JAMA: Higher ultraviolet B (UVB) radiation exposure, directly related to time outdoors and sunlight exposure, was associated with reduced odds of myopia (nearsightedness), and exposure to UVB between ages 14 and 29 years was associated with the highest reduction in odds of adult myopia, according to a study published online by JAMA Ophthalmology.
Myopia is a complex trait influenced by numerous environmental and
genetic factors and is becoming more common worldwide, most dramatically
in urban Asia, but rises in prevalence have also been identified in the
United States and Europe. This has major implications, both visually
and financially, for the global burden from this potentially
Astrid E. Fletcher, Ph.D., of the London School of Hygiene and
Tropical Medicine, and colleagues examined the association of myopia
with UVB radiation, serum vitamin D concentrations and vitamin D pathway
genetic variants, adjusting for years in education. The study included a
random sample of participants 65 years and older from 6 study centers
from the European Eye Study. Of 4,187 participants, 4,166 attended an
eye examination including refraction, gave a blood sample, and were
interviewed by trained fieldworkers using a structured questionnaire.
After exclusion for various factors, the final study group included 371
participants with myopia and 2,797 without.
The researchers found that an increase in UVB exposure at age 14 to
19 years and 20 to 39 years was associated with reduced odds of myopia;
those in the highest tertile (group) of years of education had twice the
odds of myopia. No independent associations between myopia and serum
vitamin D3 concentrations or variants in genes associated
with vitamin D metabolism were found. An unexpected finding was that the
highest quintile (group) of plasma lutein concentrations was associated
with reduced odds of myopia.
“The association between UVB, education, and myopia remained even
after respective adjustment. This suggests that the high rate of myopia
associated with educational attainment is not solely mediated by lack of
time outdoors,” the authors write.
“As the protective effect of time spent outdoors is increasingly used
in clinical interventions, a greater understanding of the mechanisms
and life stages at which benefit is conferred is warranted.”
(JAMA Ophthalmol. Published online December 1,
2016.doi:10.1001/jamaophthalmol.2016.4752; this study is available
pre-embargo at the For The Media website.)