Abstract
BACKGROUND: Cognitive impairment and dementia present significant global health challenges, particularly in low-income and rural populations. As the prevalence of cognitive impairment continues to rise, early identification of risk factors is essential to prevent further cognitive impairment and mitigate the associated socioeconomic burden. This study aims to explore the associations between novel obesity indices-conicity index (C-index), relative fat mass (RFM), and Chinese visceral adiposity index (CVAI)-and cognitive impairment in a low-income rural population in Tianjin, China. METHODS: This cross-sectional study included 1,132 participants aged 60 years and older from rural Tianjin, China. Data were gathered through face-to-face interviews, covering socio-demographic and clinical information. Physical measurements were taken, including height, weight, and waist circumference. Cognitive function was assessed using the Mini-Mental State Examination (MMSE). The C-index, RFM, and CVAI were calculated using standard formulas and categorized into quartiles. Multivariate logistic regression was conducted to examine the associations between obesity indices and cognitive impairment, adjusting for potential confounders. Restricted cubic spline (RCS) curves were utilized to explore the nonlinear relationship between RFM and cognitive impairment. Subgroup analyses were performed based on gender and age groups. RESULTS: The study found that 47.7% of the participants exhibited cognitive impairment. Univariate analysis revealed significant associations between cognitive impairment and several factors, including gender, age, waist circumference, smoking history, alcohol consumption, diabetes mellitus, and fasting blood glucose (FBG). Multivariate analysis indicated a significant association between RFM and cognitive impairment, with individuals in the third quartile of RFM having 59% higher odds of prevalent cognitive impairment compared to those in the lowest quartile (OR = 1.59, 95% CI: 1.05-2.41, p = 0.028), and demonstrated a U-shaped association (p = 0.005). Higher RFM was protective in men (OR = 0.94, p = 0.003) but not in women and no age-specific effects emerged. CONCLUSION: This study underscores the significant role of relative fat mass in cognitive health, revealing a nonlinear relationship in which both high and low levels of RFM are linked to an increased risk of cognitive impairment. Given the cross-sectional design, temporal ordering cannot be established and causality cannot be inferred; our findings indicate associations between RFM and prevalent cognitive impairment and highlight the need for longitudinal confirmation in low-income rural populations.