversity and public health interventions

Contact with natural environments enriches the human microbiome, promotes immune balance and protects against allergies and inflammatory disorders. In Finland, the allergy &amp; asthma epidemic became slowly visible in mid 1960s. After the World War II, Karelia was split into Finnish and Soviet Union (now Russia) territories. This led to more marked environmental and lifestyle changes in the Finnish compared with Russian Karelia. The Karelia Allergy Study 2002–2022 showed that allergic conditions were much more common on the Finnish side. The Russians had richer gene-microbe network and interaction than the Finns, which associated with better balanced immune regulatory circuits and lower allergy prevalence. In the Finnish adolescents, a biodiverse natural environment around the homes associated with lower occurrence of allergies. Overall, the plausible explanation of the allergy disparity was the prominent change in environment and lifestyle in the Finnish Karelia from 1940s to 1980s. The nationwide Finnish Allergy Programme 2008–2018 implemented the biodiversity hypothesis into practice by endorsing immune tolerance, nature contacts, and allergy health with favorable results. A regional health and environment programme, Nature Step to Health 2022–2032, has been initiated in the City of Lahti, EU Green Capital 2021. The programme integrates prevention of chronic diseases (asthma, diabetes, obesity, depression), nature loss, and climate crisis in the spirit of Planetary Health. Allergic diseases exemplify inappropriate immunological responses to natural environment. Successful management of the epidemics of allergy and other non-communicable diseases may pave the way to improve human and environmental health.

Residential greenspace and childhood asthma: An intra-city study

Interest in assessing the effects of exposure to greenspace on human health has been increasing due to rapid urbanization, and rising trends of physical inactivity and air pollution. However, findings on the link between greenspace and child respiratory health, especially asthma, are inconsistent. We investigated the association between greenspace surrounding residential addresses and asthma in children. A city-wide cross-sectional study was conducted, involving 16,605 children aged 3-12 years, in Shanghai, China. Data on asthma symptoms and covariates were collected from validated self-reported questionnaires. Residential greenspace was measured using satellite-derived normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI). Information on ambient temperature and particulate matter with dynamic diameter <1 μm (PM₁) and 2.5 μm (PM_2.5) was also collected from satellite data. Logistic regression models were performed to assess the associations of greenspace exposure with childhood asthma as well as the effect modification by covariates. The prevalence of current asthma in children was 4.8 % in this study. An interquartile range increase in mean NDVI from 2016 to 2018 was associated with decreased odds of asthma in 2019 at 500 m, and 250 m resolutions (0.82, 95 % confidence interval (CI): 0.74 to 0.93; and 0.82, 95 % CI: 0.72 to 0.94, respectively) after adjustment for covariates. The greenspace-asthma association was modified by ambient temperature and residential area. Sensitivity analyses using various models and EVI exposure showed the robustness of the results. In conclusion, higher individual-level exposure to greenspace was associated with decreased odds of asthma in children, and the association appeared to be modified by different environmental and socio-demographic factors. These findings provide additional evidence for promoting urban greenness to protect children's health and well-being.

Association between exposure to greenness and atopic march in children and adults-A systematic review and meta-analysis

Introduction

Allergic diseases are a global public health problem. Food allergy, atopic dermatitis (AD), allergic rhinoconjunctivitis, allergic rhinitis (AR) and asthma represent the natural course of allergic diseases, also known as the "atopic march". In recent years, a large number of studies have been published on the association between greenness exposure and allergic diseases. However, systematic reviews on the association between greenness exposure and multiple allergic diseases or atopic march are lacking.

Methods

In this study, PubMed, EMBASE, ISI Web of Science, and Scopus were systematically searched. Meta-analyses were performed if at least three studies reported risk estimates for the same outcome and exposure measures.

Results

Of 2355 records, 48 studies were included for qualitative review. Five birth cohort studies, five cross-sectional studies, and one case-control study were included for asthma meta-analysis, respectively. Four birth cohort studies were included for AR meta-analysis. Our results support that exposure to a greener environment at birth reduces the risk of asthma and AR in childhood. In addition, higher greenness exposure was associated with decreased odds of current asthma in children.

Discussion

There was a large heterogeneity among the included studies and most of them did not specify the vegetation type and causative allergens. Therefore the study results need to be further validated. In addition, a small number of studies evaluated the association between greenness and food allergy, AD and allergic rhinoconjunctivitis. More research is needed to strengthen our understanding of the association between greenness and allergic diseases.