An overview of the design, implementation, and analyses of longitudinal studies on aging

Impact of the National Essential Public Health Service Package on Blood Pressure Control in Chinese People With Hypertension: Retrospective Population-Based Longitudinal Study

Background

The National Essential Public Health Service Package (NEPHSP) was launched in 2009 to tackle poor blood pressure control in Chinese people with hypertension; however, it's effect is still unclear.

Objective

In a retrospective population-based longitudinal study, we aimed to evaluate effect of the NEPHSP on blood pressure control.

Methods

A total of 516,777 patients registered in the NEPHSP were included. The blood pressure control data were assessed based on the Residence Health Record System dataset. We longitudinally evaluated the effects of the NEPHSP on blood pressure control by analyzing changes in blood pressure at quarterly follow-ups. Both the degree and trend of the blood pressure changes were analyzed. We conducted stratified analysis to explore effects of the NEPHSP on blood pressure control among subgroups of participants with specific characteristics.

Results

The mean baseline systolic blood pressure (SBP) and diastolic blood pressure (DBP) were 147.12 (SD 19.88) mm Hg and 85.11 (SD 11.79) mm Hg, respectively. The control rates of baseline SBP and DBP were 39.79% (205,630/516,777) and 69.21% (357,685/516,777). Compared to baseline, the mean SBP decreased in each quarter by 5.06 mm Hg (95% CI -5.11 to -5.00; P<.001), 6.69 mm Hg (95% CI; -6.74 to -6.63; P<.001), 10.30 mm Hg (95% CI -10.34 to -10.23; P<.001), and 6.63 mm Hg (95% CI -6.68 to -6.57; P<.001). The SBP control rates increased in each quarter to 53.12% (274,493/516,777; β coefficient=0.60, 95% CI 0.59-0.61; P<.001), 56.61% (292,537/516,777; β coefficient=0.76, 95% CI 0.75-0.77; P<.001), 63.4% (327,648/516,777; β coefficient=1.08, 95% CI 1.07-1.09; P<.001), and 55.09% (284,711/516,777; β coefficient=0.69, 95% CI 0.68-0.70; P<.001). Compared to baseline, the mean DBP decreased in each quarter by 1.75 mm Hg (95% CI -1.79 to -1.72; P<.001), 2.64 mm Hg (95% CI -2.68 to -2.61; P<.001), 4.20 mm Hg (95% CI -4.23 to -4.16; P<.001), and 2.64 mm Hg (95% CI -2.68 to -2.61; P<.001). DBP control rates increased in each quarter to 78.11% (403,641/516,777; β coefficient=0.52, 95% CI 0.51-0.53; P<.001), 80.32% (415,062/516,777; β coefficient=0.67, 95% CI 0.66-0.68; P<.001), 83.17% (429,829/516,777; β coefficient=0.89, 95% CI 0.88-0.90; P<.001), and 79.47% (410,662/516,777; β coefficient=0.61, 95% CI 0.60-0.62; P<.001). The older age group had a larger decrease in their mean SBP (β coefficient=0.87, 95% CI 0.85-0.90; P<.001) and a larger increase in SBP control rates (β coefficient=0.054, 95% CI 0.051-0.058; P<.001). The participants with cardiovascular disease (CVD) had a smaller decrease in their mean SBP (β coefficient=-0.38, 95% CI -0.41 to -0.35; P<.001) and smaller increase in SBP control rates (β coefficient=-0.041, 95% CI -0.045 to -0.037; P<.001) compared to the blood pressure of participants without CVD.

Conclusions

The NEPHSP was effective in improving blood pressure control of Chinese people with hypertension. Blood pressure control of older individuals and those with CVD need to be intensified.

Longitudinal Studies of Aging in Sub-Saharan Africa: Review, Limitations, and Recommendations in Preparation of Projected Aging Population

Background and Objectives

The United Nations has projected a 218% increase in older people in Sub-Saharan Africa (SSA) between 2019 and 2050, underscoring the need to explore changes that would occur over this time. Longitudinal studies are ideal for studying and proffering solutions to these changes. This review aims to understand the breadth and use of longitudinal studies on aging in the SSA regions, proffering recommendations in preparation for the projected aging population.

Research Design and Methods

This paper is the third of a four-part series paper of a previous systematic mapping review of aging studies in SSA. We updated the search (between 2021 and 2023) and screened the titles/abstracts and full-text articles by a pair of independent reviewers. Data were extracted using a standardized data-charting form, identifying longitudinal studies in SSA.

Results

We identified 193 studies leveraging 24 longitudinal study data sets conducted at 28 unique sites. The World Health Organization's Study on Global AGEing and Adult Health (WHO-SAGE) (n = 59, 30.5%) and Health and Aging in Africa: A Longitudinal Study of an INDEPTH Community in South Africa (HAALSI) (n = 51, 26.4%) were the most used longitudinal data sets. Four studies used more than one longitudinal study data set. Eighteen of the longitudinal study data sets were used only in 1-4 studies. Most (n = 150, 77.7%) of the studies used a cross-sectional analytical approach.

Discussion and Implications

Longitudinal studies on aging are sparingly being utilized in SSA. Most analyses conducted across the longitudinal data set were cross-sectional, which hindered the understanding of aging changes that occurred over time that could better inform aging policy and interventions. We call for funding bodies, such as WHO-SAGE, to develop funding competitions that focus on conducting longitudinal analyses, such as structural equation modeling, highlighting changes occurring among the aging population in SSA.

Leveraging Observational Cohorts to Study Diet and Nutrition in Older Adults: Opportunities and Obstacles

By 2060, the number of adults aged ≥65 y is expected to double, and the ≥85 y segment of the population is expected to triple in the United States. US federal nutrition guidance is based on the premise that healthy diets contribute to delaying the onset and progression of many age-related diseases and disability. Yet, little is known about the dietary intakes or nutritional needs across the older adulthood age span. This review aims to identify community-based cohorts that collected information on dietary intake of adults ≥65 y in the United States. Thirty-two cohorts met all inclusion criteria. We summarized information on the cohorts' design, demographics, and diet assessment. We also identified key gaps in the existing databases that, if filled, could enhance their utility to address certain research questions. This review serves as a valuable inventory of cohorts that can be leveraged to answer key questions about the diet and nutritional needs of the oldest old, who represent the fastest growing segment of the population in the United States.

How to Arrange Follow-Up Time-Intervals for Longitudinal Brain MRI Studies in Neurodegenerative Diseases

Background

Longitudinal brain MRI monitoring in neurodegeneration potentially provides substantial insights into the temporal dynamics of the underlying biological process, but is time- and cost-intensive and may be a burden to patients with disabling neurological diseases. Thus, the conceptualization of follow-up time-intervals in longitudinal MRI studies is an essential challenge and substantial for the results. The objective of this work is to discuss the association of time-intervals and the results of longitudinal trends in the frequently used design of one baseline and two follow-up scans.

Methods

Different analytical approaches for calculating the linear trend of longitudinal parameters were studied in simulations including their performance of dealing with outliers; these simulations were based on the longitudinal striatum atrophy in MRI data of Huntington’s disease patients, detected by atlas-based volumetry (ABV).

Results

For the design of one baseline and two follow-up visits, the simulations with outliers revealed optimum results for identical time-intervals between baseline and follow-up scans. However, identical time-intervals between the three acquisitions lead to the paradox that, depending on the fit method, the first follow-up scan results do not influence the final results of a linear trend analysis.

Conclusions

This theoretical study analyses how the design of longitudinal imaging studies with one baseline and two follow-up visits influences the results. Suggestions for the analysis of longitudinal trends are provided.

Time-Use and Mental Health in Older Adults: A Scoping Review

Time-use of older adults can be different than in earlier life, especially during the transition from pre- to post-retirement or after experiencing major life events, and the changes could affect their mental health. However, the extent and nature of such research in gerontology have not been examined to date. Therefore, this scoping review sought to map the literature on time-use and mental health in the older population to examine the extent and nature of those research activities. A scoping review was conducted using four databases-PubMed, Scopus, CINAHL, and EMBASE according to PRISMA guidelines. Data were extracted using a pretested tool to develop a descriptive analysis and thematic summary. A total of 11 articles met the eligibility criteria. Seven out of 11 studies involved cross-sectional design, while the remainder were longitudinal studies. The longitudinal studies mainly were secondary data analysis. Time-use data were mainly collected using daily diaries, and the most common mental health outcome included was depression. Only two studies did not evaluate the direct relationship between time-use and mental health. Our review has revealed studies evaluating time-use and mental health in older adults. Limitations of review and recommendations for future studies are discussed.

Ethical guidance for geriatric clinical research in China

In China, the population is aging rapidly, and the elderly have enormous medical needs. However, the elderly are underrepresented in clinical research, potentially forcing them to use medical devices and treatments that may be not suitable for them. Elderly patients are characterized by multiple comorbidities, concomitant treatments, and high incidence of cognitive impairment, and consequently are at increased risk of participating in clinical research. To reduce the risks involved with the elderly participating in clinical research, guidance on the ethical review of geriatric research is necessary. Based on a literature review and panel discussion, we have developed the Ethical Guidance for Geriatric Clinical Research, aiming to provide guidance on the ethical review of geriatric clinical research.

Development of the default-mode network during childhood and adolescence: A longitudinal resting-state fMRI study

The default-mode network (DMN) is a set of functionally connected regions that play crucial roles in internal cognitive processing. Previous resting-state fMRI studies have demonstrated that the intrinsic functional organization of the DMN undergoes remarkable reconfigurations during childhood and adolescence. However, these studies have mainly focused on cross-sectional designs with small sample sizes, limiting the consistency and interpretations of the findings. Here, we used a large sample of longitudinal resting-state fMRI data comprising 305 typically developing children (6-12 years of age at baseline, 491 scans in total) and graph theoretical approaches to delineate the developmental trajectories of the functional architecture of the DMN. For each child, the DMN was constructed according to a prior parcellation with 32 brain nodes. We showed that the overall connectivity increased in strength from childhood to adolescence and became spatially similar to that in the young adult group (N = 61, 18-28 years of age). These increases were primarily located in the midline structures. Global and local network efficiency in the DMN also increased with age, indicating an enhanced capability in parallel information communication within the brain system. Based on the divergent developmental rates of nodal centrality, we identified three subclusters within the DMN, with the fastest rates in the cluster mainly comprising the anterior medial prefrontal cortex and posterior cingulate cortex. Together, our findings highlight the developmental patterns of the functional architecture in the DMN from childhood to adolescence, which has implications for the understanding of network mechanisms underlying the cognitive development of individuals.

Methodological considerations in designing and implementing the harmonized diagnostic assessment of dementia for longitudinal aging study in India (LASI-DAD)

The Harmonized Diagnostic Assessment of Dementia for Longitudinal Aging Study in India (LASI-DAD) is a population-representative, prospective cohort study of late-life cognition and dementia. It is part of an ongoing international research collaboration that aims to measure and understand cognitive impairment and dementia risk by collecting a set of cognitive and neuropsychological assessments and informant reports, referred to as the Harmonized Cognitive Assessment Protocol (HCAP). LASI-DAD provides nationally representative data drawn from a subsample of the ongoing Longitudinal Aging Study in India (LASI). One of LASI-DAD's distinctive features is its rich geriatric assessment, including the collection of venous blood samples and brain imaging data for a subsample of respondents. In this paper, we discuss the methodological considerations of developing and implementing the HCAP protocol in India. The lessons we learned from translating and applying the HCAP protocol in an environment where illiteracy and innumeracy are high will provide important insights to researchers interested in measuring and collecting data on late-life cognition and dementia in developing countries. We further developed an innovative blood management system that enables us to follow the collection, transportation, assay, and storage of samples. Such innovation can benefit other population surveys collecting biomarker data.

On the horizon of aging and physical activity research

This viewpoint is the result of a Horizon Round Table discussion of Exercise and Aging held during the 2017 Saltin International Graduate School in Exercise and Clinical Physiology in Gatineau, Quebec. This expert panel discussed key issues and approaches to future research into aging, across human physiological systems, current societal concerns, and funding approaches. Over the 60-min round table discussion, 3 major themes emerged that the panel considered to be "On the Horizon" of aging research. These themes include (i) aging is a process that extends from womb to tomb; (ii) the importance of longitudinal experimental studies; and (iii) the ongoing need to investigate multiple systems using an integrative approach between scientists, clinicians, and knowledge brokers. With a focus on these themes, we aim to identify critical questions, challenges, and opportunities that face scientists in advancing the understanding of exercise and aging.

Trajectories of allostatic load among older Americans and Britons: longitudinal cohort studies

BACKGROUND

Difference in life expectancy between males and females has been suggested to rest on sex difference in physiological dysregulation. But allostatic load, a physiological index, has not been carefully examined for an extended period beyond middle age. We aim to draw longitudinal trajectories of allostatic load in a national sample of older Americans and Britons; also to examine sex-based trajectories and factors behind their differences.

METHODS

We studied men and women aged ≥50 years participating in the Health and Retirement Study Waves 8-11, 2006-2012 (N = 15,583 person-years) and the English Longitudinal Study of Ageing Waves 2, 4 and 6, 2004-2012 (N = 14,765 person-years). Because of the difference in provenance, we included different number of biomarkers to calculate allostatic load in HRS and ELSA. In HRS we used 8 biomarkers (systolic and diastolic blood pressure, haemoglobin A1c, high-density lipoprotein, total cholesterol, waist circumference, cystatin C, and C-reactive protein), while ELSA allostatic load was constructed from 10 biomarkers (systolic and diastolic blood pressure, haemoglobin A1c, high-density lipoprotein, total cholesterol, waist circumference, BMI, triglyceride, fibrinogen and C-reactive protein). A growth curve model was fitted to repeated observations of allostatic load, demographic characteristics, socioeconomic position, comorbidities and health behaviours (smoking, drinking, and physical exercise). To account for attrition, a joint model was applied.

RESULTS

The analysis showed that allostatic load increases linearly with age in the U.S. However, there are different levels for males and females. In England allostatic load follows such different paths that their trajectories cross in later life.

CONCLUSIONS

Sex-based trajectories of allostatic load showed distinct female advantage and are mostly consistent with female advantage in life expectancy.

[Effectiveness of "Active health promotion in old age" : Results regarding compression of morbidity by target groups in 13.8 years of observation in LUCAS]

BACKGROUND AND OBJECTIVE

Healthy ageing as defined by the World Health Organization (WHO) is the development and maintenance of functional competence. Unfavourable ageing is described by the term frailty and is characterised by a decline in functional reserves. The frailty process can be influenced in a positive way. Previous interventions concerned mostly hospital patients and residents of nursing homes. In this study we examined the maintenance of functional competence in an urban community setting.

MATERIAL AND METHODS

The programme "Active health promotion in old age" was carried out by a health advisory team with geriatric expertise for independent persons 60 years and older without disabilities. Its effectiveness was evaluated in the Longitudinal Urban Cohort Ageing Study (LUCAS) over a period of 13.8 years. Survival and disability-free survival were calculated separately for persons with a high level of functional competence (many reserves) and persons with few functional reserves, using Kaplan-Meier curves. Adjustments were made for unequal distribution of age, gender, educational level, chronic diseases and functional status using multivariate Cox regressions. This methodology facilitates the study of interrelationships between mortality and morbidity (compression of morbidity) including an impact from life style interventions.

RESULTS

Participants with a high level of functional competence had longer disability-free lifes (p < 0.001), and their average proportion of life time with disability was shorter than either for non-participants, or those with low functional competence.

CONCLUSION

There is evidence from these analyses on compression of morbidity that the health promotion programme had its strongest effects in persons with high functional competence, exactly those people for whom it has been developed.

Description and cohort characterization of the Longevity Study: learning from our elders

The purpose of this article is to describe the Longevity Study: Learning From Our Elders, a research program on healthy aging that began in 2007 at the Center for Healthy Aging at Banner Sun Health Research Institute. As of June 2015, 1139 participants (age range of 50-110 years) completed baseline assessments with the majority living in the Sun Cities retirement communities northwest of Phoenix, Arizona but expanding throughout the state. The registry includes over 830 currently active participants with 450 aged 80 years and older, 188 aged 90 and older, and 27 centenarians. Data from in-person interviews at the Center for Healthy Aging in Sun City or in the participants' residences which includes sociodemographic, medical, cognitive, physical and psychosocial variables have been collected since the study's inception. This paper outlines some of the key demographic and clinical characteristics of the Longevity Study, its progress, and future directions. It also reflects on how exceptional aging individuals function psychosocially, cognitively and physically, particularly among individuals aged 85 and older.

Factors influencing health-related quality of life after primary percutaneous coronary intervention for ST-elevation myocardial infarction

AIMS

This study compared health-related quality of life (HRQOL) between patients aged ≥ 70 and <70 years at 4 weeks and 6 months after primary percutaneous coronary intervention (PPCI) and examined predictors of HRQOL.

BACKGROUND

HRQOL is an important patient outcome following PPCI for ST elevation myocardial infarction (STEMI) including pre-hospital field triage.

METHODS

A comparative cohort design was conducted on STEMI patients undergoing PPCI. HRQOL was measured using the Medical Outcomes Short Form-12 (SF-12) and the Seattle Angina Questionnaire (SAQ) at 4 weeks and 6 months post-PPCI.

RESULTS

HRQOL improved significantly from 4 weeks to 6 months in all aspects measured except anginal frequency and mental health. Patients aged ≥ 70 years had poorer physical HRQOL (SF-12) and physical limitations (SAQ), but better mental HRQOL (SF-12), angina frequency and QOL (SAQ) at both time points. Age, length of hospital stay, gender, partnership status and number of stents deployed are independent predictors of HRQOL improvement over time.

CONCLUSION

People ≥ 70 years reported better cardiac-specific quality of life, primarily from angina relief and improved mental function, despite worse physical limitations. HRQOL assessment is an important gauge of health status after PPCI for STEMI.

Case-crossover studies of therapeutics: design approaches to addressing time-varying prognosis in elderly populations

BACKGROUND

Self-controlled analysis methods implicitly adjust for time-invariant confounding within individuals. A person's prognosis often varies over time and affects both therapy choice and subsequent health outcomes. Current approaches may not be able to fully address this within-person confounding. We evaluated the potential impact of time-varying prognosis in self-controlled studies of treatment effects and the extent to which alternative adjustment strategies could mitigate these biases.

METHODS

We used Medicare data linked to prescription drug data from a pharmaceutical assistance program to conduct case-crossover studies of the relationship between intermittent use of five classes of preventive medications (statins, oral hypoglycemics, antihypertensives, osteoporosis, and glaucoma medications) and death-relationships that are strongly biased because of healthy-user and sick-stopper effects. We used the case-case time-control design to adjust for confounding from exposure trends related to prognosis. Each class of medications was evaluated separately, with the remaining four used as reference drugs to estimate prognosis-related exposure trends.

RESULTS

The case-crossover odds ratios were 0.39, 0.38, 0.40, 0.39, and 0.45 for statin, antihypertensive, glaucoma, hypoglycemic, and osteoporosis drugs, respectively. After adjusting for the estimated noncausal prognosis-related trends in drug exposure among all eligible cases, odds ratios were clustered closer to null (0.99, 0.95, 1.02, 0.99, and 1.16, respectively).

CONCLUSIONS

Consideration of the sociology of medication use leading to health outcomes is essential in designing and analyzing self-controlled studies of treatment effects. Although the case-case time-control design was able to reduce bias from prognosis-related exposure trends in our examples, the difficulty in identifying appropriate reference exposures could be prohibitive.

The Longitudinal Urban Cohort Ageing Study (LUCAS): study protocol and participation in the first decade

Background

We present concept, study protocol and selected baseline data of the Longitudinal Urban Cohort Ageing Study (LUCAS) in Germany. LUCAS is a long-running cohort study of community-dwelling seniors complemented by specific studies of geriatric patients or diseases. Aims were to (1) Describe individual ageing trajectories in a metropolitan setting, documenting changes in functional status, the onset of frailty, disability and need of care; (2) Find determinants of healthy ageing; (3) Assess long-term effects of specific health promotion interventions; (4) Produce results for health care planning for fit, pre-frail, frail and disabled elderly persons; (5) Set up a framework for embedded studies to investigate various hypotheses in specific subgroups of elderly.

Methods/Design

In 2000, twenty-one general practitioners (GPs) were recruited in the Hamburg metropolitan area; they generated lists of all their patients 60 years and older. Persons not terminally ill, without daily need of assistance or professional care were eligible. Of these, n = 3,326 (48 %) agreed to participate and completed a small (baseline) and an extensive health questionnaire (wave 1). In 2007/2008, a re-recruitment took place including 2,012 participants: 743 men, 1,269 women (647 deaths, 197 losses, 470 declined further participation). In 2009/2010 n = 1,627 returned the questionnaire (90 deaths, 47 losses, 248 declined further participation) resulting in a good participation rate over ten years with limited and quantified dropouts. Presently, follow-up data from 2007/2008 (wave 2) and 2009/2010 (wave 3) are available. Data wave 4 is due in 2011/2012, and the project will be continued until 2013. Information on survival and need of nursing care was collected continuously and cross-checked against official records. We used Fisher’s exact test and t-tests. The study served repeatedly to evaluate health promotion interventions and concepts.

Discussion

LUCAS shows that a cohort study of older persons is feasible and can maintain a good participation rate over ten years, even when extensive self-reported health data are collected repeatedly through self-filled questionnaires. Evidently individual health developments of elderly persons can be tracked quantifying simultaneously behaviour, co-morbidity, functional competence and their changes. In future, we expect to generate results of significance about the five study aims listed above.