08 Oct First Born Children More Likely To Be Nearsighted

MedicalResearch.com Interview with:
Professor Jeremy A. Guggenheim
School of Optometry & Vision Sciences
Cardiff University
Cardiff, UK

Medical Research: What is the background for this study?

Dr. Guggenheim: An increased risk of myopia (nearsightedness) in first-born vs. non-first-born individuals was noticed in a 2013 study, which focused on 4 cohorts of children and young adults. We wanted to know whether the link between birth order and myopia was present in an earlier generation – before the invention of mobile phones and other gadgets. Also, first-born children tend to get slightly higher exam grades than do non-first-born children, an effect that has been attributed to slightly greater investment of time and energy by parents in the education of their first-born child. A high level of education is a well-known risk factor for myopia, therefore we were interested to find out whether the association between birth order and myopia was attributable to the slightly greater educational exposure of first-born individuals 

Medical Research: What are the main findings?

Dr. Guggenheim: Our analysis of a large sample of adults from the UK Biobank Project (http://www.ukbiobank.ac.uk/) provided strong evidence that first-born individuals were more likely to be myopic than later born children, although the increased risk was only about 10%. Taken together with the results of the previous study mentioned above, this suggests that the link between birth order and myopia is of long-standing origin, and thus unrelated to the specific lifestyle of children today. In further analyses that took account of differences in educational exposure, for example years spent in full-time education, the degree of association between birth order and myopia was reduced partially. This implies that the link between birth order and myopia is in part caused by greater time spent in education by first-born children, and in part caused by other, unknown factors.

Citation:

Guggenheim JA, Williams C, for the UK Biobank Eye and Vision Consortium. Role of Educational Exposure in the Association Between Myopia and Birth Order. JAMA Ophthalmol. Published online October 08, 2015. doi:10.1001/jamaophthalmol.2015.3556.

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Professor Jeremy A. Guggenheim (2015). First Born Children More Likely To Be Nearsighted 

Last Updated on October 8, 2015 by Marie Benz MD FAAD