Effects of Tobacco and Alcohol Consumption on Sleep Quality of University Students

Transcription

1 Gema, M.; et al. Original Article Effects of Tobacco and Alcohol Consumption on Sleep Quality of University Students Tabagismo, álcool e os efeitos na qualidade Do sono em estudantes univeristários Gema Mesquita 1, Simone Ferreira 2, Sueli Rossini 3, Evelise Aline Soares 4, Rubens Reimão 5 ABSTRACT Aim: To investigate the effects of tobacco smoking and alcohol consumption on the sleep perception of 710 university students of both genders, aged years, by means of a descriptive cross-sectional study. Method: An objective questionnaire to evaluate the frequency of smoking and drinking habits. Sleep quality was evaluated by the Pittsburgh Sleep Quality Index (PSQI). Results: Smokers showed a mean sleep score of 8.1 (p = 0.008); 70.5% were classified as poor sleepers (PS), and 14.7% reported sleeping less than 5 hours per night. Non-smokers showed a mean sleep score of 6.4; 59.7% were classified as PS, and 29.9% sleep less than 5 hours per night. A non-significant association was observed in the sleep score regarding the frequency of alcohol consumption (Kruskal-Wallis p = 0.3). Conclusion: Smoking significantly influences sleep perception. The higher the frequency of alcohol consumption the higher the scores of sleep perception and the number of poor sleepers. Keywords: Habitual effectiveness of sleep, Sleep duration, Sleep disorders. 1.4 Department of Psychology of the José do Rosário Vellano University - UNIFENAS. 1,2,5 Center for Pediatric Research of the School of Medical Sciences of the State University of Campinas (UNICAMP). 3,5 Sleep Medicine Advanced Research Group, Division of Clinical Neurology, Hospital das Clinicas, University of São Paulo School of Medicine (USP), São Paulo, SP, Brazil. Address for correspondence and pre-publication contact: Dr. Rubens Reimão Av. Indianópolis, CEP São Paulo, SP - Tel. (11) reimaorubensneuro@yahoo.com 19

2 NEUROBIOLOGIA, 74 ( 1 ) jan./mar RESUMO Objetivo: Através de estudo transversal descritivo entre 710 universitários de ambos os gêneros, com idades entre 17 e 25 anos, investiga-se o efeito do tabagismo e o consumo de bebidas alcoólicas na percepção do sono. Método: utilizamos questionário objetivo, autoavaliativo para o consumo do álcool e tabaco. Para avaliar a qualidade do sono é utilizado o Índice de Qualidade do Sono de Pittsburgh (IQSP). Resultados: Os resultados apresentados mostram que entre os tabagistas obteve-se a média de 8,1 para o escore do sono (p = 0,008), 70,5% foram classificados como maus dormidores (MD) e 14,7% declararam dormir menos de 5 horas por noite; entre os não tabagistas observamos a média de 6,4 para o escore do sono, 59,7% foram classificados MD e 29,9% dormem menos de 5 horas por noite. O escore da percepção do sono foi influenciado pela frequência ao consumo de álcool, com as médias de 6,3 (consumo: menos de uma vez por semana); 6,7 (consumo: uma ou duas vezes por semana); 6,8 (consumo: três vezes por semana, ou mais) p = 0,3 Kruskal-Wallis. Conclusão: O tabagismo influencia, significativamente, a percepção do sono e quanto maior a frequência ao consumo de álcool escores do sono mais elevados e maior número de maus dormidores. Palavras chave: Eficiência habitual do sono, duração do sono, distúrbios do sono. INTRODUCTION A lcohol and tobacco are drugs usually consumed by the population in general. Alcohol, the most widely consumed drug in the world, when overused, is one of the main factors that contribute to worldwide disease. University students have been shown to exhibit typical patterns of users of alcoholic beverages and other risk factors 1,2. In small towns of the Brazilian inland, university students usually come together around tables in bars, tap houses and night clubs for fun and leisure. Culturally, such experiences induce alcohol consumption and become a behavioral pattern considered normal 3,4. Studies relating alcohol consumption and sleep patterns reported that alcohol stops the sequence and duration of sleep cycles, and also alter their total time. Alcohol has frequently been used to induce sleep. Although being effective in sleep induction, it reduces sleep during the second half of the night, and brings forth multiple awakenings, and dreams with more vivid contents associated with nightmares and sudoresis 5,6. In addition, both moderate and high doses of alcohol consumed before bedtime can narrow the airways and cause episodes of obstructive sleep apnea (OSA), even in individuals who are diagnosed as apneic 7. Besides the dangers of alcohol consumption, smoking also stands out among youths. Nicotine is responsible for cigarette-dependence. Its pharmacological action in the brain is complex. Its main effect occurs in the locus coeruleus 8, a region of the central nervous system that regulates the sleep-wake cycle. The effect of nicotine on the sleep architecture of healthy smokers has been regarded as a factor of sleep disturbances, once it reduces the duration of deep sleep and increases the time of light sleep 9. University student time management requires attention and dedication, and sleep is fundamental for academic performance. Sleep deprivation and/or inadequate sleep habits reflect on learning in and out of the school environment. A poor sleep quality can cause: reduction in motivation and concentration; memory deficit; excessive diurnal somnolence; mood changes; immunity decline, and so forth 10,11. Based on the aforementioned aspects, this study aims at evaluating the association of alcohol and tobacco consumption with sleep quality perception among university students. 20

3 Gema, M.; et al. MATERIAL AND METHOD It is a descriptive cross-sectional study of a population of 1978 Brazilian students of the Federal University of Alfenas, State of Minas Gerais, Brazil. The sample was taken randomly to reduce biases, and consisted of 710 participants: 486 females (F), and 224 males (M). The mean age was 20.7 years; standard deviation, 1.8; median, 21.0 years. Instruments The participants were invited to respond to an objective and self-rated questionnaire (yes/no) about alcohol consumption and tobacco smoking habits: frequency of alcohol consumption (less than once a week; once or twice a week; three or more times a week); quantity of cigarettes (1 to 5 cigarettes a day; half a pack of cigarettes a day; 1 pack or more a day). Sleep quality was assessed by the Pittsburgh Sleep Quality Index (PSQI) 12. Developed to provide a standardized measure of sleep quality and being used in national and international researches, the PSQI is a reliable instrument to quantify sleep quality during the previous month. It consists of 19 selfrated items grouped into seven components scored from 0 to 3 (zero to three). Its global score ranges from 0 to 21 (zero to twenty-one), with lower scores indicating a better sleep quality. Good sleepers are scored less than 5 (five), and poor sleeps, higher than 5 (five). Inclusion criteria The subjects of this study were students of the Federal University of Alfenas (UNIFAL), who were present in the classrooms and voluntarily agreed to respond to the questionnaires after having signing the informed consent form. Procedures Data were collectively collected in the classrooms from August to November During a short contact, the students were informed about the aims and methods of the study. The project Life habits, sleep complaints in young university students, which started the present research, was approved by the Research Ethics Committee of the State University of Campinas in October 24 th 2006, according to Report CAAE no Statistical Methods The statistical analysis was carried out by the UNICAMP Research Board of the School of Medical Sciences by means of the SAS System for Windows (Statistical Analysis System), version Service Pack 3 16, using the following tests: chi-square, Fischer s exact, Mann-Whitney and Krustal-Wallis 17. The significance level was 5%. RESULTS According to gender, 40.3% of females versus 19.4% of males do not consume alcohol, while 59.6% of females versus 80.3% of males are alcohol-consumers (p<0.0001). Regarding frequency, males consumed alcohol three or more times a week, much more than females: 13.8% (M) versus 6.2% (F); p = No significant difference was found in the sleep classification of the alcohol-consuming genders: 37.3% (F) sleep well, and 62.7% (F) sleep poorly; 41% (M) sleep well, and 58.9% (M) sleep poorly (p = 0.4). With regard to tobacco, males smoked significantly more than females: 3.5% (F) versus 7.5% (M). As to number of cigarettes, 50.0% (F) versus 70.5% (M) smoke from 1 to 5 cigarettes a day; 37.5% (F) versus 29.4% (M) smoke half a pack a day; 12.5% (F) versus 0.0% (M) smoke 1 pack or more a day. Regarding tobacco smokers and sleep classification: 35.3% of females and 17.7% of males are good sleepers; while 64.7% of females and 76.4% of males are poor sleepers (p= 0.4). 21

4 NEUROBIOLOGIA, 74 ( 1 ) jan./mar Table 1 Comparative analysis between alcohol consumption and sleep perception by the Pittsburgh Sleep Quality Index (PSQI) Alcohol consumption No Yes Value N % N % P Sleep perception Good sleeper Poor sleeper Total In the comparative analysis of alcohol consumers (470) and nonconsumers (240) and sleep score (PSQI), the mean was 6.3; SD 2.5; median 6.0 for alcohol nonconsumers, and medium of 6.5, SD 2.7; median 6.0 for alcohol consumers. The Mann-Whitney test revealed that the groups do not differ from one another (p = 0.3). Table 2 Comparative analysis and associations between the frequency of alcohol consumption and sleep perception Frequency of alcohol consumption Less than once Once or twice Three or more times Value P n % n % n % Sleep disorders None Occasional Frequent Use of sleep medication None Less than once Once or twice Three or more times

5 Gema, M.; et al. Diurnal somnolence None Little Mild Much Sleep classification Good sleeper Poor sleeper Total The comparative analysis between the frequency of alcohol consumption and the sleep score (PSQI) revealed the following values: less than once a week: mean of 6.3, SD 2.6; median 0.6 (n = 211); once or twice a week: mean of 6.7, SD 2.7: median 6.0 (n = 215); three or more times a week: mean of 6.8, SD 2.7; median 6.0 (n = 43). The Kruskal-Wallis test showed that the groups are not different from one another (p = 0.3) Table 3 Comparative analysis between tobacco smoking and the Pittsburgh Sleep Quality Index (PSQI) components Sleep Duration Sleep efficiency Tobacco smoking No Yes Value N % N % P >7hs ** hs hs < 5hs > 85% ** % % < 65%

6 NEUROBIOLOGIA, 74 ( 1 ) jan./mar Diurnal Somnolence None Little Mild Much Sleep classification Good sleeper , ,5 0,2 Poor sleeper , ,5 Total The component evaluating the subjective sleep quality revealed that 2.9% of smokers reported being very good sleepers versus 11.2% of nonsmokers; 41.1% reported being very poor sleepers versus 28.5% of nonsmokers (p= 0.1) Twenty-nine percent of smokers versus 17.7% of nonsmokers reported having frequent sleep disorders (p = 0.3). Regarding sleeping medication, 5.8% of smokers and 1.9% of nonsmokers reported consuming it three or more times a week (p = 0.1) The comparative analysis between smokers (34) / nonsmokers (676) and the sleep score (PSQI) revealed a mean of 6.4, SD 2.6, minimum 0.0;], median 6.0, maximum 17.0, for nonsmokers; and a mean of 8.1, SD 3.5, median 7.5, for smokers (p = 0.008). Among smokers, 44% reported consuming alcohol three or more times a week. Of these, 83.3% are poor sleepers. Twenty-nine percent reported consuming alcohol once or twice a week. Of these, 57.8% are poor sleepers. Fifteen percent reported consuming alcohol less than once a week. Of these 100% sleep poorly. Twelve percent reported not consuming alcohol. Of these, 100% sleep poorly (p = 0.1). DISCUSSION When compared with alcohol consumption among university students, our results show that tobacco smoking is the factor that most significantly contributed to increased complaints of poor sleep quality. It is important to take into consideration that in this study, being conducted among youths with a mean age of 20.7 years, the repercussions of bad habits on sleep quality may be reduced. Although our study presents a significant number of participants, and the information here given provides significant data, it is not up to us to infer generalizations because we surveyed youths from a single public university. In the literature, we could not find surveys with university students, about the effects of alcohol and tobacco on sleep patterns, which might allow a comparison with our data. The researches 5-9 that evaluate the effects of those substances on sleep patterns are mainly concerned with sleep physiology, differently from our work with data obtained by questionnaires. However, we managed to find explanations for our analyses. Our data showed that tobacco smokers had a worse perceived sleep quality, with significant complaints in the component which assess the 24

7 Gema, M.; et al. subjective quality of sleep. Besides presenting higher percentages regarding frequent sleep disorders, they spent more time in bed, consumed more sleep medication and exhibited higher means in the sleep score when compared with nonsmokers. Our study still shows that smokers did not respond to the item about no diurnal somnolence. Reports in the literature confirming our results are found in Phillips e Danner 18, who evaluated participants of both sexes, aged years, and found that smokers had significantly more complaints of sleep disorders and diurnal somnolence. The study of Zhang et al. 9, who evaluated the impact of tobacco smoking on the sleep architecture, also gives support to ours, although differing in some aspects of our protocol. According to these authors, smokers presented increased sleep latency and decreased sleep duration. When asked about sleep quality perception, 22.5% reported lack of restorative sleep when compared with 5.0% of nonsmokers, such as in our findings, when smokers reported decreased sleep duration and significantly more complaints of poor sleep. We have seen that most tobacco smokers consume alcohol frequently, but we have not found significant differences in sleep classification with or without association with alcohol consumption. Our study presented a low frequency of participants who reported being smokers in comparison with other universities. The literature reports a gradual decrease in smoking among Brazilian students: 21% in 1986; 14% in 1991; 11% in In 2005, 12.16% participants reported being tobacco smokers 20, and in 2006, tobacco smoking was 14.7% among students of the University of Brasília 21. Although our analyses did not reveal significant differences between the groups who alcohol-consumers and nonconsumers with regard to sleep patterns, we observed that alcoholconsumption contributed to increased complaints of sleep disorders; the more frequent the alcohol consumption the higher the percentages of poor sleepers the gradual increase of sleep scores. In literature we find support in the studies of Landolt et al. 22 and Vitielo 23, who observed that alcohol consumption in healthy individuals before bedtime was associated with poor sleep, fatigue and diurnal somnolence. Our data indicate that a significant number of university students reported frequent consumption of alcoholic beverages, what agrees with previous studies 1,3,24,25. We believe that the low tobacco consumption here presented reflects the Brazilian context, brought forth by governmental campaigns about tobacco smoking and also by prohibition and ban on tobacco advertising in the media. Otherwise, the high alcohol consumption may be related to the social representation of the social drinking permissiveness and to the media s incentive, which associates alcohol with agreeable events. Our study revealed that alcohol and tobacco use was more frequent among males. However, it showed no significant relation in sleep perception. CONCLUSION Since tobacco smokers reported decreased sleep duration, higher indexes of frequent symptoms of sleep disorders, more time spent in bed, higher use of sleep medication, higher sleep scores, they were classified as poor sleepers in higher percentages. The higher the frequency of alcohol consumption, the higher sleep scores, and the higher the number of poor sleepers. REFERENCES 1. Kerr-Corrêa F, Andrade AG, Bassit AZ, Boccuto NMVF. Uso de álcool e drogas por estudantes de medicina da Unesp. Rev Bras Psiquiatr 1999; 21: Murphy JG, McDevitt-Murphy ME, Barnett NP. Drink and be merry? Gender, life satisfaction, 25

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