The Linxian cataract studies. Two nutrition intervention trials

Area of Science:

• Ophthalmology
• Nutritional Science
• Gerontology

Background:

• Age-related cataracts are a leading cause of vision impairment.
• The role of nutritional factors, including vitamin and mineral supplements, in cataract development is under investigation.

Purpose of the Study:

• To investigate the impact of vitamin/mineral supplements on the incidence of age-related cataracts.
• To evaluate the effects of specific vitamin and mineral combinations on cataract prevalence.

Main Methods:

• Two randomized, double-masked, 5-6 year trials conducted in rural China.
• Participants (aged 45-74) received either multivitamin/mineral supplements or placebo (Trial 1).
• Trial 2 used a factorial design testing four different vitamin/mineral combinations.

Main Results:

• A significant reduction in nuclear cataract prevalence was observed in participants aged 65-74 receiving supplements in Trial 1 (36%) and riboflavin/niacin in Trial 2 (44%).
• No significant effect on cortical cataract prevalence was found in either trial.
• A statistically significant deleterious effect of riboflavin/niacin was noted for posterior subcapsular cataracts, though numbers were small.

Conclusions:

• Vitamin/mineral supplementation may offer a protective effect against nuclear cataract development, especially in older populations.
• The findings suggest potential benefits for specific nutrient combinations but require further investigation.
• General nutritional recommendations for cataract prevention based on these findings are premature and necessitate research in diverse populations.