Do Vitamin D Level and Dietary Calcium Intake Modify the Association Between Loop Diuretics and Bone Health?

Abstract

Abstract Loop diuretics (LD) may affect bone health by inhibiting renal calcium reuptake. However, whether vitamin D status and dietary calcium intake modify the association between LD and bone outcome is unclear. Therefore, this study aimed to evaluate whether vitamin D level or calcium intake modify the association between LD and various indices of bone health including bone mineral density (BMD) and Trabecular Bone Score (TBS). From The Rotterdam Study, a prospective population-based cohort study, we used data from 6990 participants aged > 45 year with a DXA scan (2002–2008), 6908 participants with femoral neck (FN)-BMD, 6677 participants with lumbar spine (LS)-BMD and 6476 participants with LS-TBS measurements. Use of LD was available from pharmacy dispensing records. Vitamin D (25(OH)D) level was measured in serum, and dietary calcium intake was measured with a validated food frequency questionnaire. Almost eight percent of the participants used LD. The association between LD (past-users compared to never-users) and LS-TBS was significantly different by 25(OH)D concentrations (P for interaction = 0.04). A significantly lower LS-TBS among LD past-users was observed for 25(OH)D ≥ 50 nmol/l compared to ≤ 20 and 20–50 nmol/l (β = − 0.036, 95% CI − 0.060; − 0.013 vs. β = − 0.012, 95% CI − 0.036; 0.013 and β = − 0.031, 95% CI − 0.096; 0.034, respectively). However, no other significant effect modification by 25(OH)D and dietary calcium intake was found in the associations between LD use and bone health outcomes (P-interaction > 0.13). This study suggests that the association between LD use and indices of bone health is not consistently modified by vitamin D or dietary calcium intake.