A study of Myopia among more than 100,000 UK Biobank adults also found changing associations with sex, ethnicity and educational level
Changing environmental factors as well as changing gene-environment interactions could be to blame for increasing rates of myopia, also known as nearsightedness or shortsightedness.
Changing environmental factors as well as changing gene-environment interactions could be to blame for increasing rates of myopia, also known as nearsightedness or shortsightedness, suggests a new study published this week in the open-access journal PLOS ONE by Jugnoo Rahi of University College London, and other members of the UK Biobank Eye and Vision Consortium.
Previous studies have pointed to an emerging “epidemic” of myopia, characterized by increased prevalence of myopia accompanied by both a shift toward starting at a younger age as well as greater severity. In the new study, researchers used data on 107,442 study participants aged 40 to 69 years of age. All participants underwent a detailed ophthalmic exam and provided socio-demographic data as well as information on their history of glasses and vision problems.
Overall, myopia frequency increased from 20.0% in the oldest group (64-69 year old’s) to 29.2% in the youngest group (age 40-45). Other trends varied based on the type of myopia, with a greater increase in adult-onset myopia compared to childhood-onset myopia, and a greater increase in low myopia compared to high myopia. Moreover, the average spherical equivalent — a measure of myopia severity — worsened between groups, but only for childhood-onset myopia, shifting from a average of -3.8 diopters in the oldest participants, to -4.4 in the youngest.
Among the trends, there were additional, notable differences with relation to sex, ethnicity, socioeconomic status and education. In particular, the association between higher educational attainment and myopia increased over time, from an adjusted odds ratio of 2.7 in the oldest group (95% -2.9) to an odds ratio of 4.2 in the youngest group (95% -5.2) with the greatest increase seen in childhood-onset myopia (from -4.0 to -13).
The study authors conclude that their evidence supports changing environmental factors and presumably, changing gene-environment interactions, (discernible only by distinguishing between childhood-onset and adult-onset myopia) with increasing myopia frequency.
The authors add: “Myopia is a priority of the World Health Organization’s global initiative to reduce the burden of sight impairment. We investigated environmental risk factors driving the ‘epidemic’ of increasing frequency and severity of myopia in the UK by analyzing group effects within the UK Biobank Study. Our findings suggest that the frequency of childhood-onset myopia and of high (severe) myopia will continue to increase if rising educational experience or intensity in childhood is not addressed.”
Materials provided by PLOS.