Sarcoidosis and Risk of Nephrolithiasis in US Black Women: Data from the Black Women's Health Study

Sarcoidosis is a systemic inflammatory disorder linked to dysregulation of vitamin D metabolism. This state can contribute to abnormalities in calcium metabolism, theoretically increasing the risk of nephrolithiasis (kidney stones). Sarcoidosis and risk factors for nephrolithiasis (type 2 diabetes mellitus and hypertension) are common among US Black women.

How does sarcoidosis affect the risk of nephrolithiasis in a cohort of US Black women? Does the association change by the number and type of cooccurring metabolic condition?

We conducted a cross-sectional analysis using data from the Black Women's Health Study (BWHS), a study of 59,000 US Black women 21 to 69 years of age in 1995 (baseline). Information on sarcoidosis and covariates was obtained from baseline and biennial follow-up questionnaires through 2005. The 2005 questionnaire ascertained diagnoses of nephrolithiasis. We estimated ORs and 95% CIs using logistic regression adjusting for covariates, including calcium and vitamin D supplementation, alcohol consumption, and metabolic conditions (obesity, type 2 diabetes mellitus, hypertension, and hyperlipidemia). We repeated analyses within strata of number of metabolic conditions.

The analytical sample consisted of 43,718 women who completed the 2005 BWHS questionnaire. Between 1995 (baseline) and 2005, a total of 832 women reported sarcoidosis. As of 2005, of the women reporting sarcoidosis, 3.9% reported a history of nephrolithiasis, compared with 1.9% of the nonsarcoidosis participants. Among women with sarcoidosis, compared with those without, the odds of nephrolithiasis were 1.80 (95% CI, 1.25-2.59). The association according to number of metabolic conditions (none, 1-2, and 3-4) was additionally increased for women with 3 to 4 cooccurring conditions: 1.96 (95% CI, 1.09-3.52).

Our results indicate that US Black women with sarcoidosis have an increased risk of nephrolithiasis. The findings highlight the importance of monitoring for signs of vitamin D and calcium dysregulation in the management of sarcoidosis, especially among those with cooccurring metabolic conditions.