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. 2025 Jan 19;22(1):e12649. doi: 10.1111/jjns.12649

Loneliness‐associated factors among older adults: Focus on friendship type and number of friends

Yuriko Inoue 1, Hironobu Hamada 1,✉, Hisae Nakatani 2, Ichie Ono 1
PMCID: PMC11743425  PMID: 39828632

Abstract

Aim

Loneliness among older people is prevalent. Few studies have examined the association of loneliness with the type of friendship and number of friends. This study aimed to clarify the loneliness‐related factors among older adults by gender focusing on the type of friendship and number of friends.

Methods

An anonymous, self‐administered questionnaire survey was conducted on 1610 older adults in Japan. The questionnaire included basic characteristics, health status used by the self‐administered dementia checklist, type of friendship and number of friends evaluated by the Lubben Social Network Scale, and loneliness evaluated using the University of California, Los Angeles Loneliness Scale. Univariate analysis was performed with loneliness as the dependent variable, and multiple logistic regression analysis was also performed.

Results

A total of 1082 older adults were included for analysis. The loneliness rate was 16.8%. Regarding the type of friendship and number of friends, having <3 close friends to call on for help (tangible aid) was most associated with loneliness (men odds ratio [OR]: 2.88, women OR: 3.10). Higher awareness of the participants of subjective symptoms of dementia was proportionally related to loneliness (men, OR: 3.06; women, OR: 2.40). Among women, economic insecurity (OR: 1.68), subjective health (OR: 2.12), having <3 friends with whom they feel easy to talk about private matters (emotional support) were related to loneliness (OR: 2.38).

Conclusion

The results suggested that the type of friendship and number of friends, economic insecurity, and health status might be associated with loneliness among older adults. Several factors related to loneliness might differ by gender.

Keywords: aged, dementia, friends, health status, loneliness

1. INTRODUCTION

Globally, the proportion of the older adult population has grown (World Health Organization, 2022), and loneliness among older people is prevalent (World Health Organization, 2021). Loneliness is the painful subjective feeling that results from a discrepancy between desired and actual social connections (World Health Organization, 2021). Holménet et al. reported that older adults with cognitive decline subjectively experienced loneliness more often than those without it (Holmén et al., 1992). Loneliness is an important public health issue because of its adverse effects, including poor self‐perceived health (Alhalaseh et al., 2022; Dahlberg et al., 2021; Richard et al., 2017), cognitive decline (Boss et al., 2015; Cacioppo & Hawkley, 2009), functional decline in activities of daily living such as bathing, dressing, mobility, and toileting, and an increased risk of death (Perissinotto et al., 2012). Furthermore, loneliness is a risk factor for depressive symptoms (Cacioppo et al., 2006) and suicide among older adults (De Leo & Giannotti, 2021). Meta‐analyses have found that loneliness is associated with increased risk for early mortality (Holt‐Lunstad et al., 2015). The loneliness rate among older adults was reported to range from 11.5% to 23.5% in Japan (Kino et al., 2023; Takahashi et al., 2023), and from 10% to 55% in European countries (Hansen & Slagsvold, 2016). In Japan, the Act on Promotion of Policy for Loneliness and Isolation came into effect in 2024 to prevent loneliness and provide swift and appropriate support to persons in a state of loneliness (Cabinet Secretariat, 2024).

Connections with others affect subjective well‐being and physical and mental states. In physical health, the friend‐focused network type is more beneficial than the family‐focused network type (Li & Zhang, 2015). Social activities with friends may increase subjective well‐being in older adults (Huxhold et al., 2014). The intensity of relationship between friend support and loneliness was higher compared with that of other support (i.e., family and significant other support) (Zhang & Dong, 2022). Reportedly, older adults who receive more support from friends are less likely to experience loneliness (Bu et al., 2020; Chen et al., 2019); however, research on the specific types and numbers of friends has been insufficient. In addition, several reports have examined whether gender is related to loneliness, but no consistent results have been obtained (Lin et al., 2022; Ruan et al., 2023; Savage et al., 2021). Therefore, this study aimed to clarify factors related to loneliness in older adults by gender, focusing on the type of friendship and number of friends. Identifying specific loneliness‐associated factors, including the type of friendship and number of friends, could be useful while considering interventions for reducing loneliness among community‐dwelling older adults, which may improve their quality of life including mental health.

2. METHODS

2.1. Research design

This was a cross‐sectional study using anonymous self‐administered questionnaires.

2.2. Participants

The study participants were older adults aged ≥65 years living in a rural area (with a population of approximately 27,000, aging rate of 40.9%, population density of 49.2 people/km2; older men, 43.0%; older women, 57.0%, as of May 1, 2024) in Japan. They were members of a senior citizens club, a community‐based organization for older adults offering activities supported by the national and local governments (Japan Federation of Senior Citizens Clubs, n.d.) who were able to fill out a self‐administered survey questionnaire. The sample size was set so that the data collected had events per variable of ≥10 (Peduzzi et al., 1996). Accordingly, this study requires at least 866 participants, men and women, to identify loneliness‐related factors by gender.

2.3. Survey methods

Before the survey, senior club officials provided written and verbal explanations of the significance, purpose, methods, and ethical considerations of the study and distributed questionnaires to 1610 participants. The participants completed the questionnaires voluntarily and sealed envelopes containing the questionnaires were later collected by senior club officials. The survey was conducted from December 2022 to January 2023, during which lockdowns and curfew restrictions had been eased, as stay‐at‐home orders due to COVID‐19 were associated with increased loneliness (Tull et al., 2020).

2.4. Survey contents

2.4.1. Basic characteristics

Basic characteristics included gender, age, household status, marital status, children, frequency of outing, frequency of participation in social activities, and economic insecurity. The frequency of outings and participation in social activities were categorized into at least once a week or more and less than once a week, which are proxy indicators of the levels of connectedness (Saito et al., 2019) and social isolation (Saito et al., 2010). Regarding economic insecurity, the respondents were asked about their perception of their economic situation through the question, “Do you have economic insecurity?” using a four‐point scale (not worried, not too worried, a little worried, and worried). In this study, economic insecurity was categorized into “not worried” (including “not worried,” and “not too worried”), and “worried” (including “a little worried” and “worried”).

2.4.2. Health status

Regarding health status, respondents were inquired about the presence of illness, subjective health, and subjective symptoms of dementia. Subjective health was assessed by asking, “How do you perceive your health?” using a five‐point scale (good, fairly good, normal, fairly poor, and poor). In this study, subjective health was categorized into high (including “good,” “fairly good,” and “normal”), and low (including “fairly poor” and “poor”). Subjective symptoms of dementia were assessed using a self‐administered dementia checklist (SDC) (Miyamae et al., 2016; Murayama et al., 2018; Ura et al., 2015). The SDC was developed to enable community‐dwelling older adults to recognize their declining functions at an early stage of dementia. The scale includes 10 items, each using a four‐point Likert scale and two subscales: subjective cognitive decline (five items) and instrumental activities of daily living (five items about using transport, shopping, managing money, housework, and using the telephone). The concurrent and discriminant validities of SDC were confirmed using the mini‐mental state examination (Folstein et al., 1975) and the clinical dementia rating scale (Morris, 1993), global rating devices for evaluating the severity of dementia symptoms (Miyamae et al., 2016). The score ranges from 10 to 40, with higher scores indicating greater severity of subjective dementia symptoms. In this study, subjective symptoms of dementia were divided into “no” (scores <18) and “yes” (scores ≥18) based on previous studies (Miyamae et al., 2016).

2.4.3. Type of friendship and number of friends

Social connection is a concept that encompasses the structure (e.g., social network and social isolation), functions (functions provided or perceived as available by social relationships to meet various needs, including emotional, physical, tangible, informational, and belonging need), and quality of social relationships (Holt‐Lunstad, 2018; Holt‐Lunstad, 2022). In addition, social connection is a multifactorial construct on a continuum from risk when social connection is low to protection when social connection is high (Holt‐Lunstad, 2022). The abbreviated version of the Lubben Social Network Scale (LSNS‐6), which is widely used internationally, consists of three questions that evaluate kinship ties (relatives) and three that evaluate nonkin ties (friends, including those who live in their neighborhood) (Lubben et al., 2006). The LSNS‐6 is focused on function and structure of social connection (Valtorta et al., 2016). In this study, the three nonkin ties items were used to assess the type of friendship and the number of friends. The functional aspect of friendship type consisted of two questions: “How many friends do you feel close to such that you could call on them for help?” (tangible aid) and “How many friends do you feel at ease with that you can talk about private matters?” (emotional support). The structural aspect of friendship type consisted of the following question: “How many friends do you see or hear from at least once a month?” (size and frequency of contact) (Miyashita et al., 2019; Valtorta et al., 2016). The three items were asked using a six‐point Likert scale (0, 1, 2, 3–4, 5–8, and >9) and each question was scored from 0 to 5 points; the higher the number of friends, the higher the score. Herein, five classifications were assumed while dividing the number of friends into two groups based on the six‐point Likert scale of the LSNS‐6: (i) “0” and “≥ 1,” (ii) “< 2” and “≥ 2,” (iii) “< 3” and “≥ 3,” (iv) “< 5” and “≥ 5,” and (v) “< 9” and “≥ 9.”

2.4.4. Loneliness

Loneliness was assessed using the Revised University of California, Los Angeles (UCLA) loneliness scale (Russell, 1996). In this study, the three‐item UCLA loneliness scale (Hughes et al., 2004) was used to reduce the burden on participants. This scale comprises the following three questions: “How often do you feel that you lack companionship?” “How often do you feel left out?”, and “How often do you feel isolated from others?” These are assessed on a three‐point Likert scale (hardly ever, some of the time, and often), and the score ranges from 3 to 9, with higher scores indicating greater loneliness. In this study, loneliness was categorized as “not lonely” (3–5 points on the UCLA loneliness scale) and “lonely” (6–9 points based on previous studies) (Ge et al., 2017; Qi et al., 2023; Victor et al., 2022).

2.5. Statistical analyses

The survey questionnaires with missing data on basic characteristics, health status, LSNS‐6, and UCLA loneliness scale were excluded. For statistical analysis, the differences between the two groups with respect to loneliness and basic characteristics and health status were compared using the χ2 test or Fisher's exact test and differences in age and number of close friends using the Mann–Whitney U‐test. Univariate analysis was used to identify potential influencing factors (p < 0.1) (Li et al., 2022; Wang et al., 2023; Xin et al., 2022) associated with loneliness. Consequently, models with different numbers of friends were created, and multiple logistic regression analysis (forced entry method) was performed with these independent variables as covariates. After converting the variables into dummy ones, multicollinearity was considered, and the variance inflation factor (VIF) was verified. To confirm the goodness of fit of the logistic regression analysis model, the Hosmer–Lemeshow test and the area under the curve (AUC) analysis using the receiver operating characteristic curve were performed. In addition, the models were compared using the Akaike information criterion (AIC) (Akaike, 1974) and the Bayesian information criterion (BIC) (Schwarz, 1978), and the model with the smallest values was considered the optimal model (Kuha, 2004; Moran et al., 2021). IBM SPSS Statistics for Windows version 29 (IBM Corp., Armonk, NY) was used for the analysis, and a significance level of <5% indicated a significant difference.

2.6. Ethical considerations

The participants were informed in writing and verbally that their cooperation was voluntary, they would not suffer any disadvantages for declining participation, and information that might lead to their identification was not described. Participants provided written informed consent to participate in the study. This study was approved by the Ethics Committee for Epidemiological Research of the Hiroshima university (Approval no. E2022‐0020 dated September 20, 2022). This study was conducted in accordance with the ethical standards established by the Declaration of Helsinki.

3. RESULTS

Of the 1382 filled questionnaires (response rate, 85.8%), 300 were incomplete and thus were excluded, and 1082 (men, n = 480, 44.4%; women, n = 602; 55.6%) were analyzed (valid response rate, 67.2%) (Figure 1). The scales used in the study were tested for normality (Shapiro–Wilk test) and did not follow a normal distribution (p < .001). The reliability coefficients (Cronbach's alpha coefficients) were 0.889, 0.876, and 0.845 for the SDC, LSNS‐6 (neighborhood and friends, three items), and UCLA loneliness scale, respectively.

FIGURE 1.

FIGURE 1

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Flowchart of the study participants.

3.1. Participant characteristics by gender

The characteristics of the participants by gender are shown in Table 1. The average age of participant was 80.7 ± 6.6 years, 79.0% of them lived with their family or others. Moreover, 30.0% of the participants went out less than once a week, 67.2% participated in social activities less than once a week, and 52.9% were economically insecure.

TABLE 1.

Participant characteristics by gender.

Overall (n = 1082) Men (n = 480) Women (n = 602) p‐Value
Basic characteristics
Mean age (SD) 80.7 (6.6) 79.9 (6.6) 81.3 (6.6) <.001 a
Age
65–74 197 (18.2) 106 (21.1) 91 (15.1) .007 b
75–84 565 (52.2) 247 (51.5) 318 (52.8)
>85 320 (29.6) 127 (26.5) 193 (32.1)
Household composition
Living with spouse/children/others 855 (79.0) 422 (87.9) 433 (71.9) <.001 b
Living alone 227 (21.0) 58 (12.1) 169 (28.1)
Marital status
Married 1075 (99.4) 474 (98.8) 601 (99.8) .049 c
Unmarried 7 (0.6) 6 (1.3) 1 (0.2)
Having a child (children)
Yes 1039 (96.0) 457 (95.2) 582 (96.7) .219 b
No 43 (4.0) 23 (4.8) 20 (3.3)
Frequency of outing
Once a week+ 757 (70.0) 349 (72.7) 408 (67.8) .079 b
Less than once a week 325 (30.0) 131 (27.3) 194 (32.2)
Frequency of participation in social activities
Once a week+ 355 (32.8) 137 (28.5) 217 (36.2) .008 b
Less than once a week 727 (67.2) 343 (71.5) 384 (63.8)
Economic insecurity
Not worried 510 (47.1) 225 (46.9) 285 (47.3) .878 b
Worried 572 (52.9) 255 (53.1) 317 (52.7)
Health status
Illness
No 178 (16.5) 85 (17.7) 93 (15.4) .319 b
Yes 904 (83.5) 395 (82.3) 509 (84.6)
Subjective health
High 748 (69.1) 336 (70.0) 412 (68.4) .581 b
Low 334 (30.9) 144 (30.0) 190 (31.6)
Subjective symptoms of dementia
No 781 (72.2) 349 (72.7) 432 (71.8) .730 b
Yes 301 (27.8) 131 (27.3) 170 (28.2)
Loneliness
UCLA loneliness scale score (SD) 3.85 (1.34) 3.79 (1.32) 3.89 (1.36) .244 a
Median (IQR) 3 (3–4) 3 (3–4) 3 (3–5)
Loneliness
Not lonely 900 (83.2) 405 (84.4) 495 (82.2) .348 b
Lonely 182 (16.8) 75 (15.6) 107 (17.8)
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Note: The mean age and UCLA loneliness scale score are shown as mean (standard deviation), whereas other data are shown as n (%).

Abbreviations: IQR, interquartile range; SD, standard deviation; UCLA, University of California, Los Angeles.

a

Comparisons between men and women were performed using the Mann–Whitney U‐test.

b

Comparisons between men and women were performed using the χ2 test.

c

Comparisons between men and women were performed using Fisher's exact test.

Compared with men, women were older on average (p < .001), more lived alone (p < .001), and more frequently participated in social activities (p = .008). No significant differences in the frequency of going out, economic insecurity, or health status were found between men and women.

The UCLA loneliness scale score of the participants was 3.85 ± 1.34, with no significant difference between men and women. The proportions of older adults who felt lonely were 16.8%, with no significant difference between men and women (15.6% vs. 17.8%).

3.2. Loneliness‐associated factors

3.2.1. Association of basic characteristics and health status with loneliness

The associations of basic characteristics and health status with loneliness by gender are shown in Table 2. The mean age of men who felt lonely were significantly older than men who did not feel lonely (p = .003), and the frequency of outing less than once a week was significantly higher (p = .016). Among women who felt lonely, the frequency of outing (p = .047) or participating in social activities less than once a week was significantly higher than those who did not feel lonely (p = .009), and the rate of being economically insecure was also significantly higher (p = .007). Regarding health status, older adults who felt lonely had significantly higher rates of low subjective health status and those with dementia symptoms than older adults who did not feel lonely in both genders (all, p < .001).

TABLE 2.

Associations of basic characteristics and health status with loneliness.

Men p‐value Women p‐Value
Not lonely Lonely Not lonely Lonely
(n = 405) (n = 75) (n = 495) (n = 107)
Basic characteristics
Mean age 79.6 (6.6) 82.0 (6.5) .003 a 81.1 (6.3) 82.5 (7.5) .061 a
Household composition
Living with spouse/children/others 360 (88.9) 62 (82.7) .129 b 361 (72.9) 72 (67.3) .239 b
Living alone 45 (11.1) 13 (17.3) 134 (27.1) 35 (32.7)
Marital status
Married 400 (98.8) 74 (98.7) 1.000 c 494 (99.8) 107 (100.0)
Unmarried 5 (1.2) 1 (1.3) 1 (0.2) 0 (0.0)
Having a child (children)
Yes 384 (94.8) 73 (97.3) .555 c 479 (96.8) 103 (96.3) .767 c
No 21 (5.2) 2 (2.7) 16 (3.2) 4 (3.7)
Frequency of outing
Once a week+ 303 (74.8) 46 (61.3) .016 b 348 (70.3) 60 (56.1) .047 b
Less than once a week 102 (25.2) 29 (38.7) 147 (29.7) 47 (43.9)
Frequency of participation in social activities
Once a week+ 117 (28.9) 20 (28.5) .695 b 191 (38.6) 27 (25.2) .009 b
Less than once a week 288 (71.1) 55 (73.3) 304 (61.4) 80 (74.8)
Economic insecurity
Not worried 197 (48.6) 28 (37.3) .071 b 247 (49.9) 38 (35.5) .007 b
Worried 208 (51.4) 47 (62.7) 248 (50.1) 69 (64.5)
Health status
Illness
No 74 (18.3) 11 (14.7) .453 b 80 (16.2) 13 (12.1) .298 b
Yes 331 (81.7) 64 (85.3) 415 (83.8) 94 (87.9)
Subjective health
High 299 (73.8) 37 (49.3) <.001 b 360 (72.7) 52 (48.6) <.001 b
Low 106 (26.2) 38 (50.7) 135 (27.3) 55 (51.4)
Subjective symptoms of dementia
No 317 (78.3) 32 (42.7) <.001 b 378 (76.4) 54 (50.5) <.001 b
Yes 88 (21.7) 43 (57.3) 117 (23.6) 53 (49.5)
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Note: The mean age are shown as mean (standard deviation), whereas other data are shown as n (%).

a

Comparisons were performed using the Mann–Whitney U‐test.

b

Comparisons were performed using the χ2 test.

c

Comparisons were performed using Fisher's exact test.

3.2.2. Associations of the type of friendship and number of friends with loneliness

The associations of the type of friendship and number of friends with loneliness are shown in Table 3. For both genders, compared with older adults who did not feel lonely, those who felt lonely had lower LSNS‐6 scores on all three types of friendship (all, p < .001).

TABLE 3.

Associations between the type of friendship and number of friends with loneliness.

Men p‐value Women p‐Value
Overall Not lonely Lonely Overall Not lonely Lonely
(n = 480) (n = 405) (n = 75) (n = 602) (n = 495) (n = 107)
Type of friendship and number of friends
Any close friends to call on for help (tangible aid)
LSNS score
Mean (SD) a 2.19 (1.31) 2.38 (1.26) 1.19 (1.12) <.001 2.03 (1.21) 2.22 (1.15) 1.14 (1.05) <.001
Median (IQR) a 2 (1–3) 3 (2–3) 1 (0–2) 2 (1–3) 2 (2–3) 1 (0–2)
Number of people n (%) b
0 78 (16.3) 48 (11.9) 30 (40.0) 93 (15.4) 52 (10.5) 41 (38.3)
1 56 (11.7) 44 (10.9) 12 (16.0) 82 (13.6) 62 (12.5) 20 (18.7)
2 114 (23.8) 92 (22.7) 22 (29.3) 201 (33.4) 164 (33.1) 37 (34.6)
3–4 173 (36.0) 162 (40.4) 11 (14.7) 177 (29.4) 169 (34.1) 8 (7.5)
5–8 47 (9.8) 47 (11.6) 0 (0.0) 39 (6.5) 38 (7.7) 1 (0.9)
>9 12 (2.5) 12 (3.0) 0 (0.0) 10 (1.7) 10 (2.0) 0 (0.0)
Any friends to feel at ease with talking about private matters (emotional support)
LSNS score
Mean (SD) a 2.30 (1.35) 2.49 (1.29) 1.25 (1.16) <.001 2.19 (1.20) 2.39 (1.14) 1.24 (1.03) <.001
Median (IQR) a 3 (1–3) 3 (2–3) 1 (0–2) 2 (1–3) 3 (2–3) 1 (0–2)
Number of people n (%) b
0 74 (15.4) 45 (11.1) 29 (38.7) 65 (10.8) 31 (6.3) 34 (31.8)
1 49 (10.2) 37 (9.1) 12 (16.0) 94 (15.6) 69 (13.9) 25 (23.4)
2 107 (22.3) 87 (21.5) 20 (26.7) 183 (30.4) 147 (29.7) 36 (33.6)
3–4 185 (38.5) 171 (42.2) 14 (18.7) 202 (33.6) 190 (38.4) 12 (11.2)
5–8 41 (8.5) 41 (10.1) 0 (0.0) 38 (6.3) 38 (7.7) 0 (0.0)
>  9 24 (5.0) 24 (5.9) 0 (0.0) 20 (3.3) 20 (4.0) 0 (0.0)
Any friends to see or hear from at least once a month (size and frequency of contact)
LSNS score
Mean (SD) a 2.79 (1.45) 3.00 (1.37) 1.61 (1.31) <.001 2.78 (1.33) 2.99 (1.22) 1.82 (1.39) <.001
Median (IQR) a 3 (2–4) 3 (2–4) 2 (0–3) 3 (2.4) 3 (2–4) 2 (1–3)
Number of people n (%) b
0 54 (11.3) 31 (7.7) 23 (30.7) 44 (7.3) 22 (4.4) 22 (20.6)
1 28 (5.8) 18 (4.4) 10 (13.3) 50 (8.3) 26 (5.3) 24 (22.4)
2 88 (18.3) 69 (17.0) 19 (25.3) 130 (21.6) 101 (20.4) 29 (27.1)
3–4 176 (36.7) 156 (38.5) 20 (26.7) 217 (36.0) 195 (39.4) 22 (20.6)
5–8 65 (13.5) 63 (15.6) 2 (2.7) 93 (15.4) 90 (18.2) 3 (2.8)
>9 69 (14.4) 68 (16.8) 1 (1.3) 68 (11.3) 61 (12.3) 7 (6.5)
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Note: The score for each LSNS question ranges from 0 to 5 points (0, 0 points; 1, 1 point; 2, 2 points; 3–4, 3 points; 5–8, 4 points; >9, 5 points).

Abbreviations: IQR, interquartile range; LSNS, Lubben Social Network Scale; SD, standard deviation.

a

The number of friends score are shown as the mean (SD) and median (IQR) of the LSNS score. Comparisons between the not lonely and lonely groups were performed using the Mann–Whitney U‐test.

b

Other data are shown as n (%).

3.3. Loneliness‐associated factors among older men and women

Univariate analyses of the friendship type and number of friends showed that few or none of the older adults who felt lonely had >5 friends of each friendship type (Table 3). Three models with different numbers of friends for loneliness‐related factors were created and examined (model 1, the explanatory variables showed significant differences in the univariate analysis and classified the number of friends for each friendship type into “0” and “≥1”; model 2, the explanatory variables showed significant differences in the univariate analysis and classified the number of friends for each friendship type into “<2” and “≥2”; model 3, the explanatory variables showed significant differences in the univariate analysis and classified the number of friends for each friendship type into “<3” and “≥3”). The results of the logistic regression analysis and AUC value are shown in Tables 4 and 5. The Hosmer–Lemeshow test had p > .05 for all models, the AIC and BIC values were the smallest for model 3, and the AUC value was the highest for model 3. Therefore, model 3 was the optimal model for men and women.

TABLE 4.

Loneliness‐associated factors in men.

Model 1 Model 2 Model 3
OR 95% CI p‐Value OR 95% CI p‐Value OR 95% CI p‐Value
Age 1.03 (0.99–1.08) .182 1.03 (0.98–1.07) .280 1.03 (0.98–1.08) .256
Frequency of outing
Once a week+ Ref Ref Ref
Less than once a week 1.03 (0.55–1.92) .931 0.93 (0.50–1.74) .816 0.95 (0.50–1.79) .869
Economic insecurity
Not worried Ref Ref Ref
Worried 1.33 (0.73–2.43) .355 1.47 (0.80–2.69) .216 1.62 (0.88–2.98) .124
Subjective health
High Ref Ref Ref
Low 1.99 (1.10–3.59) .023 1.90 (1.04–3.45) .037 1.81 (0.99–3.33) .056
Subjective symptoms of dementia
No Ref Ref Ref
Yes 3.02 (1.63–5.61) <.001 3.14 (1.68–5.85) <.001 3.06 (1.62–5.77) <.001
Type of friendship
Any close friends to call on for help (tangible aid) 2.50 (0.97–6.45) .057 1.81 (0.81–4.08) .151 2.88 (1.17–7.10) .021
Any friends to feel at ease with talking about private matters (emotional support) 1.41 (0.51–3.93) .510 1.78 (0.75–4.20) .191 1.51 (0.62–3.69) .370
Any friends to see or hear from at least once a month (size and frequency of contact) 1.95 (0.79–4.82) .149 2.36 (1.13–4.93) .022 2.67 (1.36–5.25) .004
Significance of the Hosmer–Lemeshow test 0.92 0.55 0.54
Model chi‐square test p < .001 p < .001 p < .001
Percentage of correct classifications 86.0 86.5 85.4
AIC 306.71 318.90 299.81
BIC 344.27 356.46 337.37
AUC 0.783 0.803 0.825
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Note: In the multiple logistic regression analysis (forced entry method), indicators that showed significant differences in the univariate analysis were used as explanatory variables (significance level, p < .1). Model 1: Indicators for which significant differences were found in univariate analysis and number of friends for each friendship type (“0” and “≥1”) were used as explanatory variables. Model 2: Indicators for which significant differences were found in univariate analysis and number of friends for each friendship type (“<2” and “≥2”) were used as explanatory variables. Model 3: Indicators for which significant differences were found in univariate analysis and number of friends for each friendship type (“<3” and “≥3”) were used as explanatory variables.

Abbreviations: AIC, Akaike's information criterion; AUC, area under the curve; BIC, Bayesian information criterion; CI, confidence interval; OR, odds ratio; Ref, reference category.

TABLE 5.

Loneliness‐associated factors in women.

Model 1 Model 2 Model 3
OR 95% CI p‐Value OR 95% CI p‐Value OR 95% CI p‐Value
Age 1.00 (0.96–1.04) .832 0.99 (0.95–1.03) .523 0.97 (0.93–1.01) .144
Frequency of outing
Once a week+ Ref Ref Ref
Less than once a week 0.92 (0.53–1.61) .771 0.86 (0.48–1.53) .602 0.92 (0.52–1.61) .769
Frequency of participation in social activities
Once a week+ Ref Ref Ref
Less than once a week 1.59 (0.94–2.70) .085 1.40 (0.82–2.39) .218 1.47 (0.86–2.52) .159
Economic insecurity
Not worried Ref Ref Ref
Worried 1.83 (1.12–2.98) .016 1.82 (1.11–2.98) .019 1.68 (1.03–2.75) .038
Subjective health
High Ref Ref Ref
Low 1.93 (1.19–3.13) .008 1.99 (1.22–3.24) .006 2.12 (1.30–3.46) .003
Subjective symptoms of dementia
No Ref Ref Ref
Yes 2.32 (1.35–3.99) .002 2.16 (1.25–3.74) .006 2.40 (1.38–4.18) .002
Type of friendship
Any close friends to call on for help (tangible aid) 2.52 (1.31–4.84) .006 1.55 (0.79–3.04) .198 3.10 (1.28–7.50) .012
Any friends to feel at ease with talking about private matters (emotional support) 2.97 (1.31–6.75) .009 1.74 (0.89–3.41) .105 2.38 (1.04–5.44) .040
Any friends to see or hear from at least once a month (size and frequency of contact) 0.98 (0.40–2.41) .967 3.08 (1.55–6.14) .001 2.18 (1.24–3.83) .007
Significance of the Hosmer–Lemeshow test 0.83 0.28 0.69
Model chi‐square test p < .001 p < .001 p < .001
Percentage of correct classifications 83.7 84.1 85.4
AIC 426.98 442.09 426.04
BIC 470.98 486.09 470.04
AUC 0.763 0.782 0.806
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Note: In the multiple logistic regression analysis (forced entry method), indicators that showed significant differences in the univariate analysis were used as explanatory variables (significance level, p < .1). Model 1: Indicators for which significant differences were found in univariate analysis and number of friends for each friendship type (“0” and “≥ 1”) were used as explanatory variables. Model 2: Indicators for which significant differences were found in univariate analysis and number of friends for each friendship type (“< 2” and “≥ 2”) were used as explanatory variables. Model 3: Indicators for which significant differences were found in univariate analysis and number of friends for each friendship type (“< 3” and “≥ 3”) were used as explanatory variables.

Abbreviations: AIC, Akaike's information criterion; AUC, area under the curve; BIC, Bayesian information criterion; CI, confidence interval; OR, odds ratio; Ref, reference category.

In men (Table 4), the odds ratios for loneliness in model 3 were 3.06 (95% confidence interval [CI], 1.62–5.77, p < .001) for having subjective symptoms of dementia, 2.88 (95% CI, 1.17–7.10, p = .021) for having <3 close friends to call on for help, and 2.67 (95% CI, 1.36–5.25, p = .004) for having <3 friends to see or hear from at least once a month. In this model, the maximum VIF value was 2.357, which did not exceed 10, indicating no multicollinearity.

Among women (Table 5), the odds ratios for loneliness in model 3 were 1.68 (95% CI, 1.03–2.75, p = .038) for having economic insecurity, 2.12 (95% CI, 1.30–3.46, p = .003) for a feeling of having poor subjective health, 2.40 (95% CI, 1. 38–4.18, p = .002) for having subjective symptoms of dementia, 3.10 (95% CI, 1.28–7.50, p = .012) for having <3 close friends to call on for help, 2.38 (95% CI, 1.04–5.44, p = .040) for having <3 friends whom they feel at ease talking about private matters, and 2.18 (95% CI, 1.24–3.83, p = .007) for having <3 friends to see or hear from at least once a month. The maximum VIF value in this model was 2.715, which did not exceed 10, indicating no multicollinearity.

4. DISCUSSION

This study showed loneliness‐associated factors among older adults by gender. With respect to the type of friendship and number of friends, having <3 close friends to call on for help was most related to loneliness. Awareness toward subjective symptoms of dementia was associated with loneliness. Economic insecurity, subjective health, or having <3 friends whom they feel at ease talking about private matters were related to loneliness only among women. This study proposed that the type of friendship and number of friends as well as economic insecurity, subjective health, and subjective symptoms of dementia might be associated with loneliness among older adults; however, several factors related to loneliness might differ by gender.

To the best of our knowledge, this is the first study to clarify the associations of the type of friendship and number of friends with loneliness among older adults by gender in the post‐COVID‐19 era. Chen et al. reported that people who received more social support from friends were less likely to experience loneliness; however, they did not describe the type of friendship and number of friends (Chen et al., 2019). Bu et al. reported that having three or more close friends is a resilience factor that protects against loneliness (Bu et al., 2020); however, the study did not mention about type of close friendship associated with loneliness. The present study presents the relationship of loneliness with the type of friendship and number of friends. This study revealed that having <3 close friends to call on for help with tangible aid was most associated with loneliness in men and women (men vs. women; odds ratio, 2.88 vs. 3.10). Previous study reported that the situation of “call on for help” for older adults would be circumstances, such as medical situations, threats, emergencies, when they needed to call for support (Vilar‐Compte et al., 2018). The discrepancy between older adults' desired and provided by or perceived to be available levels of social support might lead to feelings of loneliness. The study suggested that ascertaining the number of close friends to call on for help might be a useful indicator related to loneliness among older adults. Having <3 friends to see or hear from at least once a month were also associated with loneliness in men and women. This result echoes previous research, suggesting a relationship between small social network and loneliness (Domènech‐Abella et al., 2017).

In addition, participants who were more aware of the subjective symptoms of dementia were likely to be lonelier than those who were not. Lee et al. reported that cognitive impairment, but not dementia, and dementia status are associated with loneliness (Lee et al., 2022). Ayalon et al. reported that lower levels of memory functioning preceded with higher levels of loneliness 4 years later (Ayalon et al., 2016). Cognitive decline was associated with loss of relationships, most likely friends and neighbors (Aartsen et al., 2004). Loneliness and small social network in older adults were associated with increased mortality (Schutter et al., 2022). Continuous observation of the subjective symptoms of dementia in older adults with the support of medical, nursing, and welfare professionals could be useful in preventing loneliness and helping people escape from loneliness.

Concerning gender differences in this study, the loneliness rates were 15.6% in older men and 17.8% in older women, with no gender difference. This result supports previous meta‐analysis reporting that gender differences in loneliness disappear in old age (Maes et al., 2019). However, the results suggest that several factors related to loneliness differed by gender. Previous studies have reported that subjective health and low socioeconomic status are associated with loneliness (Hansen & Slagsvold, 2016); however, in this study, subjective health and economic insecurity were associated with loneliness only in women. The reason might be that women were older on average and a higher proportion of them lived alone than men. Women may be at greater risk for loneliness because they have a longer life expectancy than men and therefore may more likely experience losses in their social network (Cohen‐Mansfield et al., 2016). The magnitude of the causal relationship between cumulative economic hardships and poor health outcomes such as self‐rated health differed by gender, and financial stress appeared to be a strong predictor of poor health outcomes, particularly among women (Ahnquist et al., 2007). Furthermore, women who have <3 friends whom they feel at ease talking about private matters were lonely. The way to maintain the emotional closeness of friendships may differ by gender, with women needing to make an effort to spend more time talking together and men needing to increase doing more activities together (Dunbar, 2018; Roberts & Dunbar, 2015). Fiori et al. reported that the receipt of emotional support was associated with mental health in women only (Fiori & Denckla, 2012). Further studies are needed as to whether creating a social system in which older adults build social connection with close friends will prevent loneliness and improve their quality of life, including their mental health.

4.1. Research limitations

This study had several limitations. First, the survey was conducted in one limited area, and the generalizability of the findings is limited. Therefore, further research is required to clarify whether similar results will be observed in other areas with similar population density, aging rates, and social factors. In addition, environmental factors such as access to services and transportation (Levasseur et al., 2015), relationship between social participation and self‐rated health (Tobiasz‐Adamczyk & Zawisza, 2017), and poverty rates (United States Department of Agriculture, 2024) differ between rural and urban areas. Although several studies have examined the differences in loneliness between rural and urban areas, results have been inconsistent (Abshire et al., 2022; Bu et al., 2020; Takagi et al., 2022). Thus, further research needs to performed on urban areas. Second, given the cross‐sectional design of this study, longitudinal and intervention studies are warranted to verify this association. Third, the generalizability of the findings is limited because the study mainly focuses on older adults who were able to complete the survey on their own. Fourth, by asking about the actual number of friends, other models can be considered. Further research on the number of friends is needed.

5. CONCLUSIONS

The results suggest that the type of friendship and number of friends, as well as economic insecurity, subjective health, and subjective symptoms of dementia, might be associated with loneliness among older adults, and that several factors related to loneliness may differ by gender.

AUTHOR CONTRIBUTIONS

Yuriko Inoue and Hisae Nakatani contributed to the conception and design of this study; Yuriko Inoue performed the statistical analysis; Yuriko Inoue, Hisae Nakatani, and Ichie Ono carried out the data collection and analysis; Yuriko Inoue and Hironobu Hamada drafted the manuscript; Yuriko Inoue, Hironobu Hamada, Hisae Nakatani, and Ichie Ono reviewed the manuscript; Hironobu Hamada and Hisae Nakatani contributed to the project administration of this study; Hisae Nakatani supervised the whole study process. All authors read and approved the final manuscript.

FUNDING INFORMATION

This work was supported by JST SPRING (grant number JPMJSP2132), and the France Bed Medical Home Care Research Subsidy Public Interest Incorporated Foundation (grant number FBK220531026). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

CONFLICT OF INTEREST STATEMENT

The authors declare that there is no conflict of interest.

ACKNOWLEDGMENTS

The authors would like to thank the city hall staff and senior citizens club officials who cooperated with this study, and all those who participated in the survey. The authors would like to thank Enago (www.enago.jp) for the English language review.

Inoue, Y. , Hamada, H. , Nakatani, H. , & Ono, I. (2025). Loneliness‐associated factors among older adults: Focus on friendship type and number of friends. Japan Journal of Nursing Science, 22(1), e12649. 10.1111/jjns.12649

DATA AVAILABILITY STATEMENT

The data that support the findings of this study are available on request from the corresponding author.

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Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Data Availability Statement

The data that support the findings of this study are available on request from the corresponding author.

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