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Month: September 2012
Mardi 18 septembre 2012
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Impact of chlordecone exposure on the development of infants
Impact of chlordecone exposure on the development of infants
In an article published in the journal Environmental Research, researchers from Inserm (Inserm Unit 1085 – IRSET Institute for Research in Environmental and Occupational Health, in Rennes and Pointe à Pitre) in liaison with Canadian, Belgian and American researchers have investigated whether exposure to chlordecone (a pesticide used until 1993 on banana plantations in the Antilles) had an impact on the cognitive, visual and motor skills development of very young children. 1042 women were monitored during and after pregnancy and 153 infants were monitored at the age of 7 months. The results of this study show that pre- or post-natal exposure to chlordecone is associated with adverse effects on the cognitive and motor skills development of infants. They are not confirmed for older children, for whom the study is continuing.
Chlordecone is a pesticide used in theAntillesfor more than 20 years to combat banana weevil. However, its widespread use (prohibited in theAntillesfrom 1993) and persistence in the environment have caused permanent soil pollution and contamination of the population. Chlordecone is now considered to be an endocrine disruptor and a neurotoxin, and is classified by the WHO as potentially carcinogenic to humans.
To evaluate the impact on health of exposure to chlordecone, the team led by Sylvaine Cordier in Rennes and Luc Multigner in Pointe à Pitre set up a large mother and child cohort in Guadeloupe, known as TIMOUN[1] (meaning ‘child’ in Creole). The general aim of the study is to evaluate the health impact of chlordecone exposure on pregnancy and on pre- and post-natal development. The cohort consisted of 1042 women, who were monitored with their children from their pregnancy during the period 2005-2007. Researchers were particularly interested in the impact of pre-natal and post-natal exposure to chlordecone on the cognitive, visual and motor skills development of infants at the age of 7 months.
153 infants, both boys and girls, were monitored at the age of 7 months.
Pre-natal exposure to chlordecone was estimated from the levels in the umbilical cord blood. Post-natal exposure was estimated from levels in the mother’s breast milk and from the frequency of consumption by the infants of foodstuffs likely to be contaminated with chlordecone. Visual memory, visual acuity and the motor skills development of the infants was then tested.
Pre-natal exposure to chlordecone was found to be associated significantly with a reduction in the score for visual preference for novelty[2] and a low score on the fine motor skills development scale[3].
Post-natal exposure to chlordecone, estimated from the consumption of contaminated foodstuffs, was found to be associated, at the limit of statistical significance, with a reduction in the speed of acquiring visual memory and a reduction in visual preference for novelty. However, post-natal exposure to chlordecone through breastfeeding does not appear to be associated with any change in psychomotor development.
In conclusion, pre-natal exposure to chlordecone or post-natal exposure via food consumption is associated at the age of 7 months with adverse effects on cognitive and motor skills development in infants.
Although these observations based on small cohorts do not identify serious problems, they can nevertheless be compared with certain problems described in the past in adults exposed to chlordecone at work, characterised by short-term memory problems and the presence of intention tremor.
The researchers wonder whether these associations observed in infants at 7 months of age could be predictors of permanent problems when they are older. According to Sylvaine Cordier and Luc Multigner, “only by monitoring the children in future years will we be able to answer these questions”. The children in the TIMOUN cohort are now being monitored at the age of 7 years.
[1] The TIMOUN study is a biomedical research project run jointly by Inserm Unit 1085 (formerly U625) and the Departments of Obstetrics and Gynaecology (Dr Philippe Kadhel) and Paediatrics (Dr Henri Bataille) at theUniversityHospital in Pointe à Pitre.
[2] This test consists of determining a young child’s tendency to look at a new object for longer than it looks at an object that has been seen before and is familiar (preference for novelty).
[3] At 7 months, the fine motor skills are acquired for grasping objects between the fingers and the palm of the hand (corresponding to the ability to use small muscles to perform precise movements in order to reach for, grip and manipulate small objects). This is assessed for example by seeing whether the child can pick up a cube.
Lundi 17 septembre 2012
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Vendredi 14 septembre 2012
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Job strain and coronary heart disease linked
The most recent studies on the connection between ischemic cardiovascular disease and job strain have been affected by many types of bias, such as the methodology used, the definition of stress and the number of cases studied. This has led to different risk values. To find out more, French researchers at Inserm and Université Versailles Saint Quentin joined a large European consortium called IPD-WORK Consortium, which brings together thirteen cohorts in Europe. Following a far-reaching analysis of nearly 200,000 people in Europe, researchers have now confirmed that job strain and cardiovascular accidents are related. Studies show that the risk of heart attack is 23% higher in persons exposed to stress than in those who are not. Stress prevention could reduce this risk.
Result published in The Lancet on Friday September 14, 2012
In recent years, studies have investigated the role played by various psychological factors (including personality, cognition and stress) in cardiovascular diseases. The main focus has been on psychological stress, especially job strain, which combines high demand in the workplace with low control. It emerged from earlier studies that job strain could multiply the risk of coronary events by two. Other research suggests a much slighter risk. The European IPD-WORK Consortium (Individual-Participant-Data Meta-analysis in Working Populations) was set up in 2008 to investigate this topic further.
Study of 13 cohorts totalling nearly 200,000 participants
The consortium brings together thirteen European cohorts, including the French GAZEL cohort, which is made up of 20,000 EDF-GDF employees who have been monitored since 1989. Inserm researchers Marcel Goldberg, Archana Singh Manoux and Marie Zins, from Inserm unit 1018 “Research Centre for Epidemiology and Public Health” and Université Versailles Saint Quentin, have contributed to the most extensive analysis ever carried out on the relation between job strain and the onset of coronary events.
The specific feature of this analysis is that it incorporates the personal data of 193,473 participants in the European cohorts, thus allowing research teams to pinpoint the relation between job strain and risks over a large number of cases.
Seven national cohorts set up between 1985 and 2006 were studied. The countries concerned were Belgium, Denmark, Finland, France, Netherlands, Switzerland and the United Kingdom.
The study population had an average age of 42.3 years, with as many women as men. Questionnaires focusing on work-related psychosocial aspects were used to assess job strain. Among the points considered were job demand, the excessive workloads of some individuals, the conflicting demands made of them and the limited amount of time in which they were expected to complete their tasks.
The proportion of individuals exposed to job strain ranged from 12.5% to 22.3% according to previous studies. It represented 15.3% of this large study population.
At the same time, researchers identified 2,358 coronary events among the 200,000 individuals over an average monitoring period of seven years.
The importance of stress prevention
After analysing the data,
“the results obtained from the 13 European cohorts show that the risk of heart attack is 23% higher in persons exposed to stress at work than in those who are not”
explains Marcel Goldberg, a professor at Université de Versailles Saint Quentin and researcher at Inserm.The results are practically the same after allowing for the participants’ lifestyles, age, gender, socioeconomic status and geographical distribution.
Taking the population as a whole (stressed and unstressed), the researchers consider that job strain can lead to a slight, but not negligible, increase in the risk of heart attack: “In our study, 3.4% of the heart attacks reported among the 200,000 individuals can be explained by job strain. Of the 100,000 to 120,000 heart attacks occurring in France every year, that would represent roughly 3,400 to 4,000 accidents attributable to this risk factor,” Marcel Goldberg explains.
The European research team suggests reducing this risk by stepping up measures to prevent work-related stress. Preventive measures in this area could also positively affect other risk factors, such as tobacco and alcohol consumption, which recent studies have shown to be partly stress-related.
Jeudi 13 septembre 2012
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Mercredi 12 septembre 2012
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Contraception in France: new context, new practices?
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Mardi 11 septembre 2012
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