Self-reported regular Internet use, but not overuse, in older adults is linked to a lower dementia risk, new research suggests.
The investigators followed over 18,000 elderly individuals and found that regular Internet use was associated with about a 50% reduction in dementia risk compared to their counterparts who did not use the Internet regularly.
They also found that longer duration of regular Internet use was associated with a reduced risk of dementia, although excessive daily Internet use appeared to negatively affect dementia risk.
“Online engagement can develop and maintain cognitive reserve—resilience to physiological damage to the brain—and increased cognitive reserve, in turn, can compensate for brain aging and reduce the risk of dementia,” study investigator Gawon Cho, PhD student at New York University School of Global Public Health , New York City, told Medscape Medical News.
The study was published online on May 3 in Journal of the American Geriatrics Society.
Unreviewed benefits
Previous research has shown that older adult Internet users have “better overall cognitive performance, verbal reasoning, and memory,” compared to nonusers, the authors note.
However, since this body of research consists of cross-sectional analyzes and longitudinal studies with short follow-up periods, the long-term cognitive benefits of Internet use remain “unexplored.”
Additionally, despite “extensive evidence of a disproportionately high burden of dementia in people of color, individuals without higher education, and adults who have experienced other socioeconomic hardships, little is known about whether the Internet has exacerbated population-level disparities in cognitive health.” the investigators add.
Another question concerns whether excessive Internet use may actually be detrimental to neurocognitive outcomes. But “existing evidence of the negative effects of Internet use is concentrated in younger populations whose brains are still maturing.”
Cho said the motivation for the study was the lack of longitudinal studies on this topic, especially those with sufficient follow-up periods. In addition, she said, there is insufficient evidence about how changes in Internet use in older age are associated with potential dementia risk.
For the study, the investigators approached participants in the Health and Retirement Study, an ongoing longitudinal survey of a nationally representative sample of US-based older adults (age ≥ 50 years).
All participants (n = 18,154; 47.36% male; median age, 55.17 years) were dementia-free community-dwelling older adults who completed a baseline cognitive assessment from 2002 and were asked about Internet use every 2 years thereafter.
Participants were followed from 2002 to 2018 for a maximum of 17.1 years (median, 7.9 years), which is the longest follow-up period to date. Of the total sample, 64.76% were regular internet users.
The study’s primary outcome was incident dementia, based on performance on the Modified Telephone Interview for Cognitive Status (TICS-M), administered every two years.
The exposure examined in the study was cumulative Internet use in late adulthood, defined as “the number of two-year waves in which participants used the Internet regularly during the first three waves.”
In addition, participants were asked how many hours they used the Internet in the past week for activities other than watching television programs or movies.
The researchers also examined whether the link between Internet use and dementia risk varied by education level, race-ethnicity, gender, and generational cohort.
Covariates included baseline TICS-M score, health, age, household income, marital status, and residence.
U-shaped curve
Over half of the sample (52.96%) showed no changes in Internet use from baseline during the study period, while one-fifth (20.54%) showed changes in use.
The investigators found a robust association between Internet use and lower dementia risk (cause-specific hazard ratio (csHR), 0.57 (95% CI, 0.46 – 0.71))—a finding that persisted even after adjusting for self-selection to baseline use (csHR) , 0.54 (0.41 – 0.72)) and evidence of cognitive decline at baseline (csHR, 0.62 (0.46 – 0.85)).
Each additional wave of regular Internet use was associated with a 21% reduction in risk of dementia (95% CI, 13% – 29%), with additional regular periods associated with reduced dementia risk (csHR, 0.80 (95% CI, 0 .68 – 0.95)).
“The difference in risk between regular and non-regular users did not vary by education level, race-ethnicity, gender, and generation,” the investigators note.
A U-shaped association was found between daily hours of online engagement, with the lowest risk observed in those with 0.1 to 2 hours of use (compared to 0 hours of use). The risk increased in a “monotonic manner” after 2 hours, with 6.1 to 8 hours of use showing the highest risk.
This finding was not considered statistically significant, but the “consistent U-shaped trend provides a preliminary suggestion that excessive online engagement may have negative cognitive effects in older adults,” the investigators note.
“Among older adults, regular Internet users may experience a lower risk of dementia compared to non-regular users, and longer periods of regular Internet use in late adulthood may help reduce the risks of subsequent dementia incidence,” says Cho. “Yet using the Internet excessively on a daily basis may negatively affect the risk of dementia in older adults.”
Bidirectional relationship?
Comment for Medscape Medical NewsClaire Sexton, DPhil, Alzheimer’s Association senior director of scientific programs and outreach, noted that some risk factors for Alzheimer’s or other dementias cannot be changed, while others are modifiable, “either at the individual or population level.”
She called the current research “important” because it “identifies a potentially modifiable factor that may influence dementia risk.”
But, cautioned Sexton, who was not involved in the study, the results cannot establish cause and effect. In fact, the relationship can be bidirectional.
“It could be that regular internet use is associated with increased cognitive stimulation, and in turn reduced risk of dementia; or it could be that individuals at lower risk of dementia are more likely to engage in regular internet use,” she said . Thus, “intervention studies can shed more light on causation.”
The Health and Retirement Study (HRS) is sponsored by the National Institute on Aging and conducted by the University of Michigan. Cho, her co-authors, and Sexton have disclosed no relevant financial relationships.
J Am Geriatric Soc. Published online May 3, 2023. Abstract
Batya Swift Yasgur, MA, LSW, is a freelance writer with a counseling practice in Teaneck, New Jersey. She is a regular contributor to many medical publications, including Medscape and WebMD, and is the author of several consumer-oriented health books as well as “Behind the Burqa: Our Lives in Afghanistan and How We Escaped to Freedom” (memoir of two brave Afghan sisters who told their story to her).
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