Environmental Epidemiology
Pollen exposure during pregnancy and early life represents a critical environmental factor influencing childhood respiratory health. Our research demonstrates significant associations between prenatal and postnatal pollen exposures and increased incidence of childhood asthma (Melaram et al., 2024). The research integrates environmental monitoring data with detailed health outcomes to provide comprehensive risk assessments for childhood asthma development.
Studies on Pollen Exposure and Childhood Asthma
| Study | Design | Exposure Window | Key Finding |
|---|---|---|---|
| Melaram et al. (2024) | Longitudinal birth cohort | Pregnancy & infancy | OR 1.14 (1.03–1.26) prenatal for asthma; OR 1.15 (1.03–1.29) postnatal for asthma |
| Lowe et al. (2012) | Register-based cohort | Late pregnancy | OR 1.35 (1.07–1.71) for hospitalization |
| Kihlström et al. (2002) | Birth cohort | Infancy | OR 2.6 (1.2–5.6) for allergic asthma |
Adapted from a narrative review of pollen exposure studies showing associations with childhood asthma outcomes (Melaram, 2024).
Figure 1. Odds ratios of childhood asthma at age 6 showing prenatal and postnatal pollen exposure effects (Melaram et al. 2024).
Environmental exposures can induce lasting changes in gene expression through epigenetic modifications, particularly DNA methylation (DNAm). Our research investigates how prenatal pollen grain (PPG) exposure influences DNAm patterns at birth, which subsequently affect childhood allergic disease development (Melaram et al., 2025). This work bridges environmental exposure science with molecular epidemiology to understand the biological pathways linking environmental factors to health outcomes.
Key PPG-Associated CpG Sites Related with Childhood Allergic Diseases
| CpG Site | Gene | Location | β Coefficient | P-value | Disease Association (OR, 95% CI) |
|---|---|---|---|---|---|
| cg12318501 | ZNF99 | TSS1500 | -0.029 | 0.032 | Asthma protection: OR 0.11 (0.02–0.53) |
| cg00929606 | ADM2 | TSS1500 | -0.023 | 0.008 | Asthma protection: OR 0.14 (0.02–1.00) |
| cg15790214 | HCG11 | Gene body | -0.027 | ≤0.0001 | Rhinitis protection: OR 0.22 (0.07–0.72) |
Epigenome-wide study results showing CpG sites with differential methylation associated with prenatal pollen grain exposure (Melaram et al., 2025). Negative β values indicate hypomethylation.
Figure 2. Analytical process of epigenome-wide study on pollen exposure and childhood asthma and allergic rhinitis (Melaram et al., 2025).
Air pollution is a global health problem, contributing to chronic respiratory disease morbidity and mortality. Our research examines the impact of air pollution exposure during critical developmental windows on the risk of childhood allergic diseases (Melaram, 2024). This work underscores the importance of early life exposures to air pollutants and their subsequent effects on increased asthma risk.
Air Pollution Exposures in Early Life and Childhood Allergic Diseases
| Pollutant | Study Population | Exposure Period | Health Outcome | Disease Association(OR/HR, 95% CI) |
|---|---|---|---|---|
| PM₂.₅ | European birth cohorts (n=14,126) | Early life | Asthma >4 years | OR 1.29 (1.00–1.66) |
| PM₂.₅ | COPSAC birth cohort (n=411) | Postnatal | Asthma at 6 years | OR 1.51 (1.08–2.07) |
| PM₁₀ | COPSAC birth cohort (n=411) | Postnatal | Asthma at 6 years | OR 1.56 (1.14–2.09) |
| NO₂ | Canadian cohort (n=37,401) | Infancy | Incident asthma | OR 1.06 (0.96–1.16) |
| O₃ | Quebec cohort (n=1,183,865) | At birth | Asthma development | HR 1.11 (1.10–1.12) |
| SO₂ | Canadian children (n=37,401) | Pregnancy & infancy | Asthma onset | OR 1.03 (1.02–1.05) |
Adapted from narrative review of epidemiological studies examining air pollution exposures during critical developmental windows and childhood allergic disease outcomes (Melaram, 2024).
Environmental Exposures, Epigenetics, and Allergic Diseases
The association of in utero environmental exposures with childhood respiratory and allergic diseases
In ProgressLongitudinal investigation of prenatal environmental exposures and their impact on childhood respiratory outcomes.
Association of prenatal exposure to PM2.5 with DNA methylation patterns at birth - a systematic review
In ProgressComprehensive systematic review examining the relationship between maternal fine particulate matter exposure and newborn epigenetic modifications.
Daily time series analysis of ambient ozone and fine particulate matter levels in Corpus Christi, TX
Under ReviewTime series analysis investigating temporal patterns of ozone and fine particulate matter in South Texas coastal region.