Abstracts

Introduction

Dementia is a chronic and degenerative syndrome that affected around 50 million people in 2019 ¹1. 2020 Alzheimer's disease facts and figures. Alzheimers Dement 2020; 16:391-460.. Population growth, ageing, and increased prevalence of dementia-related risk factors lead Brazil to the second highest age-standardized prevalence of dementia in the world, affecting about 1.7 million people ²2. GBD 2016 Dementia Collaborators. Global, regional, and national burden of Alzheimer's disease and other dementias, 1990-2016: a systematic analysis for the Global Burden of Disease Study 2016. Lancet Neurol 2019; 18:88-106.. Whereas the number of deaths attributable to dementia decreased in the last 10 years in some Latin American countries ²2. GBD 2016 Dementia Collaborators. Global, regional, and national burden of Alzheimer's disease and other dementias, 1990-2016: a systematic analysis for the Global Burden of Disease Study 2016. Lancet Neurol 2019; 18:88-106., the mortality rate from this disease increased annually about 12% in men and 13% in women in Brazil from 2000 to 2008 ³3. Teixeira JB, Souza Junior PRB, Higa J, Theme Filha MM. Mortality from Alzheimer's disease in Brazil, 2000-2009. Cad Saúde Publica 2015; 31:850-60..

Moreover, patients with dementia have higher prevalence of comorbidities compared to cognitively healthy older people ⁴4. Bunn F, Burn A-M, Goodman C, Rait G, Norton S, Robinson L, et al. Comorbidity and dementia: a scoping review of the literature. BMC Med 2014; 12:192.. Besides leading to increased rate of hospitalization ⁵5. Phelan EA, Borson S, Grothaus L, Balch S, Larson EB. Association of incident dementia with hospitalizations. JAMA 2012; 307:165-72., the treatment of those comorbidities is more complex ⁶6. Desai U, Kirson NY, Ye W, Mehta NR, Wen J, Andrews JS. Trends in health service use and potentially avoidable hospitalizations before Alzheimer's disease diagnosis: a matched, retrospective study of US Medicare beneficiaries. Alzheimers Dement (Amst) 2019; 11:125-35., expensive ⁷7. Hill JW, Futterman R, Duttagupta S, Mastey V, Lloyd JR, Fillit H. Alzheimer's disease and related dementias increase costs of comorbidities in managed Medicare. Neurology 2002; 58:62-70., and unequal ⁴4. Bunn F, Burn A-M, Goodman C, Rait G, Norton S, Robinson L, et al. Comorbidity and dementia: a scoping review of the literature. BMC Med 2014; 12:192. in patients suffering dementia, resulting in longer and more costly hospital admissions ⁴4. Bunn F, Burn A-M, Goodman C, Rait G, Norton S, Robinson L, et al. Comorbidity and dementia: a scoping review of the literature. BMC Med 2014; 12:192.. Consequently, longer hospitalizations are linked to higher incidence of cognitive decline that may become irreversible if treated incorrectly ⁸8. Covinsky KE, Palmer RM, Fortinsky RH, Counsell SR, Stewart AL, Kresevic D, et al. Loss of independence in activities of daily living in older adults hospitalized with medical illnesses: increased vulnerability with age. J Am Geriatr Soc 2003; 51:451-8.^,99. Palleschi L, De Alfieri W, Salani B, Fimognari FL, Marsilii A, Pierantozzi A, et al. Functional recovery of elderly patients hospitalized in geriatric and general medicine units. The PROgetto DImissioni in GEriatria Study. J Am Geriatr Soc 2011; 59:193-9..

The total individual cost per year of patients with dementia in Brazil is greater than the global average in all disease stages ¹⁰10. Ferretti C, Sarti FM, Nitrini R, Ferreira FF, Brucki SMD, et al. An assessment of direct and indirect costs of dementia in Brazil. PLoS One 2018; 13:e0193209.. In 2016, only 34% of total health financing in Brazil was spent by the government. However, more than 65% of hospitalizations due to dementia were covered by the Brazilian public healthcare system (Brazilian Health Informatics Department - DATASUS. http://www2.datasus.gov.br/DATASUS/index.php, accessed on Mar/2020). In addition, around 50% of people living with dementia in Brazil have another chronic condition ¹⁰10. Ferretti C, Sarti FM, Nitrini R, Ferreira FF, Brucki SMD, et al. An assessment of direct and indirect costs of dementia in Brazil. PLoS One 2018; 13:e0193209.. Those facts show the recent past, current, and future social and economic burden of dementia in Brazil.

Although ageing is the strongest risk factor for dementia ¹¹11. Qiu C, De Ronchi D, Fratiglioni L. The epidemiology of the dementias: an update. Curr Opin Psychiatry 2007; 20:380-5., more than 50% of all its cases in low- and middle-income countries (accounting for about 70% of all dementia cases in the world ¹²12. Ferri CP, Jacob KS. Dementia in low-income and middle-income countries: different realities mandate tailored solutions. PLoS Med 2017; 14:e1002271.) could be attributable to the following modifiable risk factors: smoking, diabetes, obesity, hypertension, depression, low schooling, hearing loss, social isolation and physical inactivity ¹³13. Mukadam N, Sommerlad A, Huntley J, Livingston G. Population attributable fractions for risk factors for dementia in low-income and middle-income countries: an analysis using cross-sectional survey data. Lancet Glob Health 2019; 7:e596-603.. Indeed, a 20% reduction in the prevalence of those risk factors would lead to a reduction of 18.1% in the prevalence of dementia in Brazil by 2050 ¹⁴14. Oliveira D, Jun Otuyama L, Mabunda D, Mandlate F, Gonçalves-Pereira M, Xavier M, et al. Reducing the number of people with dementia through primary prevention in Mozambique, Brazil, and Portugal: an analysis of population-based data. J Alzheimers Dis 2019; 70 Suppl 1:S283-91..

Despite being associated with lower risk of cognitive decline in later life ¹⁵15. Hoang TD, Reis J, Zhu N, Jacobs Jr. DR, Launer LJ, Whitmer RA, et al. Effect of early adult patterns of physical activity and television viewing on midlife cognitive function. JAMA Psychiatry 2016; 73:73-9.^,1616. Rovio S, Kåreholt I, Helkala E-L, Viitanen M, Winblad B, Tuomilehto J, et al. Leisure-time physical activity at midlife and the risk of dementia and Alzheimer's disease. Lancet Neurol 2005; 4:705-11., the prevalence of regular leisure-time physical activity did not increase between 2000 and 2015 in any region of the world ¹⁷17. Guthold R, Stevens GA, Riley LM, Bull FC. Worldwide trends in insufficient physical activity from 2001 to 2016: a pooled analysis of 358 population-based surveys with 1.9 million participants. Lancet Glob Heath 2018; 6:e1077-86.. Physical inactivity is characterized in adults as do not achieve at least 150 minutes of moderate-intensity aerobic physical activity per week, or 75 minutes of vigorous-intensity aerobic physical activity per week, or an equivalent combination of both ¹⁸18. World Health Organization. Global recommendations on physical activity for health. Geneva: World Health Organization; 2010.. Although physical inactivity among older people was associated with poor cognitive function ¹⁵15. Hoang TD, Reis J, Zhu N, Jacobs Jr. DR, Launer LJ, Whitmer RA, et al. Effect of early adult patterns of physical activity and television viewing on midlife cognitive function. JAMA Psychiatry 2016; 73:73-9., high level of dependency ¹⁹19. McPhee JS, French DP, Jackson D, Nazroo J, Pendleton N, Degens H. Physical activity in older age: perspectives for healthy ageing and frailty. Biogerontology 2016; 17:567-80., and increased all-cause mortality risk ²⁰20. Gebel K, Ding D, Chey T, Stamatakis E, Brown WJ, Bauman AE. Effect of moderate to vigorous physical activity on all-cause mortality in middle-aged and older Australians. JAMA Intern Med 2015; 175:970-7., its prevalence is still high among older adults in Brazil ²¹21. Madeira MC, Siqueira FCV, Facchini LA, Silveira DS, Tomasi E, Thumé E. Atividade física no deslocamento em adultos e idosos do Brasil: prevalências e fatores associados. Cad Saúde Pública 2013; 29:165-74..

Bielemann et al. ²²22. Bielemann RM, Silva BGC, Coll CVN, Xavier MO, Silva SG. Impacto da inatividade física e custos de hospitalização por doenças crônicas. Rev Saúde Pública 2015; 49:75. reported that 14% of cost from hospitalizations due to diabetes, some types of cancer, cardiovascular diseases, and osteoporosis in Brazil were linked to physical inactivity; however, there is no data about its impact on dementia-related hospital admission. Then, we aimed to determine the economic burden of leisure-time physical inactivity in hospitalizations due to dementia in Brazil.

Method

To conduct this national-wide descriptive study, we used secondary data from the Hospital Information Systems of the Brazilian Unified National Health System (SIH/SUS, in Portuguese) (DATASUS. http://www2.datasus.gov.br/DATASUS/index.php, accessed on Mar/2020) and from the latest Brazilian National Health Survey (PNS, in Portuguese) ²³23. Szwarcwald CL, Malta DC, Pereira CA, Vieira MLFP, Conde WL, Souza Júnior PRB, et al. Pesquisa Nacional de Saúde no Brasil: concepção e metodologia de aplicação. Ciênc Saúde Colet 2014; 19:333-42.. PNS was approved by The National Commission of Ethics in Research (Regulation n. 328,159) ²³23. Szwarcwald CL, Malta DC, Pereira CA, Vieira MLFP, Conde WL, Souza Júnior PRB, et al. Pesquisa Nacional de Saúde no Brasil: concepção e metodologia de aplicação. Ciênc Saúde Colet 2014; 19:333-42.. DATASUS is an open-access non-nominal database, so no ethical approval is needed to extract data from this database.

Nationalwide data about hospitalization and total economic cost from these hospitalizations in Brazil during 2013 were extracted from SIH/SUS. We selected 2013 because it was the latest year with population-based data about physical activity in Brazil measured by validated instrument (International Physical Activity Questionnaire - IPAQ) ²⁴24. Craig CL, Marshall AL, Sjöström M, Bauman AE, Booth ML, Ainsworth BE, et al. International physical activity questionnaire: 12-country reliability and validity. Med Sci Sport Exerc 2003; 35:1381-95.. Number and cost of hospitalizations was extracted from DATASUS (http://www2.datasus.gov.br/DATASUS/index.php, accessed on Mar/2020). Total hospitalizations were considered as all new authorized hospitalization forms, transferences, and re-hospitalizations related to dementia. Total economic cost was considered as the value referred to all services to all hospitalizations throughout a specific period (2013). When applicable, we converted Brazilian Real (BRL) to US Dollar (USD) based on conversion rate in data registration year (December 31th, 2013): BRL 1.00 = USD 0.427.

The cause of hospitalizations was informed as the main diagnose that motived them. For dementia, we considered all hospitalizations from which the main diagnose was defined as dementia in Alzheimer’s disease (ICD-10: F00; G30), vascular dementia (ICD-10: F01), dementia in other disease classified elsewhere (ICD-10: F02), and unspecified dementia (ICD-10: F03), according to International Classification of Diseases, 10th revision (ICD-10) ²⁴24. Craig CL, Marshall AL, Sjöström M, Bauman AE, Booth ML, Ainsworth BE, et al. International physical activity questionnaire: 12-country reliability and validity. Med Sci Sport Exerc 2003; 35:1381-95.. We also stratified these outcomes based on sex (man/woman), age groups (less than 50 years, 50-59, 60-69, 70-79, 80 or older), ethnicity (white, black, mixed race, other - yellow, indigenous, and unknown), and region (South, Southeast, North, Northeast, and Central). Age was estimated based on date of birth and date of admission.

Rate of hospitalization was determined by dividing the number of hospitalizations by the total population and from each group (sex, ethnicity, and region). Data about total population in 2013 was extracted from Brazilian Institute of Geography and Statistics (IBGE, in Portuguese) ²⁵25. Instituto Brasileiro de Geografia e Estatística. Pesquisa Nacional por Amostra de Domicílios Contínua - PNAD Contínua. Divulgação anual. Rio de Janeiro: Instituto Brasileiro de Geografia e Estatística; 2013..

To determine the economic burden of physical inactivity in hospitalizations due to dementia, we calculated the population attributable fraction (PAF) for this exposure. We used the formula below based on previous publication ¹³13. Mukadam N, Sommerlad A, Huntley J, Livingston G. Population attributable fractions for risk factors for dementia in low-income and middle-income countries: an analysis using cross-sectional survey data. Lancet Glob Health 2019; 7:e596-603.^,2222. Bielemann RM, Silva BGC, Coll CVN, Xavier MO, Silva SG. Impacto da inatividade física e custos de hospitalização por doenças crônicas. Rev Saúde Pública 2015; 49:75.^,2626. Barnes DE, Yaffe K. The projected effect of risk factor reduction on Alzheimer's disease prevalence. Lancet Neurol 2011; 10:819-28.. The PAF aims at identifying the percental reduction in the prevalence of certain disease or health condition (e.g. hospitalization due to dementia) if certain risk factor (e.g. physical inactivity) was eliminated.

Where, p: prevalence of physical inactivity and RR: relative risk.

We used the RR calculated by Hamer & Chida ²⁷27. Hamer M, Chida Y. Physical activity and risk of neurodegenerative disease: a systematic review of prospective evidence. Psychol Med 2009; 39:3-11. in a meta-analysis with a sample of 23,168 participants from different countries (Finland, United States, China, Sweden, Canada, and France). The study identified that physical inactivity was associated with a RR of 1.82 (95%CI: 1.19; 2.78) for dementia. All included studies reported adjusted RR by covariates such as age, gender, and education level.

Self-reported physical activity behavior was extracted from PNS. This cross-sectional population-based survey was to date the most complete health survey already conducted in Brazil. It covered data about sociodemographic, health status, behavior, and healthcare utilization among Brazilian adult population (i.e. aged 18 or older). Due to its three-stage probabilistic sampling and use of weighted estimates, the information from PNS can be extrapolated to all Brazilian adult population ²³23. Szwarcwald CL, Malta DC, Pereira CA, Vieira MLFP, Conde WL, Souza Júnior PRB, et al. Pesquisa Nacional de Saúde no Brasil: concepção e metodologia de aplicação. Ciênc Saúde Colet 2014; 19:333-42.. From 81,167 households included in the PNS, 60,202 individuals completed interviews about lifestyle and health status (response rate: 74.2%). As mentioned earlier, physical activity was measured by the IPAQ, which includes questions on frequency and duration of physical activity in leisure-time. A final score was generated from multiplying the weekly frequency of physical activity by its duration in minutes. Participants that did not achieved at least 150 minutes of moderate physical activity or 75 minutes of vigorous physical activity or an equivalent combination of moderate and vigorous activity per week in leisure time were classified as physically inactive ¹⁸18. World Health Organization. Global recommendations on physical activity for health. Geneva: World Health Organization; 2010..

At descriptive analysis, hospitalization rate, total economic cost, physical inactivity prevalence, and PAF for this risk factor were stratified by sex (man, woman), age groups (< 50 years, 50-59, 60-69, 70-79, and 80+), ethnicity, (white, black, mixed race, other), and country region (Central, North, Northeast, South, Southeast). Data were imported into Stata 13.1 (https://www.stata.com/) and were reported in absolute and relative values.

Results

In 2013, 3,724 people were hospitalized due to dementia in Brazil. Among men, 61.2% of admissions were of adults aged 69 years or less and 61.5% in Southeast region. Most of hospitalizations from dementia in women occurred in patients older than 70 years (55.2%), white (44.2%), and from Southeast region (64%) (data not shown). Table 1 shows that, although the rate of hospitalizations increases with ageing, men had higher values before aged 80 compared to women.

In Brazil, the total cost of hospitalization from dementia in 2013 was BRL 17,971,833.85 (USD 7,673,973.05). More than half of cost among men were spent with individuals younger than 59 years (54.6%), white and mixed (51.5%), and from Southeast region (87.9%). Women and men had similar distribution among regions, but the proportion of cost was higher in patients older than 60 years (57.8%) and white (53.7%).

In 2013, 77.7% of Brazilian population were physically inactive during leisure time with higher prevalence among women (Table 2). Men aged less than 50 years had lower prevalence of physical inactivity compared to other male and to female age groups. Men and women aged 70 or older were more physically inactive compared to any younger group from the same sex. Women were more inactive than men regardless of ethnicity and region.

About 37% of all hospitalization from dementia in Brazil were attributable to physical inactivity in 2013, with values reaching 42.9% and 43.8% for men and women aged 80 or older, respectively, and 41% and 40.8% for black women and in North region, respectively.

Table 3 shows that the economic burden of physical inactivity in hospitalizations due to dementia was estimated in BRL 6,994,254.75 (USD 2,986,546.78). White patients and at Southeast region had higher cost attributable to physical inactivity regardless of sex. While physical inactive accounts for greater cost among men younger than 50 years, we observed that this exposure has higher impact in hospitalizations of women aged less than 50 and older than 80 years.

Discussion

Our study reported that 37% from all 3,724 hospitalizations due to dementia at Brazil in 2013 was linked to physical inactivity resulting in an economic burden of BRL 6,994,254.75 (95%CI: 2,311,879.12; 10,454,848.60). Besides, physical inactivity accounted for 43.5% of all dementia-related hospitalizations in patients aged 80 years or older. Also, women had more hospitalizations attributable to physical inactivity than men regardless of ethnicity and country’s region.

The number of studies that evaluated the economic impact of physical inactivity in hospital admissions in Brazil is limited. Sichieri et al. ²⁸28. Sichieri R, Nascimento S, Coutinho W. The burden of hospitalization due to overweight and obesity in Brazil. Cad Saúde Pública 2007; 23:1721-7. stated that physical inactivity was related to nearly 36% of all diabetes-related inpatient cost in adults aged between 20 and 60 years, values that are near what we reported for overall sample and for those aged up to 60 years (37%). Bielemann et al. ²²22. Bielemann RM, Silva BGC, Coll CVN, Xavier MO, Silva SG. Impacto da inatividade física e custos de hospitalização por doenças crônicas. Rev Saúde Pública 2015; 49:75. reported that about 15% of all hospitalizations from diabetes, breast and colon neoplasm, cerebrovascular and ischemic heart disease, hypertension, and osteoporosis in 2013 were attributable to physical inactivity in Brazil, with the lowest patient fractions from South and Central regions. In our study, despite the different population attributable factor (37%) for dementia, we found the lowest values at the same regions. Our results provide a novel perspective about how physical inactivity is associated with hospital admissions due to dementia in Brazil.

Bielemann et al. ²²22. Bielemann RM, Silva BGC, Coll CVN, Xavier MO, Silva SG. Impacto da inatividade física e custos de hospitalização por doenças crônicas. Rev Saúde Pública 2015; 49:75. exposed that all hospitalizations due to non-communicable chronic disease in Brazil accounted for USD 451,987,141.82 in 2013. From this value, USD 67,395,324.61 were attributable to physical inactivity. From 2000 to 2018, deaths from Alzheimer’s disease-type dementia increase about 146.2% in United States, a percentage higher than stroke, heart disease, and breast or prostate cancer1. Likewise, data from SIH/SUS showed that the number and economic cost of hospitalizations due to dementia increased more than any of beforementioned chronic diseases from 2010 to 2017 in Brazil. Although this value found by Bielemann et al. ²²22. Bielemann RM, Silva BGC, Coll CVN, Xavier MO, Silva SG. Impacto da inatividade física e custos de hospitalização por doenças crônicas. Rev Saúde Pública 2015; 49:75. was higher than that found in our study, dementia has impacted the Brazilian healthcare system in last years; however, a larger effect is expected in the next years. Therefore, strategies to reduce this disease economic and social burden are need, especially in Brazil.

The prevalence of physical inactivity, which is linked to around 18% of all dementia cases in the world ²⁹29. Norton S, Matthews FE, Barnes DE, Yaffe K, Brayne C. Potential for primary prevention of Alzheimer's disease: an analysis of population-based data. Lancet Neurol 2014; 13:788-94. is persistently high in Brazilian population especially in children, adolescentes ³⁰30. Hallal PC, Andersen LB, Bull FC, Guthold R, Haskell W, Ekelund U, et al. Global physical activity levels: surveillance progress, pitfalls, and prospects. Lancet 2012; 380:247-57. and older population ²¹21. Madeira MC, Siqueira FCV, Facchini LA, Silveira DS, Tomasi E, Thumé E. Atividade física no deslocamento em adultos e idosos do Brasil: prevalências e fatores associados. Cad Saúde Pública 2013; 29:165-74.. Women are more likely to develop dementia than men, especially in older ages ³¹31. Mielke MM, Vemuri P, Rocca WA. Clinical epidemiology of Alzheimer's disease: assessing sex and gender differences. Clin Epidemiol 2014; 6:37-48., what may explain the higher rate of hospitalization among women in patients aged 80 years or older. Based on our results, about 44% of hospitalizations from dementia in Brazil were linked to physical inactivity among women older than 80 years in 2017. This population stratum is affected by loss of physical and cognitive capacity, which may act as important barriers to physical activity practice ³²32. World Health Organization. World report on ageing and health. Geneva: World Health Organization; 2015.. Thus, public policies need to be designed as ageing-friendly interventions to promote physical activity practice and maintenance during aging.

Moreover, men had higher rate of hospitalization than women among individuals aged 69 years or less. Likewise, the proportion of hospitalizations attributable to physical inactivity was higher among men aged between 60 and 69 years than women. Alzheimer’s disease is the most prevalent type of dementia1, and vascular dementia appears as the second leading cause of this syndrome ³³33. O'Brien JT, Thomas A. Vascular dementia. Lancet 2015; 386:1698-706.. However, vascular dementia has higher incidence rate among men ³⁴34. Ruitenberg A, Ott A, van Swieten JC, A Hofman, Breteler MM. Incidence of dementia: does gender make a difference? Neurobiol Aging 2001; 22:575-80.. This difference may be explained by a worse cardiovascular health in men. Hypertensive ³⁵35. Alladi S, Kaul S, Meena AK, Somayajula S, Umadevi M, Reddy JM. Pattern of vascular dementia in India: study of clinical features, imaging, and vascular mechanisms from a hospital dementia registry. J Stroke Cerebrovasc Dis 2006; 15:49-56. and cerebrovascular diseases ³⁶36. Zhou DHD, Wang JYJ, Li J, Deng J, Gao C, Chen M. Frequency and risk factors of vascular cognitive impairment three months after ischemic stroke in china: the Chongqing stroke study. Neuroepidemiology 2005; 24:87-95. are common causes of vascular dementia and about 57% of all premature deaths that occurred among men between 30 and 69 years in Brazil in 2017 were due to those diseases (Brazilian Ministry of Health. http://svs.aids.gov.br/dantps/centrais-de-conteudos/paineis-de-monitoramento/mortalidade/dcnt/, accessed on Mar/2020). This picture exposes the “survival bias” in dementia prevalence: men that live longer may have better cardiovascular health, what lead to a decreased risk to develop some ageing-related illness such as Alzheimer’s disease ³⁷37. Sabia S, Fayosse A, Dumurgier J, Schnitzler A, Empana J-P, Ebmeier KP, et al. Association of ideal cardiovascular health at age 50 with incidence of dementia: 25 year follow-up of Whitehall II cohort study. BMJ 2019; 366:l4414.. Nevertheless, we still observed high rates of hospitalizations due to dementia in the oldest age group, what corroborated previous findings ¹1. 2020 Alzheimer's disease facts and figures. Alzheimers Dement 2020; 16:391-460.^,66. Desai U, Kirson NY, Ye W, Mehta NR, Wen J, Andrews JS. Trends in health service use and potentially avoidable hospitalizations before Alzheimer's disease diagnosis: a matched, retrospective study of US Medicare beneficiaries. Alzheimers Dement (Amst) 2019; 11:125-35. and emphasized the need to promote low-cost strategies such as physical activity to reduce the burden of dementia in Brazilian health system.

Furthermore, whereas high hospitalization rates were found among women, we revealed that men reported higher economic costs from hospitalization due to dementia. One third of men in Brazil do not perform annual screenings (i.e. check-up) ³⁸38. Enes CC, Nucci LB. A telephone surveillance system for noncommunicable diseases in Brazil. Public Health Rep 2019; 134:324-7.. Common imaging medical tests such echocardiogram and ultrasonography could decrease the risk for cardiovascular events that are associated with dementia. Then, hospital admissions among men are more likely to be related to advanced stages of dementia, which requires more hospital services and then increased economic cost.

Although rates of hospitalizations were the highest among subjects with ignored ethnicity classification in SIH/SUS, we could observe that it was higher among white people than among black and mixed patients in both sexes. Also, though mixed-race patients had a rate of hospital admission 60% lower than black individuals, the inpatient economic cost was 2.9 times higher when compared with black patients. Despite other studies did not find a higher prevalence of dementia in this ethnic group ³⁹39. Mehta KM, Yeo GW. Systematic review of dementia prevalence and incidence in United States race/ethnic populations. Alzheimers Dement 2017; 13:72-83.^,4040. Barros MBA, Lima MG, Medina LPB, Szwarcwald CL, Malta DC. Social inequalities in health behaviors among Brazilian adults: National Health Survey, 2013. Int J Equity Health 2016; 15:148., it was observed an increased inpatient burden of dementia among black individuals. Even though more than half of Brazilian population is declared non-white ²⁵25. Instituto Brasileiro de Geografia e Estatística. Pesquisa Nacional por Amostra de Domicílios Contínua - PNAD Contínua. Divulgação anual. Rio de Janeiro: Instituto Brasileiro de Geografia e Estatística; 2013., the country is constantly facing a racial disparity. Whites have higher monthly income and schooling years than mixed subjects ²⁵25. Instituto Brasileiro de Geografia e Estatística. Pesquisa Nacional por Amostra de Domicílios Contínua - PNAD Contínua. Divulgação anual. Rio de Janeiro: Instituto Brasileiro de Geografia e Estatística; 2013.. Likewise, non-whites are more likely to smoke, to have heavy episodic drinking, physical inactivity, sedentarism, and poor diet compared to white individuals ⁴¹41. Chiavegatto Filho ADP, Beltrán-Sánchez H, Kawachi I. Racial disparities in life expectancy in Brazil: challenges from a multiracial society. Am J Public Health 2014; 104:2156-62.. Although the higher hospitalizations rates among white patients may be explained by higher life expectancy in this group ⁴¹41. Chiavegatto Filho ADP, Beltrán-Sánchez H, Kawachi I. Racial disparities in life expectancy in Brazil: challenges from a multiracial society. Am J Public Health 2014; 104:2156-62., our results indicate a racial disparity among economic cost of hospitalizations due to dementia.

Our study has important limitations. First, the SIH/SUS did not accurately provide the ethnicity group for all patients. Nevertheless, we could report some social disparity related to economic burden of dementia among mixed and white patients. Second, we reported that RR was generated using data from six different countries. However, five of them are classified as high-income countries, what could reduce the translation of this measure into the Brazilian healthcare system. However, as already mentioned by Mukadam et al. ¹³13. Mukadam N, Sommerlad A, Huntley J, Livingston G. Population attributable fractions for risk factors for dementia in low-income and middle-income countries: an analysis using cross-sectional survey data. Lancet Glob Health 2019; 7:e596-603., there are no meta-analyses that estimated the RR for dementia by physical inactivity using data exclusively from low-and middle-income countries. Moreover, extracting RR from meta-analysis instead of individual studies is a more precise and comparable method ⁴²42. Livingston G, Sommerlad A, Orgeta V, Costafreda SG, Huntley J, Ames D, et al. Dementia prevention, intervention, and care. Lancet 2017; 390:2673-734..

Third, Levin’s formula was designed to provide PAF using unadjusted RR. Here, the RR estimated by Hamer & Chida ²⁷27. Hamer M, Chida Y. Physical activity and risk of neurodegenerative disease: a systematic review of prospective evidence. Psychol Med 2009; 39:3-11. was adjusted for some important confoundings such age, sex, and educational level. However, the usage of other methods was not possible. For example, the PAF formula suggested by Miettinen et al. ⁴³43. Mansournia MA, Altman DG. Population attributable fraction. BMJ 2018; 360:k757. requires the prevalence of the exposure (i.e. physical inactivity) among cases (i.e. hospitalized patients with dementia). Nevertheless, no nationalwide data about physical inactivity in dementia patients from Brazil is available.

Fourth, although physical activity could be measured in different domains such as work and during work/back home trip, we decided to determine physical inactivity only by leisure time for some reasons. Firstly, due to the greater potential for future interventions in this population ⁴⁴44. Mielke GI, Malta DC, Sá GBAR, Reis RS, Hallal PC. Regional differences and correlates of leisure time physical activity in Brazil: results from the Brazilian National Health Survey-2013. Rev Bras Epidemiol 2015; 18:158-69.. Secondly, the lower prevalence of physical activity in commuting domain in individuals older than 40 years in Brazilian population ⁴⁵45. Ferreira Mendes GF, Häfele V, Blumenberg C, Werneck AO, Radicchi MR, Coll CVN, et al. Comparação das estimativas de atividade física e comportamento sedentário em adultos brasileiros no VIGITEL e PNS, Brasil, 2013. Rev Bras Ativ Fís Saúde 2018;23:e0062. could overestimate our results. Thirdly, the articles included in the systematic review that generated the relative risk of physical inactivity for dementia ²⁷27. Hamer M, Chida Y. Physical activity and risk of neurodegenerative disease: a systematic review of prospective evidence. Psychol Med 2009; 39:3-11. and other that used similar methodology ²⁶26. Barnes DE, Yaffe K. The projected effect of risk factor reduction on Alzheimer's disease prevalence. Lancet Neurol 2011; 10:819-28.^,2929. Norton S, Matthews FE, Barnes DE, Yaffe K, Brayne C. Potential for primary prevention of Alzheimer's disease: an analysis of population-based data. Lancet Neurol 2014; 13:788-94. primarily used physical inactivity in leisure time to determine the impact of this risk factor in other chronic diseases such as dementia. Lastly, we presume that this classification may prevent overestimation of our findings, enable greater comparison with other populations, and illustrated the possible impact of leisure time physical activity promotion ¹³13. Mukadam N, Sommerlad A, Huntley J, Livingston G. Population attributable fractions for risk factors for dementia in low-income and middle-income countries: an analysis using cross-sectional survey data. Lancet Glob Health 2019; 7:e596-603.^,4646. Al Tunaiji H, Davis JC, Mansournia MA, Khan KM. Population attributable fraction of leading non-communicable cardiovascular diseases due to leisure-time physical inactivity: a systematic review. BMJ Open Sport Exerc Med 2019; 5:e000512..

Finally, we extracted data about hospitalizations due to dementia using the DATASUS. Although it is a federal open-access nationalwide database, there are some limitations that need to be acknowledged regarding its use. First, DATASUS comprehends data from hospitalizations covered by the Brazilian Unified National Health System - SUS (i.e. Brazilian public healthcare system). Consequently, information about hospitalization in private hospitals may be missing. However, besides the fact that two of three older adults in Brazil have no private health insurance ⁴¹41. Chiavegatto Filho ADP, Beltrán-Sánchez H, Kawachi I. Racial disparities in life expectancy in Brazil: challenges from a multiracial society. Am J Public Health 2014; 104:2156-62., two thirds of hospitalizations due to dementia were covered by the Brazilian public healthcare system in 2013 (DATASUS. http://www2.datasus.gov.br/DATASUS/index.php, accessed on Mar/2020). Second, DATASUS may have different levels of sub-notification across the country, which could underestimate our findings.

We conclude that 37% of economic cost from hospitalizations in Brazil due to dementia were attributable to physical inactivity in 2013, with the highest patient fractions occurring in older patients. These results enhance the perspective about the role of physical inactivity in burden of dementia and its impact on Brazilian healthcare system. Dementia is a chronic and progressive disorder with elevated economic and social cost. Therefore, strategies to preserve the quality of life of these patients are needed to reduce the burden for the patients, their family, and on healthcare system.

Acknowledgments

This work was supported by a partnership between Brazilian Graduate Studies Coordinating Board (CAPES), Federal University of Pelotas and the School of Human Movement and Nutrition Sciences, University of Queensland that enabled international collaborative work to be undertaken. N. Feter was funded by a scholarship from CAPES. This study was financed in part by CAPES (Finance Code 001).

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