Effects of evening exposure to electromagnetic fields emitted by 3G mobile phones on health and night sleep EEG architecture.

Studies on sleep after exposure to radiofrequency electromagnetic fields have shown mixed results. We investigated the effects of double-blind radiofrequency exposure to 1,930-1,990 MHz, UMTS 3G signalling standard, time-averaged 10 g specific absorption rate of 1.6 W kg-1 on self-evaluated sleepiness and objective electroencephalogram architecture during sleep. Eighteen subjects aged 18-19 years underwent 3.0 hr of controlled exposure on two consecutive days 19:45-23:00 hours (including 15-min break); active or sham prior to sleep, followed by full-night 7.5 hr polysomnographic recordings in a sleep laboratory. In a cross-over design, the procedure was repeated a week later with the second condition. The results for sleep electroencephalogram architecture showed no change after radiofrequency exposure in sleep stages compared with sham, but power spectrum analyses showed a reduction of activity within the slow spindle range (11.0-12.75 Hz). No differences were found for self-evaluated health symptoms, performance on the Stroop colour word test during exposure or for sleep quality. These results confirm previous findings that radiofrequency post-exposure in the evening has very little influence on electroencephalogram architecture but possible on spindle range activity.

Work and excessive sleepiness among Brazilian evening high school students: effects on days off.

Previous studies have revealed that students who work and study build up sleep deficits during the workweek, which can trigger a sleep rebound during days off. The objective of this study was to investigate the impact of working/non-working on sleepiness during days off among high school students. The study population, aged 14-21 years, attended evening classes in São Paulo, Brazil. For the study, the students completed questionnaires on living conditions, health, and work; wore actigraphs; and completed the Karolinska Sleepiness Scale (KSS). To predict sleepiness, a logistic regression analysis was performed. Excessive sleepiness was observed on the first day off among working students. Results suggest that working is a significant predictor for sleepiness and that two shifts of daily systematic activities, study and work, might lead to excessive daytime sleepiness on the first day off. Further, this observed excessive sleepiness may reflect the sleep debt accumulated during the workweek.

Sleep and sleepiness among working and non-working high school evening students.

The aim of this study was to evaluate patterns of sleepiness, comparing working and non-working students. The study was conducted on high school students attending evening classes (19:00-22:30 h) at a public school in São Paulo, Brazil. The study group consisted of working (n=51) and non-working (n=41) students, aged 14-21 yrs. The students answered a questionnaire about working and living conditions and reported health symptoms and diseases. For seven consecutive days, actigraphy measurements were recorded, and the students also filled in a sleep diary. Sleepiness ratings were given six times per day, including upon waking and at bedtime, using the Karolinska Sleepiness Scale. Statistical analyses included three-way ANOVA and t-test. The mean sleep duration during weekdays was shorter among workers (7.2 h) than non-workers (8.8 h) (t=4.34; p<.01). The mean duration of night awakenings was longer among workers on Tuesdays and Wednesdays (28.2 min) and shorter on Mondays (24.2 min) (t=2.57; p=.03). Among workers, mean napping duration was longer on Mondays and Tuesdays (89.9 min) (t=2.27; p=.03) but shorter on Fridays and Sundays (31.4 min) (t=3.13; p=.03). Sleep efficiency was lower on Fridays among non-workers. Working students were moderately sleepier than non-workers during the week and also during class on specific days: Mondays (13:00-15:00 h), Wednesdays (19:00-22:00 h), and Fridays (22:00-00:59 h). The study found that daytime sleepiness of workers is moderately higher in the evening. This might be due to a work effect, reducing the available time for sleep and shortening the sleep duration. Sleepiness and shorter sleep duration can have a negative impact on the quality of life and school development of high school students.

[Knowledge and practices by adolescents in preventing occupational injuries: a qualitative study]. / Conhecimentos e práticas de adolescentes na prevenção de acidentes de trabalho: estudo qualitativo.

OBJECTIVE: To describe knowledge and practices adopted by high school students to prevent occupational injuries. STUDY DESIGN: The study was carried out in a public school located in São Paulo, in 2003. Fifty-three evening students aged 14 to 21 years old participated the study, they were divided into two groups with and without job experience (32 and 21 students, respectively). The students answered two questions: "Why do occupational injuries occur?" and "How do you avoid occupational injuries?" Analyses were performed using the software "Quali-quanti" to structure collective discourses. ANALYSIS OF DISCOURSES: Adolescents with work experience reported that occupational injuries occur due to carelessness of the employee, bad luck of the employee, employer's negligence, lack of training, and unsafe workplace. Adolescents without work experience reported that the main causes of work injuries were carelessness of the employee and employer's negligence. Regarding the ways to protect themselves against occupational injuries, both groups reported that: they pay attention (would pay attention) and wear safety equipment (would wear) safety equipment. CONCLUSIONS: Adolescents from both groups showed limited knowledge about occupational injuries and prevention methods. Students "blamed the victim" to explain the injuries and considered "paying attention to work" as the best way to protect themselves. These facts showed that the culture of blaming the victim is present since adolescence and probably it is an outcome of a learning process of the society.

Work ability of health care shift workers: What matters?

This paper aims at identifying variables associated with inadequate work ability among nursing personnel at a public hospital, considering factors related to socio-demographic, lifestyles, working conditions, and health outcomes. A cross-sectional study was conducted in a university hospital in São Paulo, Brazil, as part of a larger research study on tolerance to 12 h night work. Nursing staff included registered nurses, nurse technicians, and nurse aides; in total, there were 996 healthcare workers (878 female; 118 male) at the time of the study. Some 696 workers (69.9%) of the population agreed to participate. Data collection (October 2004-July 2005) was based on a comprehensive questionnaire about living and working conditions (including incivility at work, work demands, work control, and support), mental and physical health symptoms (fatigue and sleep problems), and work ability. This report presents analyses of the adapted Brazilian version of the Work Ability Index (WAI) and associated variables. The study population worked one of the following shift schedules at this hospital: 12 h nights followed by 36 h off or 9 h or 6 h day (morning or afternoon) shifts. The mean age of the respondents was 34.9 (S.D.+/-10.4) years of age; 31.5% of the participants held two jobs. Statistical analyses using a hierarchical multiple logistic regression model were performed to evaluate the factors associated with inadequate (moderate and low scores) of the WAI. The significantly associated factors were socio-demographic (income responsibility, sole breadwinner, raising kids, age group), working conditions (thermal discomfort, organization of the workplace, and verbal abuse), and health outcomes (high body mass index, obesity, sleep problems, and fatigue). In spite of limitations of the study design, results indicate that the nursing profession is associated with stressful working conditions, contributing to inadequate WAI. This is in addition to bad living conditions and precarious work. Intervention measures, either at the workplace or at individual levels, are necessary to prevent a decrease in work ability, even in this quite young working population.

[Job control, job demands, social support at work and health among adolescent workers]. / Controle, exigências, apoio social no trabalho e efeitos na saúde de trabalhadores adolescentes.

OBJECTIVE: To evaluate physical and psychological dimensions of adolescent labor (such as job demands, job control, and social support in the work environment), and their relation to reported body pain, work injuries, sleep duration and daily working hours. METHODS: A total of 354 adolescents attending evening classes at a public school in Sao Paulo, Brazil, answered questionnaires regarding their living and working conditions (Karasek's Job Content Questionnaire, 1998), and their health status. Data collection took place in April and May 2001. Multiple logistic regression analysis was used to determine relations among variables. RESULTS: Psychological job demands were related to body pain (OR=3.3), higher risk of work injuries (OR=3.0) and reduced sleep duration in weekdays (Monday to Thursday) (p<0.01). Lower decision authority in the workplace (p=0.03) and higher job security (p=0.02) were related to longer daily working hours. CONCLUSIONS: It was concluded that besides physical stressors, psychological factors are to be taken into account when studying adolescent working conditions, as they may be associated with negative job conditions and health effects.

Teen at work: the burden of a double shift on daily activities.

The purpose of this study was to the evaluate time spent by working and nonworking adolescents on daily activities (work, home duties, school, transportation, other activities, leisure, sleep, and naps). Twenty-seven students, 8 male workers, 8 female workers, 5 male nonworkers, and 6 female nonworkers, ages 14-18 yrs participated in the study. They attended evening classes Monday-Friday (19:00-22:30h) in a public school in the city of São Paulo, Brazil. The students answered a comprehensive questionnaire on the characterization of their life, work, and health conditions. Simultaneously, they wore actigraphs (Ambulatory Monitoring, Inc.) and completed a diary of their daily activities (time spent at work, on home duties, commuting, leisure, other activities) for a minimum of 10 to a maximum of 17 consecutive days. The means of the variables were tested for differences by a two-factor (work and sex) ANOVA and Student-t test applied to pair-wise samples (weekdays and weekends). The average duration during weekdays of working time was 7 h 09 min and home duties 0 h 48 min. As for commuting time, there was a work effect [F(1,23) = 4.9; p = 0.04]; mean commuting time was 2 h 22 min for workers (males and females) and 1 h 25 min for nonworkers. There was a significant difference between workers and nonworkers [F(1,23) = 4.6; p = 0.04] regarding extra-cirricular class activities; workers spent a mean of 3 min/day on them as opposed to 1 h 14 min by nonworkers. The average daily time spent on leisure activities by workers was 6h 31 min; whereas, for nonworkers it was 7h 38min. Time spent in school amounted to 2h 47min for workers in comparison to 3h 22min by nonworkers. There was a significant work effect upon sleep [F(1,23)= 10.0; p <0.01]. The work effect upon nighttime sleep duration was significant [F(1,23)= 16.7; p <0.01]. Male workers showed a mean night sleep of 6 h 57 min and female workers 07h 15min. The average nighttime sleep duration for nonworkers was 9 h 06 min. There was a significant interactive effect between work and sex [F(1,23)= 5.6; p=0.03] for naps. Female workers showed took shortest nap on average (36 min; SD = 26 min), and female nonworkers the longest naps (1 h 45min; SD= 35min). Study and employment exert significant impact on the life and activities of high school students. Work affects sleep and nap duration plus the amount of time spent in school and other extra-curricular activities.

Sleep patterns of day-working, evening high-schooled adolescents of São Paulo, Brazil.

Children who grow up in developing countries of the world must work to help financially support their families, and they must also attend school. We investigated the impact of work on the sleep of working vs. nonworking high school students. Twenty-seven São Paulo, Brazil, public high school students (eight male and eight female working students plus six nonworking female and five nonworking male students) 14-18 yrs of age who attended school Monday-Friday between 19:00 to 22:30h participated. A comprehensive questionnaire about work and living conditions, health status, and diseases and their symptoms was also answered. The activity level and rest pattern (sleep at night and napping during the day) were continuously assessed by wrist actigraphy (Ambulatory Monitoring, USA). The main variables were analyzed by a two-factor ANOVA with application of the Tukey HSD test for multiple comparisons, and the length of sleep during weekdays vs. weekends was compared by Student t-test. Working students went to sleep earlier weekends [F(1,23)=6.1; p=0.02] and woke up earlier work days than nonworking students [F(1,23) = 17.3; p = 0.001]. The length of nighttime sleep during weekdays was shorter among all the working [F(1,23)= 16.7; p <0.001] than all the nonworking students. The sleep duration of boys was shorter than of girls during weekends [F(1,23)= 10.8; p <0.001]. During weekdays, the duration of napping by working and nonworking male students was shorter than nonworking female students. During weekdays working girls took the shortest naps [F(1,23)= 5.6; p = 0.03]. The most commonly reported sleep complaint during weekdays was difficulty waking up in the morning [F(1,23) = 6.5; p = 0.02]. During weekdays, the self-perceived sleep quality of working students was worse than nonworking students [F(1,23) = 6.2; p = 0.02]. The findings of this study show that work has negative effects on the sleep of adolescents, with the possible build-up of a chronic sleep debt with potential consequent impact on quality of life and school learning.

Melatonin treatment effects on adolescent students' sleep timing and sleepiness in a placebo-controlled crossover study.

During the last few decades, the incidence of sleep-onset insomnia, due to delay of circadian phase, has increased substantially among adolescents all over the world. We wanted to investigate whether a small dose of melatonin given daily, administered in the afternoon, could advance the sleep timing in teenagers. Twenty-one students, aged 14-19 yrs, with sleep-onset difficulties during school weeks were recruited. The study was a randomized, double blind, placebo (PL)-controlled crossover trial, lasting 5 wks. During the first 6 d in wks 2 and 4, the students received either PL or melatonin (1 mg) capsules between 16:30 and 18:00 h. During the first 6 d of wk 5, all students received melatonin. Wks 1 and 3 were capsule-free. In the last evening of each week and the following morning, the students produced saliva samples at home for later melatonin analysis. The samples were produced the same time each week, as late as possible in the evening and as early as possible in the morning. Both the student and one parent received automatic mobile text messages 15 min before saliva sampling times and capsule intake at agreed times. Diaries with registration of presumed sleep, subjective sleepiness during the day (Karolinska Sleepiness Scale, KSS) and times for capsule intake and saliva samplings were completed each day. Primary analysis over 5 wks gave significant results for melatonin, sleep and KSS. Post hoc analysis showed that reported sleep-onset times were advanced after melatonin school weeks compared with PL school weeks (p < .005) and that sleep length was longer (p < .05). After the last melatonin school week, the students fell asleep 68 min earlier and slept 62 min longer each night compared with the baseline week. Morning melatonin values in saliva diminished compared with PL (p < .001) and evening values increased (p < .001), indicating a possible sleep phase advance. Compared with PL school weeks, the students reported less wake up (p < .05), less school daytime sleepiness (p < .05) and increased evening sleepiness (p < .005) during melatonin weeks. We conclude that a small dose of melatonin given daily, administered in the afternoon, could advance the sleep timing and make the students more alert during school days even if they continued their often irregular sleep habits during weekends.

Explaining sleep duration in adolescents: the impact of socio-demographic and lifestyle factors and working status.

Previous studies found students who both work and attend school undergo a partial sleep deprivation that accumulates across the week. The aim of the present study was to obtain information using a questionnaire on a number of variables (e.g., socio-demographics, lifestyle, work timing, and sleep-wake habits) considered to impact on sleep duration of working (n = 51) and non-working (n = 41) high-school students aged 14-21 yrs old attending evening classes (19:00-22:30 h) at a public school in the city of São Paulo, Brazil. Data were collected for working days and days off. Multiple linear regression analyses were performed to assess the factors associated with sleep duration on weekdays and weekends. Work, sex, age, smoking, consumption of alcohol and caffeine, and physical activity were considered control variables. Significant predictors of sleep duration were: work ( p < 0.01), daily work duration (8-10 h/day; p < 0.01), sex ( p = 0.04), age 18-21 yrs (0.01), smoking( p = 0.02) and drinking habits ( p = 0.03), irregular physical exercise (p < 0.01), ease of falling asleep ( p = 0.04), and the sleep-wake cycle variables of napping ( p < 0.01), nocturnal awakenings ( p < 0.01), and mid-sleep regularity ( p < 0.01). The results confirm the hypotheses that young students who work and attend school showed a reduction in night-time sleep duration. Sleep deprivation across the week, particularly in students working 8-10 h/day, is manifested through a sleep rebound (i.e., extended sleep duration) on Saturdays. However, the different roles played by socio-demographic and lifestyle variables have proven to be factors that intervene with nocturnal sleep duration. The variables related to the sleep-wake cycle-naps and night awakenings-proved to be associated with a slight reduction in night-time sleep, while regularity in sleep and wake-up schedules was shown to be associated with more extended sleep duration, with a distinct expression along the week and the weekend. Having to attend school and work, coupled with other sociodemographic and lifestyle factors, creates an unfavorable scenario for satisfactory sleep duration.

Conhecimentos e práticas de adolescentes na prevenção de acidentes de trabalho: estudo qualitativo / Knowledge and practices by adolescents in preventing occupational injuries: a qualitative study

OBJETIVO: Descrever conhecimentos e práticas adotados por estudantes do ensino médio na prevenção de acidentes de trabalho. DELINEAMENTO DO ESTUDO: O estudo foi realizado em uma escola pública, localizada no Município de São Paulo, em 2003. Participaram 53 estudantes do período noturno, com idades entre 14 e 21 anos, divididos em dois grupos: com e sem experiência de trabalho (32 e 21 adolescentes, respectivamente). Eles responderam a duas questões: "Por quê os acidentes de trabalho ocorrem?" e "O que você faz para evitar que ocorram acidentes de trabalho?". As análises dos dados foram feitas no programa Quali-quanti, para a elaboração do discurso de sujeito coletivo. ANALISE DOS DISCURSOS: Para os adolescentes com experiência de trabalho, acidentes ocorrem devido ao descuido ou má sorte do funcionário, irresponsabilidade do patrão, falta de treinamento no trabalho e ambiente de trabalho inseguro. Os adolescentes sem experiência relataram que acidentes de trabalho ocorrem devido ao descuido do funcionário e irresponsabilidade do patrão. Sobre as formas de proteção dos acidentes de trabalho os adolescentes de ambos grupos relataram que: prestam (prestariam) atenção no trabalho e usam (usariam) equipamentos de segurança. CONCLUSÕES: Os adolescentes dos dois grupos mostraram conhecimento limitado sobre acidentes de trabalho e formas de prevenção. Os adolescentes apontaram como "culpa da vítima" as ocorrências dos acidentes de trabalho e a melhor forma de proteção "prestar atenção no trabalho". A cultura de culpar a vítima está presente desde a adolescência e provavelmente é resultado de um processo de aprendizado na sociedade.

OBJECTIVE: To describe knowledge and practices adopted by high school students to prevent occupational injuries. STUDY DESIGN: The study was carried out in a public school located in São Paulo, in 2003. Fifty-three evening students aged 14 to 21 years old participated the study, they were divided into two groups with and without job experience (32 and 21 students, respectively). The students answered two questions: "Why do occupational injuries occur?" and "How do you avoid occupational injuries?" Analyses were performed using the software "Quali-quanti" to structure collective discourses. ANALYSIS OF DISCOURSES: Adolescents with work experience reported that occupational injuries occur due to carelessness of the employee, bad luck of the employee, employer's negligence, lack of training, and unsafe workplace. Adolescents without work experience reported that the main causes of work injuries were carelessness of the employee and employer's negligence. Regarding the ways to protect themselves against occupational injuries, both groups reported that: they pay attention (would pay attention) and wear safety equipment (would wear) safety equipment. CONCLUSIONS: Adolescents from both groups showed limited knowledge about occupational injuries and prevention methods. Students "blamed the victim" to explain the injuries and considered "paying attention to work" as the best way to protect themselves. These facts showed that the culture of blaming the victim is present since adolescence and probably it is an outcome of a learning process of the society.

Job control, job demands, social support at work and health among adolescent workers

OBJETIVO: Avaliar as dimensões físicas e psicológicas do trabalho de adolescentes (demanda de trabalho, controle no trabalho e apoio social e ambiental), relacionando-os a relatos de: dores no corpo, acidentes de trabalho, duração de sono e duração diária da jornada de trabalho. MÉTODOS: Participaram do estudo 354 estudantes do período noturno de escola pública no Município de São Paulo, entre abril e maio de 2001. Esses, responderam a questionário sobre condições de vida, trabalho (escalas Karasek de controle no trabalho) e estado de saúde. Foram feitas análises de regressão logística múltipla a fim de determinar a relação entre variáveis. RESULTADOS: As exigências psicológicas mostraram-se associadas aos relatos de dores no corpo (OR=3,3), maiores riscos de ocorrência de acidentes de trabalho (OR=3,0) e redução da duração do sono durante os dias de semana (segunda a quinta-feira) (p<0,01). Baixa autoridade de decisão (p=0,03) e maior segurança no emprego (p=0,02) estão relacionadas à maior duração da jornada diária de trabalho. CONCLUSÕES: Concluiu-se que não somente os estressores físicos, mas também os psicológicos devem ser levados em consideração quando avaliadas as condições de trabalho de adolescentes, já que esses podem ser associados às más condições de trabalho e efeitos negativos na saúde.

O trabalho de jovens universitários e repercussões no sono e na sonolência: trabalhar e estudar afeta diferentemente homens e mulheres? / The work of university students and impact on sleep and sleepiness work and study affects men and women differently?

Trabalhar e estudar têm sido freqüentemente observadas entre jovens universitários. Um dos resultados dessa dupla jornada a esta população é a restrição aos horários de dormir e acordar, especialmente nos dias de trabalho. Como conseqüência da privação de sono, relatos de sonolência excessiva diurna e queda no desempenho nos estudos e no trabalho são freqüentes. Em relação às diferenças entre os sexos, poucos são os estudos que abordam as características dos padrões do ciclo vigília-sono e sonolência de universitários trabalhadores, homens e mulheres. Objetivo: Analisar o ciclo vigília-sono e sonolência de homens e mulheres que trabalham e estudam no turno noturno. Metodologia: Participaram deste projeto 82 estudantes universitários trabalhadores, de 21 a 26 anos de idade, que freqüentavam as aulas no período noturno. Na primeira etapa, os participantes preencheram o “questionário de caracterização das condições de vida, saúde e trabalho”. Na segunda etapa, os participantes utilizaram um actímetro durante 7 dias consecutivos para obtenção de dados de sono e vigília, preencheram a escala de sonolência Karolinska (KSS) e realizaram um teste de vigilância psicomotora (PVT) em diversos momentos do dia. Além disso, os estudantes preencheram um protocolo diário de atividades As análises das variáveis do ciclo vigília sono, sonolência e médias dos tempos de reação foram deitas utilizando a ANOVA para medidas repetidas. As análises das atividades diárias entre os sexos foram realizadas análises de variância (ANOVA) de 2 fatores (sexo e dia da semana) ou teste t-student. As análises das vaiáveis dependentes “ relatos de sonolência excessiva nas aulas” e “tempo dedicado nas aulas” foram realizadas através, respectivamente das análises de regressão logística e linear multivariadas. Em todas as análises utilizou-se como nível de significância α=5 por cento. Resultados: Os resultados mostraram que nos dias de trabalho as mulheres apresentaram um início de sono e meio...

Adolescentes e acidentes de trabalho. De quem é a culpa? / Adolescents and work injuries. From whom is the fault?

É objetivo desse estudo avaliar conhecimentos e práticas adotados por estudantes adolescentes trabalhadores e não trabalhadores na prevenção de riscos no trabalho. Os participantes foram alunos do Ensino Médio da rede estadual de ensino, do período noturno do município de São Paulo. Foram convidados a participar da pesquisa todos os adolescentes dentro da faixa etária de 14-21 anos. Trezentos oitenta estudantes responderam ao questionário de condições de vida a fim de obter informações sobre dados sócio-demográficos e atividade funcional (adolescentes com experiência no mercado de trabalho – trabalhadores e desempregados; e adolescentes sem experiência no mercado de trabalho – não trabalhadores). Em seguida, os adolescentes com experiência no mercado de trabalho (84 por cento) responderam a um questionário com questões sobre condições de trabalho e acidentes de trabalho. Na etapa seguinte, 32 adolescentes com experiência no mercado de trabalho e 21 adolescentes sem experiência no mercado de trabalho foram entrevistados. Nas entrevistas os estudantes foram questionados sobre conhecimentos e práticas adotadas na prática de prevenção de riscos no trabalho. Todas as entrevistas foram gravadas e transcritas. As análises foram feitas utilizando-se o software “Quali-quanti”. Através desse software foi possível a construção dos discursos do sujeito coletivo. A percepção dos adolescentes sobre a segurança no local de trabalho é diferente de acordo com a experiência de trabalho: o ambiente de trabalho seguro para 38,5 por cento adolescentes com experiência de trabalho (cexp) e para 68,3 por cento o ambiente de trabalho seria inseguro (sexp). Entre os que consideram o ambiente de trabalho inseguro, 41,0 por cento (cexp) e 22,7 (sexp) consideram inseguro devido ao ambiente físico, químico e biológico, 12,8 por cento (cexp) e 4,5 por cento (sexp) consideram inseguro devido às questões organizacionais; 5,1 por cento (cexp) e 4,5 por cento (sexp) consideram inseguro devido à falta de cuidados dos trabalhadores. Nunca pensaram nesse assunto 2,6 por cento dos adolescentes com experiência no mercado de trabalho (...).