ABSTRACT

OBJECTIVE

To estimate the prevalence of sleep problems and sleeping pill use and associated factors in the Brazilian population.

METHODS

This study was conducted with data from the 2019 Brazilian National Health Survey. Our sample consisted of 94,114 participants and the outcomes analyzed were sleep problems and sleeping pill use. Sociodemographic, lifestyle, and health characteristics were explored in a descriptive and multivariate analysis with Poisson regression, robust variance, and 5% significance.

RESULTS

We found a 35.1% (95%CI: 34.5–35.7) and 8.5% (95%CI: 8.2–8.9) prevalence of sleep problems and sleeping pill use, respectively. Sleep problems were associated with women (PR = 1.41; 95%CI: 1.36–1.46), individuals who self-assess their health as regular/poor/very poor (PR = 1.56; 95%CI: 1.51–1.62), those with chronic diseases (PR = 1.70; 95%CI: 1.64–1.78), those who use alcohol excessively (PR = 1.14; 95%CI: 1.09–1.20), and smokers (PR = 1.16; 95%CI: 1.10–1.22). Sleeping pill use was associated with women (PR = 1.57; 95%CI: 1.43–1.73), divorcees (PR = 1.46; 95%CI: 1.30–1.65), urban denizens (PR = 1.32; 95%CI: 1.21–1.45) those who self-assess their health as regular/poor/very poor (PR = 1.79; 95%CI: 1.64–1.95), those with chronic diseases (PR = 4.07; 95%CI: 3.48–4.77), and smokers (PR = 1.49; IC95%: 1.33–1.67).

CONCLUSION

This study found that the prevalence of sleep problems and sleeping pill use in Brazilians indicates the need for attention and sleep care for this population, especially in women and those with lifestyle and health conditions associated with the analyzed outcomes.

Sleep Initiation and Maintenance Disorders, epidemiology; Sleep Aids, Pharmaceutical, therapeutic use; Risk Factors; Health Surveys

INTRODUCTION

Sleep is a biological, complex, and active process which is considered essential for life and the maintenance of human health ¹1. Luyster FS, Strollo PJ Jr, Zee PC, Walsh JK; Boards of Directors of the American Academy of Sleep Medicine and the Sleep Research Society. Sleep: a health imperative. Sleep. 2012;35(6):727-34. https://doi.org/10.5665/sleep.1846
https://doi.org/10.5665/sleep.1846... . The body performs important functions during sleep, such as restoring physiological systems after wakefulness, conserving and restoring energy metabolism, strengthening the immune system, secreting hormones, consolidating memories, and maintaining neuronal integrity ¹1. Luyster FS, Strollo PJ Jr, Zee PC, Walsh JK; Boards of Directors of the American Academy of Sleep Medicine and the Sleep Research Society. Sleep: a health imperative. Sleep. 2012;35(6):727-34. https://doi.org/10.5665/sleep.1846
https://doi.org/10.5665/sleep.1846... .

Thus, poorly slept nights negatively interfere in organ and system function, impairing individuals’ quality of life and general well-being ²2. Andrade RD, Ferrari Junior GJ, Capistrano R, Teixeira CS, Beltrame TS, Felden EPG. Absenteísmo na indústria está associado com o trabalho em turnos e com problemas no sono. Cienc Trab. 2017;19(58):35-41. https://doi.org/10.4067/S0718-24492017000100035
https://doi.org/10.4067/S0718-2449201700... , contributing to the emergence of several diseases ³3. Drager LF, Lorenzi-Filho G, Cintra FD, Pedrosa RP, Bittencourt LRA, Poyares D, et al. 1 o Posicionamento Brasileiro sobre o Impacto dos Distúrbios de Sono nas Doenças Cardiovasculares da Sociedade Brasileira de Cardiologia. Arq Bras Cardiol. 2018;111(2):290-340. https://doi.org/https://doi.org/10.5935/abc.20180154
https://doi.org/https://doi.org/10.5935/... . Moreover, sleep alterations can significantly impact work productivity, increase individuals’ tendency to errors and accidents due to impaired concentration capacity ⁴4. Riontino L, Cavallero C. Individual differences in working memory efficiency modulate proactive interference after sleep deprivation. Psychol Res. 2021;85(2):480-90. https://doi.org/10.1007/s00426-020-01292-6
https://doi.org/10.1007/s00426-020-01292... , and increase work absenteeism ²2. Andrade RD, Ferrari Junior GJ, Capistrano R, Teixeira CS, Beltrame TS, Felden EPG. Absenteísmo na indústria está associado com o trabalho em turnos e com problemas no sono. Cienc Trab. 2017;19(58):35-41. https://doi.org/10.4067/S0718-24492017000100035
https://doi.org/10.4067/S0718-2449201700... .

Besides the absence of sleep disorders, maintaining a good sleep duration and a regular sleep-wake schedule are necessary to ensure sleep functions and benefits. However, these factors vary throughout life and from person to person ²2. Andrade RD, Ferrari Junior GJ, Capistrano R, Teixeira CS, Beltrame TS, Felden EPG. Absenteísmo na indústria está associado com o trabalho em turnos e com problemas no sono. Cienc Trab. 2017;19(58):35-41. https://doi.org/10.4067/S0718-24492017000100035
https://doi.org/10.4067/S0718-2449201700... .

Nowadays, lifestyle factors such as work overload, intense task routines, stress, technology use, and exposure to numerous contemporary digital stimuli near bedtime are related to shorter and poorer sleep, excessive daytime sleepiness, and sleeping pill use to attempt to solve these problems ⁵5. Bollu PC, Kaur H. Sleep medicine: insomnia and sleep. Mo Med. 2019 [cited 2021 May 25];116(1):68-75. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6390785/pdf/ms116_p0068.pdf
https://www.ncbi.nlm.nih.gov/pmc/article... .

An international survey with 10,132 participants found that 56% of individuals in the United States, 31% in Western Europe, and 23% in Japan showed sleep problems ⁶6. Léger D, Poursain B, Neubauer D, Uchiyama M. An international survey of sleeping problems in the general population. Curr Med Res Opin. 2008;24(1):307-17. https://doi.org/10.1185/030079907x253771
https://doi.org/10.1185/030079907x253771... . In Colombia, 59.6% of interviewees ⁷7. Ruiz AJ, Rondón Sepúlveda MA, Hidalgo Martínez P, Cañon Muñoz M, Otero Mendoza L, Panqueva Centanaro OP, et al. Prevalence of sleep complaints in Colombia at different altitudes. Sleep Sci. 2016;9(2):100-5. https://doi.org/10.1016/j.slsci.2016.05.008
https://doi.org/10.1016/j.slsci.2016.05.... had sleep complaints. In Brazil, the Brazilian Sleep Society found an increase in the percentage of people who reported sleep problems, from 56.7% in 2018 to 60.4% in 2019 ⁸8. Associação Brasileira do Sono. Hábitos de sono da população participante da Semana do Sono 2018 e 2019. São Paulo: ABS; 2019 [cited 2021 May 29]. Available from: http://semanadosono.com.br/wp-content/uploads/2021/01/semana-sono-cartilha-habitos-sono.pdf
http://semanadosono.com.br/wp-content/up... .

Thus, various populations, ages, and ethnicities suffer from sleep problems, and many people seek medicine use as an intervention strategy. The best known and often used sleeping pill are benzodiazepine hypnotics, sedatives, and anxiolytics, which decrease sleep latency, make individuals fall asleep faster, reduce nocturnal awakening, and increase sleep duration. However, prolonged and undue use of these drugs brings important adverse effects, including dependence and abuse risks ⁹9. Oliveira ALML, Nascimento MMG, Castro-Costa E, Firmo JOA, Lima-Costa MF, Loyola Filho AI. Increased use of benzodiazepines among older adults: Bambuí Project. Rev Bras Epidemiol. 2020;23:e200029. https://doi.org/10.1590/1980-549720200029
https://doi.org/10.1590/1980-54972020002... .

In the United States, the number of sleeping pill prescriptions increased by 293% in a decade, from 5.3 million in 1999 to 20.8 million in 2010 ¹⁰10. Ford ES, Wheaton AG, Cunningham TJ, Giles WH, Chapman DP, Croft JB. Trends in outpatient visits for insomnia, sleep apnea, and prescriptions for sleep medicines among US adults: findings from the National Ambulatory Medical Care Survey 1999-2010. Sleep. 2014;37(8):1283-93. https://doi.org/10.5665/sleep.3914
https://doi.org/10.5665/sleep.3914... . In Brazil, 7.6% of its population used sleeping pills in 2013 ¹¹11. Kodaira K, Silva MT. Sleeping pill use in Brazil: a population-based, cross-sectional study. BMJ Open. 2017;7(7):e016233. https://doi.org/10.1136/bmjopen-2017-016233
https://doi.org/10.1136/bmjopen-2017-016... . Moreover, the prevalence of sleeping pill use in older adults (aged 75 years or older) in a Brazilian city increased from 24.9% in 1997 to 33.9% in 2012 ⁹9. Oliveira ALML, Nascimento MMG, Castro-Costa E, Firmo JOA, Lima-Costa MF, Loyola Filho AI. Increased use of benzodiazepines among older adults: Bambuí Project. Rev Bras Epidemiol. 2020;23:e200029. https://doi.org/10.1590/1980-549720200029
https://doi.org/10.1590/1980-54972020002... .

In this context, considering how important sleep is for people’s health and quality of life, this study aimed to estimate the prevalence of, and factors associated with sleep problems and sleeping pill use in the Brazilian population, based on data from the 2019 National Health Survey ( Pesquisa Nacional de Saúde - PNS 2019). In this study, sleep problems refer to difficulty falling asleep (a symptom of insomnia), frequent nocturnal awakening (sleep fragmentation), and sleeping longer than usual (a result of sleep deprivation). The results of this current population-based research can serve as basis for the formulation of strategies and policies in the areas of promotion, surveillance, and health care and welfare of the Brazilian population.

METHODS

This study was conducted with data from the Brazilian National Health Survey ( Pesquisa Nacional de Saúde – PNS 2019), conducted between 2019 and 2020. PNS is a household population survey carried out by the Instituto Brasileiro de Geografia e Estatística (IBGE – Brazilian Institute of Geography and Statistics) in partnership with the Ministry of Health, aiming to assess what determines and conditions the health of Brazilians and their needs in a representative database of the Brazilian population.

Data was collected via PNS home interviews and sampling, using the Amostra Mestra do Sistema Integrado de Pesquisa Domiciliares (Master Sample of the Integrated System of Household Surveys), which allows greater territorial coverage and uses a three-stage cluster sampling process with a simple random sample. Its first stage consists of Primary Sampling Units (census tracts), the second one integrates the selected households, and the third one includes the residents aged 15 years old or above who were selected in each household to answer the survey.

At the end, 108,457 households were selected, of which 100,541 were occupied and, of these, 94,114 people were chosen as volunteers ¹²12. Stopa SR, Szwarcwald CL, Oliveira MM, Gouvea ECDP, Vieira MLFP, Freitas MPS, et al. National Health Survey 2019: history, methods and perspectives. Epidemiol Serv Saude. 2020;29(5):e2020315. https://doi.org/10.1590/S1679-49742020000500004
https://doi.org/10.1590/S1679-4974202000... . The final sample of this study consists of the 94,114 interviewed individuals aged 15 years old and above.

This study had two dependent variables: “sleep problems,” assessed by affirmative or negative answered to question “N010 – In the last two weeks, did you have sleep problems such as difficulty falling asleep, waking up often at night or sleeping more than usual?” and “sleeping pill use,” also assessed by affirmative and negative answers to question “Q132 – Did you use any sleeping pill in the last two weeks? ”

Our independent sociodemographic individual variables were gender (male or female), age (15–29, 30–59, 60 years or more), race/skin color (white, Black – Black and Brown –, and Indigenous or Asian), marital status (married, divorced, widowed or single), educational attainment (illiterate/no schooling, complete or incomplete primary education, complete or incomplete secondary education, and complete or incomplete higher education), per capita household income (up to one minimum wage, one to three minimum wages, and above three minimum wages), area of residence (urban or rural), household size (one, two to three, or four or more residents), and Family Health Strategy - FHS – coverage (yes, no or does not know).

The following lifestyle and health variables were considered: health self-assessment (very good/good; regular/poor/very poor); diagnosis of chronic, physical or mental disease, chronic health condition or long-term disease (yes, no); use of tobacco and its derivatives (smoker – currently smokes some tobacco product; former smoker – smoked some tobacco product in the past; never smoked); alcohol use (excessive use – five or more daily 50-mL doses (considered the standard) in at least a single occasion in the last 30 days; moderate use – habitual use regardless of the dose consumed in the last 30 days, but lower than excessive use; and teetotalism); vegetable consumption frequency (less than five days a week, five or more days a week); body mass index (malnutrition, eutrophy, overweight, and obesity); and weekly exercise or sports practice (in minutes). The conceptual model of dependent and independent variables are shown in Figure 1 .

Since this is a study with complex sampling, sample weight was incorporated into its design. The calculation was carried out of the prevalence of outcomes in relation to individual variables, with presentation of the respective 95% confidence intervals (95%CI).Then, a bivariate Poisson regression was performed to estimate crude prevalence ratios (PR) and 95% confidence intervals (95%CI).

Variables showing p ≤ 0.20 in the bivariate analysis were included in the multivariate Poisson regression model to estimate adjusted prevalence (PR) ratios. A hierarchical model was adopted and variables were inserted into the multivariate model as their p-values increased. Only statistically significant variables (p < 0.05) were kept in the final model. All analyses were made in the Stata software version 13 (Stata Corp., College Station, United States).

The 2019 Brazilian National Health Survey was approved by the National Committee of Ethics in Research (CONEP) at the Ministry of Health National Council of Health (CNS) under opinion no. 3.529.376, of August 23, 2019. The results of that research are in public domain and available at the Instituto Brasileiro de Geografia e Estatística website.

RESULTS

The Brazilian population shows a 35.1% (95%CI 34.5–35.7) sleep problem prevalence. Sergipe (41.60%), Piauí (38.45%), and Espírito Santo (38.43%) were the Brazilian federative units with the largest sleep problem prevalence ratios ( Figure 2 ).

We found an 8.5% (95%CI 8.2–8.9) prevalence of sleeping pill use. Espírito Santo (13.29%), Minas Gerais (11.48%), and Rio Grande do Sul (10.96%) were the Brazilian federative units with the largest sleeping pill use prevalence ratios ( Figure 2 ).

Our descriptive analysis showed a higher prevalence of sleep problems among women (41.84%), Indigenous people (39.95%), widowers (46.19%), people with no education (43.52%), those who live alone (41%), urban citizens (35.92%), those not registered in the FHS (35.62%), those who assess their health as regular/poor/very poor (51.38%), those with chronic diseases (47.51%), teetotalers (35.98%), former smokers (40.31%), those who consume vegetables less than five times a week (35.48%), those aged 60 years or older (42.05%), those with a per capita income above three minimum wages (36.35%), and people with obesity (39.04%). In addition, the mean (in minutes) of physical activity practice was 48.69 (± 1.20) ( Table 1 ).

The analysis of the association between sleep problems and sociodemographic, lifestyle and health characteristics of Brazilians in the bivariate analysis showed that all variables surveyed had p < 0.20 and were included in the multivariate regression model ( Table 1 ).

In the final model of our multivariate analysis, the highest prevalence of sleep problems was associated with women (PR = 1.41), divorcees (PR = 1.05), urban denizens (PR = 1.16), those who assess their health as regular/poor/very poor (PR = 1.56), those with chronic diseases (PR = 1.70), those who use alcohol excessively (PR = 1.14), smokers (PR = 1.16) or former smokers (PR = 1.11), and those who consume vegetables less than five times a week (PR = 1.06). Moreover, black ethnicity (PR = 0.96) and complete secondary (PR = 0.89) or primary education (PR = 0.88) were associated with a lower prevalence of sleep problems ( Table 1 ).

Our descriptive analysis showed that the prevalence of sleeping pill use was higher among women (11.51%), white individuals (10.37%), widowers (18.32%), people with no education (13,44%), those living alone (12.68%), urban denizens (8.9%), those registered in the FHS (8.68%), those who assess their health as regular/poor/very poor (15.72%), those with chronic diseases (15.2%), teetotalers (10.39%), smokers (10.48%), those who consume vegetables five times or more per week (9.13%), those aged 60 years or older (15.27%), people with obesity (10.54%), and those with a per capita income above three minimum wages (10.38%). We found an average 53.86 minutes (± 2.47) of physical activity in our sample ( Table 2 ).

The bivariate analysis of the association between sleep problems and Brazilians’ sociodemographic, lifestyle, and health characteristics showed that “FHS coverage” was the only variable which failed to show a p < 0.20. We included all other variables in the multivariate regression model.

Our final multivariate analysis model associated the higher prevalence of with women (PR = 1.57), divorcees (PR = 1.46), widowers (PR = 1.19), urban denizens (PR = 1.32), those who assess their health as regular/poor/very poor (PR = 1.79), those with chronic diseases (PR = 4.07), former smokers (PR = 1.15), smokers (PR = 1.49), and those aged 30 to 59 years old (PR = 1.50) and 60 years or older (PR = 1.50). Black (PR = 0.77) and Asian individuals (PR = 0.55), those with complete secondary education (PR = 0.80), those moderately using alcohol (PR = 0.75), and those who excessively use alcohol (PR = 0.68) were associated with a lower prevalence of sleeping pill use ( Table 2 ).

DISCUSSION

The prevalence of Brazilians aged 15 years old and older who reported sleep problems, such as difficulty falling asleep, frequent nocturnal awakening or sleeping more than usual, and used sleeping pill in the two weeks prior to research, were 35.1% and 8.5%, respectively. These prevalence ratios are higher than the 2013 PNS ones, in which 28.9% of interviewees reported sleep problems ¹³13. Gajardo YZ, Ramos JN, Muraro AP, Moreira NF, Ferreira MG, Rodrigues PRM. Problemas com o sono e fatores associados na população brasileira: Pesquisa Nacional de Saúde, 2013. Cien Saude Colet. 2021;26(2):601-10. https://doi.org/10.1590/1413-81232021262.08412020
https://doi.org/10.1590/1413-81232021262... and 7.6% used sleeping pill ¹¹11. Kodaira K, Silva MT. Sleeping pill use in Brazil: a population-based, cross-sectional study. BMJ Open. 2017;7(7):e016233. https://doi.org/10.1136/bmjopen-2017-016233
https://doi.org/10.1136/bmjopen-2017-016... .

Corroborating Brazilian studies, both outcomes analyzed in this study were more common in women ¹⁴14. Fiorelli K, Assini FL. A prescrição de benzodiazepínicos no Brasil: uma análise da literatura. ABCS Health Sci. 2017;42(1):40-4. https://doi.org/10.7322/abcshs.v42i1.948
https://doi.org/10.7322/abcshs.v42i1.948... , divorcees ¹⁵15. Feitosa DJC, Oliveira SMC. Prevalência de sintomas relacionados ao sono na atenção primária à saúde. Rev Neurocienc. 2015;23(2):165-72. https://doi.org/10.34024/rnc.2015.v23.8026
https://doi.org/10.34024/rnc.2015.v23.80... , ¹⁶16. Seixas BV. Prevalence and factors associated with use of sleeping pills among older adults in Brazil. Int J Pharm Pract. 2021;29(3):235-44. https://doi.org/10.1093/ijpp/riab003
https://doi.org/10.1093/ijpp/riab003... , urban denizens ¹⁷17. Pilz LK, Levandovski R, Oliveira MAB, Hidalgo MP, Roenneberg T. Sleep and light exposure across different levels of urbanisation in Brazilian communities. Sci Rep. 2018;8:11389. https://doi.org/10.1038/s41598-018-29494-4
https://doi.org/10.1038/s41598-018-29494... , those who negatively self-assess their health (regular/poor/very poor) ¹⁶16. Seixas BV. Prevalence and factors associated with use of sleeping pills among older adults in Brazil. Int J Pharm Pract. 2021;29(3):235-44. https://doi.org/10.1093/ijpp/riab003
https://doi.org/10.1093/ijpp/riab003... , ¹⁸18. Barros MBA, Lima MG, Ceolim MF, Zancanella E, Cardoso TAMO. Quality of sleep, health and well-being in a population-based study. Rev Saude Publica. 2019;53:82. https://doi.org/10.11606/s1518-8787.2019053001067
https://doi.org/10.11606/s1518-8787.2019... , those with chronic diseases ¹⁶16. Seixas BV. Prevalence and factors associated with use of sleeping pills among older adults in Brazil. Int J Pharm Pract. 2021;29(3):235-44. https://doi.org/10.1093/ijpp/riab003
https://doi.org/10.1093/ijpp/riab003... , ¹⁸18. Barros MBA, Lima MG, Ceolim MF, Zancanella E, Cardoso TAMO. Quality of sleep, health and well-being in a population-based study. Rev Saude Publica. 2019;53:82. https://doi.org/10.11606/s1518-8787.2019053001067
https://doi.org/10.11606/s1518-8787.2019... , smokers, and former smokers ¹¹11. Kodaira K, Silva MT. Sleeping pill use in Brazil: a population-based, cross-sectional study. BMJ Open. 2017;7(7):e016233. https://doi.org/10.1136/bmjopen-2017-016233
https://doi.org/10.1136/bmjopen-2017-016... .

The literature has widely discussed the factors associated with sleep-related differences between genders but found no consensus ¹⁹19. Pengo MF, Won CH, Bourjeily G. Sleep in women across the life span. Chest. 2018;54(1):196-206. https://doi.org/10.1016/j.chest.2018.04.005
https://doi.org/10.1016/j.chest.2018.04.... . Some authors relate women’s more fragmented sleep to hormonal and physiological variations ¹⁹19. Pengo MF, Won CH, Bourjeily G. Sleep in women across the life span. Chest. 2018;54(1):196-206. https://doi.org/10.1016/j.chest.2018.04.005
https://doi.org/10.1016/j.chest.2018.04.... or to social issues to which they are exposed, such as greater social demands and overload at work and at home ²⁰20. Saccomann ICR, Souza Neta JG, Martins BF. Fatores associados à adesão ao tratamento medicamentoso em hipertensos de uma Unidade de Saúde da Família. Rev Fac Cienc Med Sorocaba. 2015 [cited 2021 May 29];17(1):21-6. Available from: https://revistas.pucsp.br/index.php/RFCMS/article/view/20861
https://revistas.pucsp.br/index.php/RFCM... .

In general, women report a greater need for sleep and more subjective complaints of nonrestorative sleep than men ¹⁹19. Pengo MF, Won CH, Bourjeily G. Sleep in women across the life span. Chest. 2018;54(1):196-206. https://doi.org/10.1016/j.chest.2018.04.005
https://doi.org/10.1016/j.chest.2018.04.... , which may have contributed to more prevalent medicine use. Moreover, women also show better adherence to treatment and self-care, which may be related to greater adherence to medicine use ²⁰20. Saccomann ICR, Souza Neta JG, Martins BF. Fatores associados à adesão ao tratamento medicamentoso em hipertensos de uma Unidade de Saúde da Família. Rev Fac Cienc Med Sorocaba. 2015 [cited 2021 May 29];17(1):21-6. Available from: https://revistas.pucsp.br/index.php/RFCMS/article/view/20861
https://revistas.pucsp.br/index.php/RFCM... .

Corroborating other Brazilian studies, we found a higher prevalence of sleep problems ¹⁵15. Feitosa DJC, Oliveira SMC. Prevalência de sintomas relacionados ao sono na atenção primária à saúde. Rev Neurocienc. 2015;23(2):165-72. https://doi.org/10.34024/rnc.2015.v23.8026
https://doi.org/10.34024/rnc.2015.v23.80... and sleeping pill use ¹⁶16. Seixas BV. Prevalence and factors associated with use of sleeping pills among older adults in Brazil. Int J Pharm Pract. 2021;29(3):235-44. https://doi.org/10.1093/ijpp/riab003
https://doi.org/10.1093/ijpp/riab003... in divorcees. Lamela ²¹21. Lamela DJPV. Desenvolvimento após o divórcio como estratégia de crescimento humano. Rev Bras Cresc Dev Hum. 2009;19(1):114-21. https://doi.org/10.7322/jhgd.19908
https://doi.org/10.7322/jhgd.19908... (2009) conducted a literature review which considered divorce one of the most impacting stressors in adulthood since those who experience it suffer changes in many areas of their lives in a short period of time, becoming more prone or vulnerable to psychological symptoms. This may explain their higher prevalence of difficulty sleeping, frequent nocturnal awakening, unusually long sleep, and sleeping pill use.

We also found that living in urban areas is a factor impacting Brazilians’ sleep. The intensity of artificial lights in urban areas, especially at nighttime, strongly influences sleep duration and sleep-wake schedules ²²22. Ohayon MM, Milesi C. Artificial outdoor nighttime lights associate with altered sleep behavior in the American general population. Sleep. 2016;39(6):1311-20. https://doi.org/10.5665/sleep.5860
https://doi.org/10.5665/sleep.5860... . Artificial light causes changes in the body, such as melatonin suppression - a hormone which signals nighttime and induces sleep in humans - and increased nervous system activity, resulting in greater alertness and subsequent difficulty falling asleep ¹⁷17. Pilz LK, Levandovski R, Oliveira MAB, Hidalgo MP, Roenneberg T. Sleep and light exposure across different levels of urbanisation in Brazilian communities. Sci Rep. 2018;8:11389. https://doi.org/10.1038/s41598-018-29494-4
https://doi.org/10.1038/s41598-018-29494... .

The higher prevalence ratios of both outcomes were also associated with people who assess their health as regular/poor/very poor. Health self-assessment and self-reported sleep problems are closely related, i.e., satisfaction with the way one sleeps is one of the main factors in health self-assessment ²³23. Andrade RD, Felden EPG, Teixeira CS, Pelegrini A. Sono, percepção de saúde e atividade física em adolescentes universitários. Adolesc Saude. 2017;14(4):150-6. . Studies with young Brazilians ²³23. Andrade RD, Felden EPG, Teixeira CS, Pelegrini A. Sono, percepção de saúde e atividade física em adolescentes universitários. Adolesc Saude. 2017;14(4):150-6. found that self-reporting good sleep increased the probability of better health self-assessments.

On the other hand, a study with a representative sample, conducted with Brazilians aged 50 years or older, found an association between participants self-assessing their health as poor with greater sleeping pill use ¹⁶16. Seixas BV. Prevalence and factors associated with use of sleeping pills among older adults in Brazil. Int J Pharm Pract. 2021;29(3):235-44. https://doi.org/10.1093/ijpp/riab003
https://doi.org/10.1093/ijpp/riab003... . The same study shows that the presence of chronic diseases was associated with a higher prevalence of medicine use ¹⁶16. Seixas BV. Prevalence and factors associated with use of sleeping pills among older adults in Brazil. Int J Pharm Pract. 2021;29(3):235-44. https://doi.org/10.1093/ijpp/riab003
https://doi.org/10.1093/ijpp/riab003... , as did we.

In general, chronic diseases generate inflammations in the body and can cause pain, emotional changes, and other consequences due to unrestored physiological systems after wakefulness events ²⁴24. Morais LC, Zanuto EAC, Queiroz DC, Araújo MYC, Rocha APR, Codogno JS. Associação entre distúrbios do sono e doenças crônicas em pacientes do Sistema Único de Saúde. J Phys Educ. 2017 [cited 2021 Jun 2];28(1). Available from: https://periodicos.uem.br/ojs/index.php/RevEducFis/article/view/29994
https://periodicos.uem.br/ojs/index.php/... . Diseases such as hypertension, osteoporosis, arthritis/arthrosis, low back pain, depression, and obesity are associated with sleep problems ²⁴24. Morais LC, Zanuto EAC, Queiroz DC, Araújo MYC, Rocha APR, Codogno JS. Associação entre distúrbios do sono e doenças crônicas em pacientes do Sistema Único de Saúde. J Phys Educ. 2017 [cited 2021 Jun 2];28(1). Available from: https://periodicos.uem.br/ojs/index.php/RevEducFis/article/view/29994
https://periodicos.uem.br/ojs/index.php/... . Moreover, people who showed five or more concomitant health problems had a 4.19% higher prevalence of sleep problems than those with no or fewer comorbidities ¹⁸18. Barros MBA, Lima MG, Ceolim MF, Zancanella E, Cardoso TAMO. Quality of sleep, health and well-being in a population-based study. Rev Saude Publica. 2019;53:82. https://doi.org/10.11606/s1518-8787.2019053001067
https://doi.org/10.11606/s1518-8787.2019... .

Individuals who reported smoking or having smoked also had a higher prevalence in the studied outcomes. Nicotine, the main substance in cigarettes, is a stimulant associated with changes in sleep architecture, fragmenting it and decreasing its efficiency ²⁵25. Cohen A, Ben Abu N, Haimov I. The interplay between tobacco dependence and sleep quality among young adults. Behav Sleep Med. 2020;18(2):163-76. https://doi.org/10.1080/15402002.2018.1546707
https://doi.org/10.1080/15402002.2018.15... .

Moreover, a higher prevalence of sleep problems was associated with excessive alcohol use, which has harmful consequences for individuals’ overall health. Excessive alcohol consumption interferes with the physiology of sleep, especially in the second half of the night, facilitating awakenings, which fragments sleep ²⁶26. Chakravorty S, Chaudhary NS, Brower KJ. Alcohol dependence and its relationship with insomnia and other sleep disorders. Alcohol Clin Exp Res. 2016;40(11):2271-82. https://doi.org/10.1111/acer.13217
https://doi.org/10.1111/acer.13217... , reflecting poor sleep quality.

A Brazilian population-based cross-sectional study which used 2013 PNS ¹¹11. Kodaira K, Silva MT. Sleeping pill use in Brazil: a population-based, cross-sectional study. BMJ Open. 2017;7(7):e016233. https://doi.org/10.1136/bmjopen-2017-016233
https://doi.org/10.1136/bmjopen-2017-016... data found a lower prevalence of sleeping pill use associated with moderate or excessive use of alcohol, which may be due to its hypnotic effect, depressing the central nervous system, reducing sleep latency, and facilitating sleep ²⁶26. Chakravorty S, Chaudhary NS, Brower KJ. Alcohol dependence and its relationship with insomnia and other sleep disorders. Alcohol Clin Exp Res. 2016;40(11):2271-82. https://doi.org/10.1111/acer.13217
https://doi.org/10.1111/acer.13217... .

Inadequate eating habits and sleep disorders, bedtime, and poor sleep quality and duration ²⁷27. Chaput JP, Dutil C. Lack of sleep as a contributor to obesity in adolescents: impacts on eating and activity behaviors. Int J Behav Nutr Phys Act. 2016;13:103. https://doi.org/10.1186/s12966-016-0428-0
https://doi.org/10.1186/s12966-016-0428-... are another important discussion factor. One example is the association between increased fruit and vegetable consumption with improved sleep quality and duration ²⁷27. Chaput JP, Dutil C. Lack of sleep as a contributor to obesity in adolescents: impacts on eating and activity behaviors. Int J Behav Nutr Phys Act. 2016;13:103. https://doi.org/10.1186/s12966-016-0428-0
https://doi.org/10.1186/s12966-016-0428-... , which may relate to the association we found, i.e., a higher prevalence of sleep problems in individuals who reported consuming vegetables less than five times a week.

We observed an association with individuals aged over 30 years old and a higher prevalence of sleeping pill use. Considering that the age group composed by 30 to 59 year-olds has the highest work and social activity ²2. Andrade RD, Ferrari Junior GJ, Capistrano R, Teixeira CS, Beltrame TS, Felden EPG. Absenteísmo na indústria está associado com o trabalho em turnos e com problemas no sono. Cienc Trab. 2017;19(58):35-41. https://doi.org/10.4067/S0718-24492017000100035
https://doi.org/10.4067/S0718-2449201700... , they may use sleeping pill in an attempt to improve sleep quality, reduce insomnia and anxiety, and feel relaxed ¹¹11. Kodaira K, Silva MT. Sleeping pill use in Brazil: a population-based, cross-sectional study. BMJ Open. 2017;7(7):e016233. https://doi.org/10.1136/bmjopen-2017-016233
https://doi.org/10.1136/bmjopen-2017-016... .

Moreover, a Brazilian population-based study conducted with 2013 PNS data found that 21% of respondents reported depressive symptoms and that sleeping pill use was associated with people with these symptoms, which may justify the high prevalence in its use ¹¹11. Kodaira K, Silva MT. Sleeping pill use in Brazil: a population-based, cross-sectional study. BMJ Open. 2017;7(7):e016233. https://doi.org/10.1136/bmjopen-2017-016233
https://doi.org/10.1136/bmjopen-2017-016... .

The literature has observed that people aged 60 years old and above undergo physiological changes to sleep quality, quantity, and architecture as age advances, resulting in a more superficial, shorter, worse, and fragmented sleep ²⁸28. Brewster GS, Riegel B, Gehrman PR. Insomnia in the older adult. Sleep Med Clin. 2018;13(1):13-9. https://doi.org/10.1016/j.jsmc.2017.09.002
https://doi.org/10.1016/j.jsmc.2017.09.0... .

Pharmacological therapy is the most used among older adults ²⁰20. Saccomann ICR, Souza Neta JG, Martins BF. Fatores associados à adesão ao tratamento medicamentoso em hipertensos de uma Unidade de Saúde da Família. Rev Fac Cienc Med Sorocaba. 2015 [cited 2021 May 29];17(1):21-6. Available from: https://revistas.pucsp.br/index.php/RFCMS/article/view/20861
https://revistas.pucsp.br/index.php/RFCM... . In general, the use of medicine minimizes sleep alterations such as trouble falling asleep and waking throughout the night ¹⁶16. Seixas BV. Prevalence and factors associated with use of sleeping pills among older adults in Brazil. Int J Pharm Pract. 2021;29(3):235-44. https://doi.org/10.1093/ijpp/riab003
https://doi.org/10.1093/ijpp/riab003... . However, much is discussed about the long-term use of these medicines, their side effects, and the large quantity of drugs consumed by older adults ²⁰20. Saccomann ICR, Souza Neta JG, Martins BF. Fatores associados à adesão ao tratamento medicamentoso em hipertensos de uma Unidade de Saúde da Família. Rev Fac Cienc Med Sorocaba. 2015 [cited 2021 May 29];17(1):21-6. Available from: https://revistas.pucsp.br/index.php/RFCMS/article/view/20861
https://revistas.pucsp.br/index.php/RFCM... .

In this study, Black individuals were associated with a lower prevalence of sleep problems and sleeping pill use. This result corroborates an epidemiological study conducted in the United States in which white adults report taking more sleeping pill than Black ones ²⁹29. Ram S, Seirawan H, Kumar SKS, Clark GT. Prevalence and impact of sleep disorders and sleep habits in the United States. Sleep Breath. 2010;14(1):63-70. https://doi.org/10.1007/s11325-009-0281-3
https://doi.org/10.1007/s11325-009-0281-... .

However, the literature indicates that Black individuals are prone to worse, shorter, and more fragmented sleep, showing a higher risk of sleep breathing disorders than white individuals ³⁰30. Petrov ME, Lichstein KL. Differences in sleep between black and white adults: an update and future directions. Sleep Med. 2016;18:74-81. https://doi.org/10.1016/j.sleep.2015.01.011
https://doi.org/10.1016/j.sleep.2015.01.... . Despite these results, little is known about the mechanism behind ethnic sleep differences ³⁰30. Petrov ME, Lichstein KL. Differences in sleep between black and white adults: an update and future directions. Sleep Med. 2016;18:74-81. https://doi.org/10.1016/j.sleep.2015.01.011
https://doi.org/10.1016/j.sleep.2015.01.... .

Lower prevalence of sleep problems was also associated with having attended primary or high school and the lower prevalence of sleeping pill use was associated with having attended high school. Thus, the literature believes that people with higher educational attainment have the necessary knowledge on beneficial health behaviors and better habits close to bedtime, thus reducing sleep-related complaints and resulting in a lower need for sleeping pill ¹⁶16. Seixas BV. Prevalence and factors associated with use of sleeping pills among older adults in Brazil. Int J Pharm Pract. 2021;29(3):235-44. https://doi.org/10.1093/ijpp/riab003
https://doi.org/10.1093/ijpp/riab003... .

In view of the above, this study shows important potentialities since it is a representative national population-based study on sleep problems and sleeping pill in Brazil, including more than 90,000 participants aged 15 years old and above and evaluating their sociodemographic, lifestyle, and health characteristics.

However, a limitation of this study was the impossibility of identifying in greater detail from what sleep problems Brazilians suffer and what medicine they use, considering that the answers to the PNS are self-reported and our analysis ignored the evaluation of these specifications. It is important to remember that the interviewers were trained to apply the questionnaires but since this information is self-reported and questions refer to behaviors from previous weeks, it is possible that answers suffered from memory biases and differences in interviewees’ understanding.

Finally, the prevalence of sleep problems and sleeping pill use was high in the Brazilian population, an important datum for public health which shows the need for attention and care for sleep in this population. Our multivariate analysis showed the associations between sleep problems and sleeping pill use and various sociodemographic, health, and lifestyle factors. Thus, the results of this study add updated evidence of the relation between sleep and social factors and suggest more specific, further research to characterize Brazilians’ sleep problems, types, and frequency and their use of sleeping pill.

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