Body mass index was independently associated both with cognitive function (word-list learning and Digit-Symbol Substitution Test) and changes in word-list learning in healthy, nondemented, middle-aged men and women.

Changes of alertness and cognitive efficiency has been suggested in people whose circadian rhythms are disrupted, e.g. night or shift-workers. Data from field and laboratory studies have demonstrated short-term cognitive disturbances related to circadian rhythm disruption. By contrast, little is known about the long-term consequences of chronic sleep deprivation, as can be observed with shift-work, on cognitive abilities. The present paper is aimed at evaluating, on a large cross-sectional sample of workers, the long-term influence of shift-work on verbal memory and speed performances. Participants were 3237 workers aged 32, 42, 52, and 62 years of various occupational statuses included in the VISAT (Aging, Health and Work) cohort. Data collected by questionnaires included items on working hours and shift-work and sleep disorders. Cognitive abilities were assessed using neuropsychological tests. Current male shift-workers had lower cognitive performance than never exposed workers. In the same population, memory performance tended to decrease with increasing shift-work duration. Among former shift-workers, the cognitive performance of the participant having stopped shiftwork more than 4 years ago seemed to be increased, suggesting a possible reversibility of effects. In conclusion, this study demonstrated that cognitive functioning tends to be impaired by a long-term exposure to SW. As found by other authors, neuropsychological performance tends to decrease with the increases in the duration of exposure to SW.

Shift work chronically impairs cognition, with potentially important safety consequences not only for the individuals concerned, but also for society.

Cardiovascular diseases remain a major public health problem. The involvement of several occupational factors has recently been discussed, notably the organization of work schedules, e.g. shift work. To analyse the progress of knowledge on the relationship between cardiovascular risk factors and shift work. A review of English-language literature dealing with the link between cardiovascular factors and shift workers (published during 2000-2010) was conducted. Studies published in the past 10 years tend to document an impact of shift work on blood pressure, lipid profile (triglyceride levels), metabolic syndrome and, possibly, body mass index. However, the consequences on glucose metabolism are unclear. These results are not yet firmly established, but are supported by strong hypotheses. Some advice could reasonably be proposed to guide the clinical practitioner.

No abstract

The study examined whether mental stimulation received in the workplace positively affects cognitive functioning and rate of cognitive change. Data taken from the VISAT (ageing, health and work) longitudinal study concerned 3237 workers who were seen three times (in 1996, 2001 and 2006) and who were aged between 32 and 62 years at baseline. Measures of cognitive stimulation both at work and outside work were available at baseline. Cognitive efficiency was assessed on the three occasions through episodic verbal memory, attention and processing speed tests. Greater cognitive stimulation (at work and outside work) was associated with higher levels of cognitive functioning and a more favourable change over the 10-year follow-up. These results were obtained after adjustment for age, education, sex and a variety of medical, physical and psychosocial confounders. The study thus supports the hypothesis that exposure to jobs that are mentally demanding and that offer learning opportunities increases the level of cognitive functioning and possibly attenuates age-related decline. STATEMENT OF RELEVANCE: The effect of occupational activity on cognitive functioning is under-researched. This paper reports results from a substantive longitudinal study, with findings indicating that exposure to jobs that are mentally demanding are beneficial in increasing levels of cognitive functioning and possibly attenuating age-related decline.

Our results reveal the complexity that exists between BMI and environmental factors and stress the need to analyse and to handle these factors simultaneously.

SUMMARYThe effects of age and shiftwork experience (never, past, present) on sleep were studied in a sample of 3236 wage earners and retired workers by means of a questionnaire. The sample was composed of 32-, 42-, 52-, and 62-year-old subjects, and included both sexes and various occupational statuses. Age resulted in a continuously increasing frequency of sleep disturbances and hypnotic use, except for difficulty getting back to sleep and early awakening, which peaked at 52 years and then decreased at 62 years, thus suggesting a 'retirement effect'. Current and past shiftworkers reported more problems with falling asleep and early awakening than subjects who had never worked on shifts. This is a likely explanation of why the effect of age was massive in the latter group and much less pronounced in the former groups. There were no clear effects of the length or recency of shiftwork experience. This finding does not support the hypothesized permanent effect of shiftwork experience on subsequent sleep. Females had higher complaint rates at every age. There was little interaction between age and sex, but women were affected more by shiftwork as they got older, particularly as to hypnotic consumption. Some of the results support the hypothesis that a selection process excludes workers who are no longer able to cope with the demands of shiftwork. age, gender, length and recency of shiftwork, retirement, shiftwork, sleep