PURPOSE: To describe the occurrence and heritability of astigmatism in a population-based sample of Norwegian twins. METHODS: Self-reported history of astigmatism based on questionnaire responses was used to estimate the prevalence and incidence rates of astigmatism from birth through 31 years in 8,045 twins. Kaplan-Meier analysis and log-binomial regression were used to study the conditional and relative risk of astigmatism in twin pairs by sex and zygosity. Tetrachoric correlations and structural equation models were applied to estimate the genetic and environmental sources of variations in liability for astigmatism. RESULTS: Altogether 21.1% of males and 29.3% of females (p < 0.001) reported a positive history of astigmatism. Estimated incidence rates peaked in both sexes in the group aged 16-19 years and then decreased. Both conditional and relative risks of developing astigmatism were considerably higher in monozygotic than in dizygotic twins if a cotwin reported a positive history of astigmatism. The best-fitting biometrical model suggested that additive genetic, dominant genetic, and individual environmental effects explained 9% (95% CI: 0-40), 54% (95% CI: 20-69), and 38% (95% CI: 31-45) of the variation in the liability to astigmatism, respectively. No differences in heritability of astigmatism between the genders were found. CONCLUSIONS: The prevalence of self-reported astigmatism in twins is comparable with previous findings from Norway. Our results suggest considerable genetic contribution to the development of astigmatism in young adult Norwegian twins mainly due to dominant genetic effects, which are similar in both males and females.
PURPOSE: To describe the occurrence and heritability of astigmatism in a population-based sample of Norwegian twins. METHODS: Self-reported history of astigmatism based on questionnaire responses was used to estimate the prevalence and incidence rates of astigmatism from birth through 31 years in 8,045 twins. Kaplan-Meier analysis and log-binomial regression were used to study the conditional and relative risk of astigmatism in twin pairs by sex and zygosity. Tetrachoric correlations and structural equation models were applied to estimate the genetic and environmental sources of variations in liability for astigmatism. RESULTS: Altogether 21.1% of males and 29.3% of females (p < 0.001) reported a positive history of astigmatism. Estimated incidence rates peaked in both sexes in the group aged 16-19 years and then decreased. Both conditional and relative risks of developing astigmatism were considerably higher in monozygotic than in dizygotic twins if a cotwin reported a positive history of astigmatism. The best-fitting biometrical model suggested that additive genetic, dominant genetic, and individual environmental effects explained 9% (95% CI: 0-40), 54% (95% CI: 20-69), and 38% (95% CI: 31-45) of the variation in the liability to astigmatism, respectively. No differences in heritability of astigmatism between the genders were found. CONCLUSIONS: The prevalence of self-reported astigmatism in twins is comparable with previous findings from Norway. Our results suggest considerable genetic contribution to the development of astigmatism in young adult Norwegian twins mainly due to dominant genetic effects, which are similar in both males and females.
Authors: Margarida C Lopes; Pirro G Hysi; Virginie J M Verhoeven; Stuart Macgregor; Alex W Hewitt; Grant W Montgomery; Phillippa Cumberland; Johannes R Vingerling; Terri L Young; Cornelia M van Duijn; Ben Oostra; Andre G Uitterlinden; Jugnoo S Rahi; David A Mackey; Caroline C W Klaver; Toby Andrew; Christopher J Hammond Journal: Invest Ophthalmol Vis Sci Date: 2013-02-01 Impact factor: 4.799
Authors: Qing Li; Robert Wojciechowski; Claire L Simpson; Pirro G Hysi; Virginie J M Verhoeven; Mohammad Kamran Ikram; René Höhn; Veronique Vitart; Alex W Hewitt; Konrad Oexle; Kari-Matti Mäkelä; Stuart MacGregor; Mario Pirastu; Qiao Fan; Ching-Yu Cheng; Beaté St Pourcain; George McMahon; John P Kemp; Kate Northstone; Jugnoo S Rahi; Phillippa M Cumberland; Nicholas G Martin; Paul G Sanfilippo; Yi Lu; Ya Xing Wang; Caroline Hayward; Ozren Polašek; Harry Campbell; Goran Bencic; Alan F Wright; Juho Wedenoja; Tanja Zeller; Arne Schillert; Alireza Mirshahi; Karl Lackner; Shea Ping Yip; Maurice K H Yap; Janina S Ried; Christian Gieger; Federico Murgia; James F Wilson; Brian Fleck; Seyhan Yazar; Johannes R Vingerling; Albert Hofman; André Uitterlinden; Fernando Rivadeneira; Najaf Amin; Lennart Karssen; Ben A Oostra; Xin Zhou; Yik-Ying Teo; E Shyong Tai; Eranga Vithana; Veluchamy Barathi; Yingfeng Zheng; Rosalynn Grace Siantar; Kumari Neelam; Youchan Shin; Janice Lam; Ekaterina Yonova-Doing; Cristina Venturini; S Mohsen Hosseini; Hoi-Suen Wong; Terho Lehtimäki; Mika Kähönen; Olli Raitakari; Nicholas J Timpson; David M Evans; Chiea-Chuen Khor; Tin Aung; Terri L Young; Paul Mitchell; Barbara Klein; Cornelia M van Duijn; Thomas Meitinger; Jost B Jonas; Paul N Baird; David A Mackey; Tien Yin Wong; Seang-Mei Saw; Olavi Pärssinen; Dwight Stambolian; Christopher J Hammond; Caroline C W Klaver; Cathy Williams; Andrew D Paterson; Joan E Bailey-Wilson; Jeremy A Guggenheim Journal: Hum Genet Date: 2014-11-04 Impact factor: 4.132
Authors: Seyhan Yazar; Aniket Mishra; Wei Ang; Lisa S Kearns; Jenny A Mountain; Craig Pennell; Grant W Montgomery; Terri L Young; Christopher J Hammond; Stuart Macgregor; David A Mackey; Alex W Hewitt Journal: Mol Vis Date: 2013-06-06 Impact factor: 2.367