Associations between modifiable risk factors and limitation in activities of daily living among individuals aged ≥ 45 years: Evidence from the China health and retirement longitudinal study (CHARLS)

The China Health and Retirement Longitudinal Study (CHARLS) is a nationally representative longitudinal survey of persons in China 45 years of age or older and their spouses, including assessments of social, economic, and health circumstances of community-residents. CHARLS examines health and economic adjustments to rapid ageing of the population in China. The national baseline survey for the study was conducted between June 2011 and March 2012 and involved 17 708 respondents. CHARLS respondents are followed every 2 years, using a face-to-face computer-assisted personal interview (CAPI). Physical measurements are made at every 2-year follow-up, and blood sample collection is done once in every two follow-up periods. A pilot survey for CHARLS was conducted in two provinces of China in 2008, on 2685 individuals, who were resurveyed in 2012. To ensure the adoption of best practices and international comparability of results, CHARLS was harmonized with leading international research studies in the Health and Retirement Study (HRS) model. Requests for collaborations should be directed to Dr Yaohui Zhao (yhzhao@nsd.edu.cn). All data in CHARLS are maintained at the National School of Development of Peking University and will be accessible to researchers around the world at the study website. The 2008 pilot data for CHARLS are available at: http://charls.ccer.edu.cn/charls/. National baseline data for the study are expected to be released in January 2013.

This study aims to assess the relationship between modifiable dementia risk factors and both dementia and cognitive decline. Data were obtained from the Health and Retirement Study (HRS) [2008-2020], the China Health and Retirement Longitudinal Study (CHARLS) [2011-2020], and the English Longitudinal Study of Ageing (ELSA) [2010-2020]. After adjusting for confounding factors, multivariable logistic regression was utilized to analyze the relationship between modifiable dementia risk factors and dementia, while multivariable linear regression was employed to examine the relationship between these risk factors and cognitive decline. Additionally, the Cox proportional hazards model was used to assess the relationship between the number of risk factor events, clusters, and dementia risk. A total of 30,113 participants from HRS, CHARLS, and ELSA were included (44.6% male, mean age 66.04 years), with an average follow-up period of 7.29 years. A low education level was significantly associated with an increased risk of dementia and accelerated cognitive decline (Overall, OR = 2.93, 95% CI: 2.70-3.18; Overall, β = -0.25, 95% CI: -0.60 to-0.55). The presence of multiple dementia risk factors correlated with a higher dementia risk; Specifically, compared with more than 5 risk factor events, both having no dementia risk factors and having only one dementia risk factor were associated with a significantly lower risk of dementia (Overall, HR = 0.15, 95% CI: 0.11-0.22, HR = 0.22, 95% CI: 0.18-0.25). Compared to the group with no coexistence of risk factors, the clusters of excessive alcohol, diabetes, vision loss, and hearing loss (HR = 4.11; 95% CI = 3.42-4.95; p < 0.001); excessive alcohol, vision loss, smoking, and hearing loss (HR = 5.18; 95% CI = 4.30-6.23; p < 0.001); and excessive alcohol, obesity, diabetes, and smoking (HR = 5.96; 95% CI = 5.11-6.95; p < 0.001) were most strongly associated with dementia risk. Among the 11 risk factors, educational attainment has the greatest impact on dementia risk and cognitive decline. A dose-response relationship exists between the number of modifiable risk factor events and dementia risk. The coexistence of multiple risk factors is associated with dementia risk, and these associations vary by risk factor cluster.

Background: To our knowledge, a comprehensive analysis of risk factors for mortality among mid-aged and older people in China based on a large nationally representative population study over an extended period has not yet been carried out. We investigated risk factors for mortality in the China Health and Retirement Study over 9 years. We aimed to investigate the associations between socioeconomic, demographic, psychosocial, behavioral, and health-related factors and all-cause mortality. Methods: Participants aged 45 and older were enrolled in the China Health and Retirement Longitudinal Study (CHARLS) from July 2011 to March 2012 following a multi-stage stratified sampling procedure to ensure national representativeness. The lower age limit of 45 was chosen so that CHARLS could evaluate the ageing process well before people become eligible for retirement Participants are followed up regularly, with the most recent assessments in 2020. The study is multi-disciplinary, including a wide-ranging set of 32 measures of health, health behavior, demographics, and socioeconomics. We used Cox proportional hazard modeling to study the independent and joint contribution of risk factors to 9-year all-cause mortality. Findings: Some 17,708 participants were included in the baseline sample; 586 were lost to follow-up, and we excluded 459 aged under 45 at the baseline, 24 whose dates of death were unknown, and 12 with missing marital status, education, or household registration status. Of the 16,627 (51.6% were women) included in this study, 2,352 (41.5% were women) died during a median follow-up of 4.9 years (IQR 2.67-6.83). In fully adjusted models, the following factors were independent risk factors for mortality: age (HR=13 .44 for 75+ relative to aged 45-49), male sex (HR=1.60), widowed or never married (HR=1.45), low education (HR=1.50 for illiterate relative to high school or above), below-median household per capita expenditure (HR=1.14), current (HR=1.32) and past smoking (HR=1.37), poor self-rated health (HR=1.48 relative to good health), any difficulty in basic activities of daily living (HR=1.26) or instrumental activities of daily living (HR=1.35), chronic lung disease (HR=1.22), hypertension (HR=1.34), diabetes (HR=1.37) and chronic kidney disease (HR=1.38), underweight (HR=1.45), all at the significance level of p<0.01. Doctor-diagnosed cancer (HR=1.61), asthma (HR=1.19), and general cognitive impairment (HR=1.16) were significant at p<0.05. The sex-stratified analysis indicated that doctor-diagnosed cancer was not significant for women and strengthened for men (HR=2.16, p<0.05), and that past smoking was a leading risk factor for men (HR=1.41, p<0.01) but not for women. When we excluded individuals with serious illness at baseline, the association with past smoking increased in magnitude (HR=1.55, p<0.01). Interpretation: Mortality in China is multi-faceted, and risk factors include demographic, socioeconomic, behavioral, psychosocial, and health factors. An integrated analysis of risk factors is more useful for policy-making than analyses of separate factors that can inflate the magnitude of associations. To further reduce mortality, China should increase access to quality health care services, improve the prevention, diagnosis and management of chronic diseases, continue to invest in education, occupational health and healthier home environments, and devote more efforts to tobacco control and ensure adequate nutrition among older people. Funding Information: National Institute on Aging, the Natural Science Foundation of China, the China Medical Board, the World Bank, and Peking University. Declaration of Interests: We declare no competing interests. Ethics Approval Statement: The study protocol was approved by the ethical review committee (IRB) of Peking University. Written informed consent was obtained from all study participants. Ethics approval for the data collection in CHARLS was obtained from the Biomedical Ethics Review Committee of Peking University (IR1052–11015 for biomarkers and IR1052–11014 for the survey).

Hearing loss (HL) is a common health issue among older adults worldwide, and its incidence is expected to increase as the population ages. A study has shown that among the estimated 500 million people with hearing impairments worldwide, 28 million Americans suffer from hearing disabilities, and the highest number of individuals with hearing impairments is found in the 45-to-64 years old age group. Depression is a significant public health concern for middle-aged and older adults. In 2015, researchers used data from over 100,000 participants that were collected by the UK Biobank to perform a cross-sectional study and reported that the association between hearing impairment and depression was more pronounced among younger participants (aged 40–49 years) and among those with milder forms of depression. These findings suggest that the impact of hearing impairment on mental health may begin to emerge in middle age. Hearing loss may lead to more obstacles for middle-aged individuals in terms of work and social interactions, thereby increasing the risk of depression. Early intervention for hearing impairment is particularly important for middle-aged people, as it can help identify early risk factors and provide more effective interventions to improve mental health and quality of life. Therefore, building on the existing literature that predominantly focused on older adults, this study involved analysing data from the China Health and Retirement Longitudinal Study(CHARLS) database, expanding the age range to 45 years, to investigate the relationship between self-reported hearing loss and depression among middle-aged and older adults. This research used data from the 2018 China Health and Retirement Longitudinal Study (CHARLS), including data from 5207 individuals aged 45 years and older. Hearing status was self-reported by the participants, whereas depression was assessed with the 10-item Center for Epidemiologic Studies Depression Scale (CES-D-10). A multivariable logistic regression model was used to investigate the association between self-reported hearing loss and depression, controlling for sociodemographic variables that are associated with depression in middle-aged and older populations. This study involved the use of a multinomial logistic regression model to analyse the relationship between self-reported hearing loss and depression among middle-aged and older adults, with adjustments made for potential confounding variables. The analysis revealed significant relationships between depression and factors such as hearing status, sex, place of residence, self-rated health, chronic diseases, disabilities with respect to activities of daily living (ADLs), and satisfaction with life. Specifically, individuals with self-reported hearing loss, female individuals, individuals residing in rural areas, individuals with poor self-rated health, individuals with chronic diseases, and individuals with disabilities related to ADLs were more likely to experience depression. In the unadjusted model that was used to analyse the relationship between self-reported hearing loss and depression among middle-aged and older adults, both fair hearing (unadjusted OR = 1.556, 95% CI 1.377–1.758) and poor hearing (unadjusted OR = 2.001, 95% CI 1.630–2.457) were significantly associated with the prevalence of depression. After controlling for various covariates, including sex, age, residential status, education level, marital status, health status, physical disability, chronic diseases, activities of daily living (ADLs), and satisfaction with life, our study revealed that both fair hearing (adjusted OR = 1.235, 95% CI: 1.078, 1.415) and poor hearing (adjusted OR = 1.335, 95% CI: 1.063, 1.677) remained significantly correlated with the prevalence of depression among middle-aged and older adults. Previous research has focused primarily on older adults. Therefore, the present study expanded the age range to include individuals as young as 45 years old. The results show that fair hearing and poor hearing are significantly associated with the prevalence of depression among middle-aged and older adults. These findings suggest that self-reported hearing loss is a risk factor for depression in this population in China. The association between self-reported hearing loss and depression is not limited to older adults but also includes middle-aged individuals.

BackgroundFrailty is a common geriatric syndrome associated with many adverse health outcomes. Identifying the risk factors of frailty is crucial and the insulin resistance (IR) is considered as a potential target. The estimated glucose disposal rate (eGDR) is a simple and reliable surrogate marker of IR. Associations of eGDR with frailty have not been explored. This study aimed to investigate the associations of eGDR with frailty progression.MethodsWe used data from two prospective cohorts of the China Health and Retirement Longitudinal Study (CHARLS) and Health and Retirement Study (HRS). The eGDR was calculated as follows: eGDR (mg/kg/min) = 21.158 − (0.09×waist circumference) − (3.407×hypertension) − (0.551×glycosylated hemoglobin A1c) [waist circumference (cm), hypertension (yes = 1/no = 0), and glycosylated hemoglobin A1c (%)]. Participants were divided into three categories by tertiles of eGDR. Frailty index (FI) was calculated every two years and used to assess the degree of frailty which ranged from 0 to 100. Frailty progression was assessed by repeated measurements of FI during follow-up. Linear mixed-effect models were used to analyze the associations of eGDR with frailty progression.Results8872 participants from CHARLS (mean age: 58.9 years, female: 53.3%) and 5864 participants from HRS (mean age: 67.0 years, female: 59.0%) were included. The median follow-up periods were 7.0 years in the CHARLS and 12.8 years in the HRS, respectively. Compared to participants with lower tertile (T1) of eGDR, those with upper tertile (T3) of eGDR showed decelerated FI progression (CHARLS, β: -0.294, 95%CI -0.390 to -0.198, P < 0.001; HRS, β: -0.378, 95%CI -0.474 to -0.281, P < 0.001). Continuous eGDR was also associated with FI progression for significant deceleration in FI progression with per 1 SD increase in eGDR (CHARLS, β: -0.142, 95%CI -0.181 to -0.103, P < 0.001; HRS, β: -0.170, 95%CI -0.209 to -0.130, P < 0.001). These associations were still observed after excluding baseline frail participants. Furthermore, the associations of eGDR with FI progression were consistent among participants with and without diabetes.ConclusionRegardless of diabetes or not, a higher level of eGDR was associated with the decelerated frailty progression. Our findings highlight the role of eGDR in frailty progression and recommend taking effective interventions to improve eGDR for preventing frailty progression.Graphical abstractThe estimated glucose disposal rate and frailty progression. CHARLS, China Health and Retirement Longitudinal Study; HRS, Health and Retirement Study; eGDR, the estimated glucose disposal rate; FI, frailty index.

Chronic diseases have become one of the most important factors threatening human health. Subjective life expectancy (SLE) describes an individual's expectation or subjective perception of lifespan. This article aims to explore the relationship between chronic diseases and SLE, as well as the differences among different age groups and different types of chronic diseases in this relationship. China Health and Retirement Longitudinal Study (CHARLS) is a nationwide longitudinal study that evaluates the social, economic, and health conditions of middle-aged and older adult families and individuals aged 45 and above in China. In this study, CHARLS used probability proportional to size sampling (PPS sampling) to ensure the breadth and representativeness of the sample. This study selected cross-sectional data from CHARLS 2018, removed missing values, and obtained a valid sample of 10,658 middle-aged and older individuals, of whom 8564 had chronic diseases. After controlling demographic, health behavior, socioeconomic, psychological, and social security factors, an ordered logistic regression was performed to explore the relationship between chronic disease and SLE in middle-aged and older adults. The results show that chronic diseases negatively correlate with SLE in middle-aged and older adults. Middle-aged and older adults with chronic diseases are 36.2% less likely to have high life expectancy than those without chronic diseases. Many different types of chronic diseases are negatively correlated with SLE. Cancer is most negatively correlated with SLE, far exceeding other chronic diseases. Chronic disease and SLE of middle-aged and older adults have age-heterogeneous differences. For middle-aged people aged 45-59 and young older adults aged 60-79, there is a significant correlation between chronic diseases and SLE. However, there is no correlation between chronic diseases and subjective life expectancy in the older population aged 80 and above. The government and society should pay close attention to the prevention and treatment of chronic diseases among middle-aged and older adults and adjust policies and measures according to the population's age structure. In addition, the government and society should pay attention to the spiritual needs of middle-aged and older adults. The government and society should pay more attention to cancer patients. Finally, the scientific research team should also strengthen research on chronic diseases, research and development of specific drugs and vaccines, improve the cure rate of chronic diseases, promote people's health, and make people no longer afraid of diseases.

IntroductionIt is valuable to identify common latent cognitive constructs for dementia prevalence estimation across Chinese aging cohorts.MethodsBased on cognitive measures of 12015 Chinese Longitudinal Healthy Longevity Survey (CLHLS; 13 items) and 6623 China Health and Retirement Longitudinal Study (CHARLS; 9 items) participants aged 65 to 99 in 2018, confirmatory factor analysis was applied to identify latent cognitive constructs, and to estimate dementia prevalence compared to Mini‐Mental State Examination (MMSE) and nationwide estimates of the literature.ResultsA common three‐factor cognitive construct of orientation, memory, and executive function and language was found for both cohorts with adequate model fits. Crude dementia prevalence estimated by factor scores was similar to MMSE in CLHLS, and was more reliable in CHARLS. Age‐standardized dementia estimates of CLHLS were lower than CHARLS among those aged 70+, which were close to the nationwide prevalence reported by the COAST study and Global Burden of Disease.DiscussionWe verified common three‐factor cognitive constructs for both cohorts, providing an approach to estimate dementia prevalence at the national level.Highlights Common three‐factor cognitive constructs were identified in Chinese Longitudinal Healthy Longevity Survey (CLHLS) and China Health and Retirement Longitudinal Study (CHARLS).Crude dementia estimates using factor scores were reliable in both cohorts.Estimates of CHARLS were close to current evidence, but higher than that of CLHLS.

BackgroundResearch indicates a positive association between short-term diurnal temperature range (DTR) exposure and hypertension. However, the impact of long-term DTR exposure has not been thoroughly studied in population-based cohort research.MethodsThis study conducted cross-sectional (including 16,690 participants) and longitudinal analyses (including 9,650 participants) based on the China Health and Retirement Longitudinal Study (CHARLS). Daily temperature data was sourced from the National Scientific Data of the Qinghai-Tibet Plateau. We calculated the moving average of DTR exposure of all the participants in CHARLS with exposure windows of 30-day, 60-day, 180-day, 1-year, and 2-year before the interview month of CHARLS Wave1 (2011). Logistic regression and age-stratified Cox proportional hazards models were employed in our analysis.ResultsIn the cross-sectional study, 6,572 (39.4%) participants had hypertension. We found higher DTR is associated with a higher prevalence of hypertension across different exposure windows. The effect was strongest when the exposure window of DTR was 180-day, with an adjusted odds ratio (OR) of 1.261 (95% confidence interval (CI): 1.124–1.416 [highest tertile DTR vs. lowest tertile DTR]). In the cohort study, 3,020 (31.3%) participants developed hypertension during 83 months of follow-up. A higher level of DTR (hazard ratio (HR): 1.224, 95% CI: 1.077–1.391) was associated with a higher risk of incident hypertension. We found significant interactions between DTR and age (P interaction: <0.001) and residence (P interaction: 0.045).ConclusionWe found significant positive associations between DTR and prevalent and incident hypertension. Individuals younger than 65 and those living in rural areas are at an elevated risk of developing hypertension due to DTR.

This study investigated whether an individual's age at diagnosis of hypertension, which is associated with a decline in cognitive performance in the China Health and Retirement Longitudinal Study (CHARLS) participants. Our analysis was based on the CHARLS with baseline data collected between 2011 and 2018. We randomly selected a control participant for each hypertensive participant using propensity score. The cohort comprised 2413 individuals with hypertension and 2411 controls. Participants were divided into three groups as follows: non-hypertension, hypertension diagnose ≥55 years, and hypertension diagnose <55 years. Cognitive performance was measured in both visits and evaluated by the scores of the memory, executive function, and orientation and global cognitive. After multivariable adjustment, individuals with hypertension diagnosed <55 years had a significantly faster cognitive decline in memory test (β (95% CI, -1.117 [-1.405, -0.83]), orientation test (β (95% CI, -1.273 [-1.348, -1.198]) and global cognitive (β (95% CI, -1.611 [-1.744, -1.478]) compared with the corresponding controls. A longer hypertension duration was associated with worse memory test (β (95% CI, -0.069 [-0.113 to -0.025]). Among treated individuals, blood pressure control at baseline was inversely associated with the decline in orientation test (β (95% CI, -0.659 [-0.939, -0.380]), orientation test (β (95% CI, -0.259[-0.365, -0.153])and global cognitive (β (95% CI, -0.124 [-0.162, -0.086]). Our findings suggest that hypertension diagnosed in mid-life is associated with worse cognition compared to late life. Besides, longer duration of diagnosis is associated with worse memory test. In addition to hypertension, pressure control might be critical for the preservation of cognitive function.

The prevalence of cognitive impairment among middle-aged and older adults remains high. While it has been proven that cigarette smoke exposure is associated with cognitive impairment, limited research has examined its relationship with the cognitive function trajectories of middle-aged and older adults. We included data on 5084 middle-aged and older adults from the China Health and Retirement Longitudinal Study (CHARLS), version D, which covers the latest surveys from 2011 to 2018. In the CHARLS, cognitive function was measured by the Chinese version of the Mini-Mental State Examination (MMSE). Individuals exposed to cigarette smoke were categorised into four levels: non-smokers, second-hand smokers, former smokers, and current smokers. We used the latent growth mixture model (LGMM) to identify the potential heterogeneity of cognitive trajectories, and an unordered multilevel logistic regression to explore the relationship between baseline cigarette smoke exposure and cognitive function trajectories. We identified three cognitive trajectory groups: slow decline group (6.2%), stable group (84.6%), and rapid decline group (9.1%). After controlling for other variables, we found that current smokers were 1.429 times more likely to develop into the rapid decline group than non-smokers (odds ratio (OR) = 1.429; 95% confidence interval (CI) = 1.086-1.881). As we continued to include demographic factors as covariates, currents smokers were 1.454 times more likely to develop into the rapid decline group than non-smokers (OR = 1.454; 95% CI = 1.052-2.01). After we included social activities, drinking and health factors as covariates, current smokers were 1.414 times more likely to develop into the rapid decline group than non-smokers (OR = 1.414; 95% CI = 1.015-1.97). This meant that current smoking remained an independent risk factor for decline trajectories, even after accounting for demographics, social activities, and health factors, suggesting that smoking has a robust association with functional or health decline. The developmental trajectories of cognitive function among middle-aged and older adults are heterogeneous. We found that not smoking was a protective factor for cognitive function. This warrants further attention to the risk of cigarette smoking, which is a modifiable risk factor, and the subsequent adoption of interventions for smokers in order to slow down cognitive impairment and reduce its social and economic burden in the future.

BACKGROUNDDepressive symptoms differ from clinical depression. However, the relationship between depressive symptom trajectories and stroke risk across diverse geographic regions remains unclear.AIMTo address the gap in the existing understanding of the relationship between depressive symptom trajectories and stroke risk, the current study utilized three representative cohorts.METHODSIn this study, we used three representative cohorts from Asia, Europe, and the Americas: China Health and Retirement Longitudinal Study (CHARLS), English Longitudinal Study of Ageing (ELSA), and Health and Retirement Study (HRS). Depressive symptoms were assessed using the 8-item Center for Epidemiological Studies Depression scale and categorized into somatic and cognitive-affective subtypes. The trajectories of depressive symptoms were monitored over four surveys starting from baseline and classified into five distinct states: persistently low, decreasing, fluctuating, increasing, and consistently high. Self-reported physician diagnoses were used to evaluate the subsequent stroke events. Hazard ratios (HRs) and 95% confidence intervals (95%CIs) were computed using Cox proportional-risk models adjusted for potential confounding factors.RESULTSA total of 7990 participants from CHARLS (females: 52.3%, mean age: 63.4 years), 5642 participants from ELSA (females: 56.2%, mean age: 63.7 years), and 12260 participants from HRS (females: 61.4%, mean age: 64.7 years) participated in this study. The median follow-up periods were 5 years for CHARLS, 8 years for ELSA, and 10 years for HRS. In comparison with the persistently low trajectory, consistently high and fluctuating trajectories of total depressive symptoms increased the risk of stroke in all three cohorts (CHARLS: HR = 1.80, 95%CI: 1.36-2.38; ELSA: HR = 1.50, 95%CI: 1.02-2.21; HRS: HR = 1.45, 95%CI: 1.29-1.62 for consistently high; CHARLS: HR = 1.47, 95%CI: 1.14-1.90; ELSA: HR = 1.44, 95%CI: 1.17-1.77; HRS: HR = 1.26, 95%CI: 1.13-1.41 for fluctuating). Increasing trajectories enhanced the risk in the European cohort (ELSA: HR = 1.71, 95%CI: 1.06-2.74), while decreasing trajectories did not increase stroke risk in any cohort. For somatic depressive symptoms, consistently high and fluctuating trajectories increased the risk of stroke across all cohorts (CHARLS: HR = 2.16, 95%CI: 1.67-2.79; ELSA: HR = 1.94, 95%CI: 1.34-2.81; HRS: HR = 1.79, 95%CI: 1.49-2.15 for consistently high; CHARLS: HR = 1.35, 95%CI: 1.20-1.62; ELSA: HR = 1.56, 95%CI: 1.27-1.92; HRS: HR = 1.33, 95%CI: 1.20-1.46 for fluctuating). Increasing trajectories only increased the risk in the European cohort (ELSA: HR = 1.95, 95%CI: 1.11-3.43), while decreasing trajectories did not increase stroke risk in the European and American cohorts. For cognitive-affective depressive symptoms, consistently high and fluctuating trajectories increased the risk in the Asian and European cohorts (CHARLS: HR = 2.06, 95%CI: 1.52-2.81; ELSA: HR = 1.25, 95%CI: 1.02-1.54 for consistently high; CHARLS: HR = 1.63, 95%CI: 1.23-2.16; ELSA: HR = 1.58, 95%CI: 1.11-2.24 for fluctuating). Increasing trajectories increased the risk only in the American cohort (HRS: HR = 14.67, 95%CI: 1.87-114.91).CONCLUSIONConsistently high and fluctuating trajectories of total and somatic depressive symptoms were associated with an increased risk for stroke across all populations. Consistently high, fluctuating, and increasing trajectories of cognitive-affective symptoms pose a risk for certain populations. These findings highlight the importance of targeted interventions for managing depressive symptoms as potential strategies for stroke prevention, particularly in regions where specific symptom trajectories are prevalent.

Background Asthma remains a major global health burden, particularly in adults aged ≥45 years. The relationship between the composite triglyceride-glucose-body-mass-index (TYG-BMI) and asthma risk in this age group has not been defined. Methods This cross-sectional study integrated data from the Global Burden of Disease (GBD) 2021 study, the China Health and Retirement Longitudinal Study (CHARLS), and the National Health and Nutrition Examination Survey (NHANES). After exclusions, 9,432 participants from CHARLS and 1340 from NHANES were included. The TYG-BMI index was calculated and participants were divided into quartiles. Restricted cubic spline (RCS) and segmented regression models were used to analyze the relationship between TYG-BMI and asthma risk. Results The GBD 2021 data shows high BMI is the top risk factor for asthma-related DALYs globally. CHARLS and NHANES studies both find a nonlinear relationship between TYG-BMI and asthma risk, with critical points at 199.51 and 246.905, respectively. Below the threshold, asthma risk decreases (OR = 0.985, 95% CI: 0.978–0.991 in CHARLS); above it, risk increases (OR = 1.0003, 95% CI: 1.0000–1.0005 in CHARLS; OR = 1.004, 95% CI: 1.001–1.009 in NHANES). A 10-unit increase above the threshold raises asthma risk by 0.3–4%, while a 10-unit decrease reduces it by 14%. This underscores the preventive value of optimizing metabolic status. Conclusion This study provides the large-scale evidence of a nonlinear relationship between the TYG-BMI index and asthma risk in individuals aged 45 and older.

Prevalence, correlates and outcomes of multimorbidity among the middle-aged and elderly: Findings from the China Health and Retirement Longitudinal Study

Independent and combined effects of depressive symptoms and cardiometabolic risk factors on dementia incidence: a cross-country comparison in England, the United States and China.

ObjectiveRapid population ageing in China is increasing the prevalence of lower urinary tract symptoms suggestive of benign prostatic hyperplasia (LUTS/BPH) among older people. The associated economic burden is increasing as...