International journal of environmental research and public health
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Int J Environ Res Public Health · Jul 2019
Meta AnalysisDose-Response Relationship of Outdoor Exposure and Myopia Indicators: A Systematic Review and Meta-Analysis of Various Research Methods.
Myopia in children has dramatically increased worldwide. A systematic review and meta-analysis were conducted to evaluate the effects of outdoor light exposure on myopia. According to research data from 13 studies of 15,081 children aged 4-14 at baseline, outdoor light exposure significantly reduced myopia incidence/prevalence (odds ratio [OR] = 0.85, 95% confidence interval [CI]: 0.80-0.91, p < 0.00001; I2 = 90%), spherical equivalent refractive error (SER) by 0.15 D/year (0.09-0.27, p < 0.0001), and axial elongation by 0.08 mm/year (-0.14 to -0.02, p = 0.02). ⋯ Daily outdoor light exposure of more than 120 min was the most effective intervention, and weekly intervention time exhibited a dose-response relationship with all three indicators. Subgroup comparisons revealed that interventional studies report greater benefits from outdoor light exposure compared with cohort and cross-sectional studies, and individuals with myopia in intervention studies experienced slightly greater benefits than individuals without, in terms of SER and axial elongation. Therefore, this study suggests 120 min/day of outdoor light exposure at school.
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Int J Environ Res Public Health · Jul 2019
Review Historical ArticleRace and 1918 Influenza Pandemic in the United States: A Review of the Literature.
During epidemics, the poorest part of the population usually suffers the most. Alfred Crosby noted that the norm changed during the 1918 influenza pandemic in the US: The black population (which were expected to have higher influenza morbidity and mortality) had lower morbidity and mortality than the white population during the autumn of 1918. Crosby's explanation for this was that black people were more exposed to a mild spring/summer wave of influenza earlier that same year. ⋯ The results also show that the black population had lower influenza morbidity prior to 1918. The reasons for lower morbidity among the black population both at baseline and during the herald and later waves in 1918 remain unclear. Results may imply that black people had a lower risk of developing the disease given exposure, but when they did get sick, they had a higher risk of dying.