Body stature and myopia - The genes in myopia (GEM) twin study

Objective: A consensus regarding whether a myopia body stature exists is still unclear with previous literature being inconsistent and conflicting. We wished to explore the relationship of body stature and myopia using a large Australian twin cohort [The Genes in Myopia (GEM) twin study]. Methods: All twins examined in the GEM twin study were recruited from the Australian Twin Registry (ATR). Each twin underwent a standard questionnaire, comprehensive eye examination and anthropometric (height and weight) measures were obtained. Myopia was defined as spherical equivalent, equal to or worse than -0.50 Diopters (D) Results: A total of 1224 twins (690 monozygotic twins and 534 dizygotic twins) aged between 18 to 86 years (mean age = 52.36 years) were recruited into the GEM study. The mean height [meters (m)] and weight [kilograms (kg)] of all twins in the GEM study was 1.67 m (1.44 m to 1.95 m) and 71.66 kg (40 kg to 167 kg), respectively. In the heaviest individuals (greater than or equal to 80kg), there was a significant risk (OR 1.48, p = 0.01) of having myopia compared to those in the lightest quartile of weight (less than 61 kg). However, when gender was analyzed separately, this significant risk remained only for females (OR:1.79, p = 0.01). Conclusion: Females in the heaviest quartile of weight have a significantly increased risk of myopia compared to those in the lightest weight quartile in our twin study population. Our study adds to the growing consensus that anthropometric measures should be considered as potential risk factors in myopia.