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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.

Objectives-To measure the levels of exposure to nitrogen trichloride (NCl 3 ) in the atmosphere of indoor swimming pools and to examine how they relate to irritant and chronic respiratory symptoms, indices of pulmonary function, and bronchial hyperresponsiveness to methacholine in lifeguards working in the pools. Method-334 lifeguards (256 men; 78 women) recruited from 46 public swimming pools (n=228) and 17 leisure centre swimming pools (n=106) were examined. Concentrations of NCl 3 were measured with area samplers. Symptoms were assessed by questionnaire and methacholine bronchial challenge (MBC) test by an abbreviated method. Subjects were labelled MBC+ if forced expiratory volume in one second (FEV 1 ) fell by >20%. The linear dose-response slope was calculated as the percentage fall in FEV 1 at the last dose divided by the total dose given. Results-1262 samples were taken in the 63 pools. Mean NCl 3 concentrations were greater in leisure than in public pools. A significant concentration-response relation was found between irritant eye, nasal, and throat symptoms-but not chronic respiratory symptoms-and exposure concentrations. Among women, the prevalence of MBC+ was twice as great as in men. Overall, no relation was found between bronchial hyperresponsiveness and exposure. Conclusions-The data show that lifeguards exposed to NCl 3 in indoor swimming pools are at risk of developing irritant eye, nasal, and throat symptoms. Exposure to NCl 3 does not seem to carry the risk of developing permanent bronchial hyperresponsiveness, but this association might have been influenced by self selection. The possibility that subjects exposed to NCl 3 are at risk of developing transient bronchial hyperresponsiveness cannot be confidently ruled out. (Occup Environ Med 1998;55:258-263) Keywords: indoor swimming pools; lifeguards; irritation; respiratory symptoms; nitrogen trichloride World wide, many millions of people take pleasure in swimming regularly in swimming pools. Traditionally, pool attenders face the risk of developing dermatological diseases due to exposure to micro-organisms-for example, Mycobacterium balnei, Mollusculum contagiosumfound in the pool water or in the surrounding area.1 Also, those attending indoor pools are at risk of inhaling aerosols of microorganisms-for example, Legionella pneumophila-or chemical substances released by the reaction between disinfecting agents added to the pool water and organic matter of human origin. 1In 1993, the departments of several health insurance agencies in France that deal with occupational diseases reported unusually high rates of ocular and respiratory irritation among lifeguards employed at various indoor pools that used chlorine as a disinfecting agent. After this observation, exposure was monitored by chemists from our institution, and showed that among the possible irritants present in the air of the pools only the chloramines were detected in non-negligible quantities. Moreover, nitrogen trichloride (NCl 3 ) was the main chloramine present.2 This e...

Oxidative stress reflects a disturbance in the balance between the production and accumulation of reactive oxygen species (ROS). ROS are scavenged by the antioxidant system, but when in excess concentration, they can oxidize proteins, lipids, and DNA. DNA damage is usually repaired, and the oxidized products are excreted in urine. 8-hydroxy-2-deoxyguanosine is considered a biomarker for oxidative damage of DNA. It is needed to define background ranges for 8-OHdG, to use it as a measure of oxidative stress overproduction. We established a standardized protocol for a systematic review and meta-analysis to assess background ranges for urinary 8-OHdG concentrations in healthy populations. We computed geometric mean (GM) and geometric standard deviations (GSD) as the basis for the meta-analysis. We retrieved an initial 1246 articles, included 84 articles, and identified 128 study subgroups. We stratified the subgroups by body mass index, gender, and smoking status reported. The pooled GM value for urinary 8-OHdG concentrations in healthy adults with a mean body mass index (BMI) ≤ 25 measured using chemical methods was 3.9 ng/mg creatinine (interquartile range (IQR): 3 to 5.5 ng/mg creatinine). A significant positive association was observed between smoking and urinary 8-OHdG concentrations when measured by chemical analysis. No gender effect was observed.