Editorials |
Our work and its effects on our children
To what extent are occupational risk factors among adult workers also a risk for the children of workers? This issue of Occupational Medicine presents an interesting study of maternal occupation and adverse pregnancy outcomes, looking at low birth weight, small for gestational age and pre-term delivery [1]. The risk of low birth weight was high among newborns of women working in factories, mining, construction, farming and forestry. Several different occupational factors are mentioned as possible causes for these findings. In December 2006, Occupational Medicine carried an In Depth Review concerning occupational exposure and effects on the reproductive system. Adverse effects among the children of workers exposed to hazardous agents apart from the ones found during pregnancy and at birth were also briefly mentioned [2]. This is an area that has not been embraced by occupational physicians—or maybe by any physicians—yet but it might be of considerable importance for future generations. Recent research has started to focus on this issue, but to date the studies have been few in number. Health problems among children due to their parents' working life might be a serious problem for some populations. However, there was little clear reaction from the medical community after, for example, the finding of an increased odds ratio of 2.1 for developing cancer if your parents had exposure to hydrocarbons at work [3]. Dealing with this type of problem in clinical practice seems to give occupational physicians as well as other physicians a huge challenge. Are our workplace programmes good enough to prevent such problems? Can the affected children receive any kind of compensation? These are but two questions of several that might be asked and discussed by occupational physicians. This editorial attempts to shed more light on this topic to increase both the scientific discussion and the discussion about the practical consequences related to this area.Why has this issue not been investigated and debated to a larger extent before? The number of females in paid work has increased dramatically in the past 30–40 years and maybe fewer female workers historically were significant. On average, 42% of the estimated global paid working population today are women [4]. Women's presence in paid employment has given a focus on reproductive health among workers in the workplace. Initially, the focus was entirely on the possible effects on the foetus rather than on the reproductive health of the woman or the man [5]. However, attention shifted after a while to include concern for both the pregnant woman and the foetus and the wider aspects of occupational reproductive health. Reproductive problems such as miscarriages, premature births, low birth weight, still births and malformations of the newborn infant were found to be related to different occupational exposures like pesticides, organic solvents, heavy physical workload and shift work [4]. Breast milk can also be contaminated by chemical exposures, leading to problems with breast-feeding, and this also became a subject of discussion [6]. In addition, work exposures were found to influence hormonal levels and cause menstrual irregularities and infertility among female workers [5].
Because reproduction has been considered to be mainly the woman's domain, male reproductive health related to occupational exposure has been neglected over the years although interest in male occupational reproductive health has increased recently. We know today that many occupational factors may affect the male reproductive system. This has been documented for physical exposures like heat and radiation, for chemical exposures to organic solvents and pesticides, as well as to psychological distress [7]. Different types of studies of semen have been performed, and the infertility found in certain occupational reproductive studies might be caused by reduced sperm quality. There are different hypotheses and plausible biological mechanisms to explain these findings.
Over the years there has been increasing interest in the child of the exposed worker. This now extends not only to congenital malformations caused by occupational exposures but studies of other adverse health effects among the children as well. It is now clear that occupational exposure may interact with foetal development resulting in several other serious health effects [2]. For instance, the relationship between occupational exposures of parents and childhood cancer risks has been studied for several years [2]. Evidence has increased suggesting that several chemical agents and ionizing radiation may cause such effects [8]. There have also been studies of the adverse effects on the nervous system of the children of parents exposed to different agents, and in 1990 a review article stated [9] that several studies indicated that parental occupational exposure might be of importance in the development of defects in the central nervous system in offspring. This was especially related to exposure to metallic mercury and ionizing radiation, but also cadmium, organic solvents, anaesthetics and pesticides were mentioned as agents that might have similar effects. Later, several new studies were performed in this area. Maternal exposure to organic solvents during pregnancy has been suggested to be associated with poorer outcome in some cognitive and neuromotor functioning in offspring in several studies [10]. Prenatal exposure to metallic mercury has been found to be related to subtle effects on brain function of children in several studies [11].
These types of studies, involving more than one generation, are difficult and demand specific epidemiological skills and large resources. Due to this, several of the studies in this area have given inconsistent results possibly because the methods used have been very different [3]. For many agents and exposures such health effects on outcome are not yet clear. This might be one reason why the subject of children with health problems due to their parents' work has not attracted major interest among medical practitioners. Inconsistent scientific conclusions are likely to confuse and reduce interest in the subject for those practising day to day.
In preventive workplace policies, the workers themselves have of course been the focus. We have known that improving the work environment for the workers is likely to result in reduced possible adverse effects on the offspring as well. However, when our risk evaluation of workplaces has only included the effects on offspring to a minor extent, how can we know that the improvements made have been sufficient? As an example, many countries have occupational limit values for chemical compounds in working life but are they low enough to avoid all effects on offspring of workers and what do we actually know about these things?
Lead is a good example of how workplace exposure limits seem to be insufficient in dealing with such problems. When lead was found to have adverse effects on the reproductive health of women, several countries decided to operate with different occupational limit values for lead in blood for the two genders, with lower levels for females. This has created a problematic segregation of women out of certain types of work involving lead, and women have lost their jobs because the factories are not capable of reducing the exposure levels enough for them to work there. It has now been shown that lead affects the sperm quality at lower exposure levels than earlier known. However, this has not led to revision of the male limit values for most of the countries with the above-mentioned rules for lead exposure. We can learn from this that when adverse effects are found for an outcome for one gender, demands for research related to both genders must be put forward and the results must lead to practical action in working life. The reproductive health among men must not be forgotten. The preventive work and work-related health policies must include the family life of the worker, and both men and women should be guaranteed that there will be no harm to their reproductive health.
The question of compensation for children developing diseases as a result of the parent's work has not been discussed much and it can be argued that society should address the problem. There is no logic in having compensation paid for occupational illness in the worker and not their children, if the cause of the illness in the children is clear. However, establishing this might be a challenge because our diagnostic knowledge in this area is still not well developed. There is little clinical tradition in diagnosing occupational-related diseases in children. If this should be required, a sound and serious scientific discussion of criteria for such diagnoses is needed. On the other hand, we can only hope that this will not be needed, and that the problems mentioned will be minor in the future. Meanwhile, it is wise to continue to study the health of the offspring of workers to discuss the consequences of the results and to be alert regarding the potential impact of the workplace on the health of our future generations.
e-mail: bente.moen{at}isf.uib.no
References
- Ahmed P, Jaakkola JJK. Maternal occupation and adverse pregnancy outcomes: a Finnish population-based study. Occup Med (2007) 57:417–423.
[Abstract/Free Full Text] - Burdorf A, Figa-Talamanca I, Jensen TL, Thulstrup AM. Effects of occupational exposure on the reproductive system: core evidence and practical implications. Occup Med (2006) 56:516–520.
[Free Full Text] - Fabia J, Thuy TD. Occupation of father at time of birth of children dying of malignant disease. Br J Prev Soc Med (1974) 28:98–100.[Web of Science][Medline]
- WorldHealth Organization. Gender, Health and Work. Information Sheet. WHO, Geneva. http://www.who.int/gender/documents/en. (September 2004, date last accessed).
- Figa-Talamanca I. Occupational risk factors and reproductive health of women. Occup Med (2006) 56:521–531.
[Abstract/Free Full Text] - Golding J. Unnatural constituents of breast milk—medication, lifestyle, pollutants, viruses. Early Hum Dev (1997) 49((Suppl.)):S29–S43.[CrossRef][Web of Science][Medline]
- Jensen TK, Bonde JP, Joffe M. The influence of occupational exposure on male reproductive function. Occup Med (2006) 56:544–553.
[Abstract/Free Full Text] - Gold EB, Sever LE. Childhood cancers associated with parental occupational exposures. Reproductive Hazards. Occupational Medicine, State of the Art Reviews.—Gold EB, Lasley BL, Schenker M, eds. (1994) Vol. 9:495–539.
- Roeleveld N, Zielshuis GA, Gabreels F. Occupational exposure and defects of the central nervous system in offspring: review. Br J Ind Med (1990) 47:580–588.[Web of Science][Medline]
- Laski-Baker D, Barrera M, Knittel-Keren D, et al. Child neurodevelopment outcome and maternal occupational exposure to solvents. Arch Pediatr Adolesc Med (2004) 158:956–961.
[Abstract/Free Full Text] - Ramirez GB, Pagulayan O, Akagi H, et al. Study II: follow-up study at two years of age after prenatal exposure to mercury. Pediatrics (2003) 111:289–295.[CrossRef]
CiteULike 
Connotea 
Del.icio.us What's this?
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||