Serum soluble alpha-klotho klotho and cognitive functioning in older adults aged 60 and 79: an analysis of cross-sectional data of the National Health and Nutrition Examination Survey 2011 to 2014

• Published in: BMC geriatrics 2024-03, Vol.24 (1), p.245-245, Article 245
• Main Authors: Ge, Song, Dong, Fanghong, Tian, Chong, Yang, Chih-Hsiang, Liu, Minhui, Wei, Jingkai
• Format: Article
• Language: English
• Subjects: Aged; Aged patients; Aging; Alpha-klotho; Alzheimer Disease; Alzheimer's disease; Analysis; Blood pressure; Body mass index; Cardiovascular disease; Care and treatment; Cholesterol; Cognition & reasoning; Cognition - physiology; Cognition Disorders - epidemiology; Cognition in old age; Cognitive ability; Cognitive function; Coronary artery disease; Cross-Sectional Studies; Female; Fibroblast growth factor receptors; Gender differences; Heart diseases; Humans; Klotho; Klotho protein; Membrane proteins; Memory; Neurodegenerative diseases; NHANES; Nutrition Surveys; Older adults; Older people; Physical activity; Regression analysis; Standard deviation; Surveys; Variables; Womens health
• ISSN: 1471-2318; 1471-2318
• DOI: 10.1186/s12877-024-04661-7

Klotho, consisting of membrane klotho and soluble alpha-klotho, is found to be associated with better cognitive outcomes in small samples of the aged population. We aimed to examine the association of serum soluble alpha-klotho with cognitive functioning among older adults using a nationally representative sample of U.S. older adults. A total of 2,173 U.S. older adults aged 60-79 years in the National Health and Nutrition Examination Survey from 2011 to 2014 were included in this cross-sectional analysis. Serum soluble alpha-klotho was measured in the laboratory and analyzed with an ELISA kit. Cognitive function was measured using the Consortium to Establish a Registry for Alzheimer's Disease Word Learning subtest (CERAD-WL) immediate and delayed memory, the Animal fluency test (AFT), and the Digit Symbol Substitution Test (DSST). Test-specific and global cognition z-scores were calculated based on sample means and standard deviations. Multivariable linear regression models were applied to examine the association of quartiles and continuous value of serum soluble alpha-klotho with test-specific and global cognition z-scores. Subgroup analysis was conducted by sex. The following covariates were included in the analysis- age, sex, race/ethnicity, education, depressive symptoms, smoking status, body mass index (BMI), physical activity, stroke, prevalent coronary heart disease, total cholesterol, and systolic blood pressure. All the information was self-reported or obtained from health exams. Serum soluble alpha-klotho level in the lowest quartile was associated with lower z-scores for DSST (beta [β] =-0.13, 95% confidence interval [CI]: -0.25, -0.01). For subgroup analysis, serum soluble alpha-klotho level in the lowest quartile was associated with lower z-scores for DSST (β=-0.16, 95% CI: -0.32, -0.003) and global cognition (β=-0.14, 95% CI: -0.28, -0.01) among female participants. No association was found between continuous serum soluble alpha-klotho and cognitive functioning among the participants. Lower serum soluble alpha-klotho quartile was associated with poorer cognitive functioning among older women. Future studies are expected to examine the longitudinal association between klotho levels and cognitive outcomes.