Nuclear cataracts linked to ‘fat’ gene

A recent study concluded that polymorphisms at the fat mass- and obesity-associated (FTO) locus were associated with nuclear cataracts.
Tai E-Shyong, M.B.Ch.B., Department of Endocrinology, Singapore General Hospital, and his colleagues analyzed the relationship of age-related cataracts with obesity and obesity genes in an Asian population. The results are published in the March issue of the American Journal of Epidemiology.
Obesity shows an inconsistent association with cataracts, the researchers stated; in fact, causality has not been established. Polymorphisms at the FTO “fat” gene are associated with obesity and offer an opportunity to examine the obesity-cataract association using a mendelian randomization approach.
For the study, the authors conducted a population-based study among Singaporean Malay adults (2004–2006) in which nuclear, cortical, and posterior subcapsular (PSC) cataracts were assessed and defined by slit-lamp examination using Lens Opacity Classification System III. Obesity was defined as body mass index (weight in kilograms/height in meters) 30.
The study included 3,000 subjects, of which 1,339 (44.6%) had cataracts. Of this group 848 (28.3%) had nuclear cataracts; 939 (31.3%) had cortical; and 285 (9.5%) had PSC.
After multivariable adjustment for age, gender, diabetes, hypertension, smoking, and education, obesity was significantly associated with cortical cataracts (odds ratio [OR] = 1.31, 95% confidence interval [CI]: 1.01, 1.71) and PSC cataracts (OR = 1.60, 95% CI: 1.10, 2.32) but not nuclear cataract, they said. Therefore, the FTO single nucleotide polymorphisms were not associated with cortical or PSC cataract in this study population.
However, the FTO gene was associated with nuclear cataracts (OR = 1.33, 95% CI: 1.11, 1.58), even in multivariate analyses controlling additionally for body mass index, diabetes, hypertension, and smoking (OR = 1.30, 95% CI: 1.08, 1.55).

Reported by: EyeWorld News Services