Vitamin D Supplementation Does Not Reduce Need for Cataract Surgery

When routinely supplied with high-dose vitamin D, the need for cataract surgery among older adults who live in an area with a low prevalence of vitamin D deficiency is unlikely to decrease, according to findings published in Ophthalmology.

Researchers conducted a study to assess whether vitamin D supplementation reduces the incidence of cataract surgery. The study was an ancillary of the randomized D-Health Trial of monthly vitamin D for the prevention of all-cause mortality, which was conducted in Australia from 2014 to 2020. 

The researchers evaluated 19,925 participants (mean age 60-84 years) with incident cataracts . Participants took 60,000 IU of vitamin D3 (n=10,662) or a placebo (n=10,653) orally once per month for a maximum of 5 years. The primary outcome measure was the first surgical treatment for cataract. 

The study found that 3668 (18.4%) participants (mean age 69.3 years) underwent surgery in the follow-up period, 18.5% from the vitamin D group, and 18.3% from the placebo group). Incidence of cataract surgery was similar between the 2 groups (95% CI, 0.95-1.09). Subgroup analyses did not modify the effect of vitamin D supplementation on the incidence of surgery by age, sex, body mass index, predicted serum 25-hydroxyvitamin D concentration, or ambient ultraviolet radiation. 

The study authors explain that previous, observational research suggests that higher serum 25-hydroxyvitamin D concentration may be associated with lower risk of cataract, but that no randomized controlled trials (RCTs) had assessed the effect of vitamin D supplementation on the incidence of cataract. Therefore, it was not possible to compare the present results with previous RCT findings. 

While this research did not show treatment effects in its location (Australia), the study authors warn that effects may differ in other populations.

“While the results of the D-Health Trial are likely to be broadly generalizable to the Australian setting and other communities with a similar prevalence of vitamin D deficiency, they are largely uninformative about the effect on cataract of treating vitamin D deficiency or of population-wide supplementation in areas where a much higher proportion of people is vitamin D deficient,” the researchers report.

The present study observed a similar number of participants from the vitamin D group and the placebo group to receive cataract surgery during the intervention timeline, and therefore, it does not support a notion that the supplementation of vitamin D reduces the need for surgery in those living in areas with a low prevalence of vitamin D deficiency. The study was limited in that it did not account for different cataract subtypes and incomplete hospital admission data.