2019 HSR&D/QUERI National Conference

4132 — Magnesium Supplementation and Incident Diabetes Mellitus

Lead/Presenter: Qing Zeng,  DCVA Medical center
All Authors: Zeng QT (DCVA Medical Center), Ahmed A (DCVA), Cheng Y (DCVA) Blackman M (DCVA) Sheriff H (DCVA) Costello B (NIH)

It has been suggested that a higher intake of Magnesium (Mag) may lower the risk of incident Diabetes Mellitus (DM). However, according to the Office of Dietary Supplement at the National Institutes of Health, most Americans do not consume sufficient Mag. Some of the small randomized controlled trials on use of Mag supplements in patients with or without DM reported improved insulin sensitivity and metabolic control, but the results were mixed. Even less is known whether the use of available Mag supplements is associated with a lower risk of incident DM. The goal of this study is to test the hypothesis that the use of Mag supplements is independently associated with a lower risk of incident DM, leveraging the VA Corporate Data Warehouse (CDW) data.

We identified an initial cohort (n = 4,013,679) of Veterans with serum Mag measurements. Among them, 313,755 had lower than normal, 3,444,157 had normal, and 255,767 had higher than normal Mag levels. (Serum Mag normal levels were defined as follows: 1) mEq/L: 1.5-2; 2) mg/dL: 1.7-2.4; or 3) mmol/L: 0.7-1.) In the cohort, using prescription data alone, we identified 1,551,557 patients with single compound Mag exposure, 1,037,614 patients with (potential) Mag exposure (i.e. multivitamin, mineral, etc), and 2,462,122 with no evidence of exposure. Focusing on patients with low Mag level and excluding non-single compound exposure, we calculated exposure rates by gender, race, and ethnicity. We then compared the incident DM rates in between those with and without single compound Mag exposure. Finally we performed a logistic regression analysis to assess the relationship between incident DM and single compound Mag exposure using age, gender, ethnicity, and Charlston Comorbidity Index as co-variates.

In the VA cohort, a majority of the patients with Mag test (n = 2,973,000) were free of DM at the time of their first Mag test. Many (n = 565,000), however, developed DM later. Veterans with low Mag had a higher, raw incident rate of DM (21.3% vs 18.9%). In Veterans with low Mag, male had higher exposure rate to single compound Mag than female (68.1 vs 56.4%), African American higher than Caucasian (75.6 vs 70.0%) and non-Hispanic higher than Hispanic (70.8 vs 62.3%). Among those with low Mag, Veterans who received single compound Mag had lower incident rate than those with no evidence of Mag exposure (18.5% vs 27.4%). The logistic regression analysis result suggests that Mag level and single compound Mag treatment is indeed associated with DM incident. (Lower Mag: Adjusted Odds Ratio = 1.2, single compound Mag: Adjusted Odds Ratio = 0.66)

Mag supplementation in Veterans with low Mag level is associated with lower incident DM rates.

Although additional analyses are needed, initial results from this study suggest that the use of Mag supplementation may be a promising approach for DM prevention.