Night work effects on salivary cytokines TNF, IL-1ß and IL-6.

Shift work is unavoidable in modern societies, but at the same time disrupts biological rhythms and contributes to social distress and disturbance of sleep, health and well-being of shift workers. Shift work has been associated with some chronic diseases in which a chronic inflammatory condition may play a role. However, few studies investigating the association of cytokine and other inflammation markers with shift workers have been published in recent years. In this study we evaluated the effects of permanent night work on the production of tumor necrosis factor (TNF), interleukin-1ß (IL-1ß), IL-6 and melatonin in saliva. Another aim was to demonstrate the benefit of the use of salivary cytokines for studies in chronobiology, since it is an easy and non-invasive method that allows for sampling at several times. Thirty-eight healthy male workers, being 21 day workers and 17 night workers, agreed to participate in this study. Sleep was evaluated by actigraphy and activity protocols. Saliva was collected during three workdays approximately at the middle of the work shift and at bed and wake times of the main sleep episode. Saliva samples were then analyzed by enzyme-linked immunosorbent assay to measure TNF, IL-1ß, IL-6 and melatonin levels, and the results were submitted to non-parametric statistical analysis. The use of saliva instead of blood allowed for a greater number of samples from the same subjects, allowing identifying alterations in the daily production patterns of salivary cytokines TNF, IL-1ß and IL-6 that probably are linked to night work. Salivary TNF and IL-1ß levels were similar for day and night workers, with higher daily production after awakening, in the morning hours for day workers and in the afternoon for night workers. Both groups presented a significant daily variation pattern of these two cytokines. Day and night workers produced similar amounts of salivary IL-6. Nevertheless, the daily variation pattern observed among day workers, with a peak after awakening, was absent among night workers. Thus, in our study, night workers showed partially adjusted daily variation patterns for salivary TNF and IL-1ß, not seen for salivary IL-6. Results for salivary IL-6 could be better explained as a consequence of circadian disruption due to permanent night work. Our results suggest that the whole circadian system, including clocks and pineal gland, is involved in regulating cytokine profile in shift workers and that a coordinated production of these cytokines, important for an adequate inflammatory response, could be disturbed by shift work. The distinct effects that shift work may have on different cytokines could give some cues about the mechanisms involved in this association.

Short sleep duration increases salivary IL-6 production.

Morning shift sleep restriction has been associated with higher plasma IL-6 levels. The aim of this study was to investigate the effect of sleep duration on salivary IL-6. Sleep duration of morning shift workers was estimated by actigraphy. Workers with "longer sleep duration" (LSD; N = 6) and "shorter sleep duration" (SSD; N = 15) were then compared regarding salivary IL-6 levels determined at 14:00 h, bed and wake times. SSD workers did not show daily variation of IL-6 and presented higher levels at bedtime and 14:00 h compared to LSD workers. In this study, SSD is associated with an increase in salivary IL-6 content.

Avaliação dos impactos do trabalho em turnos noturnos na produção de citocinas inflamatórias salivares e na secreção dos hormônios rítmicos melatonina e cortisol / Effects of night work in salivary cytokine production and salivary melatonin and cortisol secretion

Introdução. Embora necessário ao desenvolvimento econômico e bastante disseminado na sociedade atual, o trabalho em turnos noturnos fixos contribui para consequências sociais negativas e prejuízos à saúde dos trabalhadores deste turno de trabalho. Objetivo. Investigar possíveis efeitos do trabalho em turnos fixos noturnos sobre o sono e biomarcadores hormonais e inflamatórios selecionados. Métodos. Estudo transversal em indústria de metais sanitários da cidade de São Paulo, de que participaram 17 trabalhadores do sexo masculino do turno noturno (das 21h às 6h) e 21 trabalhadores de um dos turnos diurnos (das 7h às 17 h). Dados sociodemográficos, de saúde e de condições de trabalho e sobre fadiga, sonolência, estresse e matutinidade-vespertinidade foram obtidos por questionário. O ciclo atividade/repouso foi avaliado por actimetria e por protocolo diário de atividades durante 10 dias consecutivos, abrangendo ao menos um ciclo de turnos completo. Amostras de saliva coletadas em momentos diferentes durante três dias de trabalho foram analisadas por ELISA para determinação das concentrações dos cinco biomarcadores. Todos os dados obtidos foram então submetidos às análises matemáticas e estatísticas mais adequadas a cada caso. Resultados. O trabalho noturno foi associado a uma diminuição na secreção da melatonina e a alterações em seu ritmo de secreção. Foram observadas também alterações no ritmo de secreção do cortisol e no padrão de variação diário das citocinas salivares TNF, IL-1 e IL-6. Nos trabalhadores diurnos, a privação parcial do sono foi associada a aumento significativo da concentração da IL-6 na saliva. Um maior grau de dessincronização crônica entre os trabalhadores noturnos estaria associado a um maior encurtamento do sono diurno em dias de trabalho, a uma grande variabilidade no ritmo circadiano de secreção do cortisol e a uma maior variabilidade no padrão de variação diário da produção da IL-1 salivar. Conclusões. Os resultados indicam que o trabalho noturno em turnos fixos pode vir a ocasionar prejuízos à saúde dos trabalhadores deste esquema de turnos, tornando-o desaconselhável desse ponto de vista. Diferentes graus de sincronização do sistema de temporização endógeno estariam associados a maior ou menor adaptação ao trabalho em turnos noturnos fixos, com possíveis reflexos, em médio e longo prazos, sobre a tolerância ao trabalho em turnos e os efeitos à saúde nesses trabalhadores

Daily rhythm of salivary IL-1ß, cortisol and melatonin in day and night workers.

Shiftwork-induced sleep deprivation and circadian disruption probably leads to an increase in the production of cytokines and dysregulation of innate immune system, respectively. This project aims evaluating changes in salivary IL-1 beta, cortisol, and melatonin in night workers. Method. Two day and three night healthy workers participated in this study. Sleep was evaluated by actimetry and activity protocols. Saliva was collected at waking and bedtime the last workday and the following two days-off and was analyzed by ELISA. Results. Neither sleep duration nor efficiency showed any association with salivary IL-1beta. IL-1beta levels were higher at waking than at bedtime during working days for all workers, but only one day and one night-worker maintained this pattern and hormone rhythms during days off. For this night worker, melatonin levels were shifted to daytime. A second one presented clear alterations in IL-1beta and hormone rhythms on days-off. Conclusions. Our preliminary results suggest that night work can disturb the variation pattern of salivary IL-1beta. No association of this variation with sleep was observed. It seems that disruption in hormone rhythms interfere with salivary IL-1beta production. IL- 1beta production pattern seems to be maintained when rhythms are present, in spite of a shift in melatonin secretion.

[Barriers to interventions aimed at promoting the health of health care workers in Brazil]. / Barreiras às intervenções relacionadas à saúde do trabalhador do setor saúde no Brasil.

OBJECTIVE: To search the literature for circumstances that impede injury and disease prevention and other activities intended to improve the health of the health care worker. METHODS: The SciELO database was searched for articles published in 1967-2008. This was supplemented by a PubMed search for the period 1950-2008. The following key words were used to identify articles in English, Portuguese, and Spanish: work, health personnel, occupational, risks, diseases, ergonomics, work ability, quality of life, organization, accidents, work conditions, intervention, and administration. Articles on injury and disease prevention and occupational health in a health care setting in Latin America were selected, along with articles focused on health promotion in the health sector. RESULTS: The following shortcomings were identified: activities lacked a sound theoretical foundation and were not integrated with the health services management; a failure to evaluate the effectiveness of the activity; health surveillance focused solely on a specific disease or injury; management not committed to the proposed activity; miscommunication; inability of workers to participate, or control the work environment; and, programs or efforts that were limited to changing the workers' behaviors. CONCLUSIONS: The literature shows that all the barriers identified by this study affect both the health care workers' health as well as their productivity.

Barreiras às intervenções relacionadas à saúde do trabalhador do setor saúde no Brasil: [revisão] / Barriers to interventions aimed at promoting the health of health care workers in Brazil: [review]

OBJETIVO: Identificar na literatura situações que possam impedir ou prejudicar as ações de prevenção de acidentes e doenças ou de promoção da saúde de trabalhadores do setor saúde. MÉTODO: Foi realizada uma revisão da literatura utilizando a base SciELO para o período de 1967 a 2008, complementada por busca na base PubMed para o período de 1950 a 2008. Os seguintes termos foram utilizados para identificar artigos em português, inglês e espanhol: trabalho, trabalhador, ocupacional, riscos, doenças, ergonomia, capacidade para o trabalho, qualidade de vida, organização, acidentes, condições de trabalho, intervenção e administração. Foram selecionados artigos sobre prevenção de doenças e acidentes e sobre promoção da saúde no trabalho em serviços de saúde latino-americanos. Também foram selecionados artigos sobre intervenções em ambientes de trabalho no setor saúde. RESULTADOS: Foram identificadas as seguintes situações desfavoráveis: programas de intervenção sem boa base teórica e não integrados à gestão do serviço como um todo; falhas em avaliar a eficácia das intervenções; vigilância da saúde restrita a doenças e agravos específicos; falta de compromisso da gestão com as intervenções; falhas na comunicação; falta de participação e controle por parte dos trabalhadores sobre o ambiente de trabalho; e programas e intervenções baseados exclusivamente na mudança comportamental dos trabalhadores. CONCLUSÕES: A literatura mostra que todas as barreiras citadas afetam tanto a melhoria do estado de saúde dos trabalhadores em saúde quanto a sua capacidade para o trabalho.

OBJECTIVE: To search the literature for circumstances that impede injury and disease prevention and other activities intended to improve the health of the health care worker. METHODS: The SciELO database was searched for articles published in 1967-2008. This was supplemented by a PubMed search for the period 1950-2008. The following key words were used to identify articles in English, Portuguese, and Spanish: work, health personnel, occupational, risks, diseases, ergonomics, work ability, quality of life, organization, accidents, work conditions, intervention, and administration. Articles on injury and disease prevention and occupational health in a health care setting in Latin America were selected, along with articles focused on health promotion in the health sector. RESULTS: The following shortcomings were identified: activities lacked a sound theoretical foundation and were not integrated with the health services management; a failure to evaluate the effectiveness of the activity; health surveillance focused solely on a specific disease or injury; management not committed to the proposed activity; miscommunication; inability of workers to participate, or control the work environment; and, programs or efforts that were limited to changing the workers' behaviors. CONCLUSIONS: The literature shows that all the barriers identified by this study affect both the health care workers' health as well as their productivity.