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This study examined the associations of long-term exposure to ambient fine particulate matter (PM2.5) compositions/ozone with methylation of peripheral brain-derived neurotrophic factor (BDNF) promoters. A total of 101 participants were recruited from a cohort in Shijiazhuang, Hebei province, China. They underwent baseline and follow-up surveys in 2011 and 2015. DNA methylation levels were detected by bisulfite-PCR amplification and pyrosequencing. Participants' three-year average levels of PM2.5 compositions and ozone were estimated. Bayesian kernel machine regression (BKMR) models were used to examine the joint effects of pollutants on methylation levels. Exposure to PM2.5 compositions and ozone mixtures at the 75th percentile was associated with increased methylation levels at CpG2 of BDNF promoter (203%, 95% CI: 89, 316) than the lowest level of exposure, and sulfate dominated the effect in the BKMR models.Our findings provide clues to the epigenetic mechanisms for the associations of PM2.5 compositions and ozone with BDNF. [ABSTRACT FROM AUTHOR]

Background: Myopia is a pervasive global public health concern, particularly among the younger population. However, the escalating prevalence of myopia remains uncertain. Hence, our research aims to ascertain the global and regional prevalence of myopia, along with its occurrence within specific demographic groups., Methods: An exhaustive literature search was performed on several databases covering the period from their inception to 27 June 2023. The global prevalence of myopia was determined by employing pooled estimates with a 95% CI, and further analysis was conducted to assess variations in prevalence estimates across different subgroups. Additionally, a time series model was utilised to forecast and fit accurately the future prevalence of myopia for the next three decades., Results: This study encompasses a comprehensive analysis of 276 studies, involving a total of 5 410 945 participants from 50 countries across all six continents. The findings revealed a gradual increase in pooled prevalence of myopia, ranging from 24.32% (95% CI 15.23% to 33.40%) to 35.81% (95% CI 31.70% to 39.91%), observed from 1990 to 2023, and projections indicate that this prevalence is expected to reach 36.59% in 2040 and 39.80% in 2050. Notably, individuals residing in East Asia (35.22%) or in urban areas (28.55%), female gender (33.57%), adolescents (47.00%), and high school students (45.71%) exhibit a higher proportion of myopia prevalence., Conclusion: The global prevalence of childhood myopia is substantial, affecting approximately one-third of children and adolescents, with notable variations in prevalence across different demographic groups. It is anticipated that the global incidence of myopia will exceed 740 million cases by 2050., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

This study examined the associations of long-term exposure to ambient fine particulate matter (PM 2.5 ) compositions/ozone with methylation of peripheral brain-derived neurotrophic factor (BDNF) promoters. A total of 101 participants were recruited from a cohort in Shijiazhuang, Hebei province, China. They underwent baseline and follow-up surveys in 2011 and 2015. DNA methylation levels were detected by bisulfite-PCR amplification and pyrosequencing. Participants' three-year average levels of PM 2.5 compositions and ozone were estimated. Bayesian kernel machine regression (BKMR) models were used to examine the joint effects of pollutants on methylation levels. Exposure to PM 2.5 compositions and ozone mixtures at the 75th percentile was associated with increased methylation levels at CpG2 of BDNF promoter (203%, 95% CI: 89, 316) than the lowest level of exposure, and sulfate dominated the effect in the BKMR models.Our findings provide clues to the epigenetic mechanisms for the associations of PM 2.5 compositions and ozone with BDNF.