Association between relative fat mass and cognitive function among US older men: NHANES 2011–2014

Background This study aimed to investigate the relationship between cognitive performance and relative fat mass (RFM) in older American males. Methods For the purpose of this cross-sectional research, a total of 1,321 individuals were selected from the National Health and Nutrition Examination Survey (NHANES), which was carried out between the years 2011 and 2014. Specifically, the Consortium to Establish a Registry for Alzheimer’s Disease Word Learning Test (CERAD-WL), the Animal Fluency Test (AFT), and the Digit Symbol Substitution Test (DSST) were used in order to achieve the objective of assessing cognitive function. Z-scores were calculated as a composite, generalized metric by taking the average of the standardized scores of the three previously mentioned assessments. RFM was ascertained by measuring waist circumference (WC) and height. Multivariate linear regression, threshold effect analyses, smooth curve fitting, and subgroup analyses were undertaken in order to investigate the connections that exist between RFM and cognitive function. Results The study included 1,321 male volunteers who were at least 60 years old, and complete data was provided for each individual. Fully adjusted models indicated a negative correlation between RFM and CERAD-WL scores[-0.17, (-0.32,-0.01)], DSST scores[-0.83, (-1.16,-0.50)] and Z-scores[-0.03, (-0.05, -0.01)]. It was observed that the negative correlation between RFM and Z-scores became more pronounced when RFM exceeded 35.78. Furthermore, subgroup analyses showed that the association between RFM and cognitive function was significantly impacted by education level, poverty-income ratio (PIR), smoking status, and drinking status. Conclusions In elderly men, a higher RFM was linked to lower cognitive function, suggesting that management of RFM may prove advantageous in mitigating cognitive decline among older male populations.