Loneliness before and during the COVID-19 pandemic: A systematic review with meta-analysis.

In the paper

“In total, 34 articles met the eligibility criteria”

• Also stated in: § Study Characteristics of Included Studies · plain

  “Table 1 provides a summary of the main information extracted from the 34 eligible articles, totaling 215,026 participants”

In the paper

“Of the studies reporting comparisons of loneliness pre- and during-pandemic, only one reported an overall decrease, 18 reported an overall increase, and eight reported no change”

In the paper

“Increases in loneliness were found both in younger participant groups, such as students (Beutel et al., 2021; Elmer et al., 2020; Entringer & Gosling, 2021; Rogers et al., 2021) and in older participant groups, such as community cohorts of senior citizens (Heidinger & Richter, 2020; Krendl & Perry, 2021; Wong et al., 2020)”

In the paper

“Studies showing decreasing loneliness had overwhelmingly relied on pre-pandemic assessments conducted shortly before the implementation of physical distancing, while those with comparison data from months or years before the pandemic had observed increased loneliness during the pandemic”

In the paper

“The meta-regression identified age, clinical populations, and studies’ overall RoB as predictors of increases in loneliness, but only overall RoB had statistically significant effects.”

In the paper

“As some original studies failed to report on previously identified vulnerable groups (e.g., individuals living alone), these could not be tested as predictors.”

In the paper

“Most studies had a serious overall RoB. For ten studies (seven of which were included in the main analyses), RoB was rated as moderate”

In the paper

“In summary, there was a substantial number of studies with high RoB due to confounding, whereas bias due to selective reporting of results (including effect estimates) was rare”

In the paper

“As included studies mainly derived from the US and Europe, whereas South America, Asia/Oceania, and Africa were underrepresented, the present findings might not be generalizable to populations not conforming to the WEIRD (Western, educated, industrialized, rich and democratic) stereotype (Henrich et al., 2010).”

In the paper

“In the final model (21 studies, R2 = .29), overall RoB rating (B = −0.35 [−0.64, −0.07]) was the only significant predictor, indicating that an overall lower RoB was associated with smaller effect sizes”

In the paper

“This is because loneliness is related to factors other than social isolation, including temporally stable characteristics of the individual (Mund et al., 2020) and their environment such as personality traits, need for contact and expectations of relationships (Qualter et al., 2015), physical and mental health, and cultural norms (Gierveld et al., 2018; Lim et al., 2020)”

What the sources say

• Not checked yetcites Mund et al., 2020
• Not checked yetcites Qualter et al., 2015
• Not checked yetcites Gierveld et al., 2018

In the paper

“Bias domains included in the ROBINS-I tool (Cochrane Handbook for Systematic Reviews of Interventions version 6.2, 2021, Chapter 25, section 4) were used”

• Also stated in: § Methods for Assessing Risk to Internal Validity/Risk of Bias · plain

  “For each study and domain, the RoB was independently rated by two authors as “low”, “moderate” or “serious”. Their assessments were merged”

In the paper

“which increases the risk of premature mortality and mental and physical health conditions”

• Also stated in: § Abstract · plain

  “largely due to their serious impact on longevity, mental and physical health, and well-being (Fried et al., 2020; Holt-Lunstad et al., 2015; Leigh-Hunt et al., 2017)”

What the sources say

• Not checked yetcites Fried et al., 2020
• Not checked yetcites Holt-Lunstad et al., 2015
• Not checked yetcites Leigh-Hunt et al., 2017

In the paper

“This step was conducted independently by four members of the research group (postdoctoral/senior researchers with previous experience conducting reviews and/or meta-analyses, three psychologists (two full professors) and one medical doctor (assistant professor))”

• Also stated in: § Study Selection · plain

  “Discrepancies were resolved through discussion”

• Also stated in: § Study Selection · plain

  “Senior researchers (mathematician and medical doctor/psychologist, full professors) verified the eligibility of included studies”

In the paper

“A more recent systematic review, which included neither a meta-analysis nor a meta-regression (Buecker & Horstmann, 2021), found that longitudinal studies mainly reported increases in loneliness”

What the sources say

• Not checked yetcites Buecker & Horstmann, 2021

In the paper

“Studies have reported stable (Peng & Roth, 2021; Sibley et al., 2020), as well as increases (Kovacs et al., 2021; Macdonald & Hülür, 2021) and decreases (Bartrés-Faz et al., 2021) in loneliness levels”

What the sources say

• Not checked yetcites Peng & Roth, 2021
• Not checked yetcites Sibley et al., 2020
• Not checked yetcites Kovacs et al., 2021

In the paper

“However, it remains unclear whether loneliness has increased overall since the pandemic started (e.g., Killgore et al., 2020; Sutin et al., 2020)”

What the sources say

• Not checked yetcites Killgore et al., 2020
• Not checked yetcites Sutin et al., 2020

In the paper

“This systematic review with meta-analysis was registered at PROSPERO (ID CRD42021246771)”

• Also stated in: § Abstract · plain

  “The study protocol was registered before conducting the search”

In the paper

“Throughout the systematic review, the latest PRISMA guidelines were followed (Page et al., 2021)”

What the sources say

• Not checked yetcites Page et al., 2021

In the paper

“To ascertain the results’ robustness, a series of sensitivity analyses were performed (1) including only studies with no ‘serious’ or ‘critical’ overall RoB rating, (2) combining longitudinal and pseudo-longitudinal study designs, (3) incorporating pre-pandemic assessments that overlapped with the date cut-offs specified above, and (4) excluding clinical populations”

In the paper

“A 2021 systematic review and meta-analysis of changes in mental health, focusing on longitudinal studies and natural experiments with pre-pandemic comparisons, found no evidence of increase in loneliness (based on three studies) (Prati & Mancini, 2021)”

What the sources say

• Not checked yetcites Prati & Mancini, 2021

In the paper

“For use in sensitivity analyses and meta-regression, an overall RoB rating was constructed (≥1 “serious” rating in any domain resulted in a “serious” overall RoB; overall “low” RoB was only present when all domains were rated “low” risk; otherwise, overall risk was considered “moderate”)”

In the paper

“previous research has shown that particularly sustained or chronic loneliness jeopardizes mental and physical health (Cacioppo et al., 2015; National Academies of Science, 2020)”

What the sources say

• Not checked yetcites Cacioppo et al., 2015
• Not checked yetcites National Academies of Science, 2020

In the paper

“The confidence in the finding that there has been an increase in loneliness – albeit small – during the pandemic is strengthened by the results of the sensitivity analyses, the inclusion of only high-quality and longitudinal research in the meta-analyses, the relatively large number of studies with a pooled sample of 45,734 participants, and the lack of any indication of publication bias”

In the paper

“The lack of control samples unaffected by the pandemic weakens possible causal inference, making it more difficult to attribute the increase in loneliness to the pandemic.”

In the paper

“However, the informative value of the meta-regression was still hampered by the limited number of predictors that could be tested on the basis of the available studies (which also necessitated a stepwise procedure).”

In the paper

“A previous rapid review and meta-analysis (Prati & Mancini, 2021) reported small increases in mental distress (overall g = 0.17) based on longitudinal studies”

What the sources say

• Not checked yetcites Prati & Mancini, 2021

In the paper

“Their synthesis showed no statistically significant change in loneliness (g = 0.12, p = .34)”

What the sources say

• Not checked yetcites Prati & Mancini, 2021

In the paper

“This constitutes a small (Cohen, 1992; Ferguson, 2009) effect, which was also heterogeneous”

What the sources say

• Not checked yetcites Cohen, 1992
• Not checked yetcites Ferguson, 2009

In the paper

“Based on the examination of the studentized residuals, robustness analyses revealed that there was no indication of outliers and according to the Cook’s distances, none of the studies were overly influential”

In the paper

“The numerical values of effect size indices often provide limited understanding of the real-world significance of those effects, as even statistically small effects can be of high importance (e.g., Meyer et al., 2001).”

What the sources say

• Not checked yetcites Meyer et al., 2001

In the paper

“Restriction measures were coded based on official mandates, however, this might have been imprecise if measures differed between regions and/or if the assessment spanned a period in which these rules changed.”

In the paper

“Furthermore, as the pandemic progressed differently around the world, we used regional cut-offs to distinguish whether study assessments had taken place before or during the pandemic, but individuals might also have been affected by restrictions outside their place of residence (e.g., travel bans).”

In the paper

“Furthermore, an alternative explanation for increases in loneliness in the population was recently provided by Buecker et al. (2021) who reported linear increases in emerging adults over the last decades.”

What the sources say

• Not checked yetcites Buecker et al., 2021

In the paper

“Previous research has shown positive effects of interventions enhancing social support (such as buddy-care programs) (Masi et al., 2011).”

What the sources say

• Not checked yetcites Masi et al., 2011

In the paper

“Prati and Mancini (2021) explored, using meta-regression, predictors of increases in mental health symptoms during the pandemic. They found no effects of mean age, gender, or study design, either.”

What the sources say

• Not checked yetcites Prati & Mancini, 2021