AUTHOR=Li Yu-shan , Gong Xing-ji , Du Wen-jie , Li Yang , He Dong-yong , Yao Jian , Bai Cui 

TITLE=Inverted U-shaped relationship between serum vitamin B12 and α-Klotho levels in US adults: a cross-sectional study

JOURNAL=Frontiers in Nutrition

VOLUME=11

YEAR=2024

URL=https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2024.1473196

DOI=10.3389/fnut.2024.1473196

ISSN=2296-861X

ABSTRACT=<sec id="sec1"><title>Background</title><p>Serum vitamin B12 and α-Klotho are important markers associated with aging. Limited studies have been conducted on the relationship between vitamin B12 and α-Klotho.</p></sec><sec id="sec2"><title>Objectives</title><p>This study investigated the relationship between circulating α-Klotho and vitamin B12.</p></sec><sec id="sec3"><title>Methods</title><p>A total of 4,502 American adults with circulating vitamin B12 levels and α-Klotho levels from the National Health and Nutrition Examination Survey (2011–2014) were included. A weighted multiple linear regression model was used to evaluate the correlation between vitamin B12 and α-Klotho levels. To clarify potential non-linearities, smoothed curve fitting and threshold effects analysis were employed.</p></sec><sec id="sec4"><title>Results</title><p>A statistically significant non-linear relationship was found between vitamin B12 levels and circulating α-Klotho levels after adjusting for potential confounders. We observed an inverted U-shaped relationship between serum vitamin B12 levels and circulating α-Klotho levels. Notably, serum vitamin B12 levels below the threshold (1,020 pg/mL) exhibited a positive correlation with circulating α-Klotho levels (<italic>β</italic> = 0.14, 95% confidence interval (CI): 0.09–0.18, <italic>p</italic> &lt; 0.0001). Conversely, serum vitamin B12 levels above the threshold (1,020 pg/mL) exhibited a negative correlation with circulating α-Klotho levels (<italic>β</italic> = −0.12,95% CI: −0.17−−0.06, <italic>p</italic> &lt; 0.0001). Sensitivity analyses were performed and consistent results were obtained.</p></sec><sec id="sec5"><title>Conclusion</title><p>This study demonstrated an inverted U-shaped relationship between circulating vitamin B12 and α-Klotho in American adults. The optimal concentration of serum vitamin B12 in American adults was found.</p></sec>