Compression of disability between two birth cohorts of US adults with diabetes, 1992-2012: a prospective longitudinal analysis

Disability and morbidity among US birth cohorts, 1998-2018: A multidimensional test of dynamic equilibrium theory

A substantial body of prior research has explored patterns of disability-free and morbidity-free life expectancy among older populations. However, these distinct facets of later-life health are almost always studied in isolation, even though they are very likely to be related. Using data from the US Health and Retirement Study and a multistate life table approach, this paper explores the interactions between disability, morbidity, and mortality by sex and education among four successive US birth cohorts, born from 1914 to 1923 to 1944-1953 and compared in the periods 1998-2008 and 2008-2018. We find little compression of disability but a marked expansion of morbidity across cohorts. However, disability-free life expectancy (DFLE) among those living with chronic morbidities has increased, even though at the population-level DFLE is largely unchanged. Broadly, these patterns suggest that successive cohorts of older populations in the US are experiencing a dynamic equilibrium, where the link between chronic morbidities and disability has weakened over successive cohorts. Investigating patterns by educational attainment, we find marked disparities where the least educated individuals not only live significantly fewer years free of disabilities or chronic morbidities but also have experienced an expansion in morbidity and disability. Our findings suggest that the future trajectory of disability-free life expectancy in the US is increasingly contingent on efforts to improve disease management and control the severe consequences of chronic morbidities.

EFFECTS OF ALPHA-LIPOIC ACID ON GLYCEMIC STATUS IN 2 TYPE DIABETES PATIENTS WITH СHRONIC CORONARY SYNDROME

OBJECTIVE

The aim: To study the possibilities of alpha-lipoic acid (ALA) to control the parameters of carbohydrate metabolism.

PATIENTS AND METHODS

Materials and methods: We examined 80 people with type 2 DM and coronary heart disease who suffered non-Q-myocardial infarction (non-Q-MI). All patients at the time of inclusion in the study received oral hypoglycemic agents, ACE inhibitor, β-blocker, statin and antiplatelet agent. 600 mg of ALA per day for 4 months was added to this treatment. After checking the patients for compliance with the criteria, they were divided into the main and experimental groups. The dosage of alpha-lipoic acid was determined for each of the groups. The results of the treatment were analyzed by determining the mean and standard deviations.

RESULTS

Results: At the end of the observation period, a significant decrease in the level of fasting glucose (FG) by 11.6% was found, which corresponded to the average size of the clinical effect. The values of glycosylated hemoglobin (HbA1c) and the insulin resistance index HOMA (HOMA-IR) showed only a tendency to decrease on the background of treatment. The effect of ALA on postprandial glycemia (PPG) and insulin levels was not detected in this study.

CONCLUSION

Conclusions: An additional 4-month dose of ALA in addition to baseline therapy showed a moderate effect on the decrease in FG concentration in the absence of significant dynamics in other parameters of glycemic control in the examined patients.

Expansion, Compression, Neither, Both? Divergent Patterns in Healthy, Disability-Free, and Morbidity-Free Life Expectancy Across U.S. Birth Cohorts, 1998-2016

This article explores how patterns of health, morbidity, and disability have changed across successive generations of older adults in the United States. Using a novel method for comparing state-specific partial life expectancies-that is, total life expectancy (LE), and health expectancies (HEs) in different health states, bounded between two ages-I explore changes in healthy life expectancy across successive birth cohorts of the U.S. population. Results show that little compression of disability is occurring across cohorts, LE with chronic morbidities has expanded considerably, and self-rated health is improving across cohorts, but only at ages 70+. These findings suggest that successive cohorts in the U.S. population may be on divergent paths in terms of late-life health and well-being. Exploring heterogeneity in these patterns, I find that less educated individuals have substantially lower partial LE and disability-free LE than those with more schooling, and that disability-free life is declining among those with less than a high school diploma. Differences in HEs are pervasive across racial and ethnic groups, and both disabled LE and unhealthy LE are expanding in some disadvantaged subgroups. The continued increases in partial LE with morbidities across successive cohorts, and the broad stagnation of disability-free and healthy LE, present a broad view of a U.S. population in which successive generations are not living healthier lives.

Heart Involvement in Diabetes mellitus Patients

Diabetes mellitus (DM) is one of the most significant medical and social health problems worldwide. The main cause of death in patients with DM is cardiovascular diseases, which leads to the significant decrease in quality of life and life expectancy. The aim of this literature review is analyze of the frequency, mechanisms and manifestations of heart disease in diabetes patients. A significant amount of the modern researches is devoted to the diagnosis and treatment of the diabetes complications, including diabetic cardiomyopathy (DC). According to many authors, heart disease in diabetes is associated with the formation of DC, comorbid coronary heart disease and arterial hypertension. DC occurs in 16.8–54% of patients with diabetes and is an independent factor which increases the death risk by 50–60%. Numerous scientific studies have been devoted to the diagnosis and treatment of DC, emphasizing that in order to reduce cardiovascular disease and mortality in patients with diabetes, it is necessary, above all, to achieve glycemic control. Diabetic history, age, comorbidities, atherosclerotic lesions, smoking, overweight or obesity also play an important role. The main aspects of the development and impact of diabetes on the health and life of patients are the untimely diagnosis of this disease, its multifactorial pathogenesis, progressive course and severity of complications. Due to development of the early complications and disability, studies of morphofunctional changes in the myocardium in diabetes are extremely relevant, as cardiomyopathy may increase the risk of myocardial infarction and heart failure. The rapid increase in the number of patients with diabetes, many of whom die from cardiovascular complications, makes the problem of diabetic heart disease one of the most pressing health problems. Treatment of these patients should include correction of carbohydrate metabolism, control of blood lipid composition, decrease in myocardial ischemia, correction of the myocardial metabolism and the risk of heart failure.

A comparison over 2 decades of disability-free life expectancy at age 65 years for those with long-term conditions in England: Analysis of the 2 longitudinal Cognitive Function and Ageing Studies

BACKGROUND

Previous research has examined the improvements in healthy years if different health conditions are eliminated, but often with cross-sectional data, or for a limited number of conditions. We used longitudinal data to estimate disability-free life expectancy (DFLE) trends for older people with a broad number of health conditions, identify the conditions that would result in the greatest improvement in DFLE, and describe the contribution of the underlying transitions.

METHODS AND FINDINGS

The Cognitive Function and Ageing Studies (CFAS I and II) are both large population-based studies of those aged 65 years or over in England with identical sampling strategies (CFAS I response 81.7%, N = 7,635; CFAS II response 54.7%, N = 7,762). CFAS I baseline interviews were conducted in 1991 to 1993 and CFAS II baseline interviews in 2008 to 2011, both with 2 years of follow-up. Disability was measured using the modified Townsend activities of daily living scale. Long-term conditions (LTCs-arthritis, cognitive impairment, coronary heart disease (CHD), diabetes, hearing difficulties, peripheral vascular disease (PVD), respiratory difficulties, stroke, and vision impairment) were self-reported. Multistate models estimated life expectancy (LE) and DFLE, stratified by sex and study and adjusted for age. DFLE was estimated from the transitions between disability-free and disability states at the baseline and 2-year follow-up interviews, and LE was estimated from mortality transitions up to 4.5 years after baseline. In CFAS I, 60.8% were women and average age was 75.6 years; in CFAS II, 56.1% were women and average age was 76.4 years. Cognitive impairment was the only LTC whose prevalence decreased over time (odds ratio: 0.6, 95% confidence interval (CI): 0.5 to 0.6, p < 0.001), and where the percentage of remaining years at age 65 years spent disability-free decreased for men (difference CFAS II-CFAS I: -3.6%, 95% CI: -8.2 to 1.0, p = 0.12) and women (difference CFAS II-CFAS I: -3.9%, 95% CI: -7.6 to 0.0, p = 0.04) with the LTC. For men and women with any other LTC, DFLE improved or remained similar. For women with CHD, years with disability decreased (-0.8 years, 95% CI: -3.1 to 1.6, p = 0.50) and DFLE increased (2.7 years, 95% CI: 0.7 to 4.7, p = 0.008), stemming from a reduction in the risk of incident disability (relative risk ratio: 0.6, 95% CI: 0.4 to 0.8, p = 0.004). The main limitations of the study were the self-report of health conditions and the response rate. However, inverse probability weights for baseline nonresponse and longitudinal attrition were used to ensure population representativeness.

CONCLUSIONS

In this study, we observed improvements to DFLE between 1991 and 2011 despite the presence of most health conditions we considered. Attention needs to be paid to support and care for people with cognitive impairment who had different outcomes to those with physical health conditions.

Changes in Life Expectancy and Disability-Free Life Expectancy in Successive Birth Cohorts of Older Cancer Survivors: A Longitudinal Modeling Analysis of the US Health and Retirement Study

The population of older cancer survivors in the United States is rapidly growing. However, little is currently known about how the health of older cancer survivors has changed over time and across successive birth cohorts. Using data from the US Health and Retirement Study, we parameterized a demographic microsimulation model to compare partial cohort life expectancy (LE) and disability-free LE for US men and women without cancer and with prevalent and incident cancer diagnoses for 4 successive 10-year birth cohorts, born 1918–1927 to 1948–1957. Disability was defined as being disabled in ≥1 activity of daily living. These cohorts had midpoint ages of 55–64, 65–74, and 75–84 years during the periods 1998–2008 (the “early” period) and 2008–2018 (the “later” period). Across all cohorts and periods, those with incident cancer had the lowest LE, followed by those with prevalent cancer and cancer-free individuals. We observed declines in partial LE and an expansion of life spent disabled among more recent birth cohorts of prevalent-cancer survivors. Our findings suggest that advances in treatments that prolong life for individual cancer patients may have led to population-level declines in conditional LE and disability-free LE across successive cohorts of older cancer survivors.

The impact of long-term conditions on disability-free life expectancy: A systematic review

Although leading causes of death are regularly reported, there is disagreement on which long-term conditions (LTCs) reduce disability-free life expectancy (DFLE) the most. We aimed to estimate increases in DFLE associated with elimination of a range of LTCs. This is a comprehensive systematic review and meta-analysis of studies assessing the effects of LTCs on health expectancy (HE). MEDLINE, Embase, HMIC, Science Citation Index, and Social Science Citation Index were systematically searched for studies published in English from July 2007 to July 2020 with updated searches from inception to April 8, 2021. LTCs considered included: arthritis, diabetes, cardiovascular disease including stroke and peripheral vascular disease, respiratory disease, visual and hearing impairment, dementia, cognitive impairment, depression, cancer, and comorbidity. Studies were included if they estimated HE outcomes (disability-free, active or healthy life expectancy) at age 50 or older for individuals with and without the LTC. Study selection and quality assessment were undertaken by teams of independent reviewers. Meta-analysis was feasible if three or more studies assessed the impact of the same LTC on the same HE at the same age using comparable methods, with narrative syntheses for the remaining studies. Studies reporting Years of Life Lost (YLL), Years of Life with Disability (YLD) and Disability Adjusted Life Years (DALYs = YLL+YLD) were included but reported separately as incomparable with other HE outcomes (PROSPERO registration: CRD42020196049). Searches returned 6072 unique records, yielding 404 eligible for full text retrieval from which 30 DFLE-related and 7 DALY-related were eligible for inclusion. Thirteen studies reported a single condition, and 17 studies reported on more than one condition (two to nine LTCs). Only seven studies examined the impact of comorbidities. Random effects meta-analyses were feasible for a subgroup of studies examining diabetes (four studies) or respiratory diseases (three studies) on DFLE. From pooled results, individuals at age 65 without diabetes gain on average 2.28 years disability-free compared to those with diabetes (95% CI: 0.57-3.99, p<0.01, I2 = 96.7%), whilst individuals without respiratory diseases gain on average 1.47 years compared to those with respiratory diseases (95% CI: 0.77-2.17, p<0.01, I2 = 79.8%). Eliminating diabetes, stroke, hypertension or arthritis would result in compression of disability. Of the seven longitudinal studies assessing the impact of multiple LTCs, three found that stroke had the greatest effect on DFLE for both genders. This study is the first to systematically quantify the impact of LTCs on both HE and LE at a global level, to assess potential compression of disability. Diabetes, stroke, hypertension and arthritis had a greater effect on DFLE than LE and so elimination would result in compression of disability. Guidelines for reporting HE outcomes would assist data synthesis in the future, which would in turn aid public health policy.

Are Disability Rates among People with Diabetes Increasing in Germany? A Decomposition Analysis of Temporal Change between 2004 and 2015

Objectives: We investigated changes in the prevalence of disabilities among individuals with type 2 diabetes and analyzed the contribution of comorbidities on this change. Methods: Data were drawn from the Survey of Health, Ageing, and Retirement in Europe (SHARE). We estimated predicted probabilities of impaired (instrumental) activities of daily living (IADL and ADL) by means of logistic regression. Multivariate decomposition was employed for analyzing the impact of comorbidities on changes in disability rates. Results: Among people with diabetes, ADL difficulties rose significantly from 11.3% (2004) to 19.1% (2015), while IADL difficulties increased among younger diabetics from 11.5% to 18.3%. Decomposition analysis revealed that the parallel increase in comorbidities contributed to the rise in disabilities. Discussion: We found disability rates among people with diabetes in Germany to be increasing over time, pointing toward a growing demand of tertiary prevention for these individuals to maintain functional health and quality of life.

Expansion of disability across successive Mexican birth cohorts: a longitudinal modelling analysis of birth cohorts born 10 years apart

BACKGROUND

Life expectancy (LE) in Mexico has risen rapidly since the 1950s. In high-income contexts, these increases have coincided with a compression of disability to later ages. However, little evidence on trends in disability-free LE (DFLE) exist from Mexico or elsewhere in Latin America.

METHODS

Using data from the Mexican Health and Aging Study, we compare changes in LE and DFLE in ages 50-59, 60-69 and 70-79 using birth-cohort-specific multistate lifetable models across successive 10-year birth cohorts. Disability was measured using the Katz activities of daily living (ADL) index, and limitation was measured using a seven-item questionnaire on physical functioning.

RESULTS

Overall, Mexican adults born in 1953-1962 lived 0.87 (p<0.001) fewer active years between ages 50 and 59 than individuals born in 1942-1951, a difference comprised of a 0.54-year (p<0.001) increase in physically limited LE and a 0.27-year (p<0.001) increase in ADL-disabled LE. Active LE declined by 1.13 (p<0.001) years in ages 60-69, and by 0.93 (p<0.001) years in ages 70-79, across successive 10-year birth cohorts. No substantial changes in total LE were seen in any age group, and the magnitude of the expansion of disability was larger in females than in males.

CONCLUSIONS

Our results indicate that more recently born cohorts of Mexican adults are spending more years of life with physical limitations and disabilities. These results foreshadow a need to closely monitor adult health in middle-income contexts, as the epidemiological conditions under which disability has expanded in Mexico are similar to those seen in many other countries.

Are China's oldest-old living longer with less disability? A longitudinal modeling analysis of birth cohorts born 10 years apart

BACKGROUND

China has transitioned from being one of the fastest-growing populations to among the most rapidly aging countries worldwide. In particular, the population of oldest-old individuals, those aged 80+, is projected to quadruple by 2050. The oldest-old represent a uniquely important group-they have high demand for personal assistance and the highest healthcare costs of any age group. Understanding trends in disability and longevity among the oldest-old-that is, whether successive generations are living longer and with less disability-is of great importance for policy and planning purposes.

METHODS

We utilized data from successive birth cohorts (n = 20,520) of the Chinese oldest-old born 10 years apart (the earlier cohort was interviewed in 1998 and the later cohort in 2008). Disability was defined as needing personal assistance in performing one or more of five essential activities (bathing, transferring, dressing, eating, and toileting) or being incontinent. Participants were followed for age-specific disability transitions and mortality (in 2000 and 2002 for the earlier cohort and 2011 and 2014 for the later cohort), which were then used to generate microsimulation-based multistate life tables to estimate partial life expectancy (LE) and disability-free LE (DFLE), stratified by sex and age groups (octogenarians, nonagenarians, and centenarians). We additionally explored sociodemographic heterogeneity in LE and DFLE by urban/rural residence and educational attainment.

RESULTS

More recently born Chinese octogenarians (born 1919-1928) had a longer partial LE between ages 80 and 89 than octogenarians born 1909-1918, and octogenarian women experienced an increase in partial DFLE of 0.32 years (P = 0.004) across the two birth cohorts. Although no increases in partial LE were observed among nonagenarians or centenarians, partial DFLE increased across birth cohorts, with a gain of 0.41 years (P < 0.001) among nonagenarians and 0.07 years (P = 0.050) among centenarians. Subgroup analyses revealed that gains in partial LE and DFLE primarily occurred among the urban resident population.

CONCLUSIONS

Successive generations of China's oldest-old are living with less disability as a whole, and LE is expanding among octogenarians. However, we found a widening urban-rural disparity in longevity and disability, highlighting the need to improve policies to alleviate health inequality throughout the population.

Compartmental Model Diagrams as Causal Representations in Relation to DAGs

Compartmental model diagrams have been used for nearly a century to depict causal relationships in infectious disease epidemiology. Causal directed acyclic graphs (DAGs) have been used more broadly in epidemiology since the 1990s to guide analyses of a variety of public health problems. Using an example from chronic disease epidemiology, the effect of type 2 diabetes on dementia incidence, we illustrate how compartmental model diagrams can represent the same concepts as causal DAGs, including causation, mediation, confounding, and collider bias. We show how to use compartmental model diagrams to explicitly depict interaction and feedback cycles. While DAGs imply a set of conditional independencies, they do not define conditional distributions parametrically. Compartmental model diagrams parametrically (or semiparametrically) describe state changes based on known biological processes or mechanisms. Compartmental model diagrams are part of a long-term tradition of causal thinking in epidemiology and can parametrically express the same concepts as DAGs, as well as explicitly depict feedback cycles and interactions. As causal inference efforts in epidemiology increasingly draw on simulations and quantitative sensitivity analyses, compartmental model diagrams may be of use to a wider audience. Recognizing simple links between these two common approaches to representing causal processes may facilitate communication between researchers from different traditions.

Low Normalized Grip Strength is a Biomarker for Cardiometabolic Disease and Physical Disabilities Among U.S. and Chinese Adults

BACKGROUND

Evidence highlights the importance of muscular strength as a protective factor for health and function across aging populations. The purpose of this study was to examine the extent to which low normalized grip strength (NGS) serves as a biomarker for both cardiometabolic disease and physical disability in U.S. and Chinese adults.

METHODS

Middle aged and older adults from the U.S. National Health and Nutrition Examination Survey 2011-2012 and 2013-2014 combined surveys (n = 4,544), and the 2011 wave of the China Health and Retirement Longitudinal Study (n = 6,030) were included. Strength was assessed using a handgrip dynamometer, and was normalized to body mass. Weighted logistic regression models were used to assess the association between NGS and diabetes, hyperglycemia, hypertriglyceridemia, low HDL-cholesterol, hypertension, and physical disability status, while controlling for age, sex, and sociodemographic characteristics.

RESULTS

Every 0.05 lower NGS was independently associated with a 1.49 (95% confidence interval [CI]: 1.42-1.56) and 1.17 (95% CI: 1.11-1.23) odds for diabetes; a 1.46 (95% CI: 1.39-1.53) and 1.11 (95% CI: 1.07-1.15) odds of hyperglycemia; a 1.15 (95% CI: 1.07-1.25) and 1.11 (95% CI: 1.08-1.14) odds of hypertriglyceridemia; a 1.22 (95% CI: 1.17-1.27) and 1.15 (95% CI: 1.12-1.18) odds of low HDL-cholesterol; a 1.19 (95% CI: 1.14-1.24) and 1.10 (95% CI: 1.07-1.14) odds of hypertension; and a 1.36 (95% CI: 1.29-1.42) and 1.10 (95% CI: 1.05-1.15) odds for physical disability status in U.S. and Chinese adults, respectively.

CONCLUSIONS

NGS was robustly associated with both cardiometabolic disease risk and physical disabilities in U.S. and Chinese aging adults.

Global, regional, and national disability-adjusted life-years (DALYs) for 315 diseases and injuries and healthy life expectancy (HALE), 1990-2015: a systematic analysis for the Global Burden of Disease Study 2015

BACKGROUND

Healthy life expectancy (HALE) and disability-adjusted life-years (DALYs) provide summary measures of health across geographies and time that can inform assessments of epidemiological patterns and health system performance, help to prioritise investments in research and development, and monitor progress toward the Sustainable Development Goals (SDGs). We aimed to provide updated HALE and DALYs for geographies worldwide and evaluate how disease burden changes with development.

METHODS

We used results from the Global Burden of Diseases, Injuries, and Risk Factors Study 2015 (GBD 2015) for all-cause mortality, cause-specific mortality, and non-fatal disease burden to derive HALE and DALYs by sex for 195 countries and territories from 1990 to 2015. We calculated DALYs by summing years of life lost (YLLs) and years of life lived with disability (YLDs) for each geography, age group, sex, and year. We estimated HALE using the Sullivan method, which draws from age-specific death rates and YLDs per capita. We then assessed how observed levels of DALYs and HALE differed from expected trends calculated with the Socio-demographic Index (SDI), a composite indicator constructed from measures of income per capita, average years of schooling, and total fertility rate.

FINDINGS

Total global DALYs remained largely unchanged from 1990 to 2015, with decreases in communicable, neonatal, maternal, and nutritional (Group 1) disease DALYs offset by increased DALYs due to non-communicable diseases (NCDs). Much of this epidemiological transition was caused by changes in population growth and ageing, but it was accelerated by widespread improvements in SDI that also correlated strongly with the increasing importance of NCDs. Both total DALYs and age-standardised DALY rates due to most Group 1 causes significantly decreased by 2015, and although total burden climbed for the majority of NCDs, age-standardised DALY rates due to NCDs declined. Nonetheless, age-standardised DALY rates due to several high-burden NCDs (including osteoarthritis, drug use disorders, depression, diabetes, congenital birth defects, and skin, oral, and sense organ diseases) either increased or remained unchanged, leading to increases in their relative ranking in many geographies. From 2005 to 2015, HALE at birth increased by an average of 2·9 years (95% uncertainty interval 2·9-3·0) for men and 3·5 years (3·4-3·7) for women, while HALE at age 65 years improved by 0·85 years (0·78-0·92) and 1·2 years (1·1-1·3), respectively. Rising SDI was associated with consistently higher HALE and a somewhat smaller proportion of life spent with functional health loss; however, rising SDI was related to increases in total disability. Many countries and territories in central America and eastern sub-Saharan Africa had increasingly lower rates of disease burden than expected given their SDI. At the same time, a subset of geographies recorded a growing gap between observed and expected levels of DALYs, a trend driven mainly by rising burden due to war, interpersonal violence, and various NCDs.

INTERPRETATION

Health is improving globally, but this means more populations are spending more time with functional health loss, an absolute expansion of morbidity. The proportion of life spent in ill health decreases somewhat with increasing SDI, a relative compression of morbidity, which supports continued efforts to elevate personal income, improve education, and limit fertility. Our analysis of DALYs and HALE and their relationship to SDI represents a robust framework on which to benchmark geography-specific health performance and SDG progress. Country-specific drivers of disease burden, particularly for causes with higher-than-expected DALYs, should inform financial and research investments, prevention efforts, health policies, and health system improvement initiatives for all countries along the development continuum.

FUNDING

Bill & Melinda Gates Foundation.