Journal
OPHTHALMIC EPIDEMIOLOGY
Volume 20, Issue 6, Pages 375-384Publisher
TAYLOR & FRANCIS INC
DOI: 10.3109/09286586.2013.848457
Keywords
Avon Longitudinal Study of Parents and Children; birth order; myopia; Raine Eye Health Study; refractive error; Singapore Cohort Study of Risk Factors for Myopia
Categories
Funding
- UK Medical Research Council [74882]
- Wellcome Trust [076467]
- University of Bristol
- Australian Foundation for the Prevention of Blindness
- Ophthalmic Research Institute of Australia (ORIA)
- National Health and Medical Research Council (NHMRC [1021105]
- University of Western Australia (UWA)
- Telethon Institute for Child Health Research
- Raine Medical Research Foundation
- UWA Faculty of Medicine
- Dentistry and Health Science
- Women's and Infant's Research Foundation
- Curtin University
- NHMRC
- National Eye Research Centre, Bristol (JAG, CW) [SCIAD 053]
- National Institute for Health
- National Institutes of Health [R01-EY018838]
- Paul and Evanina Bell Mackall Foundation Trust (RAS)
- Research to Prevent Blindness (RAS)
- Singapore National Medical Research Council [NMRC/0695/2003]
Ask authors/readers for more resources
Purpose: An association between birth order and reduced unaided vision (a surrogate for myopia) has been observed previously. We examined the association between birth order and myopia directly in four subject groups. Methods: Subject groups were participants in (1) the Avon Longitudinal Study of Parents and Children (ALSPAC; UK; age 15 years; N = 4401), (2) the Singapore Cohort Study of Risk Factors for Myopia (SCORM; Singapore; age 13 years; N = 1959), (3) the Raine Eye Health Study (REHS; Australia; age 20 years; N = 1344), and (4) Israeli Defense Force Pre-recruitment Candidates (IDFC; Israel; age 16-22 years; N = 888,277). The main outcome was odds ratios (OR) for myopia in first-born versus non-first-born individuals after adjusting for potential risk factors. Results: The prevalence of myopia was numerically higher in first-born versus non-first-born individuals in all study groups, but the strength of evidence varied widely. Adjusted ORs (95% confidence intervals, CIs) were: ALSPAC, 1.31 (1.05-1.64); SCORM, 1.25 (0.89-1.77); REHS, 1.18 (0.90-1.55); and IDFC, 1.04 (1.03-1.06). In the large IDFC sample, the effect size was greater (a) for the first-born versus fourth-or higher-born comparison than for the first-born versus second/third-born comparison (p<0.001) and (b) with increasing myopia severity (p<0.001). Conclusions: Across all studies, the increased risk of myopia in first-born individuals was low (OR<1.3). Indeed, only the studies with >4000 participants provided strong statistical support for the association. The available evidence suggested the relationship was independent of established risk factors such as time outdoors/reading, and thus may arise through a different causal mechanism.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available