Community-based study of cataracts among type 2 diabetics in Kinmen

Abstract

The purpose of this study was to assess the prevalence and risk factors of each type of cataract among type 2 diabetics in Kinmen, Taiwan. There were 971 type 2 diabetics ascertained from a community-based mass screening between 1991 and 1993. In 1999, a total of 578 (59.5%) patients with type 2 diabetes were examined with an eye screening performed by two senior ophthalmologists using a 45-degree thin slit-lamp biomicroscopy and ophthalmoscopy to examine the lens after dilating the pupils. The overall prevalence, including subjects with or without surgery, was 31.0% (179/578, 95% CI: 27.3-34.7%), and had a statistically significant difference for gender (chi2 = 8.78, p = 0.003) and age (chi2-trend = 11.89, p < 0.0001). Based on multiple logistic regression, the significant risk factors of all types of cataracts were age (OR = 1.16, 95% CI: 1.12-1.20), lower diastolic blood pressure (DBP) at baseline (OR = 0.47, 95% CI: 0.25-0.88), and higher triglyceride at baseline (OR = 2.19, 95% CI: 1.07-4.45). In conclusion, our results found that in addition to age, lower DBP and higher triglyceride at baseline may increase the risk of prevalent cataracts in type 2 diabetics.

A systematic review of risk factors for cataract in type 2 diabetes

“…By contrast, blood pressure was inconsistently associated with cataract in two observational studies. Becker et al found hypertension increased, while Tung et al found diastolic blood pressure ≥ 90 mmHg (after adjusting for blood pressure lowering medication) decreased, the odds of cataract . There was no association in the other observational studies.…”

“…By contrast, Janghorbani and Amini found that oral agents were protective but used diabetes treatment at the latest clinic visit in their analysis . Six observational studies did not include diabetes treatment as a variable in the modelling . Two other studies identified diabetes treatment as a covariate.…”

“…Most of the observational studies included total serum cholesterol as a candidate predictor and found no association . By contrast, dyslipidaemia was a risk factor for cataract in the study by Becker et al Serum triglycerides also significantly increased the odds of cataract in the Kinmen studies with a serum triglyceride ≥2 mmol/L at baseline associated with increased odds of AC (OR 2.19 [95% CI: 1.07‐4.45]) and PSC cataract (OR 2.35 [95%CI: 1.15‐4.79]) . This threshold is above the ADA recommended serum triglyceride target of <1.7 mmol/L for adults with diabetes…”

“…It is unlikely that a longer diabetes duration is protective against cataracts considering hyperglycaemia and diabetes itself are accepted risk factors. The Wisconsin Epidemiology Study of Diabetic Retinopathy, the Kinmen studies, and that by Olafsdottir et al all included diabetes duration and reported no association . As only three studies reported a significant relationship between diabetes duration and cataract development, with differing directions of association and methodological concerns, while others reported no statistically significant association, it is unlikely that diabetes duration per se significantly contributes to cataract development.…”

“…The four observational articles that did not show an association with glycaemia did not include baseline HbA 1c in their regression models. Olafsdottir et al and the Kinmen Study included total mean fasting plasma glucose and fasting plasma glucose at baseline, respectively, and only HbA 1c at the last follow‐up visit as potential predictors of cataract . Only one study found an association between fasting blood glucose and cataract, while five found a significant positive association with HbA 1c .…”