Melissa Araújo Ulhôa

Irregular working times and metabolic disorders among truck drivers: a review

A number of studies to better understand the complex physiological mechanism involved in regulating body weight have been conducted. More specifically, the hormones related to appetite, leptin and ghrelin, and their association to obesity have been a focus of investigation. Circadian patterns of these hormones are a new target of research. The behaviour of these hormones in individuals subject to atypical working times such as shiftwork remains unclear. Shiftwork is characterized by changes in biological rhythms and cumulative circadian phase changes, being associated with high rates of obesity and metabolic syndrome. Truck drivers, who work irregular shifts, frequently present a high prevalence of obesity, which might be associated with work-related factors and/or lifestyle. In this context, the aim of this paper was to discuss the relationship of body mass index, appetite-related hormones and sleep characteristics in truck drivers who work irregular shifts compared with day workers.

Distúrbios psíquicos menores e condições de trabalho em motoristas de caminhão

OBJECTIVE To estimate the prevalence of minor psychiatric disorders and to identify associated stressors among truck drivers. METHODS A cross-sectional study was conducted with 460 truck drivers from a cargo transportation company of the Southern and Southeastern regions of Brazil, in 2007. Workers completed a questionnaire about sociodemographic, lifestyle and working conditions data. Working conditions were the independent variables, including occupational stressors, job satisfaction and job demand-control. The outcome evaluated was the occurrence of minor psychiatric disorders. Multiple and univariate logistic regression analyses were performed. RESULTS The prevalence of minor psychiatric disorders was 6.1%. The most frequently reported stressors were traffic congestion, tracking control and extended working hours. High job demand, low social support and extended daily working hours, as reported by drivers, were associated with minor psychiatric disorders. CONCLUSIONS Work involving extended working hours was associated with the occurrence of minor psychiatric disorders, both in the analysis of general working conditions and as a factor considered to be a stressor by drivers. Thus, regulation of working hours with focus on the limitation of the daily working hours is necessary to reduce the chance of developing minor psychiatric disorders in drivers.OBJETIVO: Estimar a prevalencia de disturbios psiquicos menores e identificar estressores associados entre motoristas de caminhao. METODOS: Estudo transversal conduzido com 460 motoristas de caminhao de uma transportadora de cargas das regioes Sul e Sudeste do Brasil, em 2007. Os trabalhadores preencheram questionario com dados sociodemograficos, estilos de vida e condicoes de trabalho. As variaveis independentes foram condicoes de trabalho, incluindo estressores ocupacionais, satisfacao e demanda-controle no trabalho. O desfecho avaliado foi a ocorrencia de disturbios psiquicos menores. Foram realizadas analises de regressao logistica univariada e multipla. RESULTADOS: A prevalencia de disturbios psiquicos menores foi de 6,1%. Os estressores mais citados foram congestionamentos, controle de rastreamento e jornada extensa de trabalho. A alta demanda no trabalho, o baixo apoio social e a jornada extensa diaria referidos pelos motoristas estiveram associados aos disturbios psiquicos menores. CONCLUSOES: O trabalho em jornadas extensas foi associado a ocorrencia de disturbios psiquicos menores, tanto na analise das condicoes gerais de trabalho quanto como fator referido como estressor pelos motoristas. A regulamentacao da jornada de trabalho com limitacao de horas de trabalho diario e, portanto, uma medida necessaria para a reducao da chance de desenvolvimento de disturbios psiquicos menores em motoristas.

When Does Stress End? Evidence of a Prolonged Stress Reaction in Shiftworking Truck Drivers

This study aimed to analyze individual cortisol levels in relation to work conditions, sleep, and health parameters among truck drivers working day shifts (n = 21) compared to those working irregular shifts (n = 21). A total of 42 male truck drivers (39.8 ± 6.2 yrs) completed questionnaires about sociodemographics, job content, work environment, health, and lifestyle. Rest-activity profiles were measured using actigraphy, and cardiovascular blood parameters were collected. Salivary cortisol samples were obtained: (i) at waking time, (ii) 30 min after waking, and (iii) at bedtime, during both one workday and one day off from work. Irregular-shift workers, compared to day-shift workers, showed significantly higher waist-hip ratio, very-low-density lipoprotein (VLDL) cholesterol, tiredness after work, years working as a driver, truck vibration, and less job demand (p < .05). High cortisol levels in irregular-shift workers were correlated with certain stressors, such as short sleep duration and low job satisfaction, and to metabolic parameters, such as total cholesterol, high-density lipoprotein (HDL), low-density lipoprotein (LDL), VLDL, and triglycerides. Day-shift workers had higher cortisol levels collected 30 min after waking (p = .03) and a higher cortisol awakening response (CAR; p = .02) during workdays compared to off days. Irregular-shift workers had higher cortisol levels on their off days compared to day-shift workers (p = .03). In conclusion, for the day-shift workers, a higher cortisol response was observed on workdays compared to off days. Although no direct comparisons could be made between groups for work days, on off days the irregular-shift workers had higher cortisol levels compared to day-shift workers, suggesting a prolonged stress response in the irregular-shift group. In addition, cortisol levels were correlated with stressors and metabolic parameters. Future studies are warranted to investigate further stress responses in the context of irregular work hours. (Author correspondence: crmoreno@usp.br)

Effects of irregular-shift work and physical activity on cardiovascular risk factors in truck drivers

OBJECTIVE To analyze the putative effect of type of shift and its interaction with leisure-time physical activity on cardiovascular risk factors in truck drivers. METHODS A cross-sectional study was undertaken on 57 male truck drivers working at a transportation company, of whom 31 worked irregular shifts and 26 worked on the day-shift. Participants recorded their physical activity using the International Physical Activity Questionnaire along with measurements of blood pressure, body mass index and waist-hip ratio. Participants also provided a fasting blood sample for analysis of lipid-related outcomes. Data were analyzed using a factorial model which was covariate-controlled for age, smoking, work demand, control at work and social support. RESULTS Most of the irregular-shift and day-shift workers worked more than 8 hours per day (67.7% and 73.1%, respectively). The mean duration of experience working the irregular schedule was 15.7 years. Day-shift workers had never engaged in irregular-shift work and had been working as a truck driver for 10.8 years on average. The irregular-shift drivers had lower work demand but less control compared to day-shift drivers (p < 0.05). Moderately-active irregular-shift workers had higher systolic and diastolic arterial pressures (143.7 and 93.2 mmHg, respectively) than moderately-active day-shift workers (116 and 73.3 mmHg, respectively) (p < 0.05) as well as higher total cholesterol concentrations (232.1 and 145 mg/dl, respectively) (p = 0.01). Irrespective of their physical activity, irregular-shift drivers had higher total cholesterol and LDL-cholesterol concentrations (211.8 and 135.7 mg/dl, respectively) than day-shift workers (161.9 and 96.7 mg/dl, respectively (ANCOVA, p < 0.05). CONCLUSIONS Truck drivers are exposed to cardiovascular risk factors due to the characteristics of the job, such as high work demand, long working hours and time in this profession, regardless of shift type or leisure-time physical activity.

Shift work and endocrine disorders.

The objective of this review was to investigate the impact of shift and night work on metabolic processes and the role of alterations in the sleep-wake cycle and feeding times and environmental changes in the occurrence of metabolic disorders. The literature review was performed by searching three electronic databases for relevant studies published in the last 10 years. The methodological quality of each study was assessed, and best-evidence synthesis was applied to draw conclusions. The literature has shown changes in concentrations of melatonin, cortisol, ghrelin, and leptin among shift workers. Melatonin has been implicated for its role in the synthesis and action of insulin. The action of this hormone also regulates the expression of transporter glucose type 4 or triggers phosphorylation of the insulin receptor. Therefore, a reduction in melatonin can be associated with an increase in insulin resistance and a propensity for the development of diabetes. Moreover, shift work can negatively affect sleep and contribute to sedentarism, unhealthy eating habits, and stress. Recent studies on metabolic processes have increasingly revealed their complexity. Physiological changes induced in workers who invert their activity-rest cycle to fulfill work hours include disruptions in metabolic processes.

Minor psychiatric disorders and working conditions in truck drivers

OBJECTIVE To estimate the prevalence of minor psychiatric disorders and to identify associated stressors among truck drivers. METHODS A cross-sectional study was conducted with 460 truck drivers from a cargo transportation company of the Southern and Southeastern regions of Brazil, in 2007. Workers completed a questionnaire about sociodemographic, lifestyle and working conditions data. Working conditions were the independent variables, including occupational stressors, job satisfaction and job demand-control. The outcome evaluated was the occurrence of minor psychiatric disorders. Multiple and univariate logistic regression analyses were performed. RESULTS The prevalence of minor psychiatric disorders was 6.1%. The most frequently reported stressors were traffic congestion, tracking control and extended working hours. High job demand, low social support and extended daily working hours, as reported by drivers, were associated with minor psychiatric disorders. CONCLUSIONS Work involving extended working hours was associated with the occurrence of minor psychiatric disorders, both in the analysis of general working conditions and as a factor considered to be a stressor by drivers. Thus, regulation of working hours with focus on the limitation of the daily working hours is necessary to reduce the chance of developing minor psychiatric disorders in drivers.OBJETIVO: Estimar a prevalencia de disturbios psiquicos menores e identificar estressores associados entre motoristas de caminhao. METODOS: Estudo transversal conduzido com 460 motoristas de caminhao de uma transportadora de cargas das regioes Sul e Sudeste do Brasil, em 2007. Os trabalhadores preencheram questionario com dados sociodemograficos, estilos de vida e condicoes de trabalho. As variaveis independentes foram condicoes de trabalho, incluindo estressores ocupacionais, satisfacao e demanda-controle no trabalho. O desfecho avaliado foi a ocorrencia de disturbios psiquicos menores. Foram realizadas analises de regressao logistica univariada e multipla. RESULTADOS: A prevalencia de disturbios psiquicos menores foi de 6,1%. Os estressores mais citados foram congestionamentos, controle de rastreamento e jornada extensa de trabalho. A alta demanda no trabalho, o baixo apoio social e a jornada extensa diaria referidos pelos motoristas estiveram associados aos disturbios psiquicos menores. CONCLUSOES: O trabalho em jornadas extensas foi associado a ocorrencia de disturbios psiquicos menores, tanto na analise das condicoes gerais de trabalho quanto como fator referido como estressor pelos motoristas. A regulamentacao da jornada de trabalho com limitacao de horas de trabalho diario e, portanto, uma medida necessaria para a reducao da chance de desenvolvimento de disturbios psiquicos menores em motoristas.

Noisy and individual, but doable : Shift-work research in humans

Working around the clock is common for many occupations, as diverse as nurses, truck drivers, physicians, steel workers, and pilots. Each shift-work profession is individual in more aspects than just work hours and individual work scenarios, each posing a different impact on the health of workers. Related health problems in shift workers, therefore, are also diverse and encompass sleep problems, metabolic and cardiovascular system disturbances, as well as cancer. Little is known about how all these individual factors influence a shift workers health status, partly because many shift-work studies show inconsistent results. In addition, these individual factors create many methodological difficulties for researchers who investigate such work scenarios. This chapter presents examples from our laboratory and field studies of shift workers, which emphasize the importance of taking individual circumstances into account. Both study approaches, laboratory and field based, are needed to fully account for the difficulties that shift-work studies pose on both workers and researchers. Finally, understanding the mechanisms that underpin interindividual differences in response to shift work will advance our understanding of how to design better and healthier shift-work schedules in the future.

Associação entre prática de atividade física, escolaridade e perfil alimentar de motoristas de caminhão

Abstract The modern society’s demand has intensified unin-terrupted work among several professional catego-ries. Besides that, the society’s organization, with activities that are predominantly mechanized, has contributed to unhealthy life habits, such as lack of physical activity. The study aims to verify the association of occupational, social-demographic, anthropometric and food intake data with insuffi-cient practice of physical activities and if there are any differences in this association between day and night truck drivers. The 470 truck drivers who parti -cipated in this study answered social-demographic, physical activity and food frequency questionnaires. U nivariate logistic regression analysis was used to verify the association between insufficient physical activity and the other variables. Additionally, multi-ple logistic regression was tested to obtain models that show the association between sets of variables related to insufficient physical activity. The results indicated that practice of physical activities is as-sociated with high educational level (OR=1.84; CI = 1.22-2.76) and low alcohol consumption (OR = 1.59; CI = 1.04-2.45). High intake of whole grains (OR = 1.63; CI = 1.08-2.46) was associated with regular practice of physical activity. Among the night workers, we found the association between regular practice of physical activity, high consumption of whole grains (OR = 2.02; CI = 1.13-3.60) and low consumption of simple carbohydrates (OR = 1.91; CI = 1.08-3.37).

Effects of a carbohydrate-enriched night meal on sleepiness and sleep duration in night workers: A double-blind intervention

The aim of this study was to investigate the effects of an intervention involving night meal composition on sleepiness and sleep duration in night security guards. A total of 54 male night security guards with a mean age of 30.8 years (SD = 5.5 years) filled out a 24-h dietary recall and were submitted to anthropometric measurement. Twenty-four workers were assigned to the intervention. The intervention was carried out over three consecutive weeks under three conditions. On the first week, no change in workers’ food composition was introduced. On the second week, the amount of carbohydrates was increased by 20–30% compared with the first week’s intake, whereas during the third week protein intake was increased by 30–40% compared with baseline levels (first week). Throughout the study period, workers wore an actigraph device to estimate sleeping and waking times. A two-factor mixed model analysis with sleep duration as the outcome showed an interaction effect between body mass index (BMI) and condition (F2,56 = 3.9; p = 0.03). Sleep duration was higher in obese workers compared with nonobese workers during the Carbohydrate condition (357 and 267 min, respectively). The analysis of variance (ANOVA) showed an increase in sleepiness under all conditions at 3:00 h (F1,276 = 165.73; p < 0.01) postprandially. A significant difference in sleepiness was also found between the obese and nonobese groups (F1,276 = 14.8; p < 0.01). The effect of the night meal content on sleep duration seems to be mediated by BMI. A carbohydrate-rich meal increased the duration of sleep in obese workers, and may therefore also influence sleepiness.

Efectos del turno irregular de trabajo y actividad física en los factores de riesgo cardiovasculares en conductores de camión

OBJECTIVE To analyze the putative effect of type of shift and its interaction with leisure-time physical activity on cardiovascular risk factors in truck drivers. METHODS A cross-sectional study was undertaken on 57 male truck drivers working at a transportation company, of whom 31 worked irregular shifts and 26 worked on the day-shift. Participants recorded their physical activity using the International Physical Activity Questionnaire along with measurements of blood pressure, body mass index and waist-hip ratio. Participants also provided a fasting blood sample for analysis of lipid-related outcomes. Data were analyzed using a factorial model which was covariate-controlled for age, smoking, work demand, control at work and social support. RESULTS Most of the irregular-shift and day-shift workers worked more than 8 hours per day (67.7% and 73.1%, respectively). The mean duration of experience working the irregular schedule was 15.7 years. Day-shift workers had never engaged in irregular-shift work and had been working as a truck driver for 10.8 years on average. The irregular-shift drivers had lower work demand but less control compared to day-shift drivers (p < 0.05). Moderately-active irregular-shift workers had higher systolic and diastolic arterial pressures (143.7 and 93.2 mmHg, respectively) than moderately-active day-shift workers (116 and 73.3 mmHg, respectively) (p < 0.05) as well as higher total cholesterol concentrations (232.1 and 145 mg/dl, respectively) (p = 0.01). Irrespective of their physical activity, irregular-shift drivers had higher total cholesterol and LDL-cholesterol concentrations (211.8 and 135.7 mg/dl, respectively) than day-shift workers (161.9 and 96.7 mg/dl, respectively (ANCOVA, p < 0.05). CONCLUSIONS Truck drivers are exposed to cardiovascular risk factors due to the characteristics of the job, such as high work demand, long working hours and time in this profession, regardless of shift type or leisure-time physical activity.