The Association of Potassium Status with Parameters of Glucose Metabolism is influenced by Age in Adults

Background: Potassium status has been found to affect glucose homeostasis. Objective: This study therefore aimed at investigating relationships between potassium status or dietary intake and fasting plasma glucose (FPG) or glycated haemoglobin (HbA1c) in a sample of Austrian adults (18-80 years, n = 421, 61% women) from the Austrian Study on Nutritional Status 2012. Methods: Dietary potassium intake was obtained by two 24 h recalls. FPG, plasma K+, and urinary K+ were determined photometrically, HbA1c by HPLC. Associations between the parameters were studied using multiple regression analysis after controlling for confounders and after age stratification of the sample (18-64 y vs. 65-80 y). Results: Most of the participants had a potassium intake of less than the estimated adequate daily intake of 4000 mg/d. In the multiple regression analyses in the whole sample plasma K+ had a statistically significant positive effect on FPG only in the crude model (β = 0.128, p < 0.01) and on HbA1c also in the fully adjusted model (β = 0.129, p < 0.05). The small effects on HbA1c were also detected in the younger age group but were absent in the older population. However, in this latter, a reverse association of urinary K+ on HbA1c was observed as well as of dietary potassium intake on FPG with no effects in the younger sample. Conclusion: We suggest that age dependent differences in the association between parameters of potassium status and blood glucose regulation should also be taken into account.