Lower serum levels of certain antioxidants may be involved in the development of kidney stones, according to a large population-based study.
Investigators Peter A. Holoch, MD, and Chad R. Tracy, MD, of the University of Iowa in Iowa City, showed that mean levels of alpha-carotene, beta-carotene, and beta-cryptoxanthin are significantly lower in individuals with a history of kidney stones. These antioxidants could have a role in preventing stone formation, they concluded in an online report in the Journal of Endourology.
The study provides the first population-based evidence of an inverse relationship between various serum antioxidant levels and the self-reported prevalence of kidney stones, the researchers noted. They cautioned, however, that their findings do not show a direct causal relationship.
Previous studies have demonstrated that oxidative stress has a possible role in the development of kidney stones.
For the study, Drs. Holoch and Tracy used data from 17,695 adult participants in the National Health and Nutrition Examination Survey (1988-1994). They compared serum levels of antioxidants (alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein/zeaxanthin, lycopene, retinyl esters, vitamin A, and vitamin E) in subjects with and without a self-reported history of kidney stones.
The mean levels of alpha-carotene, beta-carotene, and beta-cryptoxanthin were a significant 9.36%, 10.79%, and 8.48% lower in subjects with a history of kidney stones, after adjusting for age, gender, body mass index, race/ethnicity, and the presence of hypertension, and diabetes.
In addition, compared with subjects in the highest quartile of alpha-carotene, those in the lowest quartile had a significant 38% increased odds of a history of kidney stones. Compared with those in the highest quartile of beta-carotene and beta-crytoxanthin, those in the lowest quartile had a significant 33% and 66% increased odds of a history of kidney stones.