Relationship Between Breastfeeding and Cataracts Among Women
by Anne Eglash MD, IBCLC, FABM
Cataracts are lenses of the eyes that become opaque and difficult to see through. They account for over 1/3 of cases of blindness worldwide. Many of us have parents who have undergone cataract removal, or pets that have become blind due to cataracts. In 2010, 24 million individuals were diagnosed with cataracts, with 61% occurring in women.
The only treatment for cataracts is surgical removal, so efforts have been made to identify risk factors and strategies to reduce the risk of cataracts.
The authors of this study used the US National Health and Nutrition Examination Survey (NHANES) data during 1999-2006 to explore the relationship between breastfeeding and the incidence of cataract extraction. They evaluated 4914 women over age 50 who had given birth, and evaluated the association between their number of infants breastfed for more than 1 month and their history of cataract removal. They adjusted the data for expected confounders, including smoking, income, age, education, alcohol use and diabetes.
The authors found that women who breastfed 1 child for at least a month had a significantly lower risk of cataract extraction, and the risk decreased further with increased number of breastfed children.
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An estimated 38 million and 50 million individuals will have cataract in the U.S. alone by 2030 and 2050, respectively. Breastfeeding is known to improve a number of health outcomes in both breastfed children and breastfeeding mothers. However, little is known about the relationship between breastfeeding and cataract, the leading cause of blindness worldwide, in breastfeeding mothers. This study was conducted to investigate the relationship between breastfeeding and maternal cataract extraction history in a nationally representative sample of the U.S. population.
A 10-year multistage, probability-sampling survey data was used to identify parous women aged ≥50 years who provided breastfeeding history and cataract extraction history (n = 4897). Breastfeeding history was considered positive if a participant reported breastfeeding at least one child for ≥1 month. The main outcome was cataract extraction history. Estimates are presented in odds ratios (OR) and 95% confidence intervals (95%CI).
Approximately half of the studied women breastfed at least one child ≥1 month, and about 18% reported cataract extraction history. Participants with a positive breastfeeding history were less likely to have a positive cataract extraction history in both age-adjusted (OR = 0.814, 95% CI = 0.670–0.989) and multivariable logistic regression (OR = 0.794, 95%CI = 0.639–0.988). Higher number of breastfed children was also associated with a lower risk of cataract extraction history (OR = 0.934, 95%CI = 0.883–0.988).
The findings suggest that breastfeeding may be associated with a decrease in the likelihood of age-related cataract extraction in parous women from the U.S. population.
The authors explain that women with metabolic syndrome-associated conditions, particularly diabetes, are at higher risk of cataract formation, and a history of breastfeeding is associated with a lower risk of type 2 diabetes with age. Interestingly, the authors found that if they controlled for diabetes, there still was evidence that breastfeeding protects from cataracts. The protective mechanism is not clear.
This is not the first study to find this association. A 2016 study in Korea that analyzed data for 3821 women over 50 also found a decreased risk of cataracts in association with longer breastfeeding.