Table 3 Consequences of loneliness and social isolation

Aedo-Neira 2022 [22]

Older adults experienced psychological decline during COVID-19, worsened by isolation and the digital divide. Emotional, family, and social support were crucial, highlighting the need for programs and policies to close the technology gap.

Yes

Yes

Yes

-

Altintas 2023 [23]

Individuals with frailty had a significantly higher mean age than those without. Among participants, 89.1% with a serious disease and 68.9% with a seriously ill loved one were frail. The mean score on the Loneliness Scale for the Elderly was statistically significant. Additionally, a significant relationship was observed between the Tilburg Frailty Indicator, its subscales, and the Loneliness Scale for the Elderly.

Yes

Yes

Yes

Yes

Berg-Weger 2020 [24]

Loneliness and social isolation are common among older adults, adversely affecting their physical and emotional well-being. Contributing factors include living alone, depression, and inadequate social support.

Yes

Yes

Yes

-

Böger 2018 [25]

Age-related changes in social networks include fewer distressing ties and greater family satisfaction, though lower satisfaction with friendships. Loneliness both influences and results from relationship quality.

-

Yes

Yes

-

Bonsaksen 2021 [26]

Group 1: Loneliness (M = 9.3, SD = 4.4), Mental Health (M = 15.1, SD = 6.5), Quality of Life (M = 6.8, SD = 2.2); Group 2: Loneliness (M = 9.1, SD = 4.4), Mental Health (M = 14.2, SD = 5.7), Quality of Life (M = 7.0, SD = 2.1).

Yes

Yes

Yes

Yes

Canjuga 2018 [27]

Low education and health relate to loneliness in elderly homes

-

Yes

Yes

Yes

Canjuga 2018 [28]

Reduced self-care ability contributes similarly to social and emotional loneliness in both groups of elderly individuals.

-

Yes

Yes

Yes

Cantarero-Prieto 2018 [29]

Social activity participation reduces chronic disease probability (OR = 0.70), while living alone increases it (OR = 1.20). Significant differences exist by macro-area: helping others decreases chronic disease risk in the Nordic region (OR = 0.58), while club participation and living alone are significant for Continental (OR = 0.65) and Southern regions (OR = 1.46), respectively.

Yes

-

Yes

No

Chen 2014 [30]

Loneliness and aging is a growing problem in China

Yes

Yes

Yes

No

Cheng 2021 [31]

Objective and subjective social isolation independently affect mental health in older adults, with attitudes toward aging significantly mediating this relationship.

-

Yes

Yes

No

Cheung 2023 [32]

The aging out of place sample was significantly less frail than the aging in place sample, with lower scores in all frailty domains, particularly social frailty. This group also had significantly lower psychological and social quality of life scores, especially in psychological QoL. Additionally, social and overall loneliness scores were significantly higher in the aging out of place sample, with the greatest difference in overall loneliness.

Yes

Yes

Yes

Yes

Creese 2021 [33]

Loneliness linked to mental and physical health declines

Yes

Yes

Yes

Yes

daCruz 2022 [34]

Physical activity has shown excellent results for mental health, being used in different treatments and populations, when considering the elderly, one of the ways to mitigate this impact on mental health is the practice of physical activity.

Yes

Yes

Yes

-

Dahlberg 2014 [35]

Significant predictors of social loneliness included being male, widowed, and experiencing low well-being, self-esteem, income comfort, family and friend contact, activity, community integration, and receipt of community care. For emotional loneliness, significant predictors included being widowed, low well-being, low self-esteem, high activity restriction, low-income comfort, and non-receipt of informal care.

Yes

Yes

Yes

Yes

Dayson 2021 [36]

One-to-one therapeutic interventions benefit those with loneliness linked to low psychological well-being from trauma or complex issues that hinder social relationships. Peer-to-peer interventions help individuals with less complex issues affecting emotional well-being. Group-based interventions are effective for individuals seeking to improve social well-being and build community connections.

Yes

Yes

Yes

-

deSousa 2022 [37]

Elderly individuals with a depressive profile showed anxiety during the COVID-19 pandemic, associated with low education, divorce, multiple mental disorders, and exposure to COVID-19 information. Elderly Brazilians in social isolation are at risk of developing depressive disorders during quarantine, underscoring the need for effective gerontological care and mental health monitoring.

-

Yes

Yes

Yes

dos Santos-Orlandi 2019 [38]

Frailty was associated with loneliness and depressive symptoms. Elderly caregivers had 158% higher odds of pre-frailty and 360% higher odds of frailty. Those with depressive symptoms had a 242% increased chance of frailty.

Yes

Yes

Yes

Yes

Dziedzic 2021 [39]

19.15% of participants had depressive symptoms, 14.18% had borderline states, and 58.83% reported moderate to high loneliness, significantly correlated with depressive symptoms.

Yes

Yes

Yes

Yes

Gale 2018 [40]

High loneliness was linked to a higher risk of becoming frail or pre-frail within four years, though it did not impact frailty index changes over six years. Social isolation was not generally associated with frailty risk, but among men, high isolation increased the likelihood of becoming frail.

Yes

Yes

Yes

Yes

Gerino 2017 [41]

The model indicates that resilience and mental health mediate the relationship between loneliness and quality of life (QoL). Loneliness negatively impacts QoL through these factors. Enhancing social support, resilience, and self-efficacy can reduce loneliness and improve mental health, ultimately enhancing perceived QoL and decreasing anxiety and depression.

Yes

Yes

Yes

-

Gyasi 2019 [42]

Loneliness and living alone are significant predictors of psychological distress in older adults, while social interactions and physical activity can help reduce this distress.

Yes

Yes

Yes

Yes

Herrera-Badilla 2015 [43]

Hypertension was the most common chronic disease. Depressive symptoms were present in 13.9%, and 29.1% had ADL disabilities. Frailty affected 14.1%, with loneliness reported by 13.2%. Frail individuals were older, mostly female, more likely to live alone, and reported more chronic diseases and depressive symptoms. Prefrail (17.6%) and frail (23.1%) participants had higher and significant loneliness rates than nonfrail individuals (6.9%). Regression analysis showed a significant association between loneliness and prefrail and frail status.

Yes

Yes

Yes

Yes

Jarach 2021 [44]

Participants aged ≥ 60, 47.6% were robust, 41.6% pre-frail, and 10.8% frail at baseline. After two years, 61.8% of robust individuals remained robust, while 30.8% became pre-frail. High loneliness and social isolation significantly increased the risk of robust individuals becoming frail or pre-frail. Overall, 33.4% of robust older adults deteriorated in frailty status, underscoring the need to address loneliness and social isolation.

Yes

Yes

Yes

-

Jiang 2021 [45]

Emotional mistreatment negatively impacts older adults’ life satisfaction, correlating with low emotional closeness and high loneliness, which further diminish life satisfaction. However, emotional closeness with children does not significantly mediate the relationship between physical mistreatment and life satisfaction.

-

Yes

Yes

No

Joseph 2023 [46]

Frail participants experienced more isolation, COVID-19 worries, and loneliness than non-frail individuals. They faced challenges like fatigue and limited mobility, leading to increased fear and reduced social interactions.

Yes

Yes

Yes

-

Koroleva 2021 [47]

Nearly one-fifth of respondents aged 50 + reported mental health effects from COVID-19, with significant links between reduced social contacts and psychoemotional changes. The most isolated group faced three times more health irregularities.

-

Yes

Yes

Yes

Liu 2019 [48]

Depression and cardiovascular disease (CVD) are the most studied outcomes linked to social isolation. A systematic review found that poor social relationships increase CHD risk by 29% and stroke by 32%. Evidence also suggests CVD may mediate the link between social isolation and mortality. Low social participation and infrequent social contact are associated with higher dementia risk.

Yes

Yes

Yes

-

Liu 2022 [49]

Personality impacts loneliness in rural elderly

-

Yes

-

-

Llorente-Barroso 2021 [50]

ICT enhances elderly individuals’ self-esteem and promotes positive emotions. It plays a crucial role during the pandemic, especially for those with higher digital literacy. However, lower digital literacy participants faced challenges due to a lack of inter-generational support, affecting their independence.

-

Yes

Yes

-

Lu 2020 [51]

Higher social isolation is linked to lower medication adherence among elderly individuals with chronic diseases, mainly due to diminished social support. Elderly patients with multimorbidity face greater social isolation and loneliness, along with lower social support and medication adherence than their non-multimorbid counterparts. Enhanced social support improves medication adherence and reduces loneliness.

Yes

Yes

Yes

-

Luo 2024 [52]

Different types of social participation affect the mental health of older adults living alone: simple communication negatively impacts depression, while self-entertainment positively influences it. Increased simple communication reduces anxiety, whereas self-entertainment raises anxiety levels.

-

Yes

Yes

Yes

Murayama 2021 [53]

The interaction between mutual aid from family and neighbours and subjective economic status significantly predicted depressive symptoms, mainly in the non-family/neighbours group. Mutual aid was associated with lower perceived isolation and fear of future isolation, with the absence of mutual aid intensifying fear, especially among those without support.

-

Yes

Yes

Yes

O’Súilleabháin 2019 [54]

Emotional loneliness predicts increased mortality risk in older adults, particularly those living alone, while social loneliness does not. Among those not living alone, no associations with mortality were found. Functional status may amplify the risk linked to emotional loneliness.

Yes

Yes

Yes

-

Palacios-Navarro 2024 [55]

Participants demonstrated significant improvements post-intervention in all domains assessed, except cognition. Statistically significant enhancements were observed in quality of life, general health, perceived loneliness, and depression, with large effect sizes indicating high clinical relevance. The intervention is deemed a valuable tool for promoting independence and well-being among community-dwelling elderly individuals.

Yes

Yes

Yes

-

Pedroso-Chaparro 2023 [56]

Ageist stereotypes impact anxiety, depression, and comorbid symptoms only in older adults who perceive themselves as elderly, with loneliness mediating this effect. Self-identification as older activates ageist stereotypes, leading to loneliness and associated psychological distress, including anxiety, depression, and combined anxiety-depression symptoms.

-

Yes

Yes

No

Pengpid 2023 [57]

Loneliness was positively associated with the prevalence and incidence of mental ill-health (e.g., poor self-rated mental health, depressive symptoms, insomnia), physical ill-health (e.g., poor self-rated physical health, hypertension, diabetes), lifestyle factors (e.g., physical inactivity), and mortality.

Yes

Yes

-

-

Sadatnia 2023 [58]

Lower loneliness levels were reported than in previous studies, highlighting the impact of individual and sociocultural factors. A significant relationship exists between loneliness and mental health in the elderly, influenced by age, marital status, living conditions, and physical illness. Married individuals had better mental health than widowed or divorced participants. Membership in organizations correlated with improved mental health. Significant relationships were also found between mental health, social functioning, depression, and all loneliness subscales: romantic, social, and family.

Yes

Yes

Yes

No

Sha 2022 [59]

Frail participants experienced greater isolation, COVID-19 worries, and loneliness than non-frail individuals. They faced challenges like fatigue, pain, and limited mobility, expressing fear of COVID-19 and reduced social interactions.

Yes

Yes

-

-

Shiovitz-Ezra 2023 [60]

Persistent loneliness correlates with sleep issues

-

Yes

-

Yes

Soh 2019 [61]

Perceived problems and loneliness influence the relationship between spousal living arrangements and mental health.

Study 1: Living with a spouse was linked to better mental health, while perceived problems correlated with lower mental health scores.

Study 2: Spousal living arrangements predicted lower loneliness, which, moderated by perceived problems, differentially impacted mental health.

-

Yes

Yes

-

Stephens 2022 [62]

Social and emotional loneliness scores were regressed on demographic variables and neighbourhood factors (satisfaction, accessibility, security, social cohesion). Neighbourhood variables significantly explained variance in loneliness. Mediation tests revealed that their effects on social loneliness were mediated by private-restricted or locally integrated networks.

-

Yes

Yes

Yes

Tanabe 2024 [63]

Subjective well-being, defined by happiness (Shiawase) and purpose (Ikigai), significantly reduces the risk of physical frailty among socially isolated middle-aged and elderly individuals. Those with high subjective well-being demonstrated a lower risk of frailty, even under high social isolation, while individuals in the high social isolation cluster exhibited a higher rate of physical frailty compared to other clusters.

Yes

Yes

Yes

Yes

Theeke 2018 [64]

Loneliness scores declined among LISTEN group participants, while scores increased for those in the attention control group after six weeks. Participants rated the intervention highly in terms of acceptability. Additionally, LISTEN participants reported fewer depressive symptoms, significant declines in systolic blood pressure, and enhanced social support 12 weeks post-intervention, suggesting that participation led to positive changes in thinking or social support behaviours.

Yes

Yes

Yes

-

Tilikainen 2017 [65]

Highlight the importance of relationship quality over quantity in understanding emotional loneliness among older individuals. In individualistic societies, loneliness is often linked to the absence of confidants or friends, whereas collectivistic cultures prioritize family interactions. Emotional loneliness frequently arises from various factors, such as the loss or absence of a partner, illustrating the complex and multifaceted nature of loneliness.

No

Yes

Yes

No

Tragantzopoulou 2021 [66]

Social isolation and loneliness linked to psychiatric and physical disorders

Yes

Yes

Yes

Yes

Vaculíková 2023 [67]

Loneliness significantly linked to sadness, depression, nervousness, and gender, with women at higher risk. Younger retirees reported high levels of loneliness (40% vs. 45%). Sadness and depression were the strongest predictors (2020: OR = 3.69; 2021: OR = 2.55). Increased loneliness was observed among older adults, particularly women, during the COVID-19 pandemic, with a decision-tree algorithm classifying 76% of cases accurately.

-

Yes

Yes

Yes

vanOurs 2021 [68]

Ageing affects both mental health and loneliness. Up to the high 70s, mental health improves and loneliness goes down. Life events, like partner loss or unemployment, worsen mental health and increase loneliness. For men, retirement boosts mental health, and highly educated women also benefit from retiring.

Yes

Yes

Yes

Yes

Vrach 2020 [69]

Social isolation and quarantine lead to increased psychological issues, such as loneliness, stress, anxiety, and depression, with long-term effects potentially resulting in PTSD, depression, and heightened suicide risk. The WHO advocates for support for isolated older adults to reduce anxiety, while Public Health England encourages maintaining social connections online. However, many older adults face challenges accessing digital resources to connect with family.

Yes

Yes

Yes

-

Yang 2022 [70]

Loneliness and self-esteem sequentially mediate the relationship between intergenerational emotional support and subjective well-being in elderly migrants, enhancing well-being by reducing loneliness and increasing self-esteem.

-

Yes

Yes

No

Yang 2024 [71]

Greater social isolation worsened mental health, particularly increasing depression and cognitive decline, with stronger effects in men and individuals over 65.

Yes

Yes

Yes

Yes

Zakizadeh 2022 [72]

Mental health in the elderly population is influenced by several factors: it declines with age and an increasing number of chronic diseases, with men reporting better mental health than women. Enhanced support from friends and reduced feelings of loneliness are associated with improved mental health, while higher loneliness correlates negatively with mental well-being. These findings underscore the significance of demographic factors, social support, and loneliness as predictors of mental health in older adults.

Yes

Yes

Yes

Yes

Zhang 2021 [73]

Never-married participants had poorer self-rated health. Those living alone reported fewer difficulties with activities of daily living (ADLs). Subjective social isolation correlated with poor self-rated health, cognitive decline, and ADL and instrumental activities of daily living (IADL) difficulties, regardless of objective social isolation and health behaviours. Kinlessness and lack of social contacts negatively affect older adults’ health.

Yes

Yes

Yes

-