Showing papers by "Vincent Cogliano published in 2007"

Carcinogenicity of shift-work, painting, and fire-fighting.

Abstract: In October, 2007, 24 scientists from ten countries met at the International Agency for Research on Cancer (IARC), Lyon, France, to assess the carcinogenicity of shift-work, painting, and fi re-fi ghting. These assessments will be published as volume 98 of the IARC Monographs. About 15–20% of the working population in Europe and the USA is engaged in shift-work that involves nightwork, which is most prevalent (above 30%) in the health-care, industrial manufactur ing, mining, transport, communication, leisure, and hospitality sectors. Among the many diff erent patterns of shiftwork, those including nightwork are the most disruptive for the circadian clock. Six of eight epidemiological studies from various geographical regions, most notably two independent cohort studies of nurses engaged in shiftwork at night, have noted a modestly increased risk of breast cancer in long-term employees compared with those who are not engaged in shiftwork at night. These studies are limited by potential confounding and inconsistent defi nitions of shiftwork, with several focused on a single profession. The incidence of breast cancer was also modestly increased in most cohorts of female fl ight attendants, who also experience circadian disruption by frequently crossing time zones. Limitations of studies in these fl ight attendants include the potential for detection bias, proxy measures of exposure, and potential uncontrolled confounding by reproductive factors and cosmic radiation. Several diff erent rodent models have been used to test the eff ect of disruption of the circadian system on tumour development. More than 20 studies investigated the eff ect of constant light, dim light at night, simulated chronic jet lag, or circadian timing of carcinogens, and most showed a major increase in tumour incidence. No clear eff ect was seen for light pulses at night or constant darkness. A similar number of studies investigated the eff ect of reduced nocturnal melatonin concentrations or removal of the pineal gland (where melatonin is produced) in tumour development and most showed increases in the incidence or growth of tumours. Exposure to light at night disturbs the circadian system with alterations of sleep-activity patterns, suppression of melatonin production, and de regul ation of circadian genes involved in cancer-related pathways. Inactivation of the circadian Period gene, Per2, promotes tumour develop ment in mice, and in human breast and endo metrial tumours, the expression of PERIOD genes is inhibited. In animals, melatonin suppression can lead to changes in the gonadotrophin axis. In humans, sleep deprivation and the ensuing melatonin suppression lead to immunodefi ciency. For example, sleep deprivation suppresses natural killer-cell activity and changes the T-helper 1/T-helper 2 cytokine balance, reducing cellular immune defence and surveillance. On the basis of “limited evidence in humans for the carcinogenicity of shift-work that involves nightwork”, and “suffi cient evidence in experimental animals for the carcinogenicity of light during the daily dark period (biological night)”, the Working Group concluded that “shift-work that involves circadian disruption is probably carcinogenic to humans” (Group 2A). Painters are potentially exposed to many chemicals used as pigments, extenders, binders, solvents, and additives. Painters can also be exposed to other workplace hazards, such as asbestos or crystalline silica. Cohort and linkage studies of painters have shown consistent and signifi cant increases in lung cancer compared with the general population. No information on tobacco smoking was available in the cohort studies; however, the increases are comparable to results from many case–control studies that controlled for smoking. A meta-analysis by the Working Group of all independent studies, including two recent large studies, showed a signifi cant excess risk of about 20% overall, and of 50% when the analysis was restricted to smoking-adjusted estimates from population-based case–control studies. Increased mortality from mesothelioma was consistently noted. Similarly, cohort and linkage studies showed consistent 20–25% increases in the occurrence of urinary bladder cancer in painters, and similar increases were noted in case– control studies that controlled for smoking. Although fi ndings for lymphatic and haemopoietic cancers in painters were inconsistent, four of fi ve case– control studies reported signifi cant increases in childhood leukaemia associated with maternal exposure to paint. The risks tended to be greater when mothers were exposed before or during, rather than after, pregnancy, and two studies showed some evidence of an increasing risk with increasing exposure. Upcoming meetings February 5–12, 2008 Industrial and cosmetic dyes and related exposures

Carcinogenicity of alcoholic beverages

Abstract: In February, 2007, 26 scientists from 15 countries met at the International Agency for Research on Cancer (IARC) in Lyon, France, to reassess the carcino-genicity of alcoholic beverages and of ethyl carbamate (urethane), a frequent contaminant of fermented foods and beverages. These assessments will be published as volume 96 of the IARC Monographs.

IARC monographs programme on the evaluation of carcinogenic risks to humans

Abstract: ln 1969, the International Agency for Research on Cancer (IARC) initiated a programme to evaluate the carcinogenic risk of chemicals to humans and to produce monographs on individua1 chemica1s. The MOl1ographs programme has since been expanded to include consideration of exposures to comp1ex mixtures of chemica1s (which occur, for example, in sorne occupations and as a result of human habits) and of exposures to other agents, such as radiation and viruses. With Supplement 6 (lARC, 1987a), the tit1e of the series was modified from IARC MO/1ographs 0/1 the Evaluation of the Carcinogel1ic Risk al Chemicals to Huma/1s to IARC Monographs 011 the Evaluatiol1

Combined estrogen-progestogen contraceptives

Abstract: Combined hormonal contraceptives consist of an estrogen and a progestogen, and act primarily by preventing ovulation through the inhibition of the follicle-stimulating hormone and luteinizing hormone. The progestogen component also renders the cervical mucus relatively impenetrable to sperm, and reduces the receptivity of the endometrium to implantation (IARC, 2007). A variety of innovations have been developed since combined hormonal contraceptives were first available in the late 1950s, including changes in drug components, doses used, and the temporal sequencing of exposure to drugs. The dominant trends have been towards less androgenic progestogens, lower doses of estrogen and progestogen, the near abandonment of hormonal contraceptives with an estrogen-only phase, a proliferation of different product formulations, and continuing development of novel delivery systems (IARC, 2007). 1.1 Identification of the agents

The IARC Monographs: a resource for precaution and prevention.

Abstract: Commentary on the editorial by Martuzzi (see page 569) In an excellent discussion, Marco Martuzzi describes the precautionary principle as meaning that scientific uncertainty must not be used as a reason to delay taking action.1 Deeply rooted in the history of public and environmental health, the precautionary principle has been embraced by ministers of health and environment across Europe. Martuzzi asserts that precaution is especially needed in areas fraught with complexity and uncertainty, for threats that may be irreversible or felt across generations, or when technological or societal change outpaces the accumulation of data. Martuzzi is correct that the role of science is central to the application of the precautionary principle, but “caution” means something different in science. The hypothesis testing at the core of the scientific method tends to avoid false positives and tolerate false negatives. To illustrate, epidemiologists make a strong distinction between the terms “association” and “causal association”. The latter is used only when there are studies of high quality and a rigorous examination shows that other factors are unlikely to explain an association.2 There are also inherent limitations to what epidemiology is able …

Combined estrogen-progestogen menopausal therapy

Abstract: Estrogen–progestogen menopausal therapy involves the co-administration of an estrogen and a progestogen to perior menopausal women. While it is indicated most clearly for control of menopausal symptoms, the use of estrogens with or without progestogens has expanded to include the treatment or prevention of a range of chronic conditions that are associated with ageing. Such widespread, long-term use was often perceived as a ‘replacement’, in that it physiologically reconstituted vital functions that were lost with menopausal ovarian failure. This pattern was propitiated by the ‘medicalization’ of the menopause, which was perceived as pathological rather than as an expected and natural event in life. Evidence from the Women’s Health Initiative, which showed a clearly harmful effect of the use of estrogen–progestogen combinations, has modified this attitude; as a result, use of the term ‘replacement’ has diminished. Patterns of exposure are also changing rapidly as the use of hormonal therapy declines, the indications are restricted and the duration of the therapy is reduced. Combined estrogen–progestogen formulations are available for oral and transdermal administration, although separate administration of each component is still frequent. Progestogens are available orally, while estrogen may be administered orally, transdermally or transvaginally. The timing of exposure to these hormones may be continuous (both estrogen and progestogen at set daily doses), sequential (estrogen daily with progestogen for the last 10–14 days of the cycle) or cyclical (as with sequential, but including 7 days without hormonal exposure).