Bariatric surgery may lead to decreased risk of cataract

Reviewed by Theresa Burkard, PhD

A large population-based Swedish cohort study found that a substantial weight loss resulting from bariatric surgery is associated with a decreased risk in the development of cataract, especially in patients who undergo the surgery before age 60, according to Theresa Burkard, PhD, of the Institute of Pharmaceutical Sciences at ETH Zürich in Switzerland.

As being overweight or obese is a risk factor for cataract development, Burkard and her colleagues conducted a study¹ to assess the association between weight loss achieved through bariatric surgery and cataract development.

The authors hypothesized that the lower incidence of cataract may result from decreased oxidative stress, less systemic inflammation, and remission of diabetes and hypertension associated with weight loss.

The primary outcome was the first diagnosis of cataract or cataract surgery.

The investigators accessed patient data in the nationwide Swedish health care registries from 2006 to 2019 of patients aged 40 to 79 who had undergone bariatric surgery.

They were matched to obese patients who had not undergone a bariatric surgery.

The follow-up period started after a 1-year run-in period, as bariatric surgery was unlikely to have an immediate effect.

Observations
A total of 22,560 patients who had undergone bariatric surgery were matched with 35,523 obese patients who had not undergone bariatric surgery.

Of those, 1151 and 2316 patients, respectively, developed cataracts. The patients were followed for a mean of 6 years.

Both groups were similar for mean age (49.9 years) and follow-up (6.5 years).

“The data showed that the risk of cataract decreased by 29% in the obesity surgery group compared [with] matched patients, with obesity but no surgery,” the investigators reported.

Age was a factor in cataract development. In patients 60 years or older, the beneficial effect of the bariatric surgery seemed to disappear, and no significant difference was seen in the risk of cataract between groups in the older patients.

Another interesting finding was that surgical techniques that led to greater weight loss and a higher risk of malabsorption of nutrients, such as duodenal switch or gastric bypass, were associated with the lowest risks of cataract (51% statistically nonsignificant decreased risk of cataract after duodenal switch, 32% statistically significant decreased risk of cataract after gastric bypass).

However, the investigators explained, sleeve gastrectomy generally leads to slightly less weight loss and malabsorption of nutrients, and there was no difference in cataract risk between patients who underwent sleeve gastrectomy and those not undergoing bariatric surgery.

No differences were seen between sexes in the reduced risk of cataract development after bariatric surgery.

“Substantial weight loss is associated with a decreased risk of cataract, especially if obesity surgery was performed before age 60 years,” the investigators concluded. “This decreased risk is an addition to the multitude of positive effects that weight loss has on eye health. Furthermore, we observed a potential dose-response relationship between the amount of weight loss and reduction in cataract incidence.”

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Theresa Burkard , PhD
E: theresa.burkard@pharma.ethz.ch
This article was adapted from Burkard’s presentation at the European Congress on Obesity 2021 virtual annual meeting. She has no financial interest in this subject matter.

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Reference
1. Pan C-W, Lin Y. Overweight, obesity, and age-related cataract: a meta-analysis. Optom Vis Sci. 2014;91(5):478-483. doi:10.1097/OPX.0000000000000243