New studies suggest social isolation is a risk factor for dementia in older adults, point to ways to reduce risk

In two studies using nationally representative data from the National Health and Aging Trends Study gathered on thousands of Americans, researchers from the Johns Hopkins University School of Medicine and Bloomberg School of Public Health have significantly added to evidence that social isolation is a substantial risk factor for dementia in community-dwelling (noninstitutionalized) older adults, and identified technology as an effective way to intervene.

Collectively, the studies do not establish a direct cause and effect between dementia and social isolation, defined as lack of social contact and interactions with people on a regular basis. But, the researchers say, the studies strengthen observations that such isolation increases the risk of dementia, and suggest that relatively simple efforts to increase social support of older adults -- such as texting and use of email -- may reduce that risk. In the United States, an estimated 1 in 4 people over age 65 experience social isolation, according to the National Institute on Aging.

"Social connections matter for our cognitive health, and it is potentially easily modifiable for older adults without the use of medication," says Thomas Cudjoe, M.D., M.P.H., assistant professor of medicine at the Johns Hopkins University School of Medicine and senior author of both of the new studies.

The first study, described Jan. 11 in the Journal of the American Geriatrics Society, used data collected on a group of 5,022 Medicare beneficiaries for a long-term study known as the National Health and Aging Trends, which began in 2011. All participants were 65 or older, and were asked to complete an annual two-hour, in-person interview to assess cognitive function, health status and overall well-being.

At the initial interview, 23% of the 5,022 participants were socially isolated and showed no signs of dementia. However, by the end of this nine-year study, 21% of the total sample of participants had developed dementia. The researchers concluded that risk of developing dementia over nine years was 27% higher among socially isolated older adults compared with older adults who were not socially isolated.

"Socially isolated older adults have smaller social networks, live alone and have limited participation in social activities," says Alison Huang, Ph.D., M.P.H., senior research associate at the Johns Hopkins Bloomberg School of Public Health. "One possible explanation is that having fewer opportunities to socialize with others decreases cognitive engagement as well, potentially contributing to increased risk of dementia."

Interventions to reduce that risk are possible, according to results of the second study, published Dec. 15 in the Journal of the American Geriatrics Society. Specifically, researchers found the use of communications technology such as telephone and email lowered the risk for social isolation.

Researchers for the second study used data from participants in the same National Health and Aging Trends study, and found that more than 70% of people age 65 and up who were not socially isolated at their initial appointment had a working cellphone and/or computer, and regularly used email or texting to initiate and respond to others. Over the four-year research period for this second study, older adults who had access to such technology consistently showed a 31% lower risk for social isolation than the rest of the cohort.

"Basic communications technology is a great tool to combat social isolation," says Mfon Umoh, M.D., Ph.D., postdoctoral fellow in geriatric medicine at the Johns Hopkins University School of Medicine. "This study shows that access and use of simple technologies are important factors that protect older adults against social isolation, which is associated with significant health risks. This is encouraging because it means simple interventions may be meaningful."

Social isolation has gained significant attention in the past decade, especially due to restrictions implemented for the COVID-19 pandemic, but more work needs to be done to identify at-risk populations and create tools for providers and caregivers to minimize risk, the researchers say. Future research in this area should focus on increased risks based on biological sex, physical limitations, race and income level.

Read more at Science Daily

Impact of COVID-19 social isolation measures on early development

An international consortium with researchers from 13 countries has investigated the impact of Covid-19 related social isolation measures on 2,200 young infants and toddlers between 8 and 36 months of age. Their findings provide insights into the effects of lockdown on language acquisition and screen time in the generation of youngsters growing up during this extraordinary period. A study on the impact of lockdown-related activities on language development, led by the University of Oslo, was published in the journal Language Development Research. A second study on the increase in screen-time during lockdown and its impact on language development, led by the University of Göttingen with the Max Planck Institute for Psycholinguistics in Nijmegen and the University of Applied Sciences and Arts Western Switzerland, was published in the journal Scientific Reports.

Shortly after lockdown began in early March 2020 across 13 countries, parents were asked to complete an online questionnaire containing questions on the child's age, exposure to different languages, number of siblings and vocabulary development. Parents were then contacted again at the end of the lockdown (for that family or in that area, in general). They were asked about the activities that they undertook with their child during lockdown, the amount of time their child had access to screens both during lockdown and before, as well as questions on how much screen time they typically had themselves and their attitudes towards children's screen time. Parents were also asked to complete a standardized vocabulary checklist indicating the number of words their child understood and/or said at the beginning, and again, at the end of lockdown so that an increase in the number of words gained over lockdown could be calculated.

The studies find that, during lockdown, children who were read to more frequently were reported by their caregivers to have learned more words, relative to their peers who were read to less frequently. However, children with increased exposure to screens learned to say fewer words, relative to their peers with less screen time. In addition, while children were exposed to more screen time during lockdown than before, overall, children were reported to have gained more words than expected during lockdown, relative to pre-pandemic levels. The increase in screen time during lockdown was greater if lockdown was longer, and in families with fewer years of education, and where parents reported using screens for longer themselves.

"Identifying the effects of parent-child activities on the child's vocabulary growth is a significant finding, given that we assessed changes in children's vocabularies over an average period of just over one month in our study," says Professor Julien Mayor, University of Oslo.

"While this suggests that the relatively short isolation did not detrimentally impact language in young children, we should be cautious in assuming this would apply during normal times or to longer lockdowns, given the extraordinary circumstances that children and their parents faced during this time," adds Associate Professor Natalia Kartushina, University of Oslo.

Indeed, the authors attribute increased screen time precisely to the unprecedented circumstances that families found themselves in during lockdown, including but not limited to the closure of day care centres, sport facilities and play groups for children. "Many caregivers were in the novel situation of caring for and entertaining their young infants at home all day without recourse to other activities and in addition to their other responsibilities. Allowing your child increased screen time is an understandable solution to this unprecedented situation, in which caregivers were juggling multiple responsibilities -- meetings at work or chores that require concentration, together with a small child who needs entertaining. We've all done it during lockdown," says Professor Nivedita Mani, University of Göttingen.

Read more at Science Daily

Lonely flies, like many humans, eat more and sleep less

COVID-19 lockdowns scrambled sleep schedules and stretched waistlines. One culprit may be social isolation itself. Scientists have found that lone fruit flies quarantined in test tubes sleep too little and eat too much after only about one week of social isolation, according to a new study published in Nature. The findings, which describe how chronic separation from the group leads to changes in gene expression, neural activity, and behavior in flies, provide one of the first robust animal models for studying the body's biological reaction to loneliness.

"Flies are wired to have a specific response to social isolation," says Michael W. Young, the Richard and Jeanne Fisher Professor and head of the Laboratory of Genetics at Rockefeller. "We found that loneliness has pathological consequences, connected to changes in a small group of neurons, and we've begun to understand what those neurons are doing."

The science of loneliness

Drosophila are social creatures. The fruit flies forage and feed in groups, serenade one another through complex mating rituals, tussle in miniature boxing matches. And then they conk out: flies sleep 16 hours each day, split between a languorous midday nap and a full night's rest.

So when Wanhe Li, a research associate in Young's lab, began investigating the biological underpinnings of chronic social isolation, she turned to the gregarious and well-studied fruit fly. "Over and over again, Drosophila have put us on the right track," says Young. "Evolution packed a great deal of complexity into these insects long ago and, when we dig into their systems, we often find the rudiments of something that is also manifest in mammals and humans."

"When we have no roadmap, the fruit fly becomes our roadmap," Li adds.

For the study, Wanhe Li first compared how flies fare under various lockdown conditions. After seven days, flies housed together in groups of varying sizes produced no anomalous behaviors. Even two flies cut off from the crowd were content with one another. But when a single fly was entirely isolated, the lonely insect began eating more and sleeping less.

Further investigation revealed that a group of genes linked to starvation were expressed differently in the brains of lonely flies -- a tempting genetic basis for the observed connection between isolation and overeating.

Li then found that a small group of brain cells known as P2 neurons were involved in the observed changes to sleep and feeding behavior. Shutting down the P2 neurons of chronically-isolated flies suppressed overeating and restored sleep; boosting P2 in flies isolated from the group for only one day caused them to eat and sleep as if they had been alone for a full week.

"We managed to trick the fly into thinking that it had been chronically isolated," says Wanhe Li. "The P2 neurons seem to be linked to the perception of the duration of social isolation, or the intensiveness of loneliness, like a timer counting down how long the fly has been alone."

The Young lab painstakingly confirmed these observations. They engineered insomniac flies, to make sure that lack of sleep alone did not cause overeating (it didn't). They tested group-reared flies to find out whether manipulating P2 neurons would cause overeating and sleep loss in socialized flies (it doesn't). Ultimately, they concluded that only a perfect storm of both P2 neuron activity and social isolation will cause flies to begin to losing sleep and overeating.

Explaining the "Quarantine 15"

Scientists have observed that many social animals -- from fruit flies to humans -- eat more and sleep less when isolated. The reason for this is unclear. One possibility, Young says, is that social isolation signals a degree of uncertainty about the future. Preparation for tough times may include being alert and awake as often as possible and eating whenever food is available.

This study can hardly confirm that humans in COVID-19 lockdowns ate more and slept less due to the same biological mechanisms that keep lonely flies hungry and sleep deprived. But now that Li and Young have identified the neurons and genes responding to chronic isolation in fruit flies, future researchers can search for corresponding connections between loneliness, overeating, and insomnia in laboratory animals and, eventually, humans.

Read more at Science Daily