Recommendations on Methods for Assessing Multimorbidity Changes Over Time: Aligning the Method to the Purpose.

BACKGROUND: The rapidly growing field of multimorbidity research demonstrates that changes in multimorbidity in mid- and late-life have far reaching effects on important person-centered outcomes, such as health-related quality of life. However, there are few organizing frameworks and comparatively little work weighing the merits and limitations of various quantitative methods applied to the longitudinal study of multimorbidity. METHODS: We identify and discuss methods aligned to specific research objectives with the goals of (i) establishing a common language for assessing longitudinal changes in multimorbidity, (ii) illuminating gaps in our knowledge regarding multimorbidity progression and critical periods of change, and (iii) informing research to identify groups that experience different rates and divergent etiological pathways of disease progression linked to deterioration in important health-related outcomes. RESULTS: We review practical issues in the measurement of multimorbidity, longitudinal analysis of health-related data, operationalizing change over time, and discuss methods that align with 4 general typologies for research objectives in the longitudinal study of multimorbidity: (i) examine individual change in multimorbidity, (ii) identify subgroups that follow similar trajectories of multimorbidity progression, (iii) understand when, how, and why individuals or groups shift to more advanced stages of multimorbidity, and (iv) examine the coprogression of multimorbidity with key health domains. CONCLUSIONS: This work encourages a systematic approach to the quantitative study of change in multimorbidity and provides a valuable resource for researchers working to measure and minimize the deleterious effects of multimorbidity on aging populations.

Mental-somatic multimorbidity in trajectories of cognitive function for middle-aged and older adults.

INTRODUCTION: Multimorbidity may confer higher risk for cognitive decline than any single constituent disease. This study aims to identify distinct trajectories of cognitive impairment probability among middle-aged and older adults, and to assess the effect of changes in mental-somatic multimorbidity on these distinct trajectories. METHODS: Data from the Health and Retirement Study (1998-2016) were employed to estimate group-based trajectory models identifying distinct trajectories of cognitive impairment probability. Four time-varying mental-somatic multimorbidity combinations (somatic, stroke, depressive, stroke and depressive) were examined for their association with observed trajectories of cognitive impairment probability with age. Multinomial logistic regression analysis was conducted to quantify the association of sociodemographic and health-related factors with trajectory group membership. RESULTS: Respondents (N = 20,070) had a mean age of 61.0 years (SD = 8.7) at baseline. Three distinct cognitive trajectories were identified using group-based trajectory modelling: (1) Low risk with late-life increase (62.6%), (2) Low initial risk with rapid increase (25.7%), and (3) High risk (11.7%). For adults following along Low risk with late-life increase, the odds of cognitive impairment for stroke and depressive multimorbidity (OR:3.92, 95%CI:2.91,5.28) were nearly two times higher than either stroke multimorbidity (OR:2.06, 95%CI:1.75,2.43) or depressive multimorbidity (OR:2.03, 95%CI:1.71,2.41). The odds of cognitive impairment for stroke and depressive multimorbidity in Low initial risk with rapid increase or High risk (OR:4.31, 95%CI:3.50,5.31; OR:3.43, 95%CI:2.07,5.66, respectively) were moderately higher than stroke multimorbidity (OR:2.71, 95%CI:2.35, 3.13; OR: 3.23, 95%CI:2.16, 4.81, respectively). In the multinomial logistic regression model, non-Hispanic Black and Hispanic respondents had higher odds of being in Low initial risk with rapid increase and High risk relative to non-Hispanic White adults. CONCLUSIONS: These findings show that depressive and stroke multimorbidity combinations have the greatest association with rapid cognitive declines and their prevention may postpone these declines, especially in socially disadvantaged and minoritized groups.

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.

Racial, ethnic, and socioeconomic disparities in trajectories of morbidity accumulation among older Americans.

Introduction: Multimorbidity, the presence of multiple chronic health conditions, generally starts in middle and older age but there is considerable heterogeneity in the trajectory of morbidity accumulation. This study aimed to clarify the number of distinct trajectories and the potential associations between race/ethnicity and socioeconomic status and these trajectories. Methods: Data from 13,699 respondents (age ≥51) in the Health and Retirement Study between 1998 and 2016 were analyzed with growth mixture models. Nine prevalent self-reported morbidities (arthritis, cancer, cognitive impairment, depressive symptoms, diabetes, heart disease, hypertension, lung disease, stroke) were summed for the morbidity count. Results: Three trajectories of morbidity accumulation were identified: low [starting with few morbidities and accumulating them slowly (i.e., low intercept and low slope); 80% of sample], increasing (i.e., low intercept and high slope; 9%), and high (i.e., high intercept and low slope; 11%). Compared to non-Hispanic (NH) White adults in covariate-adjusted models, NH Black adults had disadvantages while Hispanic adults had advantages. Our results suggest a protective effect of education for NH Black adults (i.e., racial health disparities observed at low education were ameliorated and then eliminated at increasing levels of education) and a reverse pattern for Hispanic adults (i.e., increasing levels of education was found to dampen the advantages Hispanic adults had at low education). Compared with NH White adults, higher levels of wealth were protective for both NH Black adults (i.e., reducing or reversing racial health disparities observed at low wealth) and Hispanic adults (i.e., increasing the initial health advantages observed at low wealth). Conclusion: These findings have implications for addressing health disparities through more precise targeting of public health interventions. This work highlights the imperative to address socioeconomic inequalities that interact with race/ethnicity in complex ways to erode health.

Depressive Multimorbidity and Trajectories of Functional Status among Older Americans: Differences by Racial/Ethnic Group.

OBJECTIVE: This study aims to evaluate the impact of depressive multimorbidity (ie, including depressive symptoms) on the long-term development of activities of daily living (ADL) and instrumental activities of daily living (IADL) limitations according to racial/ethnic group in a representative sample of US older adults. DESIGN: Prospective, observational, population-based 16-year follow-up study of nationally representative sample. SETTING AND PARTICIPANTS: Sample of older non-Hispanic Black, Hispanic, and nonHispanic White Americans from the Health and Retirement Study (2000‒2016, N = 16,364, community-dwelling adults ≥65 years of age). METHODS: Data from 9 biennial assessments were used to evaluate the accumulation of ADL-IADL limitations (range 0‒11) among participants with depressive (8-item Center for Epidemiologic Studies Depression score≥4) vs somatic (ie, physical conditions only) multimorbidity vs those without multimorbidity (no or 1 condition). Generalized estimating equations included race/ethnicity (non-Hispanic Black, Hispanic, non-Hispanic White), baseline age, sex, body mass index, education, partnered, and net worth. RESULTS: Depressive and somatic multimorbidity were associated with 5.18 and 2.95 times greater accumulation of functional limitations, respectively, relative to no disease [incidence rate ratio (IRR) = 5.18, 95% confidence interval, CI (4.38,6.13), IRR = 2.95, 95% CI (2.51,3.48)]. Hispanic and Black respondents experienced greater accumulation of ADL-IADL limitations than White respondents [IRR = 1.27, 95% CI (1.14, 1.41), IRR = 1.31, 95% CI (1.20, 1.43), respectively]. CONCLUSIONS AND IMPLICATIONS: Combinations of somatic diseases and high depressive symptoms are associated with greatest accumulation of functional limitations over time in adults ages 65 and older. There is a more rapid growth in functional limitations among individuals from racial/ethnic minority groups. Given the high prevalence of multimorbidity and depressive symptomatology among older adults and the availability of treatment options for depression, these results highlight the importance of screening/treatment for depression, particularly among older adults with socioeconomic vulnerabilities, to slow the progression of functional decline in later life.

Association of Psychological distress and Physical Health with Subjective and Objective Memory in Older Adults.

ObjectivesTo investigate how indicators of psychological stress and physical health differentially influence subjective and objective memory in older adults. Methods: 404 adults aged ≥55 without cognitive impairment participated in remote assessment of physical health (PHY; multimorbidity, body-mass-index), psychological distress (PDS; perceived stress, anxiety, depression), subjective memory complaints (SM), and task-based objective memory performance (OM). Results: Separately, both PHY and PDS significantly predicted SM (p < 0.01), but only PHY was associated with OM (p = 0.05). Combined models showed that PHY and PDS maintained significant association with SM (p < 0.01, R2 = 0.30), while only PHY was associated with OM (p = .07, R2 = 0.03; for associative OM, p = 0.04). Discussion: SM is associated with participants' psychological profile, highlighting the importance of addressing these factors when assessing SM. The results also reveal that remotely-administered OM tasks are more immune to participants' psychological profile, and support previously-established links between physical health and objective and subjective memory function.

Multidimensional trajectories of multimorbidity, functional status, cognitive performance, and depressive symptoms among diverse groups of older adults.

Background: Inter-relationships between multimorbidity and geriatric syndromes are poorly understood. This study assesses heterogeneity in joint trajectories of somatic disease, functional status, cognitive performance, and depressive symptomatology. Methods: We analyzed 16 years of longitudinal data from the Health and Retirement Study (HRS, 1998-2016) for n = 11,565 older adults (≥65 years) in the United States. Group-based mixture modeling identified latent clusters of older adults following similar joint trajectories across domains. Results: We identified four distinct multidimensional trajectory groups: (1) Minimal Impairment with Low Multimorbidity (32.7% of the sample; mean = 0.60 conditions at age 65, 2.1 conditions at age 90) had limited deterioration; (2) Minimal Impairment with High Multimorbidity (32.9%; mean = 2.3 conditions at age 65, 4.0 at age 90) had minimal deterioration; (3) Multidomain Impairment with Intermediate Multimorbidity (19.9%; mean = 1.3 conditions at age 65, 2.7 at age 90) had moderate depressive symptomatology and functional impariments with worsening cognitive performance; (4) Multidomain Impairment with High Multimorbidity (14.1%; mean = 3.3 conditions at age 65; 4.7 at age 90) had substantial functional limitation and high depressive symptomatology with worsening cognitive performance. Black and Hispanic race/ethnicity, lower wealth, lower education, male sex, and smoking history were significantly associated with membership in the two Multidomain Impairment classes. Conclusions: There is substantial heterogeneity in combined trajectories of interrelated health domains in late life. Membership in the two most impaired classes was more likely for minoritized older adults.

Trajectories of cognitive functioning in later life: Disparities by race/ethnicity, educational attainment, sex, and multimorbidity combinations.

Evaluating multimorbidity combinations, racial/ethnic background, educational attainment, and sex associations with age-related cognitive changes is critical to clarifying the health, sociodemographic, and socioeconomic mechanisms associated with cognitive function in later life. Data from the 2011-2018 National Health and Aging Trends Study for respondents aged 65 years and older (N = 10,548, mean age = 77.5) were analyzed using linear mixed effect models. Racial/ethnic differences (mutually-exclusive groups: non-Latino White, non-Latino Black, and Latino) in cognitive trajectories and significant interactions with sex and education (

Multimorbidity Accumulation Among Middle-Aged Americans: Differences by Race/Ethnicity and Body Mass Index.

BACKGROUND: Obesity and multimorbidity are more prevalent among U.S. racial/ethnic minority groups. Evaluating racial/ethnic disparities in disease accumulation according to body mass index (BMI) may guide interventions to reduce multimorbidity burden in vulnerable racial/ethnic groups. METHOD: We used data from the 1998-2016 Health and Retirement Study on 8 106 participants aged 51-55 at baseline. Disease burden and multimorbidity (≥2 co-occurring diseases) were assessed using 7 chronic diseases: arthritis, cancer, heart disease, diabetes, hypertension, lung disease, and stroke. Four BMI categories were defined per convention: normal, overweight, obese class 1, and obese class 2/3. Generalized estimating equations models with inverse probability weights estimated the accumulation of chronic diseases. RESULTS: Overweight and obesity were more prevalent in non-Hispanic Black (82.3%) and Hispanic (78.9%) than non-Hispanic White (70.9 %) participants at baseline. The baseline burden of disease was similar across BMI categories, but disease accumulation was faster in the obese class 2/3 and marginally in the obese class 1 categories compared with normal BMI. Black participants across BMI categories had a higher initial burden and faster accumulation of disease over time, while Hispanics had a lower initial burden and similar rate of accumulation, compared with Whites. Black participants, including those with normal BMI, reach the multimorbidity threshold 5-6 years earlier compared with White participants. CONCLUSIONS: Controlling weight and reducing obesity early in the lifecourse may slow the progression of multimorbidity in later life. Further investigations are needed to identify the factors responsible for the early and progressing nature of multimorbidity in Blacks of nonobese weight.

Physical Activity as a Mediator Between Race/Ethnicity and Changes in Multimorbidity.

OBJECTIVES: Studies report racial/ethnic disparities in multimorbidity (≥2 chronic conditions) and their rate of accumulation over time as well as differences in physical activity. Our study aimed to investigate whether racial/ethnic differences in the accumulation of multimorbidity were mediated by physical activity among middle-aged and older adults. METHOD: We assessed racial/ethnic differences in the accumulation of multimorbidity (of 9 conditions) over 12 years (2004-2016) in the Health and Retirement Study (N = 18,264, mean age = 64.4 years). Structural equation modeling was used to estimate latent growth curve models of changes in multimorbidity and investigate whether the relationship of race/ethnicity (non-Hispanic Black, Hispanic, non-Hispanic White participants) to changes in the number of chronic conditions was mediated by physical activity after controlling for age, sex, education, marital status, household wealth, insurance coverage, smoking, alcohol, and body weight. RESULTS: There was a significant increase in multimorbidity over time. Initial levels and changes in multimorbidity over time varied significantly across individuals. Indirect effects of the relationship between race/ethnicity and changes in multimorbidity as mediated by physical activity were significant, consistent with the mediational hypothesis. Black respondents engaged in significantly lower levels of physical activity than White respondents after controlling for covariates, but there were no differences between Hispanic and White respondents once education was included. Discussion: These results provide important new information for understanding how modifiable lifestyle factors may help explain disparities in multimorbidity in mid-to-late life, suggesting greater need to intervene to reduce sedentary behavior and increase physical activity.

Racial and Ethnic Differences in Multimorbidity Changes Over Time.

BACKGROUND: Our understanding of how multimorbidity progresses and changes is nascent. OBJECTIVES: Assess multimorbidity changes among racially/ethnically diverse middle-aged and older adults. DESIGN, SETTING, AND PARTICIPANTS: Prospective cohort study using latent class analysis to identify multimorbidity combinations over 16 years, and multinomial logistic models to assess change relative to baseline class membership. Health and Retirement Study respondents (age 51 y and above) in 1998 and followed through 2014 (N=17,297). MEASURES: Multimorbidity latent classes of: hypertension, heart disease, lung disease, diabetes, cancer, arthritis, stroke, high depressive symptoms. RESULTS: Three latent classes were identified in 1998: minimal disease (45.8% of participants), cardiovascular-musculoskeletal (34.6%), cardiovascular-musculoskeletal-mental (19.6%); and 3 in 2014: cardiovascular-musculoskeletal (13%), cardiovascular-musculoskeletal-metabolic (12%), multisystem multimorbidity (15%). Remaining participants were deceased (48%) or lost to follow-up (12%) by 2014. Compared with minimal disease, individuals in cardiovascular-musculoskeletal in 1998 were more likely to be in multisystem multimorbidity in 2014 [odds ratio (OR)=1.78, P<0.001], and individuals in cardiovascular-musculoskeletal-mental in 1998 were more likely to be deceased (OR=2.45, P<0.001) or lost to follow-up (OR=3.08, P<0.001). Hispanic and Black Americans were more likely than White Americans to be in multisystem multimorbidity in 2014 (OR=1.67, P=0.042; OR=2.60, P<0.001, respectively). Black compared with White Americans were more likely to be deceased (OR=1.62, P=0.01) or lost to follow-up (OR=2.11, P<0.001) by 2014. CONCLUSIONS AND RELEVANCE: Racial/ethnic older adults are more likely to accumulate morbidity and die compared with White peers, and should be the focus of targeted and enhanced efforts to prevent and/or delay progression to more complex multimorbidity patterns.

Metabolic syndrome and the benefit of a physical activity intervention on lower-extremity function: Results from a randomized clinical trial.

BACKGROUND: In older adults, increases in physical activity may prevent decline in lower-extremity function, but whether the benefit differs according to metabolic syndrome (MetS) status is uncertain. We aim to investigate whether structured physical activity is associated with less decline in lower-extremity function among older adults with versus without MetS. METHODS: We used data from the multicenter Lifestyle Interventions and Independence for Elders (LIFE) study to analyze 1535 sedentary functionally-vulnerable women and men, aged 70 to 89 years old, assessed every 6 months (February 2010-December 2013) for an average of 2.7 years. Participants were randomized to a structured, moderate-intensity physical activity intervention (PA; n = 766) or health education program (HE; n = 769). MetS was defined according to the 2009 multi-agency harmonized criteria. Lower-extremity function was assessed by 400-m walking speed and the Short Physical Performance Battery (SPPB) score. RESULTS: 763 (49.7%) participants met criteria for MetS at baseline. Relative to HE, PA was associated with faster 400-m walking speed among participants with MetS (P < 0.001) but not among those without MetS (P = 0.91), although the test for statistical interaction was marginally non-significant (P = 0.07). In contrast, no benefit of PA versus HE was observed on the SPPB score in either MetS subgroup. CONCLUSIONS: Among older adults at high risk for mobility disability, moderate-intensity physical activity conveys significant benefits in 400-m walking speed but not SPPB in those with, but not without, MetS. The LIFE physical activity program may be an effective strategy for maintaining or improving walking speed among vulnerable older adults with MetS. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01072500.

Metabolic Risk and Depression among Elderly Mexican Americans: The Roles of Nativity Status.

Objective: To evaluate the relationship between metabolic risk (MR) and depression in a sample of older Mexican Americans and examine whether the association differs by age at migration. Methods: Longitudinal study using data from the Hispanic Established Populations for the Epidemiologic Study of the Elderly (HEPESE) (N=807, mean age = 84.3). The analytical sample was compiled from wave 6 (2007) to wave 7 (2010-2011) of HEPESE. Random-effect logistic regression examined the association between MR and depression and tested the model stratified by nativity status and age at migration. Results: MR was associated with higher odds of depression for US-born Mexican Americans after controlling for potential confounders. Similarly, among Mexican Americans who migrated before age 20, MR was associated with higher odds of depression. Conclusion: The findings highlight the importance of age at migration when evaluating the health of foreign-born Mexican Americans from a life-course perspective. Particularly among Mexican Americans who migrated before age 20, those with MR were more vulnerable to depression than their counterparts without MR.

Nativity, Family, Disability: Results from the Hispanic Established Populations for the Epidemiologic Study of the Elderly.

Objectives: ativity and family support may influence attitudes and behaviors that delay or accelerate the disability process in older adults. The objectives of this study were twofold: 1) to evaluate nativity and migration cohort differences in trajectories of disability (assessed by activities of daily living [ADL]) among older Mexican Americans; and 2) to determine the role of objectively measured family support in the association between nativity, migration cohort, and disability changes over time. Methods: This is a longitudinal study with up to 18 years follow-up (1993-2011) using data from the Hispanic Established Populations for the Epidemiologic Study of the Elderly (N=2,785, mean age =72.4 years). Disability was assessed using self-reported limitations in activities of daily living (ADL). Nativity and migration cohort were self-reported. Family support was assessed by marital status and the number of their children participants saw each month. Linear growth curve models evaluated the trajectory of ADL disability over 18 years and assessed variations by nativity status, migration cohort and family support. Results: Foreign-born respondents who migrated before age 20 had more starting ADL limitations (ß= .36, P<.001) and accumulated disability faster (ß=.04, P<.01) compared with their US-born counterparts. In contrast, foreign-born respondents who migrated at later ages showed disability trajectories similar to US-born respondents. Married respondents had a lower level of disability (ß= -.14, P<.01) and a lower rate of accumulation over time (ß= -.02, P=.001) compared with participants who were not married. Discussion: Mexican Americans who migrate at younger ages may experience greater disability over time; however, family support may help mitigate the accumulation of disability among older Mexican Americans.

Short-, Medium-, and Long-term Weight Changes and All-Cause Mortality in Old Age: Findings From the National Survey of the Japanese Elderly.

BACKGROUND: Recent studies, predominantly in Western populations, suggest that both weight loss and weight gain are associated with an increased mortality risk in old age. However, evidence of this association in older Asian populations remains sparse. This study aimed to examine the association between weight change and all-cause mortality in a nationally representative sample of community-dwelling older Japanese people. METHODS: Data were obtained from the National Survey of the Japanese Elderly, which included 4869 adults aged ≥60 years. Participants were followed for up to 30 years. We considered 3 indicators of weight change according to the follow-up interval: short-term (3 years), medium-term (6-7 years), and long-term (12-13 years). Weight change was classified as loss ≥ 5%, loss 2.5%-4.9%, stable (±2.4%), gain 2.5%-4.9%, and gain ≥ 5%. Cox proportional hazards models were used to calculate the relative mortality risk of each weight change category. RESULTS: Weight loss ≥ 5% for all intervals was associated with higher mortality than stable weight and the effects were largely similar across all 3 intervals (hazard ratio [95% confidence interval]: 1.36 [1.22-1.51] for short-term, 1.36 [1.22-1.51] for medium-term, and 1.31 [1.11-1.54] for long-term). A similar pattern of results was observed among the young-old and old-old, and among men and women. The effect of weight loss on higher mortality was greater among those with a lower body mass index at baseline. CONCLUSIONS: These findings could inform clinical and public health approaches to body-weight management aimed at improving the health and survival of older adults, particularly in Asian populations.

An Agenda for Addressing Multimorbidity and Racial and Ethnic Disparities in Alzheimer's Disease and Related Dementia.

Advancements in Alzheimer's disease and related dementias (ADRD) research on the U.S. population acknowledge the importance of the high burden of ADRD on segments of the population and yet-to-be characterized risks attributable to the burden of multiple chronic diseases (multimorbidity). These realizations suggest successful strategies in caring for people with ADRD and their caregivers will rely not only on clinical treatments but also on more refined and comprehensive models of ADRD that take its broad effects on the whole-person and the whole of society into consideration. To this end, it is critical to characterize and address the relationship between ADRD and multimorbidity combinations that complicate care and lead to poor outcomes, particularly with regard to racial and ethnic disparities in the occurrence, course, and effects of ADRD. Several research and policy recommendations are presented to address the intersection of ADRD, multimorbidity, and underrepresented populations most at risk for adverse outcomes.

Socioeconomic Differences in Trajectories of Functional Capacity Among Older Japanese: A 25-Year Longitudinal Study.

OBJECTIVES: There is limited research on long-term changes in functional capacity among older Japanese, who differ significantly from their counterparts in Western, developed nations. This study aimed to identify distinct trajectories of functional capacity over a 25-year period and to explore socioeconomic differences in trajectory-group membership probabilities, using a national sample of older Japanese. DESIGN: Longitudinal panel study with 8 observation points from 1987 to 2012. SETTING AND PARTICIPANTS: The data came from the National Survey of the Japanese Elderly, which consisted of 6193 samples of community-dwelling Japanese aged 60 years and older at baseline. METHODS: Functional capacity measure included basic and instrumental activities of daily living. Group-based mixture models were used for data analysis. RESULTS: Among participants aged 60 to 74 years at baseline, 4 trajectories were identified: minimal disability (80.3%), late-onset disability (11.6%), early-onset disability (6.2%), and moderate disability (1.9%). Those aged ≥75 years at baseline experienced higher levels of disability but somewhat parallel trajectories, including minimal disability (73.3%), early-onset disability (11.2%), moderate disability (11.3%), and severe and worsening disability (4.2%). Lower socioeconomic status, including education and household income, was associated with a higher risk of experiencing trajectories of poorer functional capacity among those aged 60 to 74 years, but no such association existed among those aged ≥75 years. CONCLUSIONS AND IMPLICATIONS: We found that approximately 70% to 80% of older Japanese maintained healthy functional capacity over time. Although we could not follow those who dropped out during the observation period, this study provided useful evidence that socioeconomic disparities in functional health converge with age. Our findings inform the design of health policies and interventions aiming to maintain functional health among older adults with diverse socioeconomic backgrounds. In particular, public policies aiming to reduce socioeconomic disparities should be emphasized to promote healthy aging.

Tracking Multimorbidity Changes in Diverse Racial/Ethnic Populations Over Time: Issues and Considerations.

Multimorbidity is widely recognized as having adverse effects on health and wellbeing and may threaten the ability of older adults to live independently. Much of what is known about multimorbidity rests on research that has largely focused on one point in time, or from a static perspective. Given that there remains a lack of agreement in the field on how to standardize multimorbidity definitions and measurement, it is not surprising that analyzing and predicting multimorbidity development, progression over time, and its impact are still largely unaddressed. As a result, there are important gaps and challenges to measuring and studying multimorbidity in a longitudinal context. This Research Practice perspective summarizes pressing challenges and offers practical steps to move the field forward.

Age and gender differences in the association between body mass index and all-cause mortality among older Japanese.

ABSTRACTObjective: Increasing evidence suggests a reverse J-shaped association between body mass index (BMI) and all-cause mortality among the older population. However, findings from non-Western societies including Japan are still sparse. Furthermore, little evidence regarding variation by age and gender in the BMI-mortality relationship in old age exists. This study aimed to examine age and gender variations in the relationship between BMI and all-cause mortality among older Japanese. Design: Data came from a national representative sample of community-dwelling Japanese aged 60 years and older at baseline (n = 4,869). Participants were followed for up to 25 years. We categorized BMI into seven categories: < 18.5, 18.5-19.9, 20.0-21.4, 21.5-22.9, 23.0-24.9, 25.0-26.9, and ≥ 27.0. Cox proportional hazards models were used to assess the relative mortality risk associated with BMI categories. Results: Lower BMI (< 18.5 and 18.5-19.9) was associated with higher mortality, compared to the mid-normal weight category (BMI: 21.5-22.9), after adjusting for covariates. In contrast, high-normal weight (BMI: 23.0-24.9) and overweight (BMI: 25.0-26.9 and ≥ 27.0) were not associated with mortality. Relative to old-old (aged ≥ 75 years), the higher mortality risk associated with lower BMI (< 20) appeared to be more prominent among young-old (aged 60-74 years). A moderately increased mortality risk associated with low BMI (18.5-19.9) was identified among men but not among women. Conclusion: Among older Japanese, low BMI (< 20.0) was associated with higher mortality, while high BMI (≥ 27.0) was not. The increased mortality risk associated with low BMI is more apparent among young-old and men. These age and gender differences need to be considered in assessing healthy body weight in old age.

Racial/ethnic differences in multimorbidity development and chronic disease accumulation for middle-aged adults.

BACKGROUND: Multimorbidity-having two or more coexisting chronic conditions-is highly prevalent, costly, and disabling to older adults. Questions remain regarding chronic diseases accumulation over time and whether this differs by racial and ethnic background. Answering this knowledge gap, this study identifies differences in rates of chronic disease accumulation and multimorbidity development among non-Hispanic white, non-Hispanic black, and Hispanic study participants starting in middle-age and followed up to 16 years. METHODS AND FINDINGS: We analyzed data from the Health and Retirement Study (HRS), a biennial, ongoing, publicly-available, longitudinal nationally-representative study of middle-aged and older adults in the United States. We assessed the change in chronic disease burden among 8,872 non-Hispanic black, non-Hispanic white, and Hispanic participants who were 51-55 years of age at their first interview any time during the study period (1998-2014) and all subsequent follow-up observations until 2014. Multimorbidity was defined as having two or more of seven somatic chronic diseases: arthritis, cancer, heart disease (myocardial infarction, coronary heart disease, angina, congestive heart failure, or other heart problems), diabetes, hypertension, lung disease, and stroke. We used negative binomial generalized estimating equation models to assess the trajectories of multimorbidity burden over time for non-Hispanic black, non-Hispanic white, and Hispanic participants. In covariate-adjusted models non-Hispanic black respondents had initial chronic disease counts that were 28% higher than non-Hispanic white respondents (IRR 1.279, 95% CI 1.201, 1.361), while Hispanic respondents had initial chronic disease counts that were 15% lower than non-Hispanic white respondents (IRR 0.852, 95% CI 0.775, 0.938). Non-Hispanic black respondents had rates of chronic disease accumulation that were 1.1% slower than non-Hispanic whites (IRR 0.989, 95% CI 0.981, 0.998) and Hispanic respondents had rates of chronic disease accumulation that were 1.5% faster than non-Hispanic white respondents (IRR 1.015, 95% CI 1.002, 1.028). Using marginal effects commands, this translates to predicted values of chronic disease for white respondents who begin the study period with 0.98 chronic diseases and end with 2.8 chronic diseases; black respondents who begin the study period with 1.3 chronic diseases and end with 3.3 chronic diseases; and Hispanic respondents who begin the study period with 0.84 chronic diseases and end with 2.7 chronic diseases. CONCLUSIONS: Middle-aged non-Hispanic black adults start at a higher level of chronic disease burden and develop multimorbidity at an earlier age, on average, than their non-Hispanic white counterparts. Hispanics, on the other hand, accumulate chronic disease at a faster rate relative to non-Hispanic white adults. Our findings have important implications for improving primary and secondary chronic disease prevention efforts among non-Hispanic black and Hispanic Americans to stave off greater multimorbidity-related health impacts.