Wastewater exposure and health--a comparative study of two occupational groups.

AIMS: To investigate whether wastewater workers are at increased risk of developing cancer. METHODS: Two cohorts of workers employed by the City of Copenhagen, 591 wastewater workers and 1545 water supply workers (controls), were followed from 1965 until 1998. These two cohorts were compared in terms of cause specific mortality and cancer incidence. RESULTS: The wastewater workers' mortality exceeded that of the controls (relative risk (RR) = 1.25, 95% CI: 1.03 to 1.51). A similar small excess was seen for cancer incidence (RR = 1.27, 95% CI: 0.97 to 1.67). Though rare, there was a strongly increased incidence of primary liver cancer among the wastewater workers (RR = 8.9, 95% CI: 1.5 to 51.5). CONCLUSION: The excess mortality seen among the wastewater workers was smaller than originally feared. It may partly have been due to their occupational exposure, and for preventive purposes, exposure to wastewater and sludge should be minimised. The possibility that sewage exposure confers an increased risk of primary liver cancer deserves further investigation.

[To die alone, a big city problem?]. / At dø alene, et storbyproblem?

The question whether being found dead is a problem related to living in a big city was examined by using death certificates from a 3-month period in 1994. The rates of persons found dead were higher for both sexes in the City of Copenhagen than in the rural County of Storstrøm. The age distribution showed that the rate increased with advancing age. The vast majority were found dead in their own home, although the rate was higher in Copenhagen than in Storstrøm. Whereas the manner of death was natural for the majority of cases in both areas, more deaths with an uncertain manner of death were recorded in Copenhagen than in Storstrøm (32% vs 9%). In general, suicide or accident was more often reported in those found dead in the County of Storstrøm than in those in Copenhagen. The cause of death was unknown in 46% of deaths in Copenhagen where 16% had died from external causes, proportions that were 58% and 21%, respectively, in Storstrøm. The rate of legal autopsies was higher in subjects with an uncertain manner of death than in the rest, and was also associated with an age below 40 years. We conclude that being found dead is related to living in a big city, although the reason(s) for this remains unidentified.

Risk of Hodgkin's disease and other cancers after infectious mononucleosis.

BACKGROUND: Infectious mononucleosis, which is caused by the Epstein-Barr virus, has been associated with an increased risk for Hodgkin's disease. Little is known, however, about how infectious mononucleosis affects long-term risk of Hodgkin's disease, how this risk varies with age at infectious mononucleosis diagnosis, or how the risk for Hodgkin's disease varies in different age groups. In addition, the general cancer profile among patients who have had infectious mononucleosis has been sparsely studied. METHODS: Population-based cohorts of infectious mononucleosis patients in Denmark and Sweden were followed for cancer occurrence. The ratio of observed-to-expected numbers of cancers (standardized incidence ratio [SIR]) served as a measure of the relative risk for cancer. SIRs of Hodgkin's disease in different subsets of patients were compared with the use of Poisson regression analysis. All statistical tests including the trend tests were two-sided. RESULTS: A total of 1381 cancers were observed during 689 619 person-years of follow-up among 38 562 infectious mononucleosis patients (SIR = 1. 03; 95% confidence interval [CI] = 0.98-1.09). Apart from Hodgkin's disease (SIR = 2.55; 95% CI = 1.87-3.40; n = 46), only skin cancers (SIR = 1.27; 95% CI = 1.13-1.43; n = 291) occurred in statistically significant excess. In contrast, the SIR for lung cancer was reduced (SIR = 0.71; 95% CI = 0.58-0.86; n = 102). The SIR for Hodgkin's disease remained elevated for up to two decades after the occurrence of infectious mononucleosis but decreased with time since diagnosis of infectious mononucleosis (P: for trend <.001). The SIR for Hodgkin's disease tended to increase with age at diagnosis of infectious mononucleosis (P: for trend =.05). Following infectious mononucleosis, the SIR for Hodgkin's disease at ages 15-34 years was 3.49 (95% CI = 2.46-4.81; n = 37), which was statistically significantly higher than the SIR for any other age group (P: for difference =.001). CONCLUSION: The increased risk of Hodgkin's disease after the occurrence of infectious mononucleosis appears to be a specific phenomenon.

[Occurrence of hepatitis B and C among mentally retarded]. / Forekomst af hepatitis B og C blandt mentalt retarderede.

The objective of this study was to examine whether the prevalence of hepatitis C, like hepatitis B, is increased among the mentally retarded in Denmark. The prevalence of serological markers of hepatitis B and C was examined in an institution for the mentally retarded. A total of 126 out of 178 inhabitants (71%) with a median age of 49 years (range 23-78) participated. All subjects were anti-HCV-negative by third generation ELISA antibody test. A total of 45 (35.7%) subjects were anti-HBc-positive and 10 (7.9%) were HBsAg-positive. Among subjects with Down's syndrome (n = 20), 55% were anti-HBc-positive and 30% were HBsAg-positive as compared to 32% and 3.8% respectively among others. In conclusion, hepatitis C infection seems to be uncommon among mentally retarded persons in Denmark and the risk of acquiring infection not significantly increased as compared to that of the general population. The prevalence of serological markers for hepatitis B was high and comparable to previous studies in this population.

Risk of low birthweight in social districts of Copenhagen.

The purpose of this survey was to investigate the small-area variations in low birthweight within social services districts in Copenhagen and the relation of such variations to the socioeconomic characteristics of the district. The study was based on register data and included all live-born single on births to women living in the city of Copenhagen from 1987-90. We found a statistically significant association between district and risk of newborns being small-for-gestational age (SGA). This association was independent of adjustment for maternal age and parity. Only part of the association was explained, though this was still significant, using an index summarizing the socioeconomic living conditions in the district. Splitting up the index into its four constituent components, however, showed that the association between SGA and district was primarily due to housing conditions in the districts. Mapping the districts demonstrated a clear tendency of clustering of the high-risk areas with poor socioeconomic conditions.

Preventing sudden infant deaths--the slow diffusion of an idea.

The sudden infant death syndrome (SIDS) is among the leading causes of post-neonatal mortality in industrialised countries. Research has highlighted that many of these deaths are avoidable by adopting a few simple precautions. These include sleeping in the supine position, avoiding exposure to tobacco smoke, breast feeding where possible, and avoiding over heating. The paper traces the development of understanding of the role of sleeping position in the aetiology of SIDS and the diffusion of this knowledge among and within industrialised countries. In retrospect, evidence began to become available in the early 1980s but it was several years before it was acted upon, initially in The Netherlands and subsequently in New Zealand, the United Kingdom and Scandinavia. Several countries have mounted major national preventive campaigns, of various kinds, each of which has been associated with a reduction in deaths from SIDS, but others have not. The reasons for these differences are explored. The evidence for a causal link between sleeping position and SIDS is now very strong and the costs of implementing a policy to change behaviour is small, compared with other health care interventions. This information is now widely available in the international literature. The example of SIDS provides information on the barriers to adoption of knowledge as well as the factors that promote it.

[Vibrio vulnificus infections in Denmark during the summer of 1994]. / Vibrio vulnificus-infektioner i Danmark sommeren 1994.

The clinical manifestations and epidemiological data of 11 patients infected with Vibrio vulnificus found in Denmark during the unusually warm summer of 1994 are reported. All patients had been exposed to seawater prior to illness, but none had consumed seafood. Nine patients, including four with bacteraemia, developed skin manifestations of various degrees of severity. One patient died of septic shock despite surgery and treatment with relevant antibiotics. Four patients contracted the disease while fishing. High seawater temperature increases the risk of V. vulnificus infections even in temperate climates such as the Danish. Exposure to seawater, including handling of fresh seafood, during warm periods carries a risk of infection with V. vulnificus.

Iron status in Danish women aged 35-65 years. Relation to menstruation and method of contraception.

Iron status was assessed by serum (S-) ferritin and hemoglobin (Hb) in a population survey comprising 883 non-gravid Danish women in age cohorts of 35, 45, 55, and 65 years. Premenopausal women (n = 676) had lower S-ferritin, median 42 micrograms/l, than postmenopausal women (n = 207), median 80 micrograms/l (p < 0.0001). Of premenopausal women, 12.1% had S-ferritin < or = 20 micrograms/l (i.e. depleted iron stores), and 35.6% S-ferritin of 21-40 micrograms/l (i.e. small iron stores). Corresponding figures in postmenopausal women were 0.5% and 13.2%. Premenopausal blood donors (n = 88) had lower S-ferritin than non-donors (p < 0.001). In premenopausal women, S-ferritin levels were strongly dependent on the duration of menstrual bleeding (p < 0.0001), which in turn was related to the method of contraception. Women (n = 64) using hormonal contraceptives (the pill) had menstrual bleeding of shorter duration than those (n = 511) not using pills or intrauterine devices (IUD), who in turn had bleeding of shorter duration than those (n = 101) using IUD. Median S-ferritin in pill users was 62 micrograms/l, in those not using pills or IUD 42 micrograms/l, and in IUD users 36 micrograms/l. S-ferritin values < 40 micrograms/l (i.e. small and depleted iron stores) were seen in 25% of pill users, in 48% of those not using pills or IUD, and in 61% of IUD users.(ABSTRACT TRUNCATED AT 250 WORDS)

PIP: A sampling study was undertaken to evaluate the effect of menstruation and method of contraception on iron status, especially iron deficiency, in 883 randomly selected Danish women aged 35, 45, 55, and 65 years old. The women underwent clinical examination and related detailed medical histories, including blood donation activities within the past 5 years, method of contraception, duration of menstrual bleeding, and menopausal status. Fasting blood samples were frozen and analyzed by radioimmunoassay within 6 months. Iron depletion was defined as serum ferritin levels or=20mcg/l; iron stores were considered small or reduced at 21-40mcg/l and normal or replete at values 40mcg/l. When serum ferritin was depleted and hemoglobin was 121g/l, iron deficiency anemia was diagnosed. Median serum ferritin was 42mcg/l in premenopausal vs. 80mcg/l in postmenopausal (p0.0001). 88 premenopausal women were blood donors, and their serum ferritin (33mcg/l) was significantly lower than in nondonors (43mcg/l, p0.001). 12.1% of premenopausal women vs. 0.5% of postmenopausal women and 18.2% of premenopausal blood donors vs. 11.3% of nondonors had serum ferritin or=20mcg/l. Hemoglobin values were similar for donors and nondonors. Premenopausal women, however, had slightly, but significantly, lower hemoglobin levels than postmenopausal women. (p0.001), a difference which persisted even between women with identical ferritin levels. 30 (7.4%) premenopausal and 6 (4.8%) postmenopausal women had hemoglobin values 121g/l. Iron deficiency anemia was found in 12 (3%) premenopausal women who had a longer duration of menstrual bleeding than the nonanemic women. None of these deficient women currently used oral contraceptives or an IUD. 639 women provided information on duration of menstrual bleeding; oral contraceptive users had the shortest duration and IUD users the longest. In addition, ferritin levels were highest in present and former users of oral contraceptives, lower in those who currently used other methods, and lowest in current IUD users. Iron stores can be quickly exhausted in a large majority of premenopausal women, which means that guidelines for dietary iron intake and supplementation should take the special needs of members of a population into consideration.