A study of factors related to the incidence of cataract in patients with non-insulin dependent diabetes mellitus.

OBJECTIVE

To investigate the factors related to the development of cataract in patients with non-insulin dependent diabetes mellitus(NIDDM).

METHODS

792 NIDDM patients received ophthalmologic examinations including visual acuity, external status of the eyes, slit lamp microscopy and ophthalmoscopy. Glucose, urea nitrogen(BUN), creatinine(Cr), urine acid(UA), N-acetyl-beta 2-D-glucosaminidase (NAG), beta 2-microglobulin(beta 2-MG) and serum albumin in blood were quantitatively tested. Glucose, pH value, protein, cells, cast and ketobodies in urine were assayed. Diagnosis of cataract was based on lens opacities classification system II. Any patient meeting "NII", "CII" or "PII" level was diagnosed as cataract.

RESULTS

The incidence of cataract in this group of NIDDM was 62.37% (494/792), which significantly related to the duration of the disease course, but not to the sex of the patient. The occurrence rate of cataract in patients suffering from NIDDM of less than five years duration, from five to ten years, and more than ten years was 49.67% (228/459), 71.84% (125/174), and 88.68% (141/159), respectively. The occurrence of cataract in patients diagnosed of the disease from five to ten years and more than ten years was much higher than that of those with the course of the disease less than five years(P < 0.05 and P < 0.001, respectively). Rising concentrations of blood urea nitrogen, creatinine, glycosylated hemoglobin HbA1c(G-HbA1c), N-acetyl-beta 2-D-glucosaminidase(NAG) and beta 2-microglobulin(beta 2-MG) indicated malfunction of the kidneys, and the rate of cataract occurrence in these patients was higher.

CONCLUSIONS

This study indicates that prolongation of the duration of non-insulin dependent diabetes mellitus, renal dysfunction, as well as poor blood glucose control, may accelerate the development of cataract.