ABSTRACT:

Objective:

To estimate the association between the internet and the gain or loss cognite along of four years in older adults.

Methods:

Longitudinal study, a population-based, with older adults residents in a capital of southern Brazil (≥ 60 years) surveyed in 2009-10 (baseline) and in 2013-14 (follow-up). The outcome was assessed by clinically significant gain or loss of four or more points in the score of the Mini Mental State Examination between the two interviews. The use of internet was measured longitudinally (maintained or not internet usage, stop use of internet, started using the internet, retained the use of internet). Odds Ratios (OR) were estimated adjusted for sex, age, household income, education level and cognitive screening at baseline.

Results:

Respondents were 1.705 older adults in 2009-10 and 1.197 in 2013-14. There was a significant association between keep using internet and cognitive performance, with greater chance of cognitive gain (OR= 3.3; 95%CI 1.1 - 9.8) and lower cognitive impairment (OR = 0.39; 95%CI 0.17 - 0.88) for older adults who kept using the internet.

Conclusion:

Older adults who continue using the internet were more likely to gain significant cognitive and lower cognitive loss. Topromote the internet use in older adults can help a strategy for cognitive stimulation in older adults.

Keywords:
Computers; Cognition; Aged

INTRODUCTION

Individuals aged 60 years or older have a higher risk of cognitive decline due to the greater exposure to risk factors¹1. Nevalainen N, Riklund K, Andersson M, Axelsson J, Ögren M, Lövdén M, et al. COBRA: A prospective multimodal imaging study of dopamine, brain structure and function, and cognition. Brain Res 2015; 1612: 83-103. https://doi.org/10.1016/j.brainres.2014.09.010
https://doi.org/10.1016/j.brainres.2014.... ^,22. Bleakey CM, Charles D, Porter-Armstrong A, McNeil MD, McDonough SM, McCormack B. Gaming for health: a systematic review of the physical and cognitive effects of interactive computer games in older adults. J Appl Gerontol 2015; 34(3): 166-89. https://doi.org/10.1177/0733464812470747
https://doi.org/10.1177/0733464812470747... and impairment in mechanisms of perception, reasoning, memory¹1. Nevalainen N, Riklund K, Andersson M, Axelsson J, Ögren M, Lövdén M, et al. COBRA: A prospective multimodal imaging study of dopamine, brain structure and function, and cognition. Brain Res 2015; 1612: 83-103. https://doi.org/10.1016/j.brainres.2014.09.010
https://doi.org/10.1016/j.brainres.2014.... ^,33. Klusmann V, Evers A, Schwarzer R, Schlattmann P, Reischies FM, Heuser I, et al. Complex Mental and Physical Activity in Older Women and Cognitive Performance: A 6-month Randomized Controlled Trial. J Gerontol A Biol Sci Med Sci 2010; 65(6): 680-8. https://doi.org/10.1093/gerona/glq053
https://doi.org/10.1093/gerona/glq053... , praxia, language, attention⁴4. Diamond A, Ling DS. Conclusions about interventions, programs, and approaches forimproving executive functions that appear justified and those that, despite much hype, do not. Dev Cogn Neurosci 2016; 18(4): 34-48. https://doi.org/10.1016/j.dcn.2015.11.005
https://doi.org/10.1016/j.dcn.2015.11.00... , and learning⁵5. Stoyanova II. Ghrelin: A link between ageing, metabolism and neurodegenerative disorders. Neurobiol Dis 2014; 72 (Pt A): 72-83. https://doi.org/10.1016/j.nbd.2014.08.026
https://doi.org/10.1016/j.nbd.2014.08.02... .

Cognitive decline can significantly impair memory, learning, language, orientation, executive functions, speed of information processing, autonomy, and functional independence, affecting the quality of life and health in this population⁵5. Stoyanova II. Ghrelin: A link between ageing, metabolism and neurodegenerative disorders. Neurobiol Dis 2014; 72 (Pt A): 72-83. https://doi.org/10.1016/j.nbd.2014.08.026
https://doi.org/10.1016/j.nbd.2014.08.02... , in addition to being an important risk factor for disability, dementia, and death⁶6. Xavier AJ, d’Orsi E, de Oliveira CM, Orrell M, Demakakos P, Biddulph JP, et al. English Longitudinal Study of Aging: Can Internet/E-mail Use Reduce Cognitive Decline? J Gerontol Ser A Biol Sci Med Sci 2014; 69(9): 1117-21. https://doi.org/10.1093/gerona/glu105
https://doi.org/10.1093/gerona/glu105... .

In this perspective, cognitive interventions are being studied and encouraged. They are considered important for prevention, health and quality of life promotion, and independence of older adults with cognitive problems⁷7. Flöel A, Ruscheweyh R, Krüger K, Willemer C, Winter B, Völker K, et al. Physical activity and memory functions: Are neurotrophins and cerebral gray matter volume the missing link? Neuroimage 2010; 49(3): 2756-63. https://doi.org/10.1016/j.neuroimage.2009.10.043
https://doi.org/10.1016/j.neuroimage.200... . Consistent evidence in controlled and randomized clinical trials, through meta-analyses and systematic reviews, demonstrates that several forms of cognitively stimulating activities delay cognitive decline⁴4. Diamond A, Ling DS. Conclusions about interventions, programs, and approaches forimproving executive functions that appear justified and those that, despite much hype, do not. Dev Cogn Neurosci 2016; 18(4): 34-48. https://doi.org/10.1016/j.dcn.2015.11.005
https://doi.org/10.1016/j.dcn.2015.11.00... ^,88. Lautenschlager NT, Cox KL. Can participation in mental and physical activity protect cognition in old age?: Comment on “The Mental Activity and eXercise (MAX) trial: a randomized controlled trial to enhance cognitive function in older adults”. JAMA Int Med 2013; 173(9): 805-6. https://doi.org/10.1001/jamainternmed.2013.206
https://doi.org/10.1001/jamainternmed.20... ^,99. Cotelli M, Manenti R, Zanetti O, Miniussi C. Non-pharmacological intervention for memory decline. Front Hum Neurosci 2012; 6: 46. https://dx.doi.org/10.3389%2Ffnhum.2012.00046
https://dx.doi.org/10.3389%2Ffnhum.2012.... ^,1010. Woods B, Aguirre E, Spector AE, Orrell M. Cognitive stimulation to improve cognitive functioning in people with dementia (Review). Cochrane Database Syst Rev 2012; (2): CD005562. https://doi.org/10.1002/14651858.CD005562.pub2
https://doi.org/10.1002/14651858.CD00556... .

Among the many kinds of cognitive maintenance, stimulation, and rehabilitation, the use of computers - through the Internet - is one of the most effective and considered a good alternative therapy in groups of older adults¹1. Nevalainen N, Riklund K, Andersson M, Axelsson J, Ögren M, Lövdén M, et al. COBRA: A prospective multimodal imaging study of dopamine, brain structure and function, and cognition. Brain Res 2015; 1612: 83-103. https://doi.org/10.1016/j.brainres.2014.09.010
https://doi.org/10.1016/j.brainres.2014.... ^,1111. Ngandu T, Lehtisalo J, Solomon A, Levälahti E, Ahtiluoto S, Antikainen R, et al. A 2 year multidomain intervention of diet, exercise, cognitive training, and vascular risk monitoring versus control to prevent cognitive decline in at-risk elderly people (FINGER): a randomised controlled trial. Lancet 2015; 385(9984): 2255-63. https://doi.org/10.1016/S0140-6736(15)60461-5
https://doi.org/10.1016/S0140-6736(15)60... ^,1212. Barnes DE, Santos-Modesitt W, Poelke G, Kramer AF, Castro C, Middleton LE, et al. The Mental Activity and eXercise (MAX) trial: a randomized controlled trial to enhance cognitive function in older adults. JAMA Intern Med 2013; 173(9): 797-804. https://doi.org/10.1001/jamainternmed.2013.189
https://doi.org/10.1001/jamainternmed.20... . A systematic review by Diamond and Ling⁴4. Diamond A, Ling DS. Conclusions about interventions, programs, and approaches forimproving executive functions that appear justified and those that, despite much hype, do not. Dev Cogn Neurosci 2016; 18(4): 34-48. https://doi.org/10.1016/j.dcn.2015.11.005
https://doi.org/10.1016/j.dcn.2015.11.00... , which analyzed 84 studies to assess different types of cognitive rehabilitation programs, demonstrated that the use of computers improves creativity, cognitive flexibility, attention, performance of tasks, and other cognitive abilities. Internet use is a modifiable behavior that has proved to be effective in protecting cognitive function¹²12. Barnes DE, Santos-Modesitt W, Poelke G, Kramer AF, Castro C, Middleton LE, et al. The Mental Activity and eXercise (MAX) trial: a randomized controlled trial to enhance cognitive function in older adults. JAMA Intern Med 2013; 173(9): 797-804. https://doi.org/10.1001/jamainternmed.2013.189
https://doi.org/10.1001/jamainternmed.20... .

Use of computers also seems to influence the prevention of dementia⁸8. Lautenschlager NT, Cox KL. Can participation in mental and physical activity protect cognition in old age?: Comment on “The Mental Activity and eXercise (MAX) trial: a randomized controlled trial to enhance cognitive function in older adults”. JAMA Int Med 2013; 173(9): 805-6. https://doi.org/10.1001/jamainternmed.2013.206
https://doi.org/10.1001/jamainternmed.20... ^,99. Cotelli M, Manenti R, Zanetti O, Miniussi C. Non-pharmacological intervention for memory decline. Front Hum Neurosci 2012; 6: 46. https://dx.doi.org/10.3389%2Ffnhum.2012.00046
https://dx.doi.org/10.3389%2Ffnhum.2012.... ^,1010. Woods B, Aguirre E, Spector AE, Orrell M. Cognitive stimulation to improve cognitive functioning in people with dementia (Review). Cochrane Database Syst Rev 2012; (2): CD005562. https://doi.org/10.1002/14651858.CD005562.pub2
https://doi.org/10.1002/14651858.CD00556... and the decrease in physical, mental, and socioeconomic limitations associated with aging, improving the practice of citizenship, health, education, work, leisure, and socialization¹³13. Xavier AJ, d’Orsi E, Wardle J, Demakakos P, Smith SG, von Wagner C. Internet use and cancer-preventive behaviors in older adults: findings from a longitudinal cohort study. Cancer Epidemiol Biomarkers Prev 2013; 22(11): 2066-74. https://doi.org/10.1158/1055-9965.EPI-13-0542
https://doi.org/10.1158/1055-9965.EPI-13... ^,1414. Paiva SB, Del-Masso MCS. Information technology as a technical resource for the memories: memories of Unati-Marília in the virtual environment. J Info Sys Technol Man 2013; 10(2): 377-88. https://doi.org/10.4301/S1807-17752013000200011
https://doi.org/10.4301/S1807-1775201300... , and reducing the number of diseases. Consequently, it provides more autonomy and quality of life¹¹11. Ngandu T, Lehtisalo J, Solomon A, Levälahti E, Ahtiluoto S, Antikainen R, et al. A 2 year multidomain intervention of diet, exercise, cognitive training, and vascular risk monitoring versus control to prevent cognitive decline in at-risk elderly people (FINGER): a randomised controlled trial. Lancet 2015; 385(9984): 2255-63. https://doi.org/10.1016/S0140-6736(15)60461-5
https://doi.org/10.1016/S0140-6736(15)60... ^,1212. Barnes DE, Santos-Modesitt W, Poelke G, Kramer AF, Castro C, Middleton LE, et al. The Mental Activity and eXercise (MAX) trial: a randomized controlled trial to enhance cognitive function in older adults. JAMA Intern Med 2013; 173(9): 797-804. https://doi.org/10.1001/jamainternmed.2013.189
https://doi.org/10.1001/jamainternmed.20... ^,1515. Almeida OP, Yeap BB, Alfonso H, Hankey GJ, Flicker L, Norman PE. Older men who use computers have lowerrisk of dementia. PLoS One 2012; 7(8): e44239. https://dx.doi.org/10.1371%2Fjournal.pone.0044239
https://dx.doi.org/10.1371%2Fjournal.pon... , in addition to lowering the risk of impairment in activities of daily living¹⁶16. d’Orsi E, Xavier AJ, Steptoe A, de Oliveira C, Ramos LR, Orrell M, et al. Sociodemographic and lifestyle factors related to instrumental activities of daily living dynamics: results from the English Longitudinal Study of Ageing. J Am Geriatr Soc 2014; 62(9): 1630-9. https://doi.org/10.1111/jgs.12990
https://doi.org/10.1111/jgs.12990... .

Therefore, it is important to promote and encourage preventive public policies focused on known risk factors and cognitive stimulation programs, which seem to have the power of mitigating cognitive decline and its consequences¹¹11. Ngandu T, Lehtisalo J, Solomon A, Levälahti E, Ahtiluoto S, Antikainen R, et al. A 2 year multidomain intervention of diet, exercise, cognitive training, and vascular risk monitoring versus control to prevent cognitive decline in at-risk elderly people (FINGER): a randomised controlled trial. Lancet 2015; 385(9984): 2255-63. https://doi.org/10.1016/S0140-6736(15)60461-5
https://doi.org/10.1016/S0140-6736(15)60... . Some studies suggest that Internet use reduces the risk of cognitive decline and dementia, but none has a representative and longitudinal sample of a city. Thus, this study aims to estimate the association between Internet use and cognitive gain/loss among older adults over four years.

METHOD

TYPE OF STUDY

This is a longitudinal household-based population study, originated from the project “Health Conditions of Older Adults from Florianópolis,” called EpiFloripa Idoso (www.epifloripa.ufsc.br).

POPULATION AND SAMPLE

The research was conducted with older adults aged 60 years or older living in the urban area of Florianópolis, Santa Catarina (SC). The baseline data collection occurred from September 2009 to June 2010, and the follow-up, from November 2013 to November 2014.

The software Epi Info (version 6.04) determined the baseline sample size, based on the calculation of prevalence according to the following parameters: population size (44,460inhabitants older than 60 years), confidence interval (95%CI), unknown prevalence of phenomenon (50%), sampling error (4 percentage points), and sample design effect (estimated at 2 percent), with an increase of 20% for estimated losses and 15% for association studies, resulting in a minimum sample of 1,599 individuals. Due to the design effect and available funding, the sample was expanded to 1,911 older adults.

The baseline sample selection was clustered in two stages. The units of the first stage were the 420 urban census tracts of Florianópolis stratified by increasing income, with 80 of them being systematically selected (8 tracts for each income decile). The units of the second stage were the households, which ranged from 61 to 725 per tract. Small tracts were grouped according to geographical location and corresponding income decile, and vast tracts, divided, to reduce the coefficient of variation from 52.7% (n = 80 tracts) to 35.2% (n= 83 tracts). According to the 2000 Census, the mean number of residents per household in Florianópolis was 3.1, and the age group of interest represented approximately 11% of the population. Therefore, the mean number of older adults per census tract was one for every three households. Sixty systematically selected household visits were estimated per sector. The 83 census tracts comprised a total of 22,846 households. In this scenario, the study considered 1,911 older adults eligible, excluding institutionalized individuals (nursing homes, hospitals, prisons). Thus, the final sample consisted of 1,705 older adults interviewed (response rate of 89.1%).

In the follow-up of the study (2013-2014), the number of eligible older adults resulted from the identification of deaths and subsequent attempt to update addresses. Some personal information of the subjects (name, mother’s name, and date of birth) was used to check the Mortality Information System (Sistema de Informações sobre Mortalidade - SIM) database of the Ministry of Health, according to place of residence (SantaCatarina), for the years 2009, 2010, 2011, 2012, and 2013. Based on the information collected, the older adults with a full address received a letter informing them about the new stage of the research. Next, they were contacted by phone to updatetheir registry data. Whencommunication was not possible, the team tried to update the information through the InfoSaúde System (Health System of Florianópolis/SC), social networks, phone book, and contact with neighbors, relatives, and friends. Thestudy also excluded two older adults unintentionally registered twice in the database and another with incompatible age (individual younger than 60 years of age, mistakenly interviewed at baseline).

In both moments, losses corresponded to older adults not found after four visits in different periods and refusals in person after a visit to the household and attempt to interview. At follow-up, individuals who moved from town or were hospitalized were also considered losses. Therefore, 1,197 older adults were interviewed with longitudinal information collected in the period between 2009-2010 and 2013-2014.

INSTRUMENTS AND DATA COLLECTION

Data were collected through a face-to-face interview conducted by previously trained interviewers with the aid of personal digital assistants (baseline) and netbooks (follow-up). Standardized questionnaires preferably used instruments validated and tested in pilot studies, which were applied to 99 individuals at baseline and 76 at follow-up. The baseline administered276 questions and the follow-up, 655. Data consistency was verified weekly, and quality control was performed by a reduced phone survey with approximately 10% of randomly selected interviewees. The reproducibility of the questions presented acceptable to good agreement (baseline - Kappa between 0.6 and 0.9; and follow-up - Kappa between 0.5 and 0.9). Studies by Confortin et al.¹⁷17. Confortin SC, Schneider IJC, Antes DL, Cembranel F, Ono LM, Marques LP, et al. Condições de vida e saúde de idosos: resultados do estudo de coorte EpiFloripa Idoso. Rev Epidemiol Serv Saúde 2017; 26(2): 305-17. http://dx.doi.org/10.5123/s1679-49742017000200008
http://dx.doi.org/10.5123/s1679-49742017... and d’Orsi et al.¹⁸18. d’Orsi E, Confortin SC, Bernardo C, Bolsini C, Antes D, Schneider IJC, et al. Inquérito de Saúde Epifloripa Idoso - Métodos, aspectos operacionais e estratégias utilizadas. Rev Saúde Pública (no prelo)(s.d.). have more information about data collection and instruments used at baseline and follow-up.

STUDY VARIABLES

The outcome was the cognitive deficit screening assessed longitudinally by the gain/loss of four or more points in the mini-mental state examination (MMSE) score between the two interviews. Cognitive improvement or decline of four points is considered clinically significant, as it represents a gain or loss of at least 20% in cognitive function¹⁹19. Stein J, Luppa M, Maier W, Wagner M, Wolfsbruger S, Scherer M, et al. Assessing cognitive changes in the elderly: reliable change indices for the Mini-Mental State Eamination. Acta Psychiatr Scand 2012; 126(3): 208-18. https://doi.org/10.1111/j.1600-0447.2012.01850.x
https://doi.org/10.1111/j.1600-0447.2012... . MMSE is a cognitive assessment scale that ranges from 0 to 30 points²⁰20. Bertolucci PHF, Brucki S, Campacci SR, Juliano Y. O mini-exame do estado mental em uma população geral: impacto da escolaridade. Arq Neuropsiquiatr 1994; 52(1): 1-7. http://dx.doi.org/10.1590/S0004-282X1994000100001
http://dx.doi.org/10.1590/S0004-282X1994... .

The independent variables were: gender (female, male); age (complete years); per capita household income in Brazilian reais (R$) at the time of interview; schooling (years of schooling); Internet use after four years, assessed in a longitudinal way (continued not using the Internet; stopped using the Internet; started using the Internet; continued using the Internet); and cognitive decline at baseline - those who reached values lower than 19/20 (without schooling) and 23/24 points (with formal education)²¹21. Almeida OP. Mini exame do estado mental e o diagnóstico de demência no Brasil. Arq Bras Neuropsiquiatr 1998; 56(3B): 605-12. http://dx.doi.org/10.1590/S0004-282X1998000400014
http://dx.doi.org/10.1590/S0004-282X1998... .

DATA ANALYSIS

Interviews were downloaded from personal digital assistants (baseline) and netbooks (follow-up) in csv format, and later, data were transferred to the statistical package STATA 11.0 (Stata Corporation, College Station, United States), allowing the information to be exported directly to the construction of the database, eliminating the work of typing and, therefore, reducing possible errors that occur at this stage.

All analyses in this study considered the design effect and sample weights. First, we tested the normality of the data. To characterize the study sample and outcome prevalence, we conducted descriptive statistics with absolute and relative frequencies for qualitative variables, and measure of central tendency and dispersion for quantitative ones. Dependentvariables were expressed as mean with the respective 95%CI.

To estimate the association between longitudinal Internet use and cognitive function of the older adults interviewed, we used logistic regression, presenting the results in crude and adjusted (for gender, age, schooling, income, and cognitive decline at baseline) odds ratios (OR) and their respective 95%CI. The level of statistical significance for association was set at 5% (p < 0.05).

The outcome “gained four or more points in the MMSE score between the two interviews” excluded older adults who reached a score higher than 26 points in the 2009-2010 MMSE, as they would not be able to gain these points in the longitudinal study period (n=560). Similarly, the outcome “lost four or more points in the MMSE score between the two interviews” excluded from the study older adults with a score lower than 4 points (n = 1,171).

ETHICAL ASPECTS

The research project of the investigation complied with ethical principles, according to Resolution No. 466 of 2012 of the National Health Council. The Human Research Ethics Committee (HREC) of UFSC approved the baseline under protocol No. 352/2008, and the follow-up under No. 596,126. All participants signed the Informed Consent Form. They were also asked for post-informed consent for access to data previously collected by EpiFloripa Idoso 2009-2010.

RESULTS

At baseline, 1,705 older adults were interviewed (response proportion of 89.1%), of whom 217 died, 111 were not found, 48 were considered losses, and 129 refused to participate in the study again, totaling 1,197 individuals interviewed at follow-up (response proportion of 70.2%).

Table 1 shows that most older adults interviewed did not present clinically significant cognitive gain or loss, 7.3% (95%CI 5.8 - 8.8) gained 4 points in the MMSE and 13.9% (95%CI 11.9 - 15.9) lost 4 points, in addition to continuing not using the Internet, that is, they did not use the Internet in 2009-2010 and this behavior persisted in 2013-2014 (70.2%; 95%CI 67.6 - 72.8).

The final adjusted model (Table 2) demonstrated a statistically significant association between Internet use and clinically significant cognitive gain, with chances of cognitive improvement being 3.32 times higher for older adults who continued using the Internet (OR = 3.32; 95%CI 1.13 - 9.76) compared to those who have never used it. In addition, clinically significant cognitive gain was also associated with cognitive deficit at baseline, as older adults with potential cognitive deficit had 77% less chance of reaching significant cognitive improvement (OR = 0.23; 95%CI 0.13 - 0.41) when compared to their peers (Table 2).

The final adjusted model of the variable “lost four or more points in the MMSE” indicated a statistically significant association between Internet use and the outcome, with chances of cognitive decline being 68% lower for older adults who started using theInternet(OR=0.32; 95%CI 0.11 - 0.95) and 61% lower for those who continued usingthe Internet (OR=0.39;95%CI 0.17 - 0.88) when compared to individuals who had never used it. We also found an association between the outcome and increasing age (OR = 1.10; 95%CI 1.07 - 1.13), lower schooling (OR = 0.90; 95%CI 0.86 - 0.95), and potential cognitive deficit assessed at baseline (OR= 3.69; 95%CI 2.25 - 6.04) in relation to decreasing age, higher schooling, and not having cognitive deficit at baseline (Table 3).

DISCUSSION

This study showed that most older adults interviewed did not present clinically significant cognitive gain or loss. It is known that advancing age leads to greater exposure to risk factors for cognitive problems, especially subjective memory complaints¹1. Nevalainen N, Riklund K, Andersson M, Axelsson J, Ögren M, Lövdén M, et al. COBRA: A prospective multimodal imaging study of dopamine, brain structure and function, and cognition. Brain Res 2015; 1612: 83-103. https://doi.org/10.1016/j.brainres.2014.09.010
https://doi.org/10.1016/j.brainres.2014.... ^,22. Bleakey CM, Charles D, Porter-Armstrong A, McNeil MD, McDonough SM, McCormack B. Gaming for health: a systematic review of the physical and cognitive effects of interactive computer games in older adults. J Appl Gerontol 2015; 34(3): 166-89. https://doi.org/10.1177/0733464812470747
https://doi.org/10.1177/0733464812470747... ^,2222. Fonseca JAS, Ducksbury R, Rodda J, Whitfield T, Nagaraj C, Suresh K, et al. Factors that predict cognitive decline in patients with subjective cognitive impairment. Int Psychogeriatrics 2015; 27(10): 1671-7. https://doi.org/10.1017/S1041610215000356
https://doi.org/10.1017/S104161021500035... , which correspond to the early stage of these problems and do not yet impair cognitive losses as much²³23. World Health Organization. Dementia: a public health priority. Genebra: World Health Organization; 2012.. Cognitive impairment and dementia have lower prevalence rates when compared to memory complaints²³23. World Health Organization. Dementia: a public health priority. Genebra: World Health Organization; 2012., and, in Brazil, projections indicate a prevalence of dementia in the population aged 65 years or older around 8%²⁴24. Burlá C, Camarano AA, Kanso S, Fernandes D, Nunes R. Panorama prospectivo das demências no Brasil: um enfoque demográfico. Ciênc Saúde Col 2013; 18(10): 2949-56. http://dx.doi.org/10.1590/S1413-81232013001000019
http://dx.doi.org/10.1590/S1413-81232013... .

In addition, we found that most older adults continued not using the Internet, that is, they did not use the Internet in 2009-2010 and this behavior persisted in 2013-2014. Despite Internet being considered fundamental in modern life and used by millions of people²⁵25. Koo C, Wati Y, Lee CC, Oh HY. Internet-Addicted Kids and South Korean Government Efforts: Boot-Camp Case. Cyberpsychol Behav Soc Netw 2011; 14(6): 391-4. https://doi.org/10.1089/cyber.2009.0331
https://doi.org/10.1089/cyber.2009.0331... , older adults are the ones who least use this technology²⁶26. Miranda LM, Farias SF. Contributions from the internet for elderly people: a review of the literature. Interface 2009; 13(29): 383-94. http://dx.doi.org/10.1590/S1414-32832009000200011
http://dx.doi.org/10.1590/S1414-32832009... . A research conducted in 2014 showed that 81% of Brazilian older adults did not use the Internet²⁷27. Comitê Gestor da Internet no Brasil. Pesquisa sobre o uso das tecnologias da informação e comunicação no Brasil - TIC Domicílios e TIC Empresas 2013. São Paulo: Comitê Gestor da Internet no Brasil; 2014., a fact that is mainly due to the high cost of equipment to access the Internet and of its connectivity, lack of access points, data security, and knowledge about the use, among many other factors, causing the process of digital exclusion²⁸28. Sales MB, Amaral MA, Sene Junior IG, Sales AB. Tecnologias de Informação e Comunicação via Web: Preferências de uso de um grupo de usuários idosos. Kairós 2014; 17(3): 59-77.. Another factor that favors the exclusion is that older adults were raised in the last century when the Internet and other technological tools did not exist, which inhibits this behavior²⁶26. Miranda LM, Farias SF. Contributions from the internet for elderly people: a review of the literature. Interface 2009; 13(29): 383-94. http://dx.doi.org/10.1590/S1414-32832009000200011
http://dx.doi.org/10.1590/S1414-32832009... .

The present study found an association between Internet use by older adults and higher chance of clinically significant cognitive improvement in the MMSE (3.32 times higher for those who continued using the Internet) and lower chance of clinically significant cognitive decline (68% lower for the ones who started using the Internet and 61% lower for those who continued using the Internet) when compared to non-users.

Many studies revealed that Internet use can be a cognitively stimulating activity and that the non-use is a risk factor for mild cognitive disorders and dementia ¹1. Nevalainen N, Riklund K, Andersson M, Axelsson J, Ögren M, Lövdén M, et al. COBRA: A prospective multimodal imaging study of dopamine, brain structure and function, and cognition. Brain Res 2015; 1612: 83-103. https://doi.org/10.1016/j.brainres.2014.09.010
https://doi.org/10.1016/j.brainres.2014.... ^,44. Diamond A, Ling DS. Conclusions about interventions, programs, and approaches forimproving executive functions that appear justified and those that, despite much hype, do not. Dev Cogn Neurosci 2016; 18(4): 34-48. https://doi.org/10.1016/j.dcn.2015.11.005
https://doi.org/10.1016/j.dcn.2015.11.00... ^,88. Lautenschlager NT, Cox KL. Can participation in mental and physical activity protect cognition in old age?: Comment on “The Mental Activity and eXercise (MAX) trial: a randomized controlled trial to enhance cognitive function in older adults”. JAMA Int Med 2013; 173(9): 805-6. https://doi.org/10.1001/jamainternmed.2013.206
https://doi.org/10.1001/jamainternmed.20... ^,99. Cotelli M, Manenti R, Zanetti O, Miniussi C. Non-pharmacological intervention for memory decline. Front Hum Neurosci 2012; 6: 46. https://dx.doi.org/10.3389%2Ffnhum.2012.00046
https://dx.doi.org/10.3389%2Ffnhum.2012.... ^,1111. Ngandu T, Lehtisalo J, Solomon A, Levälahti E, Ahtiluoto S, Antikainen R, et al. A 2 year multidomain intervention of diet, exercise, cognitive training, and vascular risk monitoring versus control to prevent cognitive decline in at-risk elderly people (FINGER): a randomised controlled trial. Lancet 2015; 385(9984): 2255-63. https://doi.org/10.1016/S0140-6736(15)60461-5
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The longitudinal population study (8-year follow-up) by Xavier et al.⁶6. Xavier AJ, d’Orsi E, de Oliveira CM, Orrell M, Demakakos P, Biddulph JP, et al. English Longitudinal Study of Aging: Can Internet/E-mail Use Reduce Cognitive Decline? J Gerontol Ser A Biol Sci Med Sci 2014; 69(9): 1117-21. https://doi.org/10.1093/gerona/glu105
https://doi.org/10.1093/gerona/glu105... assessed 6,442 people (aged 50-89 years) and indicated stabilization and/or delay in cognitive decline resulting from daily Internet use, both in middle-aged and older adult individuals, especially those with lower cognitive ability.

Internet use is considered an appropriate form of cognitive stimulation because it can reduce socioeconomic limitations, increase socialization with other people and with modern society²⁹29. Ala-Mutka K, Malanowski N, Punie Y, Cabrera M. Active Ageing and the Potential of ICT for Learning. Luxemburgo: Institute for Prospective Technological Studies (IPTS), JCR-European Commission; 2008., and improve executive functions, perception mechanisms, reasoning and memory¹1. Nevalainen N, Riklund K, Andersson M, Axelsson J, Ögren M, Lövdén M, et al. COBRA: A prospective multimodal imaging study of dopamine, brain structure and function, and cognition. Brain Res 2015; 1612: 83-103. https://doi.org/10.1016/j.brainres.2014.09.010
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https://doi.org/10.1016/j.dcn.2015.11.00... . Consequently,improved cognitive performance can decrease the number of diseases and provide a better quality of life¹¹11. Ngandu T, Lehtisalo J, Solomon A, Levälahti E, Ahtiluoto S, Antikainen R, et al. A 2 year multidomain intervention of diet, exercise, cognitive training, and vascular risk monitoring versus control to prevent cognitive decline in at-risk elderly people (FINGER): a randomised controlled trial. Lancet 2015; 385(9984): 2255-63. https://doi.org/10.1016/S0140-6736(15)60461-5
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In the present study, another factor associated with the gain or loss of at least four points in the MMSE score was the potential cognitive deficit diagnosed at baseline. Older adults with potential cognitive deficit had less chance of significant cognitive gain and more chance of cognitive loss when compared to those who did not have this characteristic. This result is probably due to these individuals being at a later stage of neurodegeneration³⁰30. Andrade C, Radhakrishnan R. The prevention and treatment of cognitive decline and dementia: An overview of recent research on experimental treatments. Indian J Psychiatry 2009; 51(1): 12-25. https://doi.org/10.4103/0019-5545.44900
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Increasing age and lower schooling were associated with a clinically significant cognitive loss in relation to decreasing age and higher schooling. People aged 60 years or older have a higher prevalence of and are more exposed to risk factors for cognitive decline¹1. Nevalainen N, Riklund K, Andersson M, Axelsson J, Ögren M, Lövdén M, et al. COBRA: A prospective multimodal imaging study of dopamine, brain structure and function, and cognition. Brain Res 2015; 1612: 83-103. https://doi.org/10.1016/j.brainres.2014.09.010
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Low schooling stimulates cognitive impairment³²32. Matthews FE, Arthur A, Barnes LE, Bond J, Jagger C, Robinson L, et al. A two-decade comparison of prevalence of dementia in individuals aged 65 years and older from three geographical areas of England: results of the Cognitive Function and Ageing Study I and II. Lancet 2013; 382(9902): 1405-12. https://dx.doi.org/10.1016%2FS0140-6736(13)61570-6
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Among the main limitations of the study, we highlight the selection bias, given the lack of evaluation of hospitalized older adults, who possibly are in worse health conditions, and the survival bias, which might have reduced the proportion of individuals with greater cognitive problems. We also emphasize the recall bias, as older adults might not remember some information. In addition, the cognitive screening instrument used in this study is not the most sensitive for this purpose.

Among the positive points of this research, we underline the type of study (population-based cohort), the design and sample calculation (a probabilistic sample considering the increase of 20% for losses), and the low proportion of selective loss of follow-up (lessthan 10%).

We suggest the development of randomized intervention studies to better evidence the relationship between Internet use and cognitive function in older adults, given the great power of this kind of research.

CONCLUSION

This research showed that most older adults did not use the Internet in 2009-2010 and continued to display this behavior in 2013-2014, indicating the digital exclusion of thispopulation.

The study also found that individuals who continued using the Internet had a higher chance of cognitive improvement and a lower chance of cognitive decline compared to those who did not use this technology. Also, cognitive loss was associated with increasing age, lower schooling, and potential cognitive deficit assessed at baseline (OR = 3.69; 95%CI 2.25 - 6.04) in relation to decreasing age, higher schooling, and not having cognitive deficit at baseline.

These findings show relationships already evidenced in the literature; however, they emphasize the importance of the association between Internet use and better cognitive performance among older adults. In this regard, encouraging policies that promote digital inclusion of older adults through Internet use can help to improve or preserve cognitivefunction in this population, directly impacting the decrease in diseases related to cognitive impairment, resulting in better health and quality of life.

ACKNOWLEDGMENTS

We would like to thank the technicians of the National Institute of Geography and Statistics (Instituto Brasileiro de Geografia e Estatística - IBGE) and the Municipal Secretariat of Health of Florianópolis for the aid in the operationalization of this study.

References

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