National Electricity Company Research Articles

The Impact of Stressful Life Events on Excessive Alcohol Consumption in the French Population: Findings from the GAZEL Cohort Study

BackgroundMajor life changes may play a causative role in health through lifestyle factors, such as alcohol. The objective was to examine the impact of stressful life events on heavy alcohol consumption among French adults.MethodsTrajectories of excessive alcohol consumption in 20,625 employees of the French national gas and electricity company for up to 5 years before and 5 years after an event, with annual measurements from 1992. We used repeated measures analysis of time series data indexed to events, employing generalized estimating equations.ResultsFor women, excessive alcohol use increased before important purchase (p = 0.021), children leaving home (p<0.001), and death of loved ones (p = 0.03), and decreased before widowhood (p = 0.015); in the year straddling the event, increased consumption was observed for important purchase (p = 0.018) and retirement (p = 0.002); at the time of the event, consumption decreased for marriage (p = 0.002), divorce, widowhood, and death of loved one (all p<0.001), and increased for retirement (p = 0.035). For men, heavy alcohol consumption increased in the years up to and surrounding the death of loved ones, retirement, and important purchase (all p<0.001), and decreased after (all p<0.001, except death of loved one: p = 0.006); at the time of the event, consumption decreased for all events except for children leaving home and retirement, where we observed an increase (all p<0.001). For women and men, heavy alcohol consumption decreased prior to marriage and divorce and increased after (all p<0.001, except for women and marriage: p = 0.01).ConclusionStressful life events promote healthy and unhealthy alcohol consumption. Certain events impact alcohol intake temporarily while others have longer-term implications. Research should disentangle women's and men's distinct perceptions of events over time.

Prevalence of spondyloarthritis in reference to HLA-B27 in the French population: results of the GAZEL cohort

ObjectiveTo estimate the prevalence of spondyloarthritis (SpA) in reference to HLA-B27 in the French population.MethodsIn 1989, 20 625 employees of the French national gas and electricity company aged 35–50 years...

Lifecourse Socioeconomic Position and Alcohol Use in Young Adulthood: Results from the French TEMPO Cohort Study

The aim of the study was to examine the relationship between lifetime socioeconomic position and alcohol use in young adults. The participants (n = 1103, age 22-35 years in 2009) were the French TEMPO cohort, offspring of employees (all French nationals) of the French national gas and electricity company (GAZEL) who were in a previous cohort study. Alcohol use was assessed by the WHO AUDIT questionnaire (none, low or intermediate alcohol use, alcohol abuse). Childhood socioeconomic position was measured using parental income documented in the GAZEL study in 1989 (low: ≤ 2592€/month vs. intermediate/high: >2592€/month). Adult socioeconomic position was measured by participants' educational level (≤ high school degree vs. >high school degree). Combining family income and educational attainment, we ascertained participants' social trajectory (stable high, upward, downward and stable low). Data were analyzed using multinomial regression analyses controlled for demographic, social, psychological and family characteristics. Compared with participants with a stable high social trajectory, those with an upward, downward or low social trajectory were more likely to abstain from alcohol (compared with a stable high social trajectory, sex and age-adjusted ORs: OR = 2.22, 95% CI 1.35-3.65 for an upward social trajectory; OR = 3.20, 95% CI 1.78-5.73 for a downward social trajectory; OR = 3.27, 95% CI 1.75-6.12 for a stable low social trajectory). Additionally, participants with a downward social trajectory were disproportionately likely to abuse alcohol (sex- and age-adjusted OR: 1.48, 95% CI 0.89-2.48). In multivariate analyses, social trajectory remained associated with alcohol use. Lifelong socioeconomic position may shape patterns of alcohol use early in life.

FRI0446 Direct estimate of hla-b27 and spondyloarthritis prevalence in the general population: results of the french gazel cohort.

BackgroundSpondyloarthritis (SpA), one of the most common inflammatory joint diseases in France is associated with HLA-B27. However data on its prevalence remain scarce. Moreover, the precise frequency of SpA in...

Mortality associated with depression as compared with other severe mental disorders: A 20-year follow-up study of the GAZEL cohort.

Individuals with severe mental disorders (SMD) have an increased risk of mortality from somatic diseases. This study examined whether this risk is different in persons with depressive disorders compared to those with other SMD (i.e. schizophrenia and bipolar disorder). In 1989, 20,625 employees of the French national gas and electricity company (15,011 men and 5614 women, aged 35–50) agreed to participate in the GAZEL cohort study. Three diagnosis groups were created based on sick leave spells from 1978 onwards: 1) no SMD, 2) depressive disorders and 3) other SMD. Dates and causes of death were available from January 1, 1990 to December 31, 2010. The association of diagnosis groups with mortality was estimated with hazard ratios (HR) and 95% confidence intervals (CI) computed using Cox regression. During a mean follow-up of 19.8 years, 1544 participants died, including 1343 from a natural cause, of which 258 died from cardiovascular diseases. After adjustment for age, gender, occupational status, alcohol consumption, smoking and body-mass index, participants with a history of sickness absence for SMD had a greater risk of natural mortality (HR: 1.24, CI: 1.08–1.43), cardiovascular mortality (HR: 1.49, CI: 1.08–2.05) and non-cardiovascular natural mortality (HR: 1.19, CI: 1.02–1.39). Compared to depressive disorders, other SMD were associated with an increased risk of natural mortality (HR: 1.94, CI: 1.17–3.22) and cardiovascular mortality (HR: 3.58, CI: 1.53–8.39). Job security and systematic medical follow-up may fall short of preventing premature death among workers with sickness absence due to SMD.

现代水力发电厂无人(少人)值班模式的研究

为适应新的管理体制，赶超国际先进管理水平，原国家电力公司决定开展建设国际一流水电厂工作，并颁发《国家电力公司国际一流水力发电厂考核标准(试行)》。鲁布革水力发电厂为配合国内建设国际一流水力发电厂工作，适应当前水电厂改革形势的需要，在总结研究水电厂“无人值班”(少人值守)工作经验的基础上，不断改革值班方式。鲁布革电厂现在已经形成了一套成熟成功的无人值班模式，鲁布革电厂走在了中国水电厂无人值班工作模式的前列。 In order to adapt to the new management system and to catch up with the advanced international level, the former state power company decided to carry out the construction of the international first-class power plant, and issue the “assessment criteria of international first-class hydroelectric power plant, the national electric power company (for Trial Implementation)”. In order to construct the international first-class hydropower and meet the needs of current hydro-plant’s reform situation, Lubuge hydroelectric power plant continuously reformed the attended mode based on the research of experiences on the “unmanned on duty” (few people on duty). Lubuge power plant has now formed a set of mature and successful unattended mode, which made Lubuge power plant walk ahead in China.

Grid-connected photovoltaic (PV) systems with batteries storage as solution to electrical grid outages in Burkina Faso

This paper deals with a key solution for power outages problem experienced by many African countries and this through grid-connected photovoltaic (PV) systems with batteries storage. African grids are characterized by an insufficient power supply and frequent interruptions. Due to this fact, users who especially use classical grid-connected photovoltaic systems are unable to profit from their installation even if there is sun. In this study, we suggest the using of a grid-connected photovoltaic system with batteries storage as a solution to these problems. This photovoltaic system works by injecting the surplus of electricity production into grid and can also deliver electricity as a stand-alone system with all security needed. To achieve our study objectives, firstly we conducted a survey of a real situation of one African electrical grid, the case of Burkina Faso (SONABEL: National Electricity Company of Burkina). Secondly, as study case, we undertake a sizing, a modeling and a simulation of a grid-connected PV system with batteries storage for the LAME laboratory at the University of Ouagadougou. The simulation shows that the proposed grid-connected system allows users to profit from their photovoltaic installation at any time even if the public electrical grid has some failures either during the day or at night.

On Enterprise Operation Efficiency and Strategic Research Based on Super-efficient DEA

With the rapid development of China's electric power market today, the national provincial electric power companies, which are under the background of the principal-agent framework management, have become the main development pillars of the national electric power companies. These companies are responsible for many important businesses such as electric power market exploitation, power grid construction, electric power operation mode transformation, etc., and they are relatively independent management subject. How to evaluate the performance of provincial companies is always a focus point of the management of the national electric power company. The author tries to improve the C2R evaluation model of the DEA method and construct the super-efficient DEA evaluation model, in order to solve the problem that the sorting and selecting decision cannot be made when there are more than one effective decision unit, furthermore, to apply it to evaluate the operation efficiency of provincial companies and propose measures to improve business performance. The author hopes this can provide good ways of improving the reformation of electric power companies marketization in their reformation process.

Change in physical activity and weight in relation to retirement: the French GAZEL Cohort Study

ObjectivesTo examine the trajectories of physical activity from preretirement to postretirement and to further clarify whether the changes in physical activity are associated with changes in body weight.DesignProspective.SettingFrench national gas...

Diagnosis-specific sick leave as a long-term predictor of disability pension: a 13-year follow-up of the GAZEL cohort study

BackgroundFactors that increase the risk of labour market exclusion are poorly understood. In this study, we examined the extent to which all-cause and diagnosis-specific sick leave predict subsequent disability pension...

Why Drivers Start Drinking and Driving—A Prospective Study Over a 6-Year Period in the GAZEL Cohort

To estimate the frequency with which a group of formerly safe drivers adopt driving while alcohol-intoxicated (DWI), and to determine the factors associated with DWI adoption. Participants were current employees or recent retirees of the French national electricity and gas company. An annual cohort questionnaire that includes two questions about overall alcohol consumption is sent each year to participants. A Driving Behaviour and Road Safety (DBRS) questionnaire was administered in 2001, 2004 and 2007. Only drivers who participated in the 2001 survey received the 2004 and 2007 questionnaires. More than 462 participants ceased DWI between 2001 and 2007, while 511 adopted this behaviour for the first time. Multivariate analysis showed that the risk of adopting DWI was associated with male gender and with several changes over the preceding years: increased alcohol consumption, increased number of close friends, decreased number of close relatives and decreased attitudes in favour of strict enforcement/regulations. A large number of offenders stopped DWI between 2001 and 2007, concomitantly with an increased crackdown on road violations in France. But this success was compromised by the occurrence of new drunk drivers. Preventive strategies should target factors that facilitate DWI adoption-in particular, increased alcohol consumption and low acceptance of law enforcement initiatives.

Is There Any Additional Psychological and/or Physical Job Constraint Associated With Informal Caregiving Status? Findings From the GAZEL Cohort Study

Is There Any Additional Psychological and/or Physical Job Constraint Associated With Informal Caregiving Status? Findings From the GAZEL Cohort Study

Cost and demand functions of electricity in Gambia from 1982 to 2007

This paper argues that an electricity demand should be estimated simultaneously with the supply. It then estimates the demand for and the supply of the electricity in the Gambia using reduced form regressions and vector error correction methods. The paper finds that systems of simultaneous equations cannot be simplified to reduced form regressions to satisfy the statistical requirements, but rather the theoretical modeling requirements determine the choice of the statistical model. The vector error correction method incorporating the theoretical restrictions of the model is found to better fit the data than the reduced form regressions. From the estimation results of this method, the electricity demand is found to be price elastic and income elastic. The electricity demand is found to shrink if the company charges an average price higher than 1.3 times of the per capita GDP growth rate; and since the demand is price elastic, increasing the electricity price will result in falling revenues for the company. The electricity industry, which here refers to the national electricity company, exhibits diseconomies of scale. The industry is found inefficient, and failing to innovate and accumulate knowledge to enable it to expand output with falling average unit cost. With the current operation, the expansion of output could be undertaken only with increasing average unit cost and hence increasing electricity price.

Influence of retirement and work stress on headache prevalence: A longitudinal modelling study from the GAZEL Cohort Study

The aims of this study were to examine trajectories of headache in relation to retirement and to clarify the role of work stress and stress-prone personality. Headache prevalence during the 7 years before and after retirement was measured by annual questionnaires from GAZEL cohort comprising French national gas and electricity company employees (n = 12,913). Odds ratios and 95% confidence intervals for headache during pre- peri- and post-retirement were calculated. The role of effect modifiers (work stress, type A or hostile personality) was tested by multiplicative interactions and synergy indices. An 11-13% reduction in headache prevalence was found during pre- and post-retirement, whereas decline was much steeper (46%) during the retirement transition. In absolute terms, the decline was greater among persons with high work stress or stress-prone personality than among other participants. Retirement is associated with a decrease in headache prevalence, particularly among persons with a high amount of work stress or proneness to over-react to stress.

High alcohol consumption in middle-aged adults is associated with poorer cognitive performance only in the low socio-economic group. Results from the GAZEL cohort study

To examine the association of alcohol consumption over 10 years with cognitive performance in different socio-economic groups. Prospective cohort study, the French GAZEL study. France. Employees of France's national electricity and gas company. Alcohol intake was assessed annually, beginning in 1992, using questions on frequency and quantity of alcoholic beverages consumed in a week; used to define mean consumption and trajectory of alcohol intake over 10 years. Cognitive performance among participants aged ≥ 55 years (n = 4073) was assessed in 2002-04 using the Digit Symbol Substitution Test (DSST), a measure of psychomotor speed, attention and reasoning. Occupational position at age 35 and education were used as the markers of socio-economic position. All analyses were stratified by socio-economic position. In the low occupational group, participants consuming a mean of more than 21 drinks per week had 2.1 points lower (95% CI: -3.9, -0.3) DSST score compared to those consuming four to 14 drinks per week. In participants with primary school education, the corresponding difference was 3.6 points (95% CI: -7.1, -0.0). No association between alcohol consumption and cognitive performance was observed in the intermediate and high socio-economic groups, defined using either occupation or education. Analysis of trajectories of alcohol consumption showed that in the low socio-economic groups large increase or decrease in alcohol consumption was associated with lower cognitive scores compared to stable consumption. Our results suggest that high alcohol consumption is associated with poorer cognitive performance only in the low socio-economic group, due possibly to greater cognitive reserve in the higher socio-economic groups.

Tall tales from the hydrological crypt: are models monsters?

“Bizarre,” “monstrous”: in society as well as in science, this is the way we are used to describing objects that deviate from an expected standard. Hydrology is no exception. The bizarre or the monstrous describes every object that has a low probability of occurring, or that our models fail to represent. Actually, the bizarre or the monstrous is often a demonstration of the limits of our models rather than an intrinsic characteristic of the objects we study. This article provides a reflection on the definition of bizarre and monstrous in the context of hydrology. We base our reflection on 60 years of experience in hydrometeorological operational management and applied research at the French national electricity company (EDF-DTG). First, we describe several classical a priori models or conceptions trusted by hydrologists, sometimes erroneously. These include classical rainfall or streamflow measurement issues, certain limits of the watershed concept or problems in the spatialization of local measurements. Then we attempt to show how the misuse of statistical models can generate bizarre or monstrous results. We give examples related to outliers and to the homogeneity and stationarity hypotheses. We show how difficult it may be for operational forecasters to anticipate and believe that extreme (monstrous) events will occur in the near future. Finally, we wish to show that the bizarre or the monstrous should not be rejected in hydrology, but instead is something to study in greater depth. We believe that this type of analysis offers new opportunities to improve the explanatory and predictive capacity of our models. Citation Mathevet, T. & Garçon, R. (2010) Tall tales from the hydrological crypt: are models monsters? Hydrol. Sci. J. 55(6), 857–871.

Occupational Exposure to Solvents and Cognitive Performance in the GAZEL Cohort: Preliminary Results

Background: The impact of occupational exposure to solvents on cognitive ageing remains unclear. We examined whether long-term occupational exposure is associated with poor cognitive performance in late midlife. Methods: Participants in the GAZEL cohort, set up in 1989, are employees of the French national electricity and gas company. Data on the working environment were used to create measures of cumulative exposures to solvents using a job-exposure matrix. In 2002–2004, cognitive performance was assessed using the Digit Symbol Substitution Test (DSST) and the Mini Mental State Examination in 5,242 participants (aged 55–65 years). Results: In cross-sectional analysis using multiple logistic regression, there was a greater risk of poor cognitive performance (DSST score <25th percentile) among those with high exposure to benzene (OR = 1.58; 95% CI 1.31–1.90) and the grouped categories of chlorinated (OR = 1.39; 95% CI 1.3–2.3), aromatic (OR = 1.76; 95% CI 1.08–2.87), and petroleum solvents (OR = 1.50; 95% CI 1.23–1.81). Conclusions: These results suggest that occupational exposures to solvents may be associated later in life with cognitive impairment, even after taking into account the effects of education, employment grade, and numerous health factors.

Failure to reduce drinking and driving in France: a 6‐year prospective study in the GAZEL cohort

An unprecedented decline in alcohol consumption and road mortality has been observed recently in France, but it is still unclear whether or not these changes affected driving while alcohol-intoxicated (DWI). The objective of the study was to estimate prospectively trends of excessive speed on the roads, alcohol consumption and DWI between 2001 and 2007 in a large cohort of experienced drivers. Participants were current employees or recent retirees of the French national electricity and gas company, who volunteered to participate in a research cohort established in 1989 under strict conditions of anonymity. An annual cohort questionnaire is sent to participants that includes two questions about overall alcohol consumption. In 2001 and 2007, 10,684 participants reported their driving behaviours using the same self-administered questionnaire. Between 2001 and 2007, the proportion of participants (n = 10,684) who reported having driven at speeds at least 20 km/hour above the limit decreased from 23.7% to 4.1% in built-up areas (P < 0.001), from 34.3% to 9.3% on rural roads (P < 0.001) and from 24.3% to 2.7% on highways (P < 0.001). Regular and non-regular excessive alcohol consumption decreased from 22.7% to 19.7% and from 18.0% to 14.9%, respectively, whereas DWI increased from 22.9% to 25.3% over the same period (P < 0.001). A recent crackdown on road violations by the French government has failed to deter DWI. Given that DWI seems to be a sporadic and rarely punished behaviour, its prevention requires more coercive measures, such as using a breath alcohol ignition interlock device.

Self-rated health before and after retirement in France (GAZEL): a cohort study

Governments need to increase the proportion of the population in work in most developed countries because of ageing populations. We investigated longitudinally how self-perceived health is affected by work and retirement in older workers. We examined trajectories of self-rated health in 14 714 employees (11 581 [79%] men) from the French national gas and electricity company, the GAZEL cohort, for up to 7 years before and 7 years after retirement, with yearly measurements from 1989 to 2007. We analysed data by use of repeated-measures logistic regression with generalised estimating equations. Overall, suboptimum health increased with age. However, between the year before retirement and the year after, the estimated prevalence of suboptimum health fell from 19.2% (95% CI 18.5-19.9) to 14.3% (13.7-14.9), corresponding to a gain in health of 8-10 years. We noted this retirement-related improvement in men (odds ratio 0.68, 95% CI 0.64-0.73) and women (0.74, 0.67-0.83), and across occupational grades (low 0.72, 0.63-0.82; high 0.70, 0.63-0.77), and it was maintained throughout the 7 years after retirement. A poor work environment and health complaints before retirement were associated with a steeper yearly increase in the prevalence of suboptimum health while still in work, and a greater retirement-related improvement; however, people with a combination of high occupational grade, low demands, and high satisfaction at work showed no such retirement-related improvement. These findings suggest that the burden of ill-health, in terms of perceived health problems, is substantially relieved by retirement for all groups of workers apart from those with ideal working conditions, and that working life for older workers needs to be redesigned to achieve higher labour-market participation. Swedish Council for Working Life and Social Research, Academy of Finland, INSERM (France), BUPA Foundation (UK), European Science Foundation, and Economic and Social Research Council (UK).

Using sickness absence records to predict future depression in a working population: prospective findings from the GAZEL cohort.

We tested the hypothesis that sickness absence from work predicts workers' risk of later depression. Study participants (n = 7391) belonged to the French GAZEL cohort of employees of the national gas and electricity company. Sickness absence data (1996-1999) were obtained from company records. Participants' depression in 1996 and 1999 was assessed with the Center for Epidemiologic Studies-Depression (CES-D) scale. The analyses were controlled for baseline age, gender, marital status, occupational grade, tobacco smoking status, alcohol consumption, subthreshold depressive symptoms, and work stress. Among workers who were free of depression in 1996, 13% had depression in 1999. Compared with workers with no sickness absence during the study period, those with sickness absence were more likely to be depressed at follow-up (for 1 period of sickness absence, fully adjusted odds ratio [OR] = 1.53, 95% confidence interval [CI] = 1.28, 1.82; for 2 or more periods, fully adjusted OR = 1.95, 95% CI = 1.61, 2.36). Future depression was predicted both by psychiatric and nonpsychiatric sickness absence (fully adjusted OR = 3.79 [95% CI = 2.81, 5.10] and 1.41 [95% CI = 1.21, 1.65], respectively). Sickness absence records may help identify workers vulnerable to future depression.