Dataset Information

Sunlight exposure in infancy decreases risk of sporadic retinoblastoma, extent of intraocular disease.

ABSTRACT:

Background

Prior ecologic studies suggest that UV exposure through sunlight to the retina might contribute to increased retinoblastoma incidence.

Aims

Our study objectives were (1) to examine the relationship between exposure to sunlight during postnatal retinal development (prior to diagnosis of sporadic disease) and the risk of retinoblastoma, and (2) to examine the relationship between sun exposure during postnatal retinal development, and the extent of disease among children with unilateral and bilateral retinoblastoma.

Methods and results

We interviewed 511 mothers in the EpiRbMx case-control study about their child's exposure to sunlight during postnatal retinal cell division by examining three time periods prior to Rtb diagnosis coinciding with developmental stages in which outdoor activities vary. Weekly sun exposure was compared by age period, between unilateral (n = 259), bilateral (n = 120), and control (n = 132) children, accounting for two factors affecting UV exposure: residential elevation and reported use of coverings to shield eyes. For cases, association between sunlight exposure and clinical stage was examined by laterality at each age period. After adjusting for maternal education and elevation, sun exposure was lower in cases than controls in all three age periods especially during the first 6 months, and in children 12-23 months whose mothers did not cover their eyes when outdoors. In children diagnosed after 12 months of age, sun exposure during the second year of life (age 12-23 months) appeared inversely correlated (r = -0.25) with more advanced intraocular disease in bilateral Rtb children after adjusting for maternal education, residential elevation, and age of diagnosis (p < .09) consistent with effects of Vitamin D exposure on intraocular spread in earlier transgenic murine models of retinoblastoma, and suggesting potential chemopreventive strategies.

Conclusion

Sun exposure in early childhood is protective for retinoblastoma and may decrease degree of intraocular spread in children with bilateral Rtb.

SUBMITTER: Orjuela-Grimm M

PROVIDER: S-EPMC8714544 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Exposure to sunlight has recently been postulated as responsible for the effect that more time spent outdoors protects children from myopia, while early life exposure to natural light was reported to be possibly related to onset of myopia during childhood. In this study, we had two aims: to determine whether increasing natural light exposure has a protective effect on hyperopic defocus-induced myopia, and to observe whether early postnatal exposure to natural light causes increased risk of refractive error in adolescence. Eight rhesus monkeys (aged 20-30 days) were treated monocularly with hyperopic-defocus (-3.0D lens) and divided randomly into two groups: AL group (n=4), reared under Artificial (indoor) Lighting (08:00-20:00); and NL group (n=4), exposed to Natural (outdoor) Light for 3 hours per day (11:00-14:00), and to indoor lighting for the rest of the light phase. After being reared with lenses for ca. 190 days, all monkeys were returned to unrestricted vision until the age of 3 years. Another eight age-matched monkeys, reared with unrestricted vision under artificial lighting since birth, were employed as controls. The ocular refraction, corneal curvature and axial dimensions were measured before lens-wearing (at 23±3 days of age), monthly during the light phase, and at the age of puberty (at 1185+3 days of age). During the lens-wearing treatment, infant monkeys in the NL group were more hyperopic than those in the AL group (F=5.726, P=0.032). Furthermore, the two eyes of most NL monkeys remained isometropic, whereas 3 of 4 AL monkeys developed myopic anisometropia more than -2.0D. At adolescence, eyes of AL monkeys showed significant myopic anisometropia compared with eyes of NL monkeys (AL vs NL: -1.66±0.87D vs -0.22±0.44D; P=0.002) and controls (AL vs Control: -1.66±0.87D vs -0.05±0.85D; P<0.0001). All differences in refraction were associated with parallel changes in axial dimensions. Our results suggest that exposure to natural outdoor light might have an effect to reduced hyperopic defocus-induced myopia. Also, the data imply that early life exposure to sunlight may help to maintain normal development of emmetropization later in life, and thus lower the risk of myopic anisometropia in adolescent monkey.