Relationship between adiposity parameters and cognition: the “fat and jolly” hypothesis in middle-aged and elderly people in China
Authors: Zhang Lin , Li Jin-Long , Zhang Li-Li , Guo Lei-Lei , Li Hong , Yan Wenzhu , Li Dan 
Published: March 2019

Abstract
The association between adiposity parameters and cognition is complex. The purpose of this study was to assess the relationship between adiposity parameters and cognition in middle-aged and elderly people in China.
Data were obtained from a cross-sectional study. Cognitive function was evaluated in 5 domains, and adiposity parameters were measured. The association between adiposity parameters and cognition was analyzed using multiple linear and binary logistic regression analyses.
After controlling for confounders, men with overweight and obesity had better scores in TICS-10 ([1] total, overweight vs normal: P
= .006, β = 0.04; obesity vs normal: P
= .005, β = 0.04. [2] stratification by age, with age ≥ 59 years, overweight vs normal: P
= .006, β = 0.05; obesity vs normal: P
= .014, β = 0.05. [3] stratification by educational levels, with less than elementary education, overweight vs normal: P
= .011, β = 0.05; obesity vs normal: P
= .005, β = 0.05), immediate word recall ([1] total, overweight vs normal: P
= .015, β = 0.04. [2] stratification by age, with age 45–58 years, overweight vs normal: P
= .036, β = 0.05. [3] stratification by educational levels, with less than elementary education, overweight vs normal: P
= .044, β = 0.04; above high school, overweight vs normal: P
= .041, β = 0.09), self-rated memory ([1] stratification by age, with age ≥ 59 years, overweight vs normal: P
= .022, β = 0.05. [2] stratification by educational levels, with less than elementary education, overweight vs normal: P
= .023, β = 0.04), and drawing a picture ([1] total, overweight vs normal: OR = 1.269, 95% CI = 1.05–1.53. [2] stratification by educational levels, with less than elementary education, overweight vs normal: OR = 1.312, 95% CI = 1.06–1.63); obesity vs normal: OR = 1.601, 95% CI = 1.11–2.31 than the normal weight; women with overweight and obesity had better measure scores in the TICS-10 ([1] total, overweight vs normal: P < .0001, β = 0.06; obesity vs normal: P < .0001, β = 0.05. [2] stratification by age, with age 45–58 years, obesity vs normal: P
= .007, β = 0.05; with age ≥ 59 years: overweight vs normal: P < .0001, β = 0.07, obesity vs normal: P = .002, β = 0.06. [3] stratification by educational levels, with illiterate, overweight vs normal: P = .001, β = 0.08; obesity vs normal: P
= .004, β = 0.06; with less than elementary education, overweight vs normal: P < .0001, β = 0.07; obesity vs normal: P
= .010, β = 0.05), immediate word recall ([1] total, overweight vs normal: P
= .011, β = 0.04; obesity vs normal: P
= .002, β = 0.04. [2] stratification by age, with age 45–58 years, obesity vs normal: P
= .021, β = 0.05; with age ≥ 59 years: overweight vs normal: P
= .003, β = 0.06. [3] stratification by educational levels, with illiterate, obesity vs normal: P
= .028, β = 0.05; with less than elementary education, obesity vs normal: P
= .016, β = 0.05), delay word recall ([1] total, overweight vs normal: P
= .015, β = 0.03; obesity vs normal: P
= .031, β = 0.03. [2] stratification by age, with age ≥ 59 years: overweight vs normal: P
= .004, β = 0.06. [3] stratification by educational levels, with less than elementary education, obesity vs normal: P
= .043, β = 0.04), self-rated memory ([1] total, obesity vs normal: P
= .026, β = 0.03. [2] stratification by age, with age ≥ 59 years, overweight vs normal: P
= .044, β = 0.04; obesity vs normal: P
= .018, β = 0.05), and drawing a picture ([1] total, overweight vs normal: OR = 1.226, 95% CI = 1.06–1.42. [2] stratification by age, with age 45–58 years: overweight vs normal: OR = 1.246, 95% CI = 1.02–1.53) than the normal weight. Regarding the association between WC and cognitive function, the obesity demonstrated better mental capacity ([1] total, men: P
< .0001, β = 0.06; women: P < .0001, β = 0.05. [2] stratification by age, men with age 45–58 years: P < .0001, β = 0.08; men with ≥ 59 years: P = .006, β = 0.05. women with age 45–58 years: P = .001, β = 0.06; women with ≥ 59 years: P = .012, β = 0.04. [3] stratification by educational levels, men with illiterate: P = .045, β = 0.09; men with less than elementary education: P < .0001, β = 0.08; women with illiterate: P < .0001, β = 0.09), ability to recall immediately ([1] total, men: P
= .030, β = 0.03; women: P
= .001, β = 0.05. [2] stratification by age, women with age 45–58 years: P = .028, β = 0.04; women with ≥ 59 years: P = .007, β = 0.05. [3] stratification by educational levels, men with less than elementary education: P = .007, β = 0.05; women with illiterate: P = .027, β = 0.05; women with less than elementary education: P = .002, β = 0.06), delay word recall ([1] total, women: P
= .044, β = 0.03. [2] stratification by educational levels, men with less than elementary education: P = .023, β = 0.04), self-rated memory (stratification by educational levels, women with less than elementary education: P = .030, β = 0.04), and draw a picture ([1] total, men: OR = 1.399, 95% CI = 1.17–1.67; women: OR = 1.273, 95% CI = 1.12–1.45. [2] stratification by age, men with age 45–58 years: OR = 1.527, 95% CI = 1.15–2.03; men with age ≥ 59 years: OR = 1.284, 95% CI = 1.02–1.61; women with age 45–58 years: OR = 1.320, 95% CI = 1.10–1.58; women with age ≥ 59 years: OR = 1.223, 95% CI = 1.01–1.49. [3] stratification by educational levels, men with less than elementary education: OR = 1.528, 95% CI = 1.25–1.87; women with illiterate: OR = 1.404, 95% CI = 1.14–1.73) than the participants with normal weight after the multivariate adjustment.
Our study demonstrated a significant relationship between adiposity parameters and cognition that supports the “jolly fat” hypothesis.