World Social Psychiatry

: 2019  |  Volume : 1  |  Issue : 1  |  Page : 82--88

Social relationships and the association of loneliness with major depressive disorder in the Ibadan study of aging

Akin Ojagbemi1, Oye Gureje2,  
1 Department of Psychiatry, Old Age Unit, University of Ibadan, Ibadan, Nigeria
2 Department of Psychiatry, Neurosciences and Substance Abuse, WHO Collaborating Centre for Research and Training in Mental Health, Ibadan, Nigeria; Department of Psychiatry, Stellenbosch University, Stellenbosch, South Africa

Correspondence Address:
Prof. Oye Gureje
Department of Psychiatry, Neurosciences and Substance Abuse, WHO Collaborating Centre for Research and Training in Mental Health, Ibadan, Nigeria


Background: Socially disaffiliated elderly Nigerians are at higher risk for major depressive disorder (MDD). It is unclear whether subjective experience of loneliness has independent association with MDD. Methods: A household multistage probability sample of persons who were 65 years or older was drawn from a geographical area with approximately 25 million population. We measured loneliness using the three-item University of California at Los Angeles scale. Poor social engagement, social isolation, and MDD were assessed using the World Health Organization (WHO) Disability Assessment Schedule II and Composite International Diagnostic Interview (WHO), respectively. Results: Of 1704 respondents, 179 (16.7%) were classified as lonely. Lonely respondents were more likely to have poor social engagement (P < 0.001) and social isolation (P < 0.001). While loneliness (adjusted odds ratio [OR] = 2.3, 95% confidence interval [CI] = 1.3–4.0) and poor social engagement (adjusted OR = 3.1, 95% CI = 1.6–6.1) were independent correlates of MDD, the association of loneliness with MDD was substantially, but not totally, mediated by poor social engagement. Conclusion: The association of loneliness with late-life depression in this African sample is partly explained by poor social engagement. Interventions for loneliness based on social activity schedules and networking programs can be adapted to reduce loneliness and lower the burden of late-life depression in Africans.

How to cite this article:
Ojagbemi A, Gureje O. Social relationships and the association of loneliness with major depressive disorder in the Ibadan study of aging.World Soc Psychiatry 2019;1:82-88

How to cite this URL:
Ojagbemi A, Gureje O. Social relationships and the association of loneliness with major depressive disorder in the Ibadan study of aging. World Soc Psychiatry [serial online] 2019 [cited 2021 Apr 22 ];1:82-88
Available from:

Full Text


Loneliness, a subjective emotional experience of being alone or apart from other people, is a common problem in older people.[1] Even though loneliness may occur in the presence of available social network, it nevertheless bears a strong relationship to social isolation.[2] The occurrence of loneliness can, therefore, be expected to reflect contemporaneous factors affecting social network and social engagement. In this regard, the notion that social and emotional integration of older people is better guaranteed in “collectivist” societies[3],[4] as exist in much of Africa is worthy of exploration.

Africa has the largest increase in global migration of young people.[5] This phenomenon could potentially be a factor for social isolation on the left-behind older person.[6],[7] In studies conducted by our group,[8],[9],[10],[11] indices of social isolation, defined by diminution of contacts with family and friends, as well as living in more rural locations, were shown to have important links to the onset of late-life depression and dementia. However, very little is currently known about the subjective experience of loneliness and how this might be related to social isolation and depression in older Africans.

Loneliness has important deleterious consequences on the health and well-being of older people. The experience of loneliness in older populations of Western Europe and North America has been linked to a variety of physical health challenges.[12],[13] Other reports from high-income countries show that loneliness in old age is also associated with mental health consequences such as poor sleep,[14] altered regulation of stress,[15] alcohol dependence,[16] dementia,[17] and depression.[18]

While social isolation, which is plausibly more common among “living alone” older adults in contemporary Africa,[5],[19] may lead to depression and the experience of loneliness, the latter may also have other predisposing factors as well as unique consequences that are timely to be investigated. First, several studies conducted in Europe and North America point to the powerful effect of living in neighborhoods characterized by low education and economic status in the mechanism and consequences of loneliness in older adults.[18],[20],[21],[22] Second, in a series of studies by our group,[9],[11],[23],[24] we found some of the highest global prevalence and incidence rates of late-life depression. The extent to which the experience of loneliness contributes to this high burden of late-life depression in this population is yet unknown.

In the present study, we aim to describe the cross-sectional association of loneliness and three social relationship types (marital separation, social isolation, and poor social engagement) with major depressive disorder (MDD) in community-dwelling older Nigerians.


Sample selection and recruitment

The Ibadan Study of Ageing (ISA) comprised two interrelated studies, each setup to address pressing epidemiological and health service challenges of older adults living in communities in Nigeria. An initial cross-sectional study was conducted in 2003–2004. This was followed by a 5-year prospective observation of the same cohort in 2007, 2008, and 2009. Loneliness was first examined in the 2007 wave of ISA.

The ISA cohort is based on a stratified multistage cluster sample derived from eight neighboring states in the predominantly Yoruba-speaking region of Nigeria. This region had a population of approximately 25 million people at the time of the studies. Details of the sample selection procedure have been fully described.[8],[23] The surveys were approved by the University of Ibadan/University College Hospital, Ibadan Joint Ethical Review Board. Participants were those who provided consent, mostly verbal (either because of illiteracy or by choice), before interviews were conducted.


Face-to-face interviews were carried out in the homes of participants to assess a range of domains. All instruments used in the ISA were subjected to cultural adaptation and translation into the local Yoruba language (using the iterative back-translation method).


The experience of loneliness was assessed in the 2007 wave using the three-item University of California at Los Angeles (UCLA) scale.[25] The three-items scale was adapted from the twenty-item revised UCLA loneliness scale.[26] Respondents were asked the following questions: (1) How often do you feel you lack companionship? (2) How often do you feel isolated from others? (3) How often do you feel left out? In every case, they were offered the option of three responses on a Likert scale: often, sometimes, and not at all/never. The responses to the three-item scale produce a loneliness score of 3–9, with higher scores indicating more intense loneliness. In line with previous studies,[27],[28] ISA participants with a score of ≥6 were categorized as lonely. The three-item UCLA scale demonstrates a strong correlation with the parent twenty-item measure (r = 0.82).[25] Its reliability in the ISA was 0.87 alpha (average interitem correlation = 0.68).

Social relationships

Social network was assessed with the relevant items in the Composite International Diagnostic Interview (CIDI).[29] The items inquire about the frequency of respondent's contact with family members who do not live with the respondent as well as the frequency of contact with friends. The response options provided in the CIDI are 1 (nearly every day), 2 (2–4 days/week), 3 (1–2 days/week), 4 (1–3 days a month), 5 (less than once in a month), and 6 (never). In this report, participants with contacts that were less than once in a month were categorized as having social isolation, while those with more than once in a month contacts were grouped as having adequate social relationships. Social participation was assessed using items derived from the World Health Organization-Disability Assessment Schedule, Version 2 (WHO-DAS II).[30] Participants were asked the following two questions: “During the last 30 days, how much did you join in family activities such as eating together, talking with family members, visiting family members, working together?” and “During the last 30 days, how much did you join in community activities such as festivities, religious activities, talking with community members, working together?” Answers were rated as 1 (not at all), 2 (a little bit), 3 (quite a bit), and 4 (a lot). In this study, participants who answered “not at all” to either question were rated as having poor social participation.


MDD was assessed with the fully-structured World Mental Health Survey version of the WHO CIDI.[29] Diagnosis was made on the basis of the criteria of the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV).[31] As required by convention, the DSM-IV organic exclusion rules were imposed in making a diagnosis of MDD. Additional quantitative assessment of depression was conducted using the thirty-items Geriatric Depression Scale (GDS).[32] The GDS has been used extensively among Yoruba Nigerians where cutoff scores of ≥11 had a kappa agreement of 0.65 with psychiatrist-diagnosed depression.[33]

Other data

Participants were asked their age (in years) and the number of years of formal education attained in their lifetime. In cases where records of birth were not readily available, estimates of age were determined using a previously validated list of historical events.[34] Residence was classified as rural (<12,000 households), semi-urban (12,000–20,000 households), or urban (>20,000 households) based on the Nigerian census categorization at the time of the study. Economic status was estimated using an inventory of 21 household and personal items,[35] and calculated as the ratio of the total number of possessions they had relative to the median number of possessions of the overall sample, and classified as low (≤0.5), low-average (>0.5–1.0), high-average (>1.0–2.0), or high (>2). For reasons of low sample sizes of the higher economic categories, high average and high were merged to form a single category. Participants were also asked to rate their overall health on the day of the interview as very good, good, fair, or poor using the WHO-DAS II.[30] Use of tobacco and alcohol was categorized, based on self-report, as ever having smoked or not, and ever used alcohol or not. Those who responded in the affirmative to ever using alcohol were further classified into regular (weekly use or more often) or occasional users (less often than weekly use).

The Katz Index of independence in activities of daily living (Katz ADL)[36] was used to assess the ability of participants to perform ADL independently. Instrumental ADL was evaluated by the ability of the participants to perform seven functions in the following areas:[37] climbing a flight of stairs, reaching above the head to carry something weighing about 4.5 kg, stooping, gripping small objects with hands, shopping, and activities such as sweeping the floor with a broom or cutting grass. Each of the activities in the two domains was rated: (1) can do without difficulty, (2) can do with some difficulty, (3) can do only with assistance, and (4) unable to do activity. We classified as functionally disabled, any respondent with a rating of 3 or 4 on any item.

Data analyses

The demographic characteristics of those who survived, died, or were censored between 2003–2004 and 2007 were compared using Pearson Chi-square test, with a Rao and Scott correction[38] to account for the survey design. Descriptive statistics such as means and standard deviations were used to summarize quantitative variables, while frequencies and percentages were used for categorical variables. Characteristics of the study sample were compared according to their MDD status using the Chi-squared test or t-test for categorical or continuous variables, respectively. The analyses took account of the stratified multistage sampling procedure and the associated clustering by applying weights as appropriate. We made adjustment for differences between the sample and the total Nigerian population by applying poststratifications to the target sex and age range.

For the purpose of investigating the association between social relationship types (marital separation, social isolation, and poor social engagement) and MDD, we conducted weighted logistic regression analyses with MDD as the dependent variable. Demographic, health, and lifestyle factors that were significantly different in bivariate analyses were included as covariates in adjusted models. Similar methodology was used in investigating the association of loneliness with MDD while accounting for the effect of poor social relationships.

Odds ratios (OR's) with 95% confidence intervals (CI's) of regression analyses are presented. Data were analyzed using Stata version 14.0 (Stata Statistical Software, College Station, TX).[39] The survey commands in Stata were used to account for the study sampling scheme. A significance level of 0.05 was used throughout the analyses.


Study sample

As loneliness in the ISA was first examined in the 2007 wave, the present report is based on 1704 respondents [Figure 1] who were either successfully followed up from 2003 to 2004 (n = 1356) or newly recruited in the 2007 wave (n = 348). The characteristics of respondents in the ISA loneliness and depression study is presented in [Table 1]. Their mean age was 72.7 (±7.4) years.{Figure 1}{Table 1}

Social relationships and depression

[Table 2] shows that 223 (13.3%) ISA respondents had poor social engagement, while 774 (35.5%) had been separated from spouses either through death or divorce. A total of 136 (8.1%) were classified as having social isolation [Table 2]. The table also shows that 195 (18.2%) respondents met criteria for MDD. The mean GDS score was 5.6 (±4.1). Poor social engagement was associated with the highest odds for MDD (adjusted OR = 3.1, 95% CI = 1.6–6.1) [Table 2]. Social isolation was not significantly associated with MDD. The odds for MDD among those who were separated from spouses (unadjusted OR = 2.0, 95% CI = 1.3–3.0) became nonsignificant when the effect of poor social engagement was accounted for in multivariate regression models [Table 2].{Table 2}

Loneliness, depression, and the role of poor social relationship

The mean loneliness scale score was 3.6 (±1.4). One hundred and seventy-nine (16.7%) respondents were classified as lonely [Table 2]. In the same table, nearly 4 in 5 (77.6%) respondents meeting criteria for MDD were among those classified as lonely (unadjusted OR = 2.9, 95% CI = 2.0–4.2). In adjusted logistic regression analyses exploring the independent association of loneliness and social relationship measures with MDD, both social engagement and loneliness retained independent associations. However, while the association of social engagement with MDD remained virtually the same once loneliness was controlled for, there was a 21% reduction in the odds for MDD among lonely respondents when the effect of poor social engagement was considered (adjusted OR = 2.3, 95% CI = 1.3–4.0) [Table 2]. The probabilities of loneliness and MDD among persons in the different social relationship types are presented in [Figure 2].{Figure 2}


Loneliness was present in 16.7% of this large sample of community-dwelling older Nigerians who were participants in the ISA. Along with poor social engagement, the subjective experience of loneliness was associated with significantly increased odds for MDD. While social engagement was an independent correlate for depression irrespective of loneliness, the association of loneliness with MDD was in part moderated by social engagement.

The variety of definitions of loneliness in contemporary literature[40] makes it difficult to directly compare rates in older adults from different populations. Studies using criteria such as a single-item enquiry about the experience[41] or those including persons who were “sometimes” lonely in their categorizations[42] tend to report higher rates. A previous study applying definition of loneliness similar to those used in the ISA to a representative sample of community-dwelling older adults in the Spanish population found a prevalence of 13.1%.[27] The prevalence of 16.7% reported for loneliness in the present study is thus slightly, but not substantially, higher.

The main objective of the present study was to describe the cross-sectional association of loneliness and three social relationship types (marital separation, social isolation, and poor social engagement) with MDD in community-dwelling older Africans. We replicated the frequently reported statistical[18] and conceptual[3],[20],[43] link between loneliness and current depression in older adults. In the context of our study, the association between loneliness and current MDD was partly explained by poor social engagement.

Our finding that social isolation in itself was not independently associated with current MDD in this population was surprising in the context of global literature. A closer look at our data suggests that few ISA participants had social isolation, and nearly all had regular contact with family members. It is thus feasible that the numbers of respondents with social isolation in the present study was too small to provide sufficient power for an investigation of its link to current MDD. The finding that only few ISA participants had poor contact with family is in keeping with the well-known multigenerational living arrangement in many African societies.

Despite being surrounded by family, poor social engagement remained significantly linked to MDD in this population. This result supports the observation that expectations of wider community experience is likely higher in “collectivist” societies such as those in most parts of Africa.[3] Prior observations in communal societies of Eastern Europe[3] and Appalacia[44] point to loss of social roles and responsibilities, along with social ties, as leading risk factors for loneliness and depression among older people.

We are not aware of studies in Sub-Saharan Africa (SSA) where quantitative methodologies have been used to investigate the association of loneliness and social relationship types with MDD. We identified a recent qualitative inquiry[45] from the Nigerian Niger-delta region where groups of older persons identified lack of social interaction as an important driver of self-perceived loneliness. Lack of social interaction was expounded by participants as having little or no opportunity for a conversation and sharing of meals with others.[45] Studies from other low- and middle-income countries such as Nepal[46] and China[47] investigated the relationship of living arrangements (living alone or with family) with loneliness. Similar to their reported findings, we found that social isolation and poor social engagement significantly increased the probability of loneliness in the present study.

Emerging body of evidence[48] suggests a range of effective interventions for loneliness and its association with depression in older adults. Interventions based on social activities,[49] group discussions, self-expression using art and creative methods, going on day-trips, networking with other older adults,[50] and links to community resources[51] have been shown to be effective in preventing loneliness. The findings in the present study thus support the need for culturally appropriate interventions for loneliness and its association with depression in SSA.

Our study has important limitations. First, loneliness in the ISA was measured in the follow-up study commencing in 2007. We note that deaths and losses to follow-up were recorded between 2003–2004 and 2007. Given these attritions, it is feasible that the 2007 sample may no longer be representative of the original sample. We found that those who were lost to follow-up between 2003–2004 and 2007 were more likely to belong in the lowest age category (65–69 years). As such, we ensured that the effect of age was accounted for across our analyses. To reduce the effect of losses to follow-up on our sample size, we recruited additional participants in 2007 using our original (2003–2004) sampling technique.

Second, due to possible reverse causality in our cross-sectional analyses, we may have overestimated the magnitude of association between loneliness and poor social engagement with MDD. Relatedly, cross-sectional analyses are inadequate in providing robust evidence for the direction of association between interrelated health conditions overtime. A careful longitudinal observation is thus needed to clarify the point of onset of depression in the course of loneliness. Such information will be important for the design of comprehensive interventions and guidelines for the management of loneliness in older Africans. A major strength of our study is the sample selection procedure, spread over a wide geographical area. The study is thus a contribution to the global literature on loneliness in older adults by examining the subjective experience in a large representative sample of community-dwelling older Africans and accounting for the effect of other important correlates in its association with current depression diagnosed according to the DSM-IV criteria.


Loneliness is common among community-dwelling older Nigerians. Despite regular contact with family, this subjective experience, along with poor social engagement, substantially increased the odds of late-life MDD in this SSA context. The association of loneliness with late-life MDD in this population is partly, but not totally, explained by poor social engagement. Therefore, this subjective experience on its own, irrespective of the objective indications of social network or engagement, is an important factor among persons with MDD. There are effective interventions for loneliness based on social activity schedules and networking programs which can be adapted to the social, economic, and cultural contexts of SSA. Such context-appropriate interventions should help reduce loneliness and lower the burden of late-life depression in the subregion.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


1Ayalon L, Shiovitz-Ezra S, Palgi Y. No place like home? Potential pathways to loneliness in older adults under the care of a live-in foreign home care worker. J Psychol 2012;146:189-200.
2Cacioppo JT, Hughes ME, Waite LJ, Hawkley LC, Thisted RA. Loneliness as a specific risk factor for depressive symptoms: Cross-sectional and longitudinal analyses. Psychol Aging 2006;21:140-51.
3Fokkema T, De Jong Gierveld J, Dykstra PA. Cross-national differences in older adult loneliness. J Psychol 2012;146:201-28.
4Dykstra PA. Older adult loneliness: Myths and realities. Eur J Ageing 2009;6:91-100.
5United Nations. The International Migration Report 2017. Geneva: United Nations; 2017.
6Leigh-Hunt N, Bagguley D, Bash K, Turner V, Turnbull S, Valtorta N, et al. An overview of systematic reviews on the public health consequences of social isolation and loneliness. Public Health 2017;152:157-71.
7The Academy of Medical Sciences. Challenges and Priorities of Global Mental Health in the Sustainable Development Goals (SDG) Era. London, United Kingdom: The Academy of Medical Sciences; 2018. p. 24.
8Gureje O, Ogunniyi A, Kola L, Abiona T. Incidence of and risk factors for dementia in the Ibadan study of aging. J Am Geriatr Soc 2011;59:869-74.
9Gureje O, Oladeji B, Abiona T. Incidence and risk factors for late-life depression in the Ibadan study of ageing. Psychol Med 2011;41:1897-906.
10Ojagbemi A, Bello T, Gureje O. Cognitive reserve, incident dementia, and associated mortality in the Ibadan study of ageing. J Am Geriatr Soc 2016;64:590-5.
11Ojagbemi A, Bello T, Gureje O. Gender differential in social and economic predictors of incident major depressive disorder in the Ibadan study of ageing. Soc Psychiatry Psychiatr Epidemiol 2018;53:351-61.
12Birmingham WC, Holt-Lunstad J. Social aggravation: Understanding the complex role of social relationships on stress and health-relevant physiology. Int J Psychophysiol 2018;131:13-23.
13Mushtaq R, Shoib S, Shah T, Mushtaq S. Relationship between loneliness, psychiatric disorders and physical health ? A review on the psychological aspects of loneliness. J Clin Diagn Res 2014;8:WE01-4.
14Cacioppo JT, Hawkley LC, Berntson GG, Ernst JM, Gibbs AC, Stickgold R, et al. Do lonely days invade the nights? Potential social modulation of sleep efficiency. Psychol Sci 2002;13:384-7.
15Adam EK, Hawkley LC, Kudielka BM, Cacioppo JT. Day-to-day dynamics of experience – cortisol associations in a population-based sample of older adults. Proc Natl Acad Sci U S A 2006;103:17058-63.
16Akerlind I, Hörnquist JO. Loneliness and alcohol abuse: A review of evidences of an interplay. Soc Sci Med 1992;34:405-14.
17Cacioppo JT, Hawkley LC. Perceived social isolation and cognition. Trends Cogn Sci 2009;13:447-54.
18Cacioppo JT, Hawkley LC, Thisted RA. Perceived social isolation makes me sad: 5-year cross-lagged analyses of loneliness and depressive symptomatology in the Chicago health, aging, and social relations study. Psychol Aging 2010;25:453-63.
19Ndlovu E, Tigere R. Economic migration and the socio-economic impacts on the emigrant's family: A case of ward 8, Gweru rural district, Zimbabwe. Jamba 2018;10:414.
20Hawkley LC, Cacioppo JT. Loneliness matters: A theoretical and empirical review of consequences and mechanisms. Ann Behav Med 2010;40:218-27.
21Hawkley LC, Hughes ME, Waite LJ, Masi CM, Thisted RA, Cacioppo JT, et al. From social structural factors to perceptions of relationship quality and loneliness: The Chicago health, aging, and social relations study. J Gerontol B Psychol Sci Soc Sci 2008;63:S375-84.
22Savikko N, Routasalo P, Tilvis RS, Strandberg TE, Pitkälä KH. Predictors and subjective causes of loneliness in an aged population. Arch Gerontol Geriatr 2005;41:223-33.
23Gureje O, Kola L, Afolabi E. Epidemiology of major depressive disorder in elderly Nigerians in the Ibadan study of ageing: A community-based survey. Lancet 2007;370:957-64.
24Ojagbemi A, Abiona T, Luo Z, Gureje O. Symptomatic and functional recovery from major depressive disorder in the Ibadan study of ageing. Am J Geriatr Psychiatry 2018;26:657-66.
25Hughes ME, Waite LJ, Hawkley LC, Cacioppo JT. A short scale for measuring loneliness in large surveys: Results from two population-based studies. Res Aging 2004;26:655-72.
26Russell D, Peplau LA, Cutrona CE. The revised UCLA loneliness scale: Concurrent and discriminant validity evidence. J Pers Soc Psychol 1980;39:472-80.
27Domènech-Abella J, Lara E, Rubio-Valera M, Olaya B, Moneta MV, Rico-Uribe LA, et al. Loneliness and depression in the elderly: The role of social network. Soc Psychiatry Psychiatr Epidemiol 2017;52:381-90.
28Steptoe A, Shankar A, Demakakos P, Wardle J. Social isolation, loneliness, and all-cause mortality in older men and women. Proc Natl Acad Sci U S A 2013;110:5797-801.
29Kessler RC, Ustün TB. The world mental health (WMH) survey initiative version of the World Health Organization (WHO) composite international diagnostic interview (CIDI). Int J Methods Psychiatr Res 2004;13:93-121.
30World Health Organization. WHO-Disability Assessment Schedule II. Geneva, Switzerland: World Health Organization; 1999.
31American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders: 4th edition (DSM IV) Text Revision. 4th ed. Washington DC: American Psychiatric Association; 1994.
32Yesavage JA, Brink TL, Rose TL, Lum O, Huang V, Adey M, et al. Development and validation of a geriatric depression screening scale: A preliminary report. J Psychiatr Res 1982;17:37-49.
33Sokoya OO, Baiyewu O. Geriatric depression in nigerian primary care attendees. Int J Geriatr Psychiatry 2003;18:506-10.
34Ogunniyi A, Osuntokun BO. Determination of ages of elderly Nigerians through historical events: Validation of ajayi-igun 1963 listing. West Afr J Med 1993;12:189-90.
35Ferguson B, Tandon A, Gakidou E. Estimating permanent income using indicator variables. In: Murray C, Evans D, editors. Health Systems Performance Assessment: Diabetes, Methods and Empericism. Geneva: World Health Organisation; 2003. p. 747-60.
36Katz S, Ford AB, Moskowitz RW, Jackson BA, Jaffe MW. Studies of illness in the aged. The index of adl: A standardized measure of biological and psychosocial function. JAMA 1963;185:914-9.
37Nagi SZ. An epidemiology of disability among adults in the United States. Milbank Mem Fund Q Health Soc 1976;54:439-67.
38Rao JN, Scott AJ, The analysis of categorical data from complex sample surveys: Chi-squared tests for goodness of fit and independence in two-way tables. J Am Stat Assoc 1981;76:221-30.
39Stata Corp. Stata Statistical Software. College Station, TX: StataCorp LP; 2013.
40Bandari R, Khankeh HR, Shahboulaghi FM, Ebadi A, Keshtkar AA, Montazeri A, et al. Defining loneliness in older adults: Protocol for a systematic review. Syst Rev 2019;8:26.
41Nyqvist F, Cattan M, Andersson L, Forsman AK, Gustafson Y. Social capital and loneliness among the very old living at home and in institutional settings: A comparative study. J Aging Health 2013;25:1013-35.
42Prieto-Flores ME, Fernandez-Mayoralas G, Forjaz MJ, Rojo-Perez F, Martinez-Martin P. Residential satisfaction, sense of belonging and loneliness among older adults living in the community and in care facilities. Health Place 2011;17:1183-90.
43Buchman AS, Boyle PA, Wilson RS, James BD, Leurgans SE, Arnold SE, et al. Loneliness and the rate of motor decline in old age: The rush memory and aging project, a community-based cohort study. BMC Geriatr 2010;10:77.
44Theeke LA, Goins RT, Moore J, Campbell H. Loneliness, depression, social support, and quality of life in older chronically ill appalachians. J Psychol 2012;146:155-71.
45Ojembe BU, Ebe Kalu M. Describing reasons for loneliness among older people in Nigeria. J Gerontol Soc Work 2018;61:640-58.
46Chalise HN, Kai I, Saito T. Social support and its correlation with loneliness: A cross-cultural study of Nepalese older adults. Int J Aging Hum Dev 2010;71:115-38.
47Cheng P, Jin Y, Sun H, Tang Z, Zhang C, Chen Y, et al. Disparities in prevalence and risk indicators of loneliness between rural empty nest and non-empty nest older adults in Chizhou, China. Geriatr Gerontol Int 2015;15:356-64.
48Hagan R, Manktelow R, Taylor BJ, Mallett J. Reducing loneliness amongst older people: A systematic search and narrative review. Aging Ment Health 2014;18:683-93.
49Pynnönen K, Törmäkangas T, Rantanen T, Tiikkainen P, Kallinen M. Effect of a social intervention of choice vs. control on depressive symptoms, melancholy, feeling of loneliness, and perceived togetherness in older Finnish people: A randomized controlled trial. Aging Ment Health 2018;22:77-84.
50Tsai HH, Tsai YF. Changes in depressive symptoms, social support, and loneliness over 1 year after a minimum 3-month videoconference program for older nursing home residents. J Med Internet Res 2011;13:e93.
51Saito T, Kai I, Takizawa A. Effects of a program to prevent social isolation on loneliness, depression, and subjective well-being of older adults: A randomized trial among older migrants in Japan. Arch Gerontol Geriatr 2012;55:539-47.