SYDNEY, AUSTRALIA. There is evidence that the development of cataracts, the most important cause of blindness worldwide, is associated with smoking, diabetes, and the use of corticosteroids. Now researchers at the University of Sydney report that a high salt (sodium chloride) intake is also associated with an increased risk of cataracts. Their study involved 2873 people between the ages of 49 and 97 years (median age of 65 years) who had photographs taken of their eyes (right and left lenses) and also completed a 145-item food intake questionnaire. Among the participants there were 620 cases of cortical cataracts, 350 of nuclear cataracts, and 160 of posterior subcapsular cataracts (the most disabling type). The researchers discovered a clear correlation between sodium intake and the incidence of posterior subcapsular cataracts. Study participants with a sodium intake of 3000 mg/day or more were twice as likely to have subcapsular cataracts than were participants with an intake of 1270 mg/day or less. This association held true even after adjusting for the effects of age, sex, smoking history, diabetes, hypertension, and the use of corticosteroids. The researchers found no correlation between sodium intake and the incidence of nuclear and cortical cataracts. They conclude that a reduced salt diet may help prevent cataracts in older individuals.
Cumming, Robert G., et al. Dietary sodium intake and cataract: the Blue Mountains Eye Study. American Journal of Epidemiology, Vol. 151, March 15, 2000, pp. 624- 26