Skip to content

Association between birth weight and refractive error in adulthood: a Mendelian randomization study

Research output: Contribution to journalArticle

Original languageEnglish
Number of pages6
JournalBritish Journal of Ophthalmology
Early online date16 May 2019
DOIs
DateAccepted/In press - 26 Apr 2019
DateE-pub ahead of print - 16 May 2019
DatePublished (current) - 16 May 2019

Abstract

Background
Pathological myopia is one of the leading causes of blindness globally. Lower birth weight (BW) within the normal range has been reported to increase the risk of myopia, although findings conflict. We sought to estimate the causal effect of BW on refractive error using Mendelian randomisation (MR), under the assumption of a linear relationship.

Methods
Genetic variants associated with BW were identified from meta-analysis of a genome-wide association study (GWAS) for self-reported BW in 162 039 UK Biobank participants and a published Early Growth Genetics (EGG) consortium GWAS (n=26 836). We performed a one-sample MR analysis in 39 658 unrelated, adult UK Biobank participants (independent of the GWAS sample) using an allele score for BW as instrumental variable. A two-sample MR sensitivity analysis and conventional ordinary least squares (OLS) regression analyses were also undertaken.

Results
In OLS analysis, BW showed a small, positive association with refractive error: +0.04 D per SD increase in BW (95% CI 0.02 to 0.07; p=0.002). The one-sample MR-estimated causal effect of BW on refractive error was higher, at +0.28 D per SD increase in BW (95% CI 0.05 to 0.52, p=0.02). A two-sample MR analysis provided similar causal effect estimates, with minimal evidence of directional pleiotropy.

Conclusions
Our study suggests lower BW within the normal range is causally associated with a more myopic refractive error. However, the impact of the causal effect was modest (range 1.00 D covering approximately 95% of the population).

Download statistics

No data available

Documents

Documents

  • Full-text PDF (accepted author manuscript)

    Rights statement: This is the author accepted manuscript (AAM). The final published version (version of record) is available online via BMJ at https://bjo.bmj.com/content/early/2019/05/15/bjophthalmol-2018-313640. Please refer to any applicable terms of use of the publisher.

    Accepted author manuscript, 578 KB, PDF document

DOI

View research connections

Related faculties, schools or groups