Multimorbidity, inflammation, and disability: a longitudinal mediational analysis

Gender-specific association of the accumulation of chronic conditions and disability in activities of daily living with depressive symptoms

BACKGROUND

In the era of rapid aging with a rising prevalence of multimorbidity, complex interactions between physical and psychological conditions have challenged the health care system. However, little is known about the association of the accumulation of chronic conditions and disability in activities of daily living with depressive symptoms, especially in developed countries.

METHODS

This population-based cohort study used data from the Health and Retirement Study. A total of 22,335 middle-aged and older adults participated in the 2014 (T1), 2016 (T2), and 2018 (T3) waves of the cohort were included. The accumulation of chronic conditions and disability were defined as the number of chronic diseases and the five activities of daily living. Depressive symptoms were measured by the Center for Epidemiologic Studies Depression Scale. A longitudinal mediation model with a cross-lagged panel model was run. As robust check, the models were applied with a longer follow-up period (from 2012 to 2018). Additionally, results were estimated in China.

RESULTS

Bidirectional associations have been found among the accumulation of chronic conditions, disability, and depressive symptoms, especially between disability and depression. Disability (T2) mediated 11.11 % and 16.87 % of the association between the accumulation of chronic conditions (T1) and depression (T3) for men and women in the United States. The results were consistent in robust analysis.

CONCLUSIONS

This study found that men and women routinely experienced disability and depressive symptoms because of the accumulation of chronic conditions. In terms of depressive symptoms, women were more sensitive to the accumulation of chronic conditions through disability.

How Useful are Mid-Arm and Calf Circumferences to Indicate Reduced Muscle Mass in Order to Recognize GLIM-Defined Malnutrition in Elderly Individuals?

AIMS

The aim of this study was to estimate cutoff values of mid-upper arm circumference (MUAC) and calf circumference (CC) for reduced muscle mass and analyze their accuracy in identifying malnutrition among individuals of 65 years of age or older in Bosnia and Herzegovina.

MATERIALS AND METHODS

The study is a secondary analysis dataset assessing nutritional risk and malnutrition among 446 community-dwellers and nursing home residents in Bosnia and Herzegovina. Malnutrition assessment included phenotypic criterions (weight loss, low body mass index, and reduced muscle mass) and etiologic criterions (inadequate food intake, disease-related inflammation, or albumin levels) according to recommendations of the Global Leadership Initiative on Malnutrition (GLIM). Receiver operating curves were used to calculate MUAC and CC's cutoff values as compared to the Mini Nutritional Assessment (MNA).

RESULTS

The optimal cutoff value for MUAC in men was 24 cm (AUC = 0.910, sensitivity 100%, specificity 77%), and in women 23 cm (AUC = 0.792, sensitivity 64%, specificity 83%). Optimal cutoff value of CC in men was 31 cm (AUC = 0.818, sensitivity 100%, specificity 67%) and in women 29 cm (AUC = 0.882, sensitivity 86%, specificity 74%). Two hundred fifty nine elderly individuals were categorized as malnourished/at risk for malnutrition per MNA. The prevalence of malnutrition based on GLIM criteria ranged from 19% to 30%.

CONCLUSIONS

The study suggested that MUAC and CC may be used as the alternative indicators of muscle mass when other assessment methods are unavailable. Future validation and reliability studies for GLIM using anthropometric parameters as a proxy of reduced muscle mass are needed.

Association between multimorbidity and informal long-term care use in China: a nationwide cohort study

BACKGROUND

The impact of multimorbidity on long-term care (LTC) use is understudied, despite its well-documented negative effects on functional disabilities. The current study aims to assess the association between multimorbidity and informal LTC use in China. We also explored the socioeconomic and regional disparities.

METHODS

The study included 10,831 community-dwelling respondents aged 45 years and older from the China Health and Retirement Longitudinal Study in 2011, 2015, and 2018 for analysis. We used a two-part model with random effects to estimate the association between multimorbidity and informal LTC use. Heterogeneity of the association by socioeconomic position (education and income) and region was explored via a subgroup analysis. We further converted the change of informal LTC hours associated with multimorbidity into monetary value and calculated the 95% uncertainty interval (UI).

RESULTS

The reported prevalence of multimorbidity was 60·0% (95% CI: 58·9%, 61·2%) in 2018. We found multimorbidity was associated with an increased likelihood of receiving informal LTC (OR = 2·13; 95% CI: 1·97, 2·30) and more hours of informal LTC received (IRR = 1·20; 95% CI: 1·06, 1·37), ceteris paribus. Participants in the highest income quintile received more hours of informal LTC care (IRR = 1·62; 95% CI: 1·31, 1·99). The estimated monetary value of increased informal LTC hours among participants with multimorbidity was equivalent to 3·7% (95% UI: 2·2%, 5·4%) of China's GDP in 2018.

CONCLUSION

Our findings substantiate the threat of multimorbidity to LTC burden. It is imperative to strengthen LTC services provision, especially among older adults with multimorbidity and ensure equal access among those with lower income.

Environmental exposures in early-life and general health in childhood

BACKGROUND

Early-life environmental exposures are suspected to be involved in the development of chronic diseases later in life. Most studies conducted so far considered single or few exposures and single-health parameter. Our study aimed to identify a childhood general health score and assess its association with a wide range of pre- and post-natal environmental exposures.

METHODS

The analysis is based on 870 children (6-12 years) from six European birth cohorts participating in the Human Early-Life Exposome project. A total of 53 prenatal and 105 childhood environmental factors were considered, including lifestyle, social, urban and chemical exposures. We built a general health score by averaging three sub-scores (cardiometabolic, respiratory/allergy and mental) built from 15 health parameters. By construct, a child with a low score has a low general health status. Penalized multivariable regression through Least Absolute Shrinkage and Selection Operator (LASSO) was fitted in order to identify exposures associated with the general health score.

FINDINGS

The results of LASSO show that a lower general health score was associated with maternal passive and active smoking during pregnancy and postnatal exposure to methylparaben, copper, indoor air pollutants, high intake of caffeinated drinks and few contacts with friends and family. Higher child's general health score was associated with prenatal exposure to a bluespace near residency and postnatal exposures to pets, cobalt, high intakes of vegetables and more physical activity. Against our hypotheses, postnatal exposure to organochlorine compounds and perfluorooctanoate were associated with a higher child's general health score.

CONCLUSION

By using a general health score summarizing the child cardiometabolic, respiratory/allergy and mental health, this study reinforced previously suspected environmental factors associated with various child health parameters (e.g. tobacco, air pollutants) and identified new factors (e.g. pets, bluespace) warranting further investigations.

The Mediation and Moderation Effect Association among Physical Activity, Body-Fat Percentage, Blood Pressure, and Serum Lipids among Chinese Adults: Findings from the China Health and Nutrition Surveys in 2015

Physical activity (PA) is of benefit and particularly important for cardiovascular disease risk factors as being sedentary becomes a lifestyle habit. Research into Chinese complex association among physical activity, body-fat percentage (BF%), blood pressure, and serum lipids is limited. The present study is based on an observational study among adults (>18 years old) residing in fifteen provinces in China. Data of 10,148 adult participants in the 2015 China Health and Nutrition Survey (CHNS) were analyzed. The simple mediation effect models with covariates were utilized to assess the association among PA and blood pressure or serum lipids, and BF% was played as a mediator. The serial multiple-mediator models with covariates were constructed to the further analysis of the relationship between PA and blood pressure, and BF% was the mediator 1 and blood lipids were the mediator 2. Based on the above hypothesis, the moderated mediation models with covariates were used to analyze the association among PA, BF%, and blood pressure; in addition, BF% was used as the mediator and blood lipids played as the moderator. In the simple mediation models, the model with a dependent variable was high-density lipoprotein cholesterol (HDL-C) or low-density lipoprotein cholesterol (LDL-C); BF% was played as the partly mediation effect and the proportion of contribution was 0.23 and 0.25, respectively. In the serial multiple-mediator models, blood lipids, as the second mediator, played the mediation effect; however, the effect was smaller than the BF%. In the moderated mediation model, blood lipids had the moderation effect as the moderator variable. HDL-C played a moderating role in the latter pathway of the "PA→BF%→SBP/DBP" mediation model, and LDL-C/TC played a moderating role in the direct effect of the "PA→BF%→DBP". In conclusion, BF% played a mediating role in the relationship between PA and blood pressure. HDL-C, LDL-C, and TC were more likely to act as moderating variables in the mediation model "PA→BF%→SBP/DBP". PA could directly and indirectly benefit to control the CVD risk factors simultaneously.

The Associations of Individual and Subclasses of Nonesterified Fatty Acids With Disability, and Mobility Limitation in Older Adults: The Cardiovascular Health Study

BACKGROUND

We sought to determine the associations between individual nonesterified fatty acids (NEFAs) and disability and mobility limitation.

METHODS

We studied 1 734 participants in the Cardiovascular Health Study (CHS), an ongoing population-based cohort study of community-living older American adults. We measured 35 individual NEFA species in fasting serum samples obtained at the 1996-1997 clinic visit. Using yearly assessments of activities of daily living and self-reported mobility, we identified participants with incident disability or mobility limitation during 15 years of follow-up. Cox proportional hazards regression models were used to determine the associations between per SD increment in the individual NEFAs and incident disability and mobility limitations with adjustment for potential confounding factors.

RESULTS

Higher concentrations of total and a broad range of individual NEFA species were associated with risk of disability and mobility limitation (disability: HR per SD of total NEFA [SD = 174.70] = 1.11, 95% CI = 1.04-1.18, p = .001; mobility limitation: HR per SD of total NEFA = 1.09, 95% CI = 1.02-1.16, p = .01). Among individual saturated NEFAs (SFAs), myristic (14:0) and palmitic (16:0) acids were significantly associated with higher risk of both disability and mobility limitations, but longer-chain FAs were not. Most individual monounsaturated (MUFA), n-6 polyunsaturated fatty acids (PUFAs), and trans FAs were positively significantly associated with higher risks of both disability and mobility limitation. In contrast, most n-3 PUFA species were not associated with disability or mobility limitation.

CONCLUSIONS

Higher risks of disability and mobility limitation were observed for proinflammatory intermediate-chain SFAs, MUFAs, n-6 PUFAs, and trans FAs. Our findings indicated no significant association for anti-inflammatory n-3 PUFAs.

The Mediating Role of Depression in Association Between Total Sleep Time and Instrumental Activities of Daily Living in China

Objectives: This study aims to investigate the mediating role of depression and the moderating effect of gender in the relationship between total sleep time (TST) and instrumental activities of daily living (IADL) in middle-aged and elderly people (aged 45 or above).

Methods: The data used in this study is from the China Health and Retirement Longitudinal Study (CHARLS), including a total of 10,460 respondents. Associations between TST, IADL, depression, and gender were analyzed using logistic regression and Karlson, Holm, and Breen (KHB) methods.

Results: Short (OR = 1.42, 95% CI = 1.28–1.58 of ≤6 h) and long TST (OR = 1.16, 95% CI = 1.02–1.32 of 8–9 h; OR = 1.35, 95% CI = 1.19–1.54 of >9 h) were both associated with IADL. The mediation effect analyses observed that depression explained 64.80% of the total effect of short TST (≤6 h) and IADL, but was insignificant in long TST (8–9 h and >9 h). Meanwhile, gender has moderating effects on the mediation effect model.

Conclusion: The study suggests that health interventions that focused on the dimensions of TST and depression are crucial for preventing functional disability while accounting for gender differences.

Life-course social connectedness: Comparing data-driven and theoretical classifications as predictors of functional limitations in adulthood

A life course perspective on social relationships highlights the importance of specific relationships at specific times in life, but analyses that account for life course trajectories in social relationships are rare. This study compares theoretical and data-driven approaches to classifying life course relationships, including multiple dimensions of social connectedness at different time points across the life course. We examine each approach's ability to predict later-life functional limitations, given that functional impairment is prevalent among middle-aged and older adults. Data were from three waves of the Midlife in the United States (MIDUS) study (n = 6909). Relationship variables (parental affection, parental discipline, social support, social strain, and positive relations with others) were from wave 1 or wave 2. Functional limitations were measured at wave 3. Results showed that the data-driven approach had more predictive power than the theoretical approach. Additionally, results suggested that including only positive relationship features was nearly as robust as including both positive and negative relationship features. Overall, the data-driven approach outperformed the theoretical approach and revealed relationship trajectories consistent with life course cumulative processes.

Multimorbidity and Functional Disability among Older Adults: The Role of Inflammation and Glycemic Status - An Observational Longitudinal Study

INTRODUCTION

Specific multimorbidity combinations, in particular those including arthritis, stroke, and cognitive impairment, have been associated with high burden of activities of daily living (ADL)-instrumental activities of daily living (IADL) disability in older adults. The biologic underpinnings of these associations are still unclear.

METHODS

Observational longitudinal study using data from the Health and Retirement Study (N = 8,618, mean age = 74 years, 58% female, 25% non-white) and negative binomial regression models stratified by sex to evaluate the role of inflammatory and glycemic biomarkers (high-sensitivity C-reactive protein (hs-CRP) and HbA1c) in the association between specific multimorbidity combinations (grouped around one of eight index diseases: arthritis, cancer, cognitive impairment, diabetes, heart disease, hypertension, lung disease, and stroke; assessed between 2006 and 2014) and prospective ADL-IADL disability (2 years later, 2008-2016). Results were adjusted for sociodemographic characteristics, body mass index, number of coexisting diseases, and baseline ADL-IADL score.

RESULTS

Multimorbidity combinations indexed by arthritis (IRR = 1.1, 95% CI = 1.01-1.20), diabetes (IRR = 1.19, 95% CI = 1.09-1.30), and cognitive impairment (IRR = 1.11, 95% CI = 1.01-1.23) among men and diabetes-indexed multimorbidity combinations (IRR = 1.07, 95% CI = 1.01-1.14) among women were associated with higher ADL-IADL scores at increasing levels of HbA1c. Across higher levels of hs-CRP, multimorbidity combinations indexed by arthritis (IRR = 1.06, 95% CI = 1.02-1.11), hypertension (IRR = 1.06, 95% CI = 1.02-1.11), heart disease (IRR = 1.06, 95% CI = 1.01-1.12), and lung disease (IRR = 1.14, 95% CI = 1.07-1.23) were associated with higher ADL-IADL scores among women, while there were no significant associations among men.

CONCLUSION

The findings suggest potential for anti-inflammatory management among older women and optimal glycemic control among older men with these particular multimorbidity combinations as focus for therapeutic/preventive options for maintaining functional health.

Longitudinal impact of metabolic syndrome and depressive symptoms on subsequent functional disability among middle-aged and older adults in China

BACKGROUND

Few studies examining the impact of metabolic syndrome and depressive symptoms on subsequent functional disability are available.

OBJECTIVES

To determine the impact of baseline metabolic syndrome and depressive symptoms on subsequent functional disability.

METHODS

This study used data from the 2011 baseline and 2013, 2015 and 2018 follow-up waves of the China Health and Retirement Longitudinal Study (CHARLS). Functional status was assessed by activities of daily living (ADLs) and instrumental ADLs (IADLs). Analyses were restricted to middle-aged and older adults (≥50 years) free of functional disability at baseline. Metabolic syndrome, depressive symptoms, and covariates were measured at baseline. New-onset ADL and IADL disability were obtained in follow-up measurements. Competitive risks based on survival analysis were conducted to examine the impact of baseline metabolic syndrome and depressive symptoms on subsequent functional disability after covariates were controlled.

RESULTS

Baseline depressive symptoms significantly predicted functional disability over a 7-year follow-up after adjusting for covariates (Hazard ratio [HR] = 1.54, 95% confidence intervals [CI] = 1.40-1.70 for ADL disability; HR=1.36, 95% CI=1.25-1.48 for IADL disability). Metabolic syndrome significantly predicted ADL disability (HR=1.25, 95% CI=1.14-1.38) but not IADL disability (HR=1.02, 95% CI=0.94-1.10). No significant additive interaction between metabolic syndrome and depressive symptoms on functional disability was found.

CONCLUSION

The current study found that baseline depressive symptoms were significantly associated with both ADL and IADL disabilities, while metabolic syndrome significantly predicted ADL disability. In addition, some indications showed that the effect in those with both conditions was greater than the sum of the effects separately.

Multimorbidity, depressive symptoms and disability in activities of daily living amongst middle-aged and older Chinese: Evidence from the China Health and Retirement Longitudinal Study

BACKGROUND

Given that multimorbidity is strongly associated with disability in activities of daily living (ADL) and the mechanism still remains unclear, this study sought to investigate the mediating effect of depressive symptoms on such association.

METHODS

A longitudinal dataset was drawn from the China Health and Retirement Longitudinal Study (CHARLS, 2011-2015), including 3951 adults aged 45 years and above. By sex, logistic regression and mediation analysis (the Karlson, Holm, and Breen Method) were employed.

RESULTS

The presence of multimorbidity was associated with increased odds of having depressive symptoms and developing ADL disability, and depressive symptoms was significantly associated with ADL disability among middle-aged and older women. Mediation analysis illustrated that depressive symptoms accounted for 6.36% of the effect of multimorbidity on ADL disability in women.

LIMITATIONS

Results might not generalize to all middle-aged and older Chinese due to missing data on depressive symptoms and ADL.

CONCLUSIONS

Multimorbidity increased the likelihood of ADL disability onset partially through depressive symptoms in middle-aged and older women, suggesting that emphasizing mental wellness of females with multimorbidity are necessary to prevent impairments in physical function.

Multimorbidity increases the risk for sarcopenia onset: Longitudinal analyses from the English Longitudinal Study of Ageing

BACKGROUND

Cross-sectional studies have demonstrated that multimorbidity is associated with sarcopenia. However, to date, this association has not been extensively investigated longitudinally. Therefore, the aim of the present paper was to explore the association between multimorbidity at baseline and sarcopenia onset over 12 years of follow-up in a large representative sample of the English older adult population.

METHODS

Representative data from the English Longitudinal Study of Ageing (ELSA) were analyzed. Multimorbidity at baseline was defined as ≥2 medical conditions, of 17 conditions included. Participants were considered to have sarcopenia if they had low handgrip strength and skeletal muscle mass (i.e., lower skeletal mass index) at waves 4, 6, 8. Multivariable logistic regression analysis was conducted to assess prospective associations between multimorbidity at baseline and sarcopenia at follow-up.

RESULTS

2873 older participants (mean age: 69.1 years, 54% females) who did not have sarcopenia at baseline were included. The prevalence of multimorbidity at baseline was 57.3%. Over twelve years of follow-up, 394 participants (=13.7% of the initial population) became sarcopenic. The presence of multimorbidity at baseline was associated with an increased risk of sarcopenia during follow-up (OR = 2.06; 95%CI: 1.61-2.62) in the univariable analysis, and even after adjusting for multiple potential confounders (OR = 1.23; 95%CI: 1.01-1.61).

CONCLUSIONS

In this large representative sample of older adults from the UK, multimorbidity at baseline was associated with a higher risk of sarcopenia during twelve-year follow-up. It may be prudent to target those with multimorbidity to aid in the prevention of sarcopenia.

The Association Between Cytomegalovirus and Disability by Race/Ethnicity and Sex: Results From the Health and Retirement Study

Recent studies have documented a decline in the overall prevalence of disability in the United States; however, racial/ethnic and sex disparities continue to persist. Cytomegalovirus (CMV) infection, a socially patterned exposure, may be a key mechanism in understanding these previously documented disparities. Using data from a nationally representative study, the 2016 Health and Retirement Study, we employed Poisson log-binomial models to estimate the prevalence of disability in a comparison of CMV-seropositive and -seronegative adults and investigated effect modification by race/ethnicity and sex. Among the 9,029 participants (55% women; mean age = 67.4 years), 63% were CMV-seropositive and 15% were disabled. CMV seropositivity was highest among non-Hispanic Black (88%) and Hispanic (92%) adults as compared with non-Hispanic White adults (57%). We found evidence for effect modification in the association between CMV and disability by sex but not race/ethnicity. While the 95% confidence intervals in the fully adjusted models included the null value, in comparison with seronegative women, our results suggest a greater prevalence of disability among CMV-seropositive women (prevalence ratio = 1.16, 95% confidence interval: 0.97, 1.38) but not among men (prevalence ratio = 0.85, 95% confidence interval: 0.69, 1.06). Results provide initial support for the hypothesis that CMV may be an important determinant of sex disparities in disability.

Not Seeing Double: Discordance in Disease, Function, and Their Longitudinal Associations in Monozygotic Twins

OBJECTIVE

Prior research on the causality and directionality between disease and functional limitations is ambiguous. The current study used longitudinal monozygotic twin data to test both directions linking disease burden and functional limitations in middle-aged and older adults, controlling for genetic and familial factors. We also examined potential moderation by psychological well-being.

METHODS

The twin subsample from the first two waves of the longitudinal Midlife in the United States (MIDUS) study was used (wave 1, 1995-1996; wave 2, 2004-2006). Only monozygotic twins (n = 713) were included in analyses. In separate multilevel models, we examined disease burden at MIDUS 2 predicted by functional limitations at MIDUS 1 and MIDUS 2 functional limitations predicted by disease burden at MIDUS 1.

RESULTS

Disease burden and functional limitations at MIDUS 2 varied substantially within families. There was no within-family association of earlier functional limitations with change in later disease burden (b = 0.40, p = .39), but there was a within-family association such that the twin with higher baseline disease burden had a greater increase in functional limitations than his/her co-twin (b = 0.06, p = .02). Well-being was not a moderator in either model.

CONCLUSIONS

We found support for a potentially causal association between earlier disease burden and later increases in functional limitations, consistent with the Disablement Process Model. Sensitivity analyses confirm the detected within-family effect. Possible mechanisms linking disease burden and functional limitations are discussed as potential targets for future research.

Mediation analysis for the relationship between dyslipidemia and coronary artery disease via hypersensitive C-reactive protein in a case-control study

BACKGROUND

The pathological basis of coronary artery disease (CAD) is atherosclerosis which is associated with inflammation and dyslipidemia. However, the involvement of hypersensitive C-reactive protein (hs-CRP) in lipid metabolism and how it affects the pathogenesis of CAD is uncertain.

OBJECTIVE

To explore whether the relationship between dyslipidemia and CAD is partly mediated by hs-CRP levels.

METHODS

Three hundred fifteen pairs of randomly sexand age-matched CAD and non-CAD subjects collected from Zhongda Hospital Affiliated to Southeast University were involved in the final analysis. We gathered information about each subjects clinical history as well as their results of detected hs-CRP and lipid levels. Linear regression analysis was used to determine the association between dyslipidemia and hs-CRP levels in which univariate and multivariate logistic regression analyzes were performed to determine the relationship between hs-CRP levels and CAD as well as dyslipidemia and CAD. Mediation analysis was used to evaluate whether hs-CRP levels act as a mediator of the relationship between dyslipidemia and CAD.

RESULTS

Dyslipidemia and hs-CRP levels were significantly associated with an increased risk of CAD, with β = 0.594 (P = 0.001) and β = 0.016 (P = 0.024), respectively, and there was a correlation between dyslipidemia and hs-CRP levels (β = 3.273, P = 0.004). Mediation analysis results revealed that the correlation between dyslipidemia and CAD was 8.27% mediated by hs-CRP levels with a direct effect of 0.621 and an indirect effect of 0.056.

CONCLUSION

Hs-CRP levels played a partial mediation role in the association between dyslipidemia and CAD.