Urban-rural differentials in age-related biological risk among middle-aged and older Chinese

The Association Between Urbanization and Frailty Status in China

Background: A frailty index (FI) can identify individuals with frailty in a population of interest. Previous literature suggests a need for frailty assessment methods for older adults in China and that urbanization may impact frailty status. We used a FI to examine the association between frailty and urbanization as living in a less urbanized area may put older adults at a higher risk frailty and poor healthcare outcomes. Methods: We included adults aged 55 years and older (n = 7695) from the China Health and Nutrition Survey (2018). The FI was based on health outcomes correlating with a deficit score divided by number of health items: robust (<0.08), pre-frail (0.08-0.24), and frail (≥0.25). We used multinomial logistic regression models to examine associations between urbanization tertile (low, medium, and high) and frailty, using our novel FI. We also conducted sub-analyses examining how urbanization level modifies the relationship between frailty status and region of residence, and education and income levels. Results: Living in an area of low versus high urbanization was associated with higher odds of frail versus robust (1.5; 1.2-2.0), and pre-frail versus robust (1.6; 1.4-2.0) status in the fully adjusted model. Generally, higher odds of worse frailty status (e.g., pre-frail or frail) was associated with lower tertiles of urbanization for region, income, and education when compared to the highest urbanization tertile. Conclusions: A FI can help identify specific characteristics that may benefit from individualized interventions to counteract frailty. Living in less urbanized areas was associated with higher odds of pre-frailty and frailty. Inclusion of urbanization level, geographic residence, and social determinants of health in FI development can help identify older adults most at risk of frailty and contribute to individual and policy-level frailty prevention interventions.

The Association Between Cardiometabolic Risk and Cognitive Function Among Older Americans and Chinese

BACKGROUND

Cardiometabolic risk (CMR) is associated with cognitive health, but the association can be affected by broader social, economic, and medical contexts. The United States and China have very different developmental and epidemiological histories, and thus CMR among older people could be linked to cognitive function differently in the 2 countries.

METHODS

Cross-sectional and longitudinal ordinary least squares regression models were estimated for each country using nationally representative samples of populations over age 50: 7 430/4 474 Americans and 6 108/3 655 Chinese in the cross-sectional/longitudinal samples.

RESULTS

In the United States, higher CMR is associated with worse cognitive function (b = -0.08, p < .016). Longitudinally, CMR increase is associated with worse cognitive function at a marginally significant level (b = -0.10, p = .055). No relationship between CMR level or change and cognitive function is observed in China. Higher education levels are linked to better cognitive function and slower cognitive decline in both countries. Unlike older Americans, relative to those with very low education levels, among older Chinese with the highest education level, a higher CMR links to better cognitive function (b = 0.63, p = .013) and slower cognitive decline (b = 0.35, p = .062); Nevertheless, a rapid increase in CMR is additionally harmful (b = -0.54, p = .050) for cognitive function and may lead to faster cognitive decline (b = -0.35, p = .079).

CONCLUSIONS

The significant relationship between CMR and cognitive function in the United States suggests the importance of monitoring and controlling CMR factors at older ages. The insignificant relationship in China may be explained by the high CMR among those with high education levels, highlighting the need for improving cardiometabolic health through education and promoting healthy lifestyles.

Prevalence and risk factors of sarcopenia without obesity and sarcopenic obesity among Chinese community older people in suburban area of Shanghai: A cross-sectional study

Objectives

The aim of the present study was to explore the prevalence and risk factors of sarcopenia without obesity (S) and sarcopenic obesity (SO) among community-dwelling older people in the Chongming District of Shanghai, China, according to the Asian Working Group for Sarcopenia (AWGS) 2019 Consensus as the diagnostic criteria of sarcopenia.

Methods

In this cross-sectional study, a total of 1,407 subjects aged ≥65 years were included, where the mean age of the subjects was 71.91 ± 5.59 years and their mean body mass index (BMI) was 24.65 ± 3.32 kg/m². According to the Asian Working Group for Sarcopenia (AWGS) 2019 Consensus, sarcopenia was defined as a low appendicular skeletal muscle mass index (≤7.0 kg/m² in males and ≤5.7 kg/m² in females), decreased handgrip strength (<28.0 kg in males and <18.0 kg in females), and/or low gait speed (<1.0 m/s) or poor 5-time chair stand test (5CST) (≥12s). The SO met both the diagnostic criteria for sarcopenia and obesity, meanwhile obesity was defined as an increased percentage of body fat (PBF) (≥25% in males and ≥35% in females). Univariate and multiple logistic regression analyses were performed to explore the risk factors of both S and SO.

Results

The prevalence of S and SO was 9.74% (M: 9.29%, F: 10.05%) and 9.95% (M: 13.94%, F: 7.14%). Lower BMI (OR = 0.136, 95% CI: 0.054-0.340, p < 0.001), lower hip circumference (OR = 0.858, 95% CI: 0.816-0.903, p < 0.001), farming (OR = 1.632, 95% CI: 1.053-2.530, p = 0.028), higher high-density lipoprotein cholesterol (HDL-C) level (OR = 2.235, 95% CI: 1.484-3.367, p < 0.001), and a sleep duration <7 h (OR = 0.561, 95% CI: 0.346-0.909, p = 0.019) were risk factors for S. While aging (70-74 y, OR = 1.923, 95% CI: 1.122-3.295, p = 0.017; 75-79 y, OR = 3.185, 95% CI: 1.816-5.585, p < 0.001; ≥80 y, OR = 7.192, 95% CI: 4.133-12.513, p < 0.001), male (OR = 1.981, 95% CI: 1.351-2.904, p < 0.001), higher BMI (OR = 4.865, 95% CI: 1.089-21.736, p = 0.038), higher monocyte level (OR = 4.203, 95% CI: 1.340-13.181, p = 0.014), and a sleep duration >9 h (OR = 1.881, 95% CI: 1.117-3.166, p = 0.017) were risk factors for SO.

Conclusion

Our study showed the high prevalence of S and SO among community-dwelling older people in the Chongming District. The SO was more prevalent in males. Behavioral factors and lifestyle (such as farming and sleep duration) were associated more with the development of S, while age and male gender were associated more with the development of SO.

Life Course Socioeconomic Status and Healthy Longevity in China

In 2020, China's population aged 60 or older exceeded 264 million, representing 25% of the global population in that age-group. Older adults in China experienced periods of dramatic political and social unrest in early life, as well as economic transformations leading to drastic improvements in living standards during adulthood and older age. However, the implications of life course socioeconomic status (SES) trajectories for healthy longevity in later life have not been systematically studied in China. We utilize data from the China Health and Retirement Longitudinal Study (CHARLS) to comprehensively investigate how early-life conditions and adult SES combine to influence healthy longevity in later life. We find that both childhood and adulthood SES are associated with late-life health. The largest disparities in life expectancy (LE) and disability-free LE are found between those with persistently low SES throughout life and those with consistently high SES. At age 45, the gap in total LE between the most advantaged and least advantaged groups is six years for men and five years for women. Despite China's major policy changes prioritizing equity in income and health care in recent decades, our findings suggest that dramatic health inequalities among older adults remain. Our findings extend the literature on the effect of socioeconomic patterns across the life course on gradients in later-life health and highlight continuing disparities in healthy longevity among older adults in China.

The association between the community SARS exposure and allostatic load among Chinese older adults

Objectives

Previous studies have found that severe acute respiratory syndrome (SARS) was associated with the physical and psychological stress of those infected. However, research is sparse regarding the long‐term health consequence of community SARS exposure for older adults.

Methods

Using data from the 2011 and 2015 China Health and Retirement Longitudinal Study (CHARLS), we estimated multilevel regression models of allostatic load (AL) in the years after the SARS epidemic among 7735 respondents. Interaction terms between SARS epidemic exposure and social participation or community environment were included to examine potential effects.

Results

We found that community SARS exposure was associated with greater AL for those who had no social participation. Among those who were in worse community environment, community SARS exposure was strongly related to elevated load in the cardiovascular system. However, for those had social participation and lived in better community environment, community SARS exposure manifested no association with AL years later. Active social participation and better community environment could offset the negative association between SARS exposure and AL.

Conclusions

Taken together, these findings helped determine the positive direction of future social efforts and policy decisions to guide the global recovery from the devastating COVID‐19 pandemic.

Depression and Elevated Inflammation Among Chinese Older Adults: Eight Years After the 2003 SARS Epidemic

BACKGROUND AND OBJECTIVES

This study examined associations between exposure to the 2003 Severe Acute Respiratory Syndrome (SARS) epidemic and Chinese older adults' depression and inflammation 8 years after the crisis. Further, this study investigated the buffering effects of perceived social support and social participation.

RESEARCH DESIGN AND METHODS

Data were drawn from the 2011 China Health and Retirement Longitudinal Survey, including N = 4,341 Chinese adults aged 60 years and older. For the survey, local officials identified whether the 2003 SARS outbreak was one of the major disasters in the history of their communities. Depression was assessed by the Center for Epidemiological Studies-Depression scale and inflammation was measured by C-reactive protein (CRP) collected from participants via venous blood draws.

RESULTS

Results from multilevel logistic regression models revealed that Chinese older adults living in communities exposed to SARS were more likely to have elevated CRP compared to those not living in such communities. Moreover, community SARS exposure was associated with greater risks of depression for Chinese older adults who had no perceived social support. Among Chinese older adults who had low levels of social participation, community SARS exposure was more strongly related to elevated CRP.

DISCUSSION AND IMPLICATIONS

Findings suggest community-level exposure to the SARS epidemic had enduring consequences for Chinese older adults' health. However, active social participation and supportive social ties provided important resources that may buffer against negative effects of exposure to the SARS epidemic.

Urban health advantage or urban health penalty? Urban-rural disparities in age trajectories of physiological health among Chinese middle-aged and older women and men

During the past decades, China has experienced rapid urbanization and aging. This study investigated sex-stratified urban-rural disparities in age trajectories of physiological health in China. We obtained data from 21686 individuals aged 45 years or above from 2011 baseline survey of the China Health and Retirement Longitudinal Study (CHARLS) and the 2015 follow-up. It examined 11 biomarkers of physiological health classified into four summary indices: cardiovascular index, metabolic index, inflammation index, and allostatic load. This study found that the "urban health penalty" approach dominates the "urban health advantage" approach in middle and early old age, but the dominance of the "urban health penalty" approach is offset or even reversed by the "urban health advantage" approach in older age.

Trajectories of rural-urban disparities in biological risks for cardiovascular disease among Chinese middle-aged and older adults

This study examined rural-urban differences in age trajectories of biological risks for cardiovascular disease (CVD) among Chinese middle-aged and older adults. Data were from the 2011 wave of China Health and Retirement Longitudinal Study, including 11,528 respondents (M_age = 59.15) from 440 communities. CVD risk factors included C-reactive protein (CRP), high-density lipoprotein (HDL), body mass index (BMI), and waist circumference (WC). Multilevel models revealed that rural adults had higher levels of HDL and lower levels of CRP and BMI on average, compared to urban adults. We also found significant rural-urban differences in the age trajectories of CVD risks. Rural-urban disparities in CVD risks increased from middle to later life, and converged at later old age. Findings suggest that rural-urban differences in cardiovascular health are not static, but rather vary throughout adulthood.