Sleep duration,nightshift work,and the timing of meals and urinary levels of 8-isoprostane and 6-sulfatoxymelatonin in Japanese women

It has been hypothesized that disruption of circadian rhythms affects human health. Shift work and sleep deprivation are thought to disrupt the normal light–dark cycle, although the disruption due to shiftwork may be dependent on sleep deprivation. Both conditions have been suggested to be associated with an increased risk of cardiometabolic disorders. Non-photic environmental factors, such as the timing of eating, are also thought to regulate circadian rhythm and thus, may have effects on health, but the evidence from human studies is scarce. Oxidative stress is a risk factor of cardiometabolic disorders. Some laboratory studies suggest an involvement of circadian clock genes in the regulation of the redox system. The present study aimed to examine the association of sleeping habits, nightshift work, and the timing of meals with urinary levels of 8-isoprostane, a marker of oxidative stress, and 6-sulfatoxymelatonin, the principal metabolite of melatonin. Study subjects were 542 women who had previously attended a breast cancer mass screening in a community in Japan. Information on bedtimes and wake-up times, history of nightshift work, and the timing of meals was obtained by a self-administered questionnaire. The 8-isoprostane and 6-sulfatoxymelatonin were measured using the first morning void of urine and expressed per mg of creatinine. The geometric mean of 8-isoprostane levels was 12.1% higher in women with ≤6 hours of sleep than that in those with >8 hours of sleep on weekdays, and longer sleep duration on weekdays was significantly associated with lower urinary levels of 8-isoprostane after controlling for covariates (p for trend = 0.04). Women who were currently working the nightshift had a 33.3% higher geometric mean of 8-isoprostane levels than those who were not working nightshift (p = 0.03). Urinary 6-sulfatoxymelatonin levels were unrelated to sleep habits or nightshift work. Women who ate breakfast at irregular times had a 19.8% higher geometric mean of 8-isoprostane levels than those who ate breakfast at a regular time or who did not eat (p = 0.02). Women who ate nighttime snacks at irregular times had a 16.2% higher geometric mean of 8-isoprostane levels than those who did not eat nighttime snacks or who ate nighttime snacks at a regular time (p = 0.003). Among women who ate dinner at a regular time, earlier times for dinner were associated with higher 8-isoprostane and 6-sulfatoxymelatonin levels (p values for trends were 0.01 and 0.02, respectively). However, the times of dinner and nighttime snack are overlapping, and the time of last meal of the day was not associated with 8-isoprostane and 6-sulfatoxymelatonin levels. The time of breakfast or lunch was not associated with these biomarkers among women who ate the meal at regular times. Disturbing the rhythmicity of daily life may be associated with oxidative stress.     

The epidemiology of morningness/eveningness: influence of age, gender, ethnicity, and socioeconomic factors in adults (30-49 years)

The Horne and Ostberg Morningness/Eveningness Questionnaire (MEQ) is widely used to differentiate between morning and evening types, but there is very little epidemiological evidence about the distribution of MEQ chronotypes in the general population. The purpose of the present study was to simultaneously investigate the influence of demographic, socioeconomic, and work factors on the distribution of morningness/eveningness. A New Zealand version of the MEQ was mailed to 5000 New Zealand adults, ages 30 to 49 years, who were randomly selected from the electoral rolls (55.7% response rate). A total of 2526 questionnaires were included in the analyses. According to the Horne and Ostberg classification, 49.8% of the total population was classified as morning type compared to 5.6% having an evening-type preference. However, using new cutoffs for middle-aged working adults described by Taillard et al. (2004), 24.7% of the population was morning type and 26.4% was evening type. After controlling for ethnicity, gender, and socioeconomic deprivation, participants ages 30 to 34 years were more likely to be definitely evening type (odds ratio [OR] = 1.59, p < 0.05) and less likely to be morning type (moderately morning type, OR = 0.59, p < 0.01, or definitely morning type, OR = 0.59, p < 0.05) compared to those ages 45 to 49 years. Work schedules were also important predictors of chronotype, with night workers more likely to be definitely evening type (OR = 1.49, p = 0.05) and the unemployed less likely to be moderately morning type (OR = 0.64, p < 0.05) compared to other workers. Evening types were 2.5 times more likely to report that their general health was only poor or fair compared to morning types (p < 0.01). This study confirms that the original criteria of Horne and Ostberg (1976) are not useful for classifying chronotypes in a middle-aged population. The authors conclude that morningness/eveningness preference is largely independent of ethnicity, gender, and socioeconomic position, indicating that it is a stable characteristic that may be better explained by endogenous factors.     

Absence of harmful effects of protracted negative air ionisation

The absence of harmful effects of protracted negative air ionisation was studied in 5 weather-sensitive women and 5 normal men chosen at random. Negative ions were generated by the Modulion of Amcor-Amron (Herzliya, Israel). The patients were exposed separately during 8 sleeping hours and 8 working hours to the apparatus at 1–2 m distance in a 4 × 4 m room, for 2 months. Thus they were exposed to a daily uptake of 1 × 10⁴ negative ions/cm³ for 16 h/day during 2 months. Urinary 17-KS, 17-OH, adrenaline and noradrenaline excretion was not affected by the negative ionisation. However serotonin, 5-HIAA, histamine and thyroxine excretion — if increased before — diminished by 50% on an average. There were no changes in body weight, blood pressure, pulse, respiratory rate, oral morning temperature, dynamometer grip strength, routine liver function tests, urinary pH, albumen, glucose, ketones, bilirubin, or occult blood, red and white blood count and ECG records. The EEG revealed the typical changes due to negative air ionisation: stabilising of frequency, increased amplitudes, spreading of brainwaves from the perceptive occipital area to the conceptive frontal area and synchronisation of both hemisphere tracings.     

Evening Chronotype Is Associated with Changes in Eating Behavior,More Sleep Apnea,and Increased Stress Hormones in Short Sleeping Obese Individuals

Background

Short sleep duration and decreased sleep quality are emerging risk factors for obesity and its associated morbidities. Chronotype, an attribute that reflects individual preferences in the timing of sleep and other behaviors, is a continuum from morningness to eveningness. The importance of chronotype in relation to obesity is mostly unknown. Evening types tend to have unhealthy eating habits and suffer from psychological problems more frequently than Morning types, thus we hypothesized that eveningness may affect health parameters in a cohort of obese individuals reporting sleeping less than 6.5 hours per night.

Methodology and Principal Findings

Baseline data from obese (BMI: 38.5±6.4 kg/m²) and short sleeping (5.8±0.8 h/night by actigraphy) participants (n = 119) of the Sleep Extension Study were analyzed (www.ClinicalTrials.gov, identifier {"type":"clinical-trial","attrs":{"text":"NCT00261898","term_id":"NCT00261898"}}NCT00261898). Assessments included the Horne and Ostberg Morningness-Eveningness questionnaire, a three-day dietary intake diary, a 14-day sleep diary, 14 days of actigraphy, and measurements of sleep apnea. Twenty-four hour urinary free cortisol, 24 h urinary norepinephrine and epinephrine levels, morning plasma ACTH and serum cortisol, fasting glucose and insulin, and lipid parameters were determined. Eveningness was associated with eating later in the day on both working and non-working days. Progression towards eveningness was associated with an increase in BMI, resting heart rate, food portion size, and a decrease in the number of eating occasions and HDL-cholesterol. Evening types had overtly higher 24 h urinary epinephrine and morning plasma ACTH levels, and higher morning resting heart rate than Morning types. In addition, Evening types more often had sleep apnea, independent of BMI or neck circumference.

Conclusions

Eveningness was associated with eating later and a tendency towards fewer and larger meals and lower HDL-cholesterol levels. In addition, Evening types had more sleep apnea and higher stress hormones. Thus, eveningness in obese, chronically sleep-deprived individuals compounds the cardiovascular risk associated with obesity.     

Postprandial triacylglycerol responses in simulated night and day shift: gender differences.

A number of reports suggest that shift workers have an increased risk of coronary heart disease (CHD). One contributing factor may be the consumption of meals at night with consequent altered postprandial responses. This study investigated circulating triacylglycerol (TAG), a possible risk factor for CHD, after meals during a simulated day and night shift. Twenty-five healthy participants (10 women and 15 men) were studied. They were given a pre-meal at 0800 h and a test meal at 1330 h on a simulated day shift and then an identical pre-meal at 2000 h and test meal at 0130 h, respectively, on a simulated night shift with maintained wakefulness. Blood was sampled for 9 h after the test meal for analysis of basal and postprandial plasma TAG levels. ANOVA for repeated measures indicated higher TAG in men compared with women (p < 0.0001) and higher responses at night in both genders (p = 0.027). Incremental area under the curve (IAUC) analysis indicated that men had significantly increased postprandial TAG levels at night compared with the day: (IAUC 0-540 min, mean +/- SEM) 253.29 +/- 28.73 versus 148.33 +/- 17.28 mmol/L x min, respectively, p = 0.025. In women, night and day responses (61.16 +/- 8.93 versus 34.09 +/- 7.87 mmol/L x min, respectively, p = 0.457) were not significantly different. Circulating TAG remained elevated for longer at night in the men compared with the women (p = 0.009). This study demonstrates the existence of gender and time-of-day differences in TAG responses to a meal. These raised TAG levels at night, for a prolonged time in men, may be relevant to the increased risk of CHD in shift workers.     

Sleep/Wake Cycle Parameters and Sleep/Fatigue Complaints in Female Night Workers

Adaptation to shift-work is influenced by the way workers schedule their lives, including allocation of sleep episodes. Female workers (n = 29) engaged at an assembly line were studied as to individual differences in sleep parameters in order to verify whether those differences could be related to the manifestation of sleep and fatigue complaints. The sample was composed of women (20–40 y) working at night from Monday to Friday. Sleep data were based on daily sleep logs which were filled out by the workers for 10 consecutive weeks. In the analyses of sleep data both diurnal episodes between consecutive night shifts and noctural sleep episodes preceding working nights were taken into account. Worker's complaints were analyzed through questions extracted from an interview form encompassing questions on fatigue associated with the work schedule and on dissatisfaction with sleep on weekdays and weekends. The analysis of diurnal episodes showed no significant correlation between the total amount of sleep per day and the total number of complaints. Nevertheless, the latter was correlated to the length of the first sleep episode on a day, which usually began in the morning. As to sleep onset times, significant correlations were not detected concerning the first diurnal episodes. The analysis of nocturnal episodes did not reveal any significant correlation between sleep parameters and complaints. Results indicate that workers whose sleep onsets were allocated to the morning and were able to sleep for many consecutive hours, tended to show less complaints, suggesting that the temporal allocation of diurnal sleep and its length are relevant in the determination of how these workers perceive fatigue and sleep quality.     

Sleep/Wake Cycle Parameters and Sleep/Fatigue Complaints in Female Night Workers

Adaptation to shift-work is influenced by the way workers schedule their lives, including allocation of sleep episodes. Female workers ( n = 29) engaged at an assembly line were studied as to individual differences in sleep parameters in order to verify whether those differences could be related to the manifestation of sleep and fatigue complaints. The sample was composed of women (20-40 y) working at night from Monday to Friday. Sleep data were based on daily sleep logs which were filled out by the workers for 10 consecutive weeks. In the analyses of sleep data both diurnal episodes between consecutive night shifts and noctural sleep episodes preceding working nights were taken into account. Worker's complaints were analyzed through questions extracted from an interview form encompassing questions on fatigue associated with the work schedule and on dissatisfaction with sleep on weekdays and weekends. The analysis of diurnal episodes showed no significant correlation between the total amount of sleep per day and the total number of complaints. Nevertheless, the latter was correlated to the length of the first sleep episode on a day, which usually began in the morning. As to sleep onset times, significant correlations were not detected concerning the first diurnal episodes. The analysis of nocturnal episodes did not reveal any significant correlation between sleep parameters and complaints. Results indicate that workers whose sleep onsets were allocated to the morning and were able to sleep for many consecutive hours, tended to show less complaints, suggesting that the temporal allocation of diurnal sleep and its length are relevant in the determination of how these workers perceive fatigue and sleep quality.     

TEMPERATURE PROFILES,AND THE EFFECT OF SLEEP ON THEM,IN RELATION TO MORNINGNESS-EVENINGNESS IN HEALTHY FEMALE SUBJECTS

There were 15 healthy female subjects, differing in their position on the “morningness-eveningness” scale, studied for 7 consecutive days, first while living a sedentary lifestyle and sleeping between midnight and 08:00 and then while undergoing a “constant routine.” Rectal temperature was measured at regular intervals throughout this time, and the results were subjected to cosinor analysis both before and after “purification” for the effects of physical activity. Results showed that there was a phase difference in the circadian rhythm of core temperature that was associated with the morningness score, with calculations that “morning types” would be phased earlier than “evening types” by up to about 3h. This difference in phase (which was also statistically significant when the group was divided by a median split into a “morning group” and an “evening group”) could not be attributed to effects of waking activity and existed in spite of the subjects keeping the same sleep-wake schedule. Moreover, it persisted when the subjects' data had been purified and when the data were obtained from the constant routine. That is, there was an endogenous component to this difference in phase of the core temperature. The morning group also showed a greater fall of core temperature during sleep; this was assessed in two ways, the main one being a comparison of constant routine and nychthemeral data sets after correction for any effects of activity. Even though the morning group was sleeping at a later phase of their circadian temperature rhythm than was the evening group, neither group showed a fall of temperature due to sleep that varied with time elapsed since the temperature acrophase. It is concluded that another factor that differs between morning and evening types is responsible for this difference. (Chronobiology International, 18(2), 227–247, 2001)     

Effects of environmental lead levels on the urinary kallikrein excretion of exposed workers

Ten men, working in a factory making car batteries, were hospitalized in order to establish the diagnosis of lead intoxication. The urinary kallikrein activity, determined in their 24-hr urines, was found to be lower than that of a control group. Kallikrein activity was then determined in morning urines of another group of 25 lead exposed men working in the same factory. The urines of this group were collected before and after some environmental improvements which reduced lead concentration in the factory ambient air. The urinary kallikrein excretion of exposed workers was very low before environmental improvements. After the lead reduction in the environmental air, the urinary kallikrein excretion of the same workers was significantly increased; nevertheless, it remained still lower than the control group.     

Do Predictors of Career Success Differ between Swedish Women and Men? Data from the Swedish Longitudinal Occupational Survey of Health (SLOSH)

The aim of this prospective study was to explore predictors of objective career success among Swedish women and men, focussing on gender differences. Data were drawn from the 2008 and 2010 waves of the Swedish Longitudinal Occupational Survey of Health (SLOSH) with a total of 3670 female and 2773 male participants. Odds ratios and 95% confidence intervals for job promotion and an above-average salary increase between 2008 and 2010 were obtained through binary logistic regression analyses. Individual and organisational factors measured in 2008 were used as predictors in analyses stratified by sex. Mutual adjustment was performed for these variables, as well as for labour market sector and staff category at baseline. In both sexes, younger age predicted both job promotion and an above-average salary increase. Job promotion was also in both sexes predicted by being part of decision-making processes, having conflicts with superiors, and being eager to advance. Furthermore, promotion was predicted by, among men, being educated to post-graduate level and having an open coping strategy and, among women, working >60 hours/week. An above-average salary increase was predicted in both sexes by having a university education. Postgraduate education, having children living at home, and being very motivated to advance predicted an above-average salary increase among women, as did working 51–60 hours/week and being part of decision-making processes in men. Gender differences were seen in several predictors. In conclusion, the results support previous findings of gender differences in predictors of career success. A high level of education, motivation to advance, and procedural justice appear to be more important predictors of career success among women, while open coping was a more important predictor among men.     

Morningness–eveningness,depressive symptoms,and emotional eating: A population-based study

The aim of this study was to increase understanding of the associations between different dimensions of morningness–eveningness, depressive symptoms, and emotional eating in the general population. The participants were 25-to-74-year-old Finnish men (n?=?2325) and women (n?=?2699) from the National FINRISK Study conducted in 2007. The Center for Epidemiological Studies – Depression Scale and the Three-Factor Eating Questionnaire-R18 were used to measure depressive symptoms and emotional eating. Chronotype was assessed with a shortened version of Horne and Östberg’s Morningness–Eveningness Questionnaire (MEQ). Structural equation modeling was used as an analytical approach. Confirmatory factor analysis indicated a two-factor structure for the six-item MEQ with separate factors for morning alertness and circadian preference for daily activities (r?=?0.65). Higher alertness in the morning and preference for morning hours were both related to lower depressive symptoms (β_{total effect}?=??0.36 and ?0.11, respectively) and emotional eating (β_{total effect}?=??0.20 and ?0.09; β_{indirect effect through depressive symptoms} = ?0.12 and ?0.04, respectively), even though the relationships with morning alertness were stronger. However, the associations of circadian preference with depressive symptoms and emotional eating were reversed after adjustment for morning alertness. Finally, among participants who rarely or never experienced sleeping sufficiently, those in the lowest (i.e. eveningness) and higher (i.e. morningness) circadian preference/morning alertness quartiles had the highest depressive symptom scores. In conclusion, the findings emphasize the importance of separating between different dimensions of chronotype when examining its relationships with psychological factors such as depressive symptoms and overeating tendencies.     

The preference for an additional child among married women in Seoul, Korea

South Korea reported a total fertility rate (TFR) of 1.08 in 2005. This is the lowest level of all nations in the Organisation for Economic Co-operation and Development (OECD). Recently, the decline in the fertility rate has been a dominant phenomenon in Korea's major cities. This study investigated the relationship between social environmental factors and fertility intentions for married women in Seoul, the capital of Korea, using a sample of 2211 married women who responded to the Seoul Citizens Health and Social Indicators Survey, 2005. Here, the effects of selected social environmental characteristics on fertility intentions are explored using multivariate logistic regression models. The relationships among a woman's age, number of living children, job type, housing type, and social group participation were strong indicators of the intention to have additional children. Younger women living with fewer children generally have a higher intention to have additional children. Among women's job types, blue-collar workers have a lower preference for additional children than white-collar workers and housewives. Married women participating in social groups have a lower preference for additional children than non-participants. Women's participation in social activities appears to have various benefits, both individually and socially. However, whereas women's participation in economic activities has been linked to questions of fertility in previous studies, the relationship between fertility and social activities has been downplayed. Women's participation in social activities has increased over the past several decades, and the trend continues to grow. Therefore, women's participation in social activities must be accepted as the status quo, and compatibility between women's participation in social activities and childrearing needs to be increased. Consequently, a strong foundation for a fertility-friendly environment is needed, focusing on blue-collar workers and participation in social activities by married women.     

The Amount of Diurnal Sleep, and Complaints of Fatigue and Poor Sleep, in Night-Working Women: The Effects of Having Children

This study deals with female industrial night workers. There is little scientific literature on this topic since, until recently, such shift systems have in most countries been restricted to men. The amount of diurnal sleep, as well as complaints about fatigue and poor sleep, were compared in women who were (n = 17) or were not (n = 26) caring for children. The women were engaged at an assembly line, working nights (22:00-06:00) from Monday to Friday. They filled out sleep logs for 10 consecutive weeks and were interviewed about complaints concerned with fatigue and poor sleep. A comparison of the diurnal sleeps taken between consecutive night shifts showed that the average total length of daily sleep, as well as the time of onset of the first sleep, did not differ between the groups; however, workers who had children tended to show, in comparison with their childless colleagues, more sleep episodes per day and a shorter first sleep. The total number of complaints about poor sleep and fatigue did not differ between the groups; nevertheless, workers with children complained more of difficulty in falling asleep, had a greater dissatisfaction with the amount of sleep on weekdays, and tended to show an increasing fatigue as the week progressed. We conclude that there are social pressures in women who care for children that are in addition to those that are a general consequence of night work. These results reinforce a need for the implementation of measures that organise child care, so helping a mother who wishes to work also outside the home.     

Effects of shift changes on female workers at a dish factory

This study investigated the effects of working night shifts on social and family life by examining changes in workers' daily life before and after a change in their shifts. Subjects were 40 women aged 27-59 years, working at a dish factory. During the health examination of night workers in autumn of 2000, the subjects were directly interviewed about changes in their lives induced by the shift change. Question parameters consisted of 8 items including 30 sub-items related to social and family life, such as sleep, rest, meals, sports, family time, hobbies, neighborhood association and social activities. The subjects selected one of four response categories: "becoming worse", "no change", "becoming better" and "difficult to determine." With regard to the percentage of "becoming worse", meal-related items ranked high in all of the shift types. "Family time" and "hobbies" showed high percentages in the subjects transferring from day shifts to night shifts, and in those transferring from early-morning shifts to night shifts. "Rest", "sports" and "hobbies" showed high percentages in the subjects transferring from night shifts to midnight shifts. Decreased sleeping hours were confirmed in all of the shift types, while the subjects tended to sleep more soundly. As the workers transfer to shifts at earlier hours, they were obliged to make sacrifices in various aspects of their social and family life. Therefore, much assistance in this regard should be given to them.     

The Amount of Diurnal Sleep,and Complaints of Fatigue and Poor Sleep,in Night-Working Women: The Effects of Having Children

This study deals with female industrial night workers. There is little scientific literature on this topic since, until recently, such shift systems have in most countries been restricted to men. The amount of diurnal sleep, as well as complaints about fatigue and poor sleep, were compared in women who were (n = 17) or were not (n = 26) caring for children. The women were engaged at an assembly line, working nights (22:00-06:00) from Monday to Friday. They filled out sleep logs for 10 consecutive weeks and were interviewed about complaints concerned with fatigue and poor sleep. A comparison of the diurnal sleeps taken between consecutive night shifts showed that the average total length of daily sleep, as well as the time of onset of the first sleep, did not differ between the groups; however, workers who had children tended to show, in comparison with their childless colleagues, more sleep episodes per day and a shorter first sleep. The total number of complaints about poor sleep and fatigue did not differ between the groups; nevertheless, workers with children complained more of difficulty in falling asleep, had a greater dissatisfaction with the amount of sleep on weekdays, and tended to show an increasing fatigue as the week progressed. We conclude that there are social pressures in women who care for children that are in addition to those that are a general consequence of night work. These results reinforce a need for the implementation of measures that organise child care, so helping a mother who wishes to work also outside the home.     

Food insecurity is not associated with lower energy intakes

We examined the association between food insecurity and total daily energy intakes in American men and women. We estimated the number of daily snacks and meals consumed by individuals in different food security categories. Also, we calculated the energy contribution, energy density, and food group sources of those snacks and meals. Using the 1999-2002 National Health and Nutrition Examination Survey (NHANES), we examined the Food Security Survey Module (FSSM) and dietary information from the 24-h recall. Differences in energy intakes between groups were not significant. Women who were food insecure without hunger (FIWOH) and food insecure with hunger (FIWH) had significantly fewer meals than food secure (FS) women. The energy contribution of each meal and the total energy contributed from snacking were both significantly greater for FIWOH women than for FS women. The number of meals was significantly lower whereas the daily number of snacking occasions and the total energy from snacking were significantly increased for FIWOH men relative to FS men. FIWOH men consumed snack foods that had significantly lower energy density than those consumed by FS men. Among men and women, the major sources of meal energy were the grain group, the meat, poultry, and fish group, and the sugar, sweets, and beverages group whereas the major source of snacking energy was the sugar, sweets, and beverages group. Total energy intakes were not different for FI individuals; however, their meal and snack behaviors were different. Focusing solely on total energy intake would miss important consequences of food insecurity.     

Sleeping on the Job during Night Shifts May Be Associated with Extended Night Shifts and/or Variable Night Shift Onset Times

Continuous rotating shiftworkers temporarily working overtime slept at least once during the working hours of their night shifts. They worked at an electric power distribution plant in São Paulo (Brazil). In order to detect factors that could be associated with sleeping on the job, we compared those who slept (sleep group – S) with those who did not sleep (non-sleep group – NS) as to the number of night shifts, the average length of night shifts, the variability in night shift onset and offset times and the length of sleep episodes at home between consecutive night shifts. Data collection was based on dairies filled in by the workers for 30 consecutive days. For both S and NS groups, the number of night shifts for each worker varied from 5 to 9, no difference being found between groups. Individual means of night shifts length varied from 9.4 ± 0.3 hr to 14.2 ± 0.6 hr; they were significantly longer in the S than in the NS group. Night shift onset times were shown to be significantly more variable in the S than in the NS group, whereas offset times did not differ significantly between groups. Length of sleep episodes at home was not significantly different between groups. Workers who slept on the job were those who had longer working bouts and / or more variable night shift onset times. Differences among workers may be due to individual strategies to cope with a situation in which the work schedule included night shifts that were much longer than the established 8 hours, and with many changes in onset times from one night shift to the next.     

The values of alpha 2-macroglobulin in the serum of persons at work with X-rays

Summary A group of 86 persons (65 women, 21 men) working at the risk of ionizing radiation (IR) was examined for the levels of alpha 2-macroglobulin ( ₂-M), and compared to a group of an age matched healthy population. Whereas the difference in men did not reach a level of significance, significant difference was assessed in women: in a subgroup older than 40 y exposed to the IR a rise of ₂-M levels was noted in correlation with the age. Multiple correlation coefficients showed a synergistic influence of both age and exposure to IR. The results are discussed from the point of view of the hypothesis that in exposed women a shifting realizes of usual old age changes to younger age group. A possibility is suggested to use the examination of ₂-M levels for preventive control of workers at the risk of IR.     

Collegiate rowing crew performance varies by morningness-eveningness

During adolescence and early adulthood, most humans are predisposed developmentally, both biologically and socially, toward evening/night activity. The morningness-eveningness (M-E) tendency to be an evening-preferring (E-type) rather than a morning-preferring (M-type) or intermediate/neither (N-type) "chronotype" may affect athletic performance at various times of day. This study evaluated M-E effects on rowing performance of an intact, experienced, university club crew with near-daily early morning (0500-0700 hours) and late afternoon (1630-1800 hours) training schedules. The hypothesis tested was that chronotype would modify circadian effects during morning and afternoon performances. Eight men and eight women (mean age 19.6 +/- 1.5 years) were tested in a randomized, counterbalanced design. A standard qualifying 2000-m ergometer rowing sprint and a nonroutine standing broad jump task were measured during early morning and late afternoon, separated by 3 days of rest. Each subject's chronotype was determined using two standard self-rating M-E scales, resulting in eight E-type (three women/five men), four M-type (two women/two men), and four N-type (three women/one man) subjects. The rowing results show that E-type and N-type subjects did not differ between morning and afternoon rowing performances, whereas M-type subjects rowed significantly faster in the morning. In contrast, the standing broad jump showed no consistent time-of-day or chronotype effect. These findings suggest that basic performance timing in young athletes is determined to some extent by naturally occurring M-E predispositions. Further, modification of time-of-day influences may be possible by routine practice at the same time each day, as was suggested here by the absence of evening superiority in performances. Understanding their personal M-E tendencies could allow young athletes to arrange training schedules at specific times of day to help counteract any natural circadian influences that might work against their performance.     

Effect of retirement on alcohol consumption: longitudinal evidence from the French Gazel cohort study

Background

Little is known about the effect of retirement on alcohol consumption. The objectives were to examine changes in alcohol consumption following retirement, and whether these patterns differ by gender and socioeconomic status.

Methods and Findings

We assessed alcohol consumption annually from 5 years before to 5 years after retirement among 10,023 men and 2,361 women of the French Gazel study. Data were analyzed separately for men and women, using repeated-measures logistic regression analysis with generalized estimating equations. Five years prior to retirement, the prevalence of heavy drinking was about 16% among men, and not patterned by socioeconomic status. Among women, this prevalence was 19.5% in managers, 14.7% in intermediate occupations, and 12.8% in clerical workers. Around retirement, the estimated prevalence of heavy drinking increased in both sexes. In men, this increase was 3.1 percentage points for managers, 3.2 in intermediate occupations, 4.6 in clerical workers, and 1.3 in manual workers. In women, this increase was 6.6 percentage points among managers, 4.3 in intermediate occupations, and 3.3 among clerical workers. In men the increase around retirement was followed by a decrease over the following four years, not significant among manual workers; among women such a decrease was also observed in the non-managerial occupations. It is difficult to assess the extent to which the results observed in this cohort would hold for other working populations, other conditions of employment, or in other cultural settings. A plausible explanation for the increase in heavy drinking around retirement could be that increased leisure time after retirement provides more opportunities for drinking, and not having to work during the day after may decrease constraints on drinking.

Conclusions

Our findings of increased consumption around retirement suggest that information about negative effects of alcohol consumption should be included in pre-retirement planning programs.