Women’s Health
Kidney Function and Biomarkers of Folate and Vitamin B12 Status in Women of Reproductive Age in Southern India Doreen Larvie* Doreen Larvie Heather M. Guetterman Erin G. Sley Beena Bose Christina B. Johnson Amy Fothergill Arick Wang Shameem Jabbar Mindy Zhang Christine M. Pfeiffer Yan Ping Qi Charles E. Rose Jennifer L. Williams Saurabh Mehta Rebecca Kuriyan Prakash B. Narasimhan Krista S. Crider Julia L. Finkelstein
Background: Red blood cell (RBC) and serum folate concentrations may be altered in individuals with impaired kidney function. However, there is limited population-level data among women of reproductive age (WRA), including in settings without exposure to folic acid fortification.
Methods: We examined the associations of estimated glomerular filtration rate (eGFR) with biomarkers of folate and vitamin B12 in WRA (n=966; 15-40 y; not pregnant/lactating) in a population-based biomarker survey in Southern India. RBC and serum folate, serum creatinine, total vitamin B12, holo-transcobalamin, methylmalonic acid (MMA), and homocysteine were evaluated in archived samples (2017-2019). Serum creatinine was used to calculate eGFR (a measure of kidney function), using the Chronic Kidney Disease Epidemiology Collaboration equation. eGFR stages (stage 1: ≥90, 2: 60-<90, 3: 30-<60, and 4: <30 mL/min/1.73 m2) and eGFR <90 mL/min/1.73 m2 [lower eGFR and higher stages (compared to higher eGFR values and lower stages) indicate impaired kidney function] were considered in analyses. ANOVA was used to compare continuous nutritional biomarkers by eGFR stage.
Results: A total of 96.3% of WRA were at eGFR stage 1 (n=930), 3.5% were at stage 2 (n=34), and <1% were at stage 3 (n=1) or stage 4 (n=1) (geometric mean: 118 [95% CI: 117-119 mL/min/1.73 m2]). In univariate analyses, WRA with eGFR <90 vs.≥90 mL/min/1.73 m2 had lower serum folate concentrations (12.3 [10.4-14.4] vs.16.6 [16.1-17.2] nmol/L, p=0.003). However, there were no differences for serum folate <7.0 nmol/L vs. ≥ 7.0 nmol/L, RBC folate concentrations, or biomarkers of vitamin B12 status [e.g., homocysteine, and MMA], comparing eGFR <90 vs. ≥90 mL/min/1.73 m2.
Conclusions: In this population, those with impaired kidney function had lower serum but comparable RBC folate concentrations. Further research on folate biomarkers and kidney function may enhance screening and biomarker assessment to improve women’s health.