(P06-35-26) Population-Based Serum Magnesium Reference Intervals for U.S. Adolescents and Adults: NHANES 2021–2023

Objectives: To characterize serum magnesium concentrations in the contemporary U.S. population and derive updated, population-based reference intervals for adolescents and adults using NHANES 2021–2023.

Methods: We conducted a cross-sectional analysis of nonpregnant, nonlactating civilian participants in NHANES 2021–2023. Reference intervals were estimated in accordance with current International Federation of Clinical Chemistry recommendations. Primary analyses stratified adolescents (12–18 y) by sex and adults (≥19 y) by sex, age, and metabolic health status (overall population; metabolically healthy; hypertension; diabetes; and chronic kidney disease [CKD]). Between-group differences were evaluated using linear regression, and sensitivity analyses examined the robustness of the main results.

Results: The analytic sample included 787 adolescents and 5,474 adults. Mean serum magnesium was modestly lower in girls than boys. Using the total adolescent population, the estimated reference interval was 1.70–2.19 mg/dL (0.70–0.90 mmol/L; 1.40–1.80 mEq/L) for boys and 1.64–2.18 mg/dL (0.68–0.90 mmol/L; 1.35–1.79 mEq/L) for girls. Among adults, mean serum magnesium was lower in individuals with diabetes, hypertension, or CKD compared with metabolically healthy adults, and lower in women than men; differences across adult life-stage categories were minimal. Using the metabolically healthy adult subgroup, the reference interval was 1.72–2.26 mg/dL (0.71–0.93 mmol/L; 1.42–1.86 mEq/L) for men and 1.70–2.21 mg/dL (0.70–0.91 mmol/L; 1.40–1.82 mEq/L) for women. Estimated prevalence of chronic latent magnesium deficiency (CLMD) among adults was 67.8%.

Conclusions: These NHANES 2021–2023 analyses provide updated U.S. population-based reference intervals for serum magnesium in adolescents and adults and indicate that a large share of adults may be at elevated risk for CLMD.

Funding Sources: Pharmavite, LLC