Living alone, widowhood, and loneliness among older males and females: longitudinal evidence from South Korea

Intense inspiratory muscle work evokes a sympathetically mediated pressor reflex, termed the respiratory muscle metaboreflex, in which young females demonstrate an attenuated response relative to males. However, the effects of ageing and female sex hormones on the respiratory muscle metaboreflex are unclear. We tested the hypothesis that the pressor response to inspiratory work would be similar between older males and females, and higher relative to their younger counterparts. Healthy, normotensive young (26±3years) males (YM; n=10) and females (YF; n=10), as well as older (64±5years) males (OM; n=10) and females (OF; n=10), performed inspiratory pressure threshold loading (PTL) to task failure. Older adults had a greater mean arterial pressure (MAP) response to PTL than young (P<0.001). YF had a lower MAP compared to YM (+10±6 vs. +19±15mmHg, P=0.026); however, there was no difference observed between OF and OM (+26±11 vs. +27±11mmHg, P=0.162). Older adults had a lower heart rate response to PTL than young (P=0.002). There was no effect of sex between young females and males (+19±9 and +27±11bpm, P=0.186) or older females and males (+17±7 and +20±7bpm, P=0.753). We conclude the respiratory muscle metaboreflex response is heightened in older adults, and the sex effect between older males and post-menopause females is absent, suggesting an effect of circulating sex hormones. KEY POINTS: The arterial blood pressure response to the respiratory muscle metaboreflex is greater in older males and females. Compared to sex-matched young individuals, there is no sex differences in the blood pressure response between older males and post-menopause females. Our results suggest the differences between males and females in the cardiovascular response to high levels of inspiratory muscle work is abolished with reduced circulating female sex hormones.

BackgroundNeuroimaging studies in younger adults have demonstrated sex differences in brain processing of painful experimental stimuli. Such differences may contribute to findings that women suffer disproportionately from pain. It is not known whether sex-related differences in pain processing extend to older adults.MethodsThis cross-sectional study investigated sex differences in pain reports and brain response to pain in 12 cognitively healthy older female adults and 12 cognitively healthy age-matched older male adults (age range 65–81, median = 67). Participants underwent psychophysical assessments of thermal pain responses, functional MRI, and psychosocial assessment.ResultsWhen compared to older males, older females reported experiencing mild and moderate pain at lower stimulus intensities (i.e., exhibited greater pain sensitivity; Cohen’s d = 0.92 and 0.99, respectively, p < 0.01) yet did not report greater pain-associated unpleasantness. Imaging results indicated that, despite the lower stimulus intensities required to elicit mild pain detection in females, they exhibited less deactivations than males in regions associated with the default mode network (DMN) and in regions associated with pain affect (bilateral dorsolateral prefrontal cortex, somatomotor area, rostral anterior cingulate cortex (rACC), and dorsal ACC). Conversely, at moderate pain detection levels, males exhibited greater activation than females in several ipsilateral regions typically associated with pain sensation (e.g., primary (SI) and secondary somatosensory cortices (SII) and posterior insula). Sex differences were found in the association of brain activation in the left rACC with pain unpleasantness. In the combined sample of males and females, brain activation in the right secondary somatosensory cortex was associated with pain unpleasantness.ConclusionsCognitively healthy older adults in the sixth and seventh decades of life exhibit similar sex differences in pain sensitivity compared to those reported in younger individuals. However, older females did not find pain to be more unpleasant. Notably, increased sensitivity to mild pain in older females was reflected via less brain deactivation in regions associated with both the DMN and in pain affect. Current findings elevate the rACC as a key region associated with sex differences in reports of pain unpleasantness and brain deactivation in older adults. Also, pain affect may be encoded in SII in both older males and females.Electronic supplementary materialThe online version of this article (doi:10.1186/s13293-015-0041-y) contains supplementary material, which is available to authorized users.

Impact of age and sex on the relationship between carotid intima-media thickness and frailty level in the Canadian Longitudinal Study of Aging

Health care systems need better strategies to identify older adults at risk for costly care to select target populations for interventions to reduce health care burden. Cognitive impairment and frailty are among the two most common geriatric syndromes. We examined the association between cognitive frailty and health care utilization and costs. Participants aged 50 and over were drawn from four prospective cohorts of aging, including the China Health and Retirement Longitudinal Study (CHARLS), the Korean Longitudinal Study of Aging (KLoSA), the Mexican Health and Aging Study (MHAS), and the Survey of Health, Ageing and Retirement in Europe (SHARE). We classified participants according to their cognitive impairment and frailty status into the following groups: none, only cognitive impairment, only frailty and cognitive frailty. We used negative binomial regression models and sample selection models to explore the association between cognitive frailty and health care utilization and costs. Compared to participants without cognitive impairment and frailty, participants in the only frailty or cognitive frailty groups had higher average annual outpatient visits and inpatient admissions. Only cognitive impairment was significantly negatively associated with the probability of outpatient visits or out-of-pocket (OOP) costs. Only frailty was significantly associated with a higher probability of outpatient visits or more OOP costs. The association between cognitive frailty and outpatient visits varied by cohort. In KLoSA, cognitive frailty was associated with a lower probability of outpatient visits, whereas the other three cohorts show the opposite. Cognitive frailty was associated with higher outpatient costs in CHARLS, KLoSA and MHAS. Only frailty and cognitive frailty were associated with a higher likelihood of inpatient admission in each cohort, and they were also linked to higher inpatient costs in both KLoSA and SHARE. But cognitive frailty was associated with lower inpatient costs in MHAS. This study highlights the significant positive association between cognitive frailty and health care utilization and OOP costs in most countries. By recognizing the multifaceted nature of cognitive impairment and frailty, healthcare providers and policymakers can work towards more effective interventions and support systems that address the needs of middle-aged and older adults, ultimately improving their quality of life and reducing health care costs.

This population-based study examined the relative and combined relationships of chronic medical illness (CMI) and depressive symptoms with health care utilization among older adults in South Korea. A nationally representative sample of 3224 older adults participating in the Korean Longitudinal Study of Ageing (KLoSA) were categorized into four groups based on clinical characteristics: CMI only; depressive symptoms only; CMI and depressive symptoms; and neither CMI nor depressive symptoms. We estimated the use of various health care services by the groups while adjusting for clinical and sociodemographic characteristics. Depressive symptoms, as measured by the short-form Center for Epidemiological Studies-Depression scale (CES-D10), were prevalent, often occurring together with CMI in community-dwelling older adults in South Korea. Having depressive symptoms was positively associated with the use of inpatient services, outpatient physician services, and public health centers. The odds of using health care services were larger among older people with both depressive symptoms and CMI than depressive symptoms only. Self-reported depressive symptoms and self-reported CMI are prevalent among older adults in South Korea, often occurring together and possibly increasing health care utilization. These findings imply a need for chronic disease management targeting older people with complex mental and medical conditions and evaluation of its effects on health outcomes and service use.

To examine the association of changes in loneliness with subsequent cardiometabolic comorbidity (CMM) among middle-aged and older Chinese and South Korean adults. We used the harmonized individual-level data from the China Health and Retirement Longitudinal Study (CHARLS, n = 9381) from China and the Korean Longitudinal Study of Aging (KLoSA, n = 5052) from South Korea. In both CHARLS and KLoSA, loneliness was measured using a single item from the 10-item Center for Epidemiological Studies Depression Scale (CESD-10) at baseline and in the second survey. CMM was defined as the presence of two or more cardiometabolic conditions, including diabetes, heart disease, and stroke, based on physician-diagnosed self-report. Within each cohort, we used the multivariable Cox proportional hazards models to estimate adjusted hazard ratios (aHRs) with 95% confidence intervals (CIs) of incident CMM according to changes in loneliness (never, initiated, relieved, and persistent) over 7 years (CHARLS) or 6 years (KLoSA) of follow-up. In CHARLS, initiated (aHR 1.42, 95%CI 1.14-1.78), relieved (aHR 1.40, 95%CI 1.16-1.70), and persistent (aHR 2.03, 95%CI 1.64-2.51) loneliness were associated with an increased likelihood of experiencing CMM. In KLoSA, both relieved (aHR 1.72, 95%CI 1.07-2.76) and persistent (aHR 1.86, 95%CI 1.21-2.88) loneliness were significantly associated with CMM, whereas the initiated loneliness showed no significant association (aHR 1.25, 95%CI 0.76-2.07). Changes in loneliness were associated with an increased risk of subsequent CMM in both China and South Korea, with the strongest associations observed among individuals experiencing persistent loneliness. These findings indicate that loneliness is a dynamic and potentially modifiable risk factor for cardiometabolic multimorbidity across different sociocultural contexts. Early identification and targeted interventions addressing loneliness may contribute to the prevention of CMM among middle-aged and older adults.

The Total Sulphur Amino Acid Requirement Is Higher in Older Men Than Women

Significant differences exist in the coverage and target population of social health insurance between South Korea and China. This study investigated the effects of different types of social health insurance on cognition trajectories and survival of older people with cognitive impairments. Data were drawn from the Korean Longitudinal Study of Aging (N = 1812) and the Chinese Longitudinal Healthy Longevity Survey (N = 1168) from 2008 to 2018. Growth mixture models were built to identify cognition trajectories. Logistic regression and Cox proportional hazards models were performed to identify risk factors. Results indicate that although social health insurance improved overall health outcomes among older people with cognitive impairments, there were significant socioeconomic inequalities in its protective influence. Results suggest that South Korea’s Medical Aid and China’s Basic Medical Health Scheme showed positive influences on cognition trajectories among illiterate older people. In contrast, results indicate that, in China, older adults with cognitive impairments from higher socioeconomic backgrounds benefited more from social health insurance in terms of cognition trajectories and survival. This study urges governments to consider expanding healthcare provision to protect the most vulnerable older people with cognitive impairments in general and those from low socioeconomic backgrounds in particular.

BackgroundFew studies have explored the relationship between the number of children and depression in older adults, especially across multiple countries.MethodsIn this Multi-National Cross-Sectional Analysis, we included the Health and Retirement Study (HRS, US), the English Longitudinal Study of Ageing (ELSA), the Survey of Health, Ageing and Retirement in Europe (SHARE), the Chinese Longitudinal Healthy Longevity Survey (CLHLS), the Korean Longitudinal Study of Aging (KLoSA), and the Longitudinal Aging Study in India (LASI), encompassing a total of 20 countries. The number of children was based on self-reports from the participants. The Center for Epidemiologic Studies Depression Scale (CESD) and the European Depression Scale (EURO-D) were used to assess depression. Logistic regression was used to evaluate the relationship between the number of children and depression, adjusting for potential confounders. A random-effects meta-regression model was used to examine differences in the relationship between the number of children and depression between Asian and Western countries. To explore potential non-linear relationships, restricted cubic spline (RCS) curves were utilized, and threshold effect analyses were performed to validate. Additionally, subgroup analyses were stratified by age, sex, and marital status.ResultsA total of 110,015 participants from six datasets were included. The prevalence of depressive symptoms ranged from 10.7% in the UK to 48.8% in Poland. Childlessness was most common in ELSA (15.8%), followed by SHARE (9.6%) and HRS (8.4%), while lower proportions were observed in CLHLS (1.5%), KLoSA (2.3%), and LASI (3.1%). In Western countries, childlessness was not significantly associated with depression (HRS: OR = 1.00, 95% CI: 0.83–1.23; ELSA: OR = 0.90, 95% CI: 0.69–1.17; SHARE: OR = 1.05, 95% CI: 0.97–1.15). However, in Asian countries, it was linked to a higher risk (CLHLS: OR = 2.00, 95% CI: 1.29–3.12; KLoSA: OR = 1.78, 95% CI: 1.24–2.55; LASI: OR = 1.33, 95% CI: 1.19–1.49). A random-effects meta-analysis confirmed this regional difference (β = 0.35, 95% CI: 0.15–0.55; P < 0.001). A non-linear association was observed between the number of children and depression in LASI and SHARE, with risk initially decreasing and then rising beyond a threshold. Subgroup analysis found a stronger association among ≤ 75 years individuals and men in KLoSA. In HRS, childlessness was associated with a higher risk of depression only among those living alone.ConclusionsThe relationship between the number of children and depression varies across countries. Individuals in Asian countries may be more prone to depression than those in Western nations when they do not have children.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12888-025-07206-3.

Rapid‐onset vasodilation (ROV) in response to a single muscle contraction is attenuated with aging. Moreover, sex‐related differences in muscle blood flow and vasodilation during dynamic exercise have been observed in young and older adults. The purpose of the present study was to explore if sex‐related differences in ROV exist in young (n=36; 21 male/15 female; 25 ± 1 yr) and older (n=32; 19 male/13 female; 66 ± 1 yr) adults. Subjects performed single forearm contractions at relative intensities of 10%, 20%, and 40% maximal voluntary contraction (MVC). Brachial artery blood velocity and diameter were measured with Doppler ultrasound, and forearm vascular conductance (FVC; ml·min−1·100 mmHg−1) was calculated from blood flow (ml·min−1) and blood pressure (mmHg) and used as a measure of peak ROV (peak change in FVC from baseline). Due to significant differences in MVC and consequent differences in weight used for each relative intensity between males and females, the data were analyzed two additional ways. First, responses were normalized for workload (i.e. peak FVC per kg of weight lifted). Second, the peak ROV responses in a subset of subjects (n=44; 12 young male, 10 young female, 11 older male, 11 older female) with similar absolute workloads (10–12kg) were compared. Lastly, the magnitude of change in peak ROV with increasing intensity (calculated as the slope of a linear regression line between 10, 20, and 40% MVC) was calculated and compared between groups. Peak ROV was attenuated in females across all relative intensities in the young and older groups (P &lt; 0.05). When normalized for workload, peak ROV was attenuated with age in both males and females at all intensities (P&lt;0.05) except at 10% for females (P=0.47). However, sex‐related differences were not observed within age when normalized by workload at any intensity (P&gt;0.05). In the subset of subjects with a similar absolute workload (~11kg), age‐related differences in ROV remained in both the female and male groups (P&lt;0.05). Older females demonstrated an attenuated peak ROV compared to their older male counterparts (91 ± 6 vs. 121 ± 11 ml·min−1·100 mmHg−1, P&lt;0.03), whereas no sex differences in peak ROV were observed between young females and males (134 ± 8 vs. 154 ± 11 ml·min−1·100 mmHg−1, P=0.15). Examining the slope of the peak ROV response across contraction intensities revealed a main effect of age (P&lt;0.05), with the slope being blunted in older compared to young subjects. When separated by sex, the slope was smaller in older compared to young females (5.5 ± 0.7 vs. 8.9 ± 0.9 FVC units/intensity, P&lt;0.05) but not between older and young males (7.0 ± 0.50 vs. 8.2 ± 1.0 FVC units/intensity, P=0.38). Our data suggest that sex‐related differences in the rapid vasodilatory response to single muscle contractions exist in older but not young adults, such that older females have a blunted response compared to older males.

While smoking is a crucial health risk, it adversely affects oral health, particularly becoming riskier for older adults who have smoked for a long time. This study identifies the patterns of smoking behavior changes in older adults aged 65 years and older and examines how the smoking behavior changes affect their oral health. Longitudinal data were derived from Korean Longitudinal Study of Aging (KLoSA) between 2006 and 2018, targeting the older adults 65 years and older in South Korea. The independent variable was the amount of smoking, and the dependent variable was oral health. For data analysis, SPSS 25.0 and M-plus 8.0 programs were utilized. As a result, the patterns of changes in smoking behavior of the older adults finally derived were 'non-smoking,' 'decreasing,' 'high-level maintenance,' and 'decreasing after increasing.' Furthermore, the relationship between the smoking behavior change pattern of the older adults and oral health was revealed. Specifically, as for the smoking behavior change pattern of the older adults, it was confirmed that the oral health was better in the 'non-smoking' pattern compared to the 'high-level maintenance' pattern. On the other hand, it was confirmed that the 'decreasing' pattern and the 'decreasing after rising' pattern did not significantly affect oral health. The findings imply that even if older adults smoked a lot in the past, if they quit smoking at some point, it can positively affect their oral health. Furthermore, it is suggested to allow public officials, medical professionals, and welfare experts to actively intervene for older adults to stop smoking for their oral health.

AimsAlthough it has been hypothesized that air pollution, particularly PM2.5 and PM10, causes depressed symptoms, their interactions with greenness have not yet been confirmed. This study examined the association between depression symptoms and air pollution, as well as the potential moderating effects of greenness.MethodsA total of 7657 people from all around South Korea were examined using information from the Korean Longitudinal Study of Aging, for the years 2016, 2018 and 2020. Depressive symptoms were assessed using the CES-D 10 score (Center for Epidemiology Studies of Depression scale, Boston form), and annual air pollution levels (PM2.5, PM10) and greenness (NDVI, Landsat Normalized Difference Vegetation Index) at the district level (si-gun-gu) were considered for the association analysis. The investigation was primarily concerned with determining how the CES-D 10 score changed for each 10 increase in PM2.5 and PM10 according to NDVI quantiles, respectively. The analysis used generalized estimating equation models that were adjusted with both minimal and complete variables. Subgroup analyses were conducted based on age groups (<65, ≥65 years old), sex and exercise status.ResultsThe impact of PM10 on depression in the fourth quantile of NDVI was substantially less in the fully adjusted linear mixed model (OR for depression with a 10 increment of PM10: 1.29, 95% CI: 1.06, 1.58) than in the first quantile (OR: 1.88, 95% CI: 1.58, 2.25). In a similar vein, the effect of PM2.5 on depression was considerably reduced in the fourth quantile of NDVI (OR for depression with a 10 increment of PM2.5: 1.78, 95% CI: 1.30, 2.44) compared to the first (OR: 3.75, 95% CI: 2.75, 5.10). Subgroup analysis results demonstrated beneficial effects of greenness in the relationship between particulate matter and depression.ConclusionsThis longitudinal panel study found that a higher quantile of NDVI was associated with a significantly reduced influence of air pollution (PM10, PM2.5) on depression among older individuals in South Korea.

Potentiated respiratory metaboreflex in older males and females: afferent or efferent mechanisms?

IntroductionAs the world's population ages, the prevalence of cognitive impairment associated with age increases. This increase is particularly pronounced in Asia and South-America. The objective of this study was to investigate separately the longitudinal association of physical activity and cognitive function in; older adults in Mexico and South Korea. Materials and MethodsThis is a secondary analysis of two surveys, The Mexican Health and aging Study (MHAS) (n = 5853) and Korean Longitudinal Study of aging (KLoSA) (n = 5188), designed to study the aging process of older adults living in Mexico and South Korea. Participants older than 50 years were selected from rural and urban areas achieving a representative sample. Physical activity was assessed using self-report. Cognition was assessed using Cross-Cultural Cognitive Examination (CCCE) and Minimental state examination (MMSE) in Mexico and South Korea respectively. Here we investigate the longitudinal association between physical activity and cognition during 3 years for MHAS and 4 years for KLoSA using multiple linear regression analyses. ResultsThe prevalence of physical activity was 40.68 % in MHAS and 35.57 % in KLoSA. In the adjusted longitudinal multivariate analysis, an independent association was found between physical activity and MMSE score OR 0.0866 (CI 0.0266-0.1467 p-value 0.0047) in the Korean older adults, while there was no significant association in MHAS. ConclusionsPhysical activity could have a protective effect on the cognitive decline associated with aging in the Korean population.

Nustatyta, kad vyrai gali pasiekti didesnę absoliučiąją raumenų jėgą, tačiau jie yra mažiau atsparūs nuovargiui nei moterys. Taip pat senyvo amžiaus suaugusieji gali ilgiau palaikyti santykinai submaksimalią jėgą nei jaunesnio amžiaus suaugę asmenys, nors senėjimo procesas neatsiejamas nuo žymaus raumenų masės ir jėgos sumažėjimo. Tačiau vis dar nėra aiškūs lyties skirtumai amžiaus aspektu tiriant motorinės sistemos nuovargį po maksimalių izometrinių susitraukimų, kadangi nuovargis priklauso nuo užduoties pobūdžio, trukmės, intensyvumo ir testuojamų raumenų grupės. Tyrimo tikslas – įvertinti skirtingo amžiaus ir lyties suaugusiųjų keturgalvio šlaunies raumens nuovargio po nepertraukiamo maksimalių pastangų izometrinio krūvio skirtumus. Tyrime dalyvavo 24 jauni (18–29 m.) ir 20 senyvo amžiaus (65–75 m.) vyrų ir moterų. Prieš eksperimentines procedūras tiriamiesiems buvo atlikti antropometriniai matavimai TBF‑300 kūno kompozicijos analizatoriumi „Tanita“ (West Drayton, UK). Vėliau atlikti baziniai matavimai: maksimalioji valinga jėga (MVJ) įvertinta dinamometru (System 3; Biodex Medical Systems, Shirley, NY, USA), nevalinga jėga (20 Hz, 100 Hz) įvertinta naudojant elektrostimuliaciją (MG 440; Medicor, Budapest, Hungary). Eksperimentą sudarė nepertraukiamas, 30 s trunkantis izometrinis krūvis, kuriam atlikti reikia maksimalių keturgalvio šlaunies raumens susitraukimų, su įterpto impulso (P100TT) metodika, kuria apskaičiuojamas centrinės aktyvacijos rodiklis (CAR). Po eksperimento praėjus 5 ir 10 min įvertintas valingos (MVJ) ir nevalingos (20 Hz, 100 Hz) jėgos atsigavimas. Tyrimo rezultatai parodė, kad pradinės jaunų tiriamųjų nevalingos jėgos, MVJ ir CAR reikšmės buvo didesnės nei senyvo amžiaus tiriamųjų. Taip pat vyrai pasiekė didesnę MVJ ir aukštesnį CAR nei to paties amžiaus moterys (p < 0,05). 30 s krūvio metu MVJ sumažėjo visų grupių tiriamųjų (p < 0,05), tačiau lyties aspektu statistiškai reikšmingas MVJ skirtumas išliko tik tarp jaunų tiriamųjų (p < 0,05). MVJ rodikliai po 10 min iki pradinio lygio grįžo visų grupių tiriamųjų (p < 0,05). Varginančio krūvio metu CAR reikšmingai nepakito tik senyvo amžiaus moterų. Jaunų tiriamųjų CAR iki pradinio lygio grįžo jau po 5 min (p < 0,05), tačiau senyvo amžiaus vyrų CAR pradinį lygį pasiekė praėjus 10 min. Jauniems vyrams pasireiškė didesnis periferinis nuovargis nei kitoms grupėms (p < 0,001). Periferinis nuovargis skyrėsi amžiaus aspektu, tačiau lyties įtakos nenustatyta. Pagrindinės tyrimo išvados: senyvo amžiaus moterys buvo atsparesnės nuovargiui nei to paties amžiaus vyrai ir jauni suaugusieji, nes varginančio krūvio metu MVJ, nors sumažėjo visų grupių tiriamųjų, labiausiai sumažėjo jauno amžiaus tiriamųjų. Taip pat senyvo amžiaus moterų centrinės aktyvacijos lygis buvo žemesnis nei kitų grupių, o lėčiausiai sunormalėjo senyvo amžiaus vyrams. Didesnis periferinis nuovargis nustatytas jauniems vyrams nei moterims, taip pat ir jauniems nei senyvo amžiaus suaugusiesiems.