Obesity is a significant public health issue, as obesity and being overweight are risk factors for various chronic diseases. However, the "obesity paradox" proposed in recent years has garnered widespread attention. The relationship between Body Mass Index (BMI) and mortality in the elderly remains unclear.
To explore the impact of BMI on mortality in the elderly in China.
The demographic features, BMI, chronic diseases and laboratory tests among the elderly at ages of 60 years and greater were recruited from April 2015 to December 2015. The patients were followed up with a cut-off date of April 30, 2024, with all-cause mortality and death from cardiovascular causes as the endpoint events. A multivariable Cox proportional hazards regression model was used to examine the association between BMI and the risk of death.
Otally 599 subjects were enrolled, including 477 men (79.6%) and an average age of (77±8) years. There were 18 subjects (3.0%) with underweight, 273 (45.6%) with overweight and 87 (14.5%) with obesity. During the follow-up period (8.81 years) , 158 subjects died. Restricted cubic splines revealed a U-shaped association between BMI and mortality. Multivariable Cox proportional hazards regression analysis revealed an increased risk of all-causes mortality among the underweight elderly (HR=2.76, 95%CI=1.37-5.55) after adjustment for age, gender, chronic diseases, and so on. Additionally, a low BMI is an independent risk factor for cardiovascular event mortality in the elderly (HR=5.55, 95%CI=1.83-16.78) . However, no association was observed between overweight and obesity and death.
The relationship between BMI and mortality forms a U-shaped curve, with underweight being an independent risk factor for mortality in the elderly. No association has been found between being overweight/obese and an increased risk of mortality. Therefore, attention should be given to weight management in the elderly.
Due to the rise in obesity rates worldwide, the prevalence of cardiometabolic comorbidities (CMM) is increasing year by year. Body roundness index (BRI) is a new obesity measure of visceral adipose tissueand the risk of BRI and CMM in people with normal body weight has been poorly studied.
To explore the relationship between BRI and high-risk CMM in normal body weight population, and to explore the role of triacylglycerol glucose product (TyG) index in this association.
A total of 42 437 subjects with a body mass index (BMI) of 18.50-23.99 kg/m2 who participated in the early screening and comprehensive intervention project of high-risk groups of cardiovascular diseases in Anhui Province in 2017—2021 were selected. According to gender and CMM, the participants were divided into male non-CMM group (n=14 546) , male CMM group (n=2 741) , female non-CMM group (n=20 901) and female CMM group (n=4 249) , and they were divided into four levels according to the BRI quartile of different sexes (Male: M1, M2, M3, M4. Females: F1, F2, F3, F4) . The Bonferroni method was used to compare the differences in the prevalence of CMM among different genders and age groups. Multivariate Logistic regression analysis was used to explore the relationship between BRI quartile level and CMM risk. The mediate function of R (version 4.4.2) software was used to explore the mediating effect of the association between BRI and CMM after adjusting for covariates, and the mediating effect of TyG index was analyzed by medsens function.
The proportion of age, education in high school or above, BMI, total cholesterol (TC) , triglycerides (TG) , low-density lipoprotein cholesterol (LDL-C) , RC, fasting blood glucose (FPG) , TyG index, BRI, SBP, diastolic blood pressure (DBP) , hypertension, diabetes mellitus, dyslipidemia, heart disease, and stroke in the CMM group were higher than those in the non-CMM group, and the proportion of smoking and high-density lipoprotein cholesterol (HDL-C) were lower than those in the non-CMM group (P<0.05) . In the female group, the age, BMI, TC, TG, LDL-C, RC, FPG, TyG index, BRI, SBP, DBP, hypertension, diabetes, dyslipidemia, heart disease, and stroke in the CMM group were higher than those in the non-CMM group, and the proportion of education in high school or above and HDL-C in the female group were lower than those in the non-CMM group (P<0.05) . There were statistically significant differences in the prevalence of CMM, alcohol consumption ratio, TC, TG, LDL-C, RC, FPG, TyG index, SBP and DBP among different genders (P<0.05) , and the prevalence of CMM increased with the increase of BRI level (Ptrend<0.001 for males and <0.001 for females) . The prevalence of CMM was different among different genders and age groups (P<0.001) , and the proportion of CMM people over 50 years old (male 89.4%, females 91.2%) is much larger than that under 50 years of age (males 10.6%, female 8.8%) . Multivariate Logistic regression showed that the risk of CMM at M2/F2, M3/F3, and M4/F4 levels was increased compared with BRI M1/F1 levels, regardless of whether confounders were adjusted for confounders (P<0.001) . In the mediating analysis of the association between BRI and CMM, after adjusting for covariates such as gender, age, education, smoking and alcohol consumption, the proportion mediated by TyG index (54.62%, 95%CI=50.19%-60.00%) was much higher than that of RC (22.98%, 95%CI=20.70%-26.00%) and SBP (24.05%, 95%CI=22.05%-27.00%) . The association between BRI and CMM disease was more significantly mediated.
In people with normal body weight, BRI levels were positively correlated with the risk of CMM, and the TyG index played a significant mediating role in this association.
Previous studies have suggested associations between the triglyceride glucose index (TyG) , body mass index (BMI) , and cognitive function. However, when exploring the association between TyG and cognitive function, these studies have tended to give less consideration to the potential influence of BMI, and the relationship among these three factors remains unclear. Examining the effect of BMI on the association between TyG and cognitive function is of great significance for developing precise interventions to prevent cognitive decline in older adults.
To explore the effect of BMI on the association between TyG and cognitive function in older adults, and to provide a reference for the prevention of cognitive decline in older adults.
From July to August 2019, the rural elderly residents aged 60 years and older were selected using the multi-stage cluster sampling method from 12 villages in 2 counties (districts) of Guizhou Province, and questionnaire surveys, general physical examinations, cognitive function assessments, and laboratory measurements were carried out among them. Cognitive function was evaluated using the Mini-Mental State Examination (MMSE) scale, and TyG was calculated using laboratory indices (triglyceride, fasting blood glucose) . Spearman rank correlation analysis and multiple linear regression model were used to investigate the association between TyG and cognitive function and the interaction effect between TyG levels and BMI subgroups on cognitive function in older adults.
The results of the interaction analysis of the impact of TyG and BMI on cognitive function showed that in model 1 without adjusting for covariates, the interaction term between TyG and low-BMI had an effect on MMSE scores of older adults (β=-0.515, 95%CI=-0.809--0.222, P<0.001) . In model 2 after adjusting for the relevant covariates, the interaction term between TyG and low-BMI still had an effect on MMSE scores in older adults (β=-0.351, 95%CI=-0.601--0.102, P<0.05) . Further stratification of body mass index followed by multiple linear regression analyses showed that in the under weight group, TyG was negatively associated with MMSE scores (rs=-0.330, P<0.001) , higher TyG was associated with cognitive decline (β=-0.251, 95%CI=-0.421--0.081, P<0.05) , and taking the TyG index Q1 group as a reference, the risk of cognitive decline was significantly increased in both Q3 and Q4 groups (Q3: β=-0.453, 95%CI=-0.862--0.043, P<0.05; Q4: β=-0.503, 95%CI=-0.957--0.050, P<0.05) . TyG was not associated with MMSE in the normal weight group and the overweight and obese group.
The association between TyG and cognitive function is influenced by BMI, and an association between high TyG and cognitive decline has been found in the under weight older adults. Enhanced monitoring and control of insulin resistance in the under weight group may be helpful in preventing or delaying cognitive decline in older adults.
