Extroversion and neuroticism and the associated risk of cancer: A Danish cohort study

The authors have investigated the effect of personality, as measured with the Eysenck Personality Inventory, on the incidence of cancer among 1,031 persons participating in a Danish health survey in 1976-1977 and followed up for 20 years. They thereby accrued a total of 19,993 person-years. The expected number of cancer cases was estimated on the basis of age-, sex-, and site-specific incidence rates in Copenhagen County, DENMARK: Overall, 113 malignancies were observed among the cohort members between the date of interview and December 31, 1996. Since 114.3 were expected from county incidence rates, the standardized incidence ratio was 0.99 (95% confidence interval: 0.81, 1.19). No statistically significant deviation of the relative risk from unity was seen for any measure of personality, and no excess risk was seen for any particular type of cancer. A regression model, in which adjustment was made for age, sex, calendar period, alcohol consumption, tobacco smoking, psychiatric illness as rated by the interviewing doctor, marital status, and social class, showed no excess risk of cancer among persons considered to be in medium- or high-risk groups according to the Eysenck Personality INVENTORY: The authors' data provide no support for the hypothesis of an association between personality and the risk of cancer.

Cellular telephones and cancer--a nationwide cohort study in Denmark

BACKGROUND

Use of cellular telephones is increasing exponentially and has become part of everyday life. Concerns about possible carcinogenic effects of radiofrequency signals have been raised, although they are based on limited scientific evidence.

METHODS

A retrospective cohort study of cancer incidence was conducted in Denmark of all users of cellular telephones during the period from 1982 through 1995. Subscriber lists from the two Danish operating companies identified 420 095 cellular telephone users. Cancer incidence was determined by linkage with the Danish Cancer Registry. All statistical tests are two-sided.

RESULTS

Overall, 3391 cancers were observed with 3825 expected, yielding a significantly decreased standardized incidence ratio (SIR) of 0.89 (95% confidence interval [CI] = 0.86 to 0.92). A substantial proportion of this decreased risk was attributed to deficits of lung cancer and other smoking-related cancers. No excesses were observed for cancers of the brain or nervous system (SIR = 0.95; 95% CI = 0.81 to 1.12) or of the salivary gland (SIR = 0.72; 95% CI = 0.29 to 1.49) or for leukemia (SIR = 0.97; 95% CI = 0.78-1.21), cancers of a priori interest. Risk for these cancers also did not vary by duration of cellular telephone use, time since first subscription, age at first subscription, or type of cellular telephone (analogue or digital). Analysis of brain and nervous system tumors showed no statistically significant SIRs for any subtype or anatomic location.

CONCLUSIONS

The results of this investigation, the first nationwide cancer incidence study of cellular phone users, do not support the hypothesis of an association between use of these telephones and tumors of the brain or salivary gland, leukemia, or other cancers.

Anorexia nervosa and cancer risk

OBJECTIVE

Energy restriction reduces the incidence of malignant tumors in experimental animals, but evidence for a similar effect in humans is lacking. To test the hypothesis in humans, we investigated cancer incidence among patients with anorexia nervosa, who have had an extremely low intake of calories for prolonged periods of their lives.

METHODS

Patients with anorexia nervosa (2151 women and 186 men) during 1970-1993 were identified in the population-based Danish Psychiatric Case Register and the National Registry of Patients. The cohort was linked to the Danish Cancer Registry, and cancer incidence among cohort members was compared with that of the general population.

RESULTS

The overall cancer incidence among women with anorexia nervosa was reduced by a factor of 0.80 (95% confidence interval 0.52-1.18) below that of the general population on the basis of 25 observed and 31.4 expected cases. Among men, two cases of cancer were observed, both confined to the brain, whereas 0.2 cases were expected.

CONCLUSIONS

The finding of a slight reduction in cancer risk among women with anorexia nervosa may support the theory that a low-energy diet may decrease tumor development in humans. However, longer follow-up and control for confounding factors are needed to obtain more convincing evidence.

Incidence of vestibular schwannoma in Denmark, 1977-1995

OBJECTIVE

To establish the incidence rate of vestibular schwannomas (VS) (acoustic neuromas) in Denmark.

BACKGROUND

The worldwide incidence rates of VS vary from 1 to 20 cases per million population per year.

METHODS

The nationwide and population-based age-specific, sex-specific, and calendar year-specific incidence rates of VS in Denmark between 1977 and 1995 are presented. Information on cases of VS was obtained from the Danish Cancer Registry and a clinical database situated at the University Hospital of Gentofte. A total of 795 cases were reported during the period of the study.

RESULTS

The incidence rate increased from 5 cases per million population per year in 1977-1981 to 10 cases in 1992-1995; the increase was from 5 to 11 cases among women and 5 to 9 cases among men. The age-specific incidence rates show that VS is rarely diagnosed in persons under 30, but the incidence rate appears to increase among women after menopause.

CONCLUSION

The overall incidence rate of VS increased linearly during the study period, probably owing to the introduction of more precise diagnostic procedures, increased awareness among physicians and patients of the symptoms of VS, improved registration of benign tumors in Denmark, and the use of data from two sources.

Exposure to electromagnetic fields and risk of central nervous system disease in utility workers

Occupational exposure to electromagnetic fields has been associated with neurological diseases such as amyotrophic lateral sclerosis, senile dementia, Parkinson disease, and Alzheimer disease. I studied the incidence of central nervous system diseases in 30,631 persons employed in Danish utility companies between 1900 and 1993. I linked the cohort to the nationwide, population-based Danish National Register of Patients and compared the numbers of cases of these diseases observed between 1978 and 1993 with the corresponding rates in the general population. In addition I fit to the data on utility workers a multiplicative Poisson regression model in relation to estimated levels of exposure to 50-Hz electromagnetic fields. Overall, there was an increase in risk for senile dementia and motor neuron diseases combined. The incidences of Parkinson disease, Alzheimer disease, and other diseases of the central nervous system were essentially unrelated to exposure to electromagnetic fields. A decreased risk of epilepsy compared with the general population probably reflects a healthy worker effect; I observed an increased risk of epilepsy based on internal comparisons. The increased risk for senile dementia and motorneuron diseases may be associated with above-average levels of exposure to electromagnetic fields.

Anal carcinoma in inflammatory bowel disease

We followed 9602 patients with Crohn's disease or ulcerative colitis for anal squamous cell carcinoma for up to 18 years. No significant increase was observed: two cases occurred vs 1.3 expected during 99,229 person-years of observation, (standardized incidence ratio = 1.6; 95 confidence interval: 0.2-5.7). Anal squamous cell carcinoma is rare even in inflammatory bowel disease.

1alpha,25-dihydroxyvitamin D3 induced differentiation of cultured human keratinocytes is accompanied by a PKC-independent regulation of AP-1 DNA binding activity

1alpha,25(OH)2D3 and its analogs are potent mediators of keratinocyte differentiation in vitro. The precise mechanism of this action is still unknown. The nuclear transcription factor activator protein 1 seems to play an important role in keratinocyte differentiation. The purpose of this study was to investigate the effect of 1alpha,25(OH)2D3 on activator protein 1 DNA binding activity in cultured human keratinocytes. In a time-course study of human keratinocytes incubated with 1alpha,25(OH)2D3 (10-7-10-11 M) a significant dose-dependent increase in activator protein 1 DNA binding activity as determined by electrophoretic mobility shift assay was seen after 36 h. This increase was followed by a significant dose-dependent decrease in activator protein 1 DNA binding activity after 72 h. When differentiation was induced by raising the calcium concentration in the culture medium from 0.09 to 0.3 mM a similar increase in activator protein 1 DNA binding activity was observed after incubation for 48 h. Pharmacologic down-modulation of the protein kinase C activity with GF 109203X reversed the calcium-induced increase in activator protein 1 DNA binding activity and abolished keratinocyte differentiation as determined by a transglutaminase assay. In contrast, activator protein 1 DNA binding activity and keratinocyte differentiation were not affected when protein kinase C activity was down-modulated in the experiments with 1alpha,25(OH)2D3. The activator protein 1 complex in human keratinocytes consists of dimers of Fra-1, Fra-2, c-Jun, JunD, and c-Fos. Our results demonstrate that 1alpha, 25(OH)2D3- and calcium-induced keratinocyte differentiation are accompanied by changes in activator protein 1 DNA binding activity. Protein kinase C activation appears to be essential for the calcium-dependent induction of keratinocyte differentiation, whereas a protein-kinase-C-independent activation of activator protein 1 DNA binding and keratinocyte differentiation is responsible for the 1alpha,25(OH)2D3-induced effects.

A cross-sectional study of dietary habits and urinary glucose excretion - a predictor of non-insulin-dependent diabetes mellitus

OBJECTIVE

To investigate the association between consumption of certain foods and macronutrients and urinary glucose excretion, which is a predictor of non-insulin-dependent diabetes mellitus.

DESIGN

A cross-sectional study, Denmark, 1993-97.

SUBJECTS

Participants in the Danish study 'Diet, Cancer and Health'. After exclusion of persons with postprandial urine samples and persons with diabetes or other diseases potentially resulting in glycosuria, the study population included 14 743 men and 18 064 women aged 50-64 y. We identified 183 men and 43 women with glucose in their urine.

RESULTS

Consumption of poultry was negatively associated with glycosuria in both men (odds ratio, OR=0.87; 95% confidence interval, 95% CI=0.77-0.98) and women (OR=0.69; 0.48-1.00). Fiber from fruit showed a weak negative association with glycosuria in both men (0. 95; 0.90-1.01) and women (0.89; 0.78-1.02), whereas a significant negative association with total fiber (0.68; 0.51-0.91) and fiber from vegetables (0.94; 0.88-0.99) was seen in men. Intake of fish tended to reduce the risk of glycosuria in women only (0.80; 0.63-1. 02), whereas ingestion of milk products increased their risk significantly (1.15; 1.06-1.24).

CONCLUSION

Although statistical significance and consistency in the two sexes were not achieved for all end-points, the study indicates a protective effect of dietary products like poultry, fruit and cereals against glycosuria and suggests a promoting effect of milk.

SPONSORSHIP

The Danish National Board of Health and the Danish Cancer Society.

Crohn's disease and cancer risk (Denmark)

OBJECTIVES

The large number of studies of intestinal cancer among patients with Crohn's disease have provided inconsistent risk estimates in regard to risk of both colorectal and small intestinal cancer. We investigated incidence of cancer among Crohn's disease patients in comparison with the incidence in the general population of Denmark.

METHODS

From the Danish National Registry of Patients we identified 2645 patients who had been hospitalized with Crohn's disease during 1977-1989. Cancer incidence for up to 17 years was determined in the cohort and compared to an expected number derived from national cancer incidence rates.

RESULTS

The 15 observed cases of colorectal cancer were close to the expected number of 13.1 (SIR = 1.1; 95% CI 0.6-1.9), whereas the five cases of small intestinal cancer (three adenocarcinomas and two carcinoids) observed corresponded to an 18-fold increased risk (SIR = 17.9; 95% CI 5.8-42).

CONCLUSIONS

A potential excess of colorectal cancer among subgroups of patients with Crohn's disease was not detectable in the overall risk estimate for colorectal cancer. Only for small intestinal cancer was a significantly elevated risk found among these patients hospitalized with Crohn's disease.

Antidepressant medications and risk for cancer

Antidepressants appear to promote tumor growth in experimental studies; however, results from epidemiologic studies are inconclusive. We used a population-based cohort study to estimate the incidence of cancer after antidepressant treatment in 39,807 adult users of antidepressants identified in the Prescription Database of the County of North Jutland, Denmark between January 1, 1989 and December 31, 1995. Information on cancer occurrence was obtained from the Danish Cancer Registry. We categorized exposure according to use of tricyclic antidepressants, tetracyclic antidepressants, selective serotonin reuptake inhibitors, or monoamine oxidase inhibitors. In the follow-up period beginning 1 year after first known prescription, there were 966 cancers among users of antidepressants; our population estimate suggested an expected number of 946 for an overall standardized incidence ratio of 1.0 (95% confidence interval = 1.0-1.1). Users of tricyclic antidepressants had an excess of non-Hodgkin's lymphoma, with the risk increasing with the number of prescriptions of tricyclic antidepressants. The standardized incidence ratio was 2.5 (95% confidence interval, 1.4-4.2) for those with five or more prescriptions. Our results provide little evidence that antidepressants promote cancer at other sites, except for a possible effect of tricyclic antidepressants and tetracyclic antidepressants on non-Hodgkin's lymphoma.

Crohn's disease and cancer risk (Denmark)

OBJECTIVES

The large number of studies of intestinal cancer among patients with Crohn's disease have provided inconsistent risk estimates in regard to risk of both colorectal and small intestinal cancer. We investigated incidence of cancer among Crohn's disease patients in comparison with the incidence in the general population of Denmark.

METHODS

From the Danish National Registry of Patients we identified 2645 patients who had been hospitalized with Crohn's disease during 1977-1989. Cancer incidence for up to 17 years was determined in the cohort and compared to an expected number derived from national cancer incidence rates.

RESULTS

The 15 observed cases of colorectal cancer were close to the expected number of 13.1 (SIR = 1.1; 95% CI 0.6-1.9), whereas the five cases of small intestinal cancer (three adenocarcinomas and two carcinoids) observed corresponded to an 18-fold increased risk (SIR = 17.9; 95% CI 5.8-42).

CONCLUSIONS

A potential excess of colorectal cancer among subgroups of patients with Crohn's disease was not detectable in the overall risk estimate for colorectal cancer. Only for small intestinal cancer was a significantly elevated risk found among these patients hospitalized with Crohn's disease.

Phylogeography of three closely related African bovids (tribe Alcelaphini)

The phylogeography of three species of African bovids, the hartebeest (Alcelaphus buselaphus), the topi (Damaliscus lunatus), and the wildebeest (Connochaetes taurinus), is inferred from sequence variation of 345 sequences at the control region (d-loop) of the mtDNA. The three species are closely related (tribe Alcelaphini) and share similar habitat requirements. Moreover, their former distribution extended over Africa, as a probable result of the expansion of open grassland on the continent during the last 2.5 Myr. A combination of population genetics (diversity and structure) and intraspecific phylogeny (tree topology and relative branch length) methods is used to substantiate scenarios of the species history. Population dynamics are inferred from the distribution of sequence pairwise differences within populations. In the three species, there is a significant structuring of the populations, as shown by analysis of molecular variance (AMOVA) pairwise and hierarchical differentiation estimations. In the wildebeest, a pattern of colonization from southern Africa toward east Africa is consistent with the asymmetric topology of the gene tree, showing a paraphyletic position of southern lineages, as well as their relatively longer branch lengths, and is supported by a progressive decline in population nucleotide diversity toward east Africa. The phylogenetic pattern found in the topi and the hartebeest differs from that of the wildebeest: lineages split into monophyletic clades, and no geographical trend is detected in population diversity. We suggest a scenario where these antelopes, previously with wide pan-African distributions, became extinct except in a few refugia. The hartebeest, and probably also the topi, survived in refugia north of the equator, in the east and the west, respectively, as well as one in the south. The southern refugium furthermore seems to have been the only place where the wildebeest has survived.

Molar pregnancy and risk for cancer in women and their male partners

OBJECTIVE

It was our aim to evaluate the hypothesis that molar pregnancy is a marker of increased risk for cancer.

STUDY DESIGN

This was a nationwide cohort study of 1520 women, identified from the Danish National Register of Patients, in whom a molar pregnancy was diagnosed during the period 1977-1992 and of 1295 male partners of these women, traced in the Danish Central Population Register.

RESULTS

Linkage of the female roster with the Danish Cancer Registry through 1994 revealed 19 cases of gestational choriocarcinoma, whereas 0.04 was expected from the rates for the general population. Twenty cases of cancers of other types were observed with 24.9 expected (standardized incidence ratio, 0.8; 95% confidence interval, 0.5-1.2), but no specific type of cancer other than gestational choriocarcinoma occurred at a rate significantly different from that expected. Among the 1295 male partners notified in the Central Population Register, a total of 22 cancers were observed with 21.9 expected (standardized incidence ratio, 1.0; 95% confidence interval, 0.7-1.5).

CONCLUSION

Molar pregnancy is not associated with an increased risk for cancer other than gestational carcinoma.

Antibodies to Japanese encephalitis virus in human sera collected from Irian Jaya. Follow-up of a previously reported case of Japanese encephalitis in that region

Japanese encephalitis virus (JEV) and other arboviruses are demonstrating an emergence in the southern part of New Guinea Island. JE was previously unknown in this part of the world until 1995 when it was found in the Torres Strait, northern Australia. In this study 96 sera collected from residents of the Timika region of Irian Jaya were tested for antibodies to JEV and related arboviruses by epitope-specific blocking ELISA. Of the 9 sera deemed to be positive for JEV antibodies by ELISA, 5 were collected from persons indigenous to Timika, and who had not travelled to regions where JE is known to be active. This indicates that these individuals were infected with JEV in the Timika area and supports a recent report of a clinical case of JE in this region. Non-immune expatriates visiting or working in the Lowland areas of Irian Jaya and/or Papua New Guinea should consider immunization against JE. Precautions should always be taken to avoid being bitten by any mosquito both in the daytime and at night.

Occurrence of Shewanella algae in Danish coastal water and effects of water temperature and culture conditions on its survival

The marine bacterium Shewanella algae, which was identified as the cause of human cases of bacteremia and ear infections in Denmark in the summers of 1994 and 1995, was detected in seawater only during the months (July, August, September, and October) when the water temperature was above 13 degrees C. The bacterium is a typical mesophilic organism, and model experiments were conducted to elucidate the fate of the organism under cold and nutrient-limited conditions. The culturable count of S. algae decreased rapidly from 10(7) CFU/ml to 10(1) CFU/ml in approximately 1 month when cells grown at 20 to 37 degrees C were exposed to cold (2 degrees C) seawater. In contrast, the culturable count of cells exposed to warmer seawater (10 to 25 degrees C) remained constant. Allowing the bacterium a transition period in seawater at 20 degrees C before exposure to the 2 degrees C seawater resulted in 100% survival over a period of 1 to 2 months. The cold protection offered by this transition (starvation) probably explains the ability of the organism to persist in Danish seawater despite very low (0 to 1 degrees C) winter water temperatures. The culturable counts of samples kept at 2 degrees C increased to 10(5) to 10(7) CFU/ml at room temperature. Most probable number analysis showed this result to be due to regrowth rather than resuscitation. It was hypothesized that S. algae would survive cold exposure better if in the biofilm state; however, culturable counts from S. algae biofilms decreased as rapidly as did counts of planktonic cells.

Multiple sclerosis among utility workers

The incidence of MS was assessed in a nationwide cohort study of 31,990 employees of Danish utility companies between 1900 and 1993. Overall, 32 cases of MS were diagnosed, as compared with 23.7 expected from national incidence rates, to yield a standardized incidence ratio of 1.35 (95% confidence interval, 0.92 to 1.91). We found no support for the hypothesis of an association between occupational exposure to electromagnetic fields and the risk of MS.

[Risk of cancer among Danish electricity workers. A cohort study]

We report the incidence of cancer in a large cohort of employees identified from all 99 Danish utility companies. Personal data, and information on employment and exposure to magnetic fields and asbestos were obtained from manual files at the companies, the Danish Supplementary Pension Fund and the public payroll administration. A total of 32,006 individuals with more than three months of employment were linked with the files of the Danish Cancer Registry. Overall, 3008 cancers were observed, with 2825 expected, yielding a small but significantly increased risk of 1.06 (95% CI, 1.03-1.10). No excess was observed for all leukemias or for cancers of the brain or breast among men or women. There was no association of electromagnetic field exposure with risk of these cancers even when the level and length of exposure to magnetic fields were taken into account. Increased risks for cancers of the lung and pleural cavity were seen mainly for workers whose jobs involve exposure to asbestos. Our results do not support the hypothesis of an association between occupational exposures to magnetic fields in the electric utility industry and the risk for cancer.

Lipid-lowering medication and risk of cancer

Low or declining levels of serum cholesterol have been associated with increased mortality from cancer. We conducted a population-based cohort study of 1882 patients from one Danish county who received lipid-lowering drugs between January 1, 1991 and December 31, 1994. During the follow-up period of up to 4 years, 41 cancers were observed among users of lipid-lowering drugs, with 42.9 expected, to yield an age- and sex-standardized incidence ratio of 1.0 (95% confidence interval, 0.7-1.3). Although limited by small numbers and short follow-up period, examination by site of cancer and type of drug provided no evidence of an association. Further research is needed, however, with longer follow-up to assess more fully any potential cancer risk with these medications.

Gallstones, cholecystectomy and risk of cancers of the liver, biliary tract and pancreas

To examine the association between gallstones and cholecystectomy, we conducted a nationwide population-based cohort study in Denmark. Patients with a discharge diagnosis of gallstones from 1977 to 1989 were identified from the Danish National Registry of Patients and followed up for cancer occurrence until death or the end of 1993 by record linkage to the Danish Cancer Registry. Included in the cohort were 60 176 patients, with 471 450 person-years of follow-up. Cancer risks were estimated by standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) stratified by years of follow-up and by cholecystectomy status. Among patients without cholecystectomy, the risks at 5 or more years of follow-up were significantly elevated for cancers of liver (SIR = 2.0, CI = 1.2-3.1) and gallbladder (SIR = 2.7, CI = 1.5-4.4) and near unity for cancers of extrahepatic bile duct (SIR = 1.1), ampulla of Vater (SIR = 1.0) and pancreas (SIR = 1.1). The excess risk of liver cancer was seen only among patients with a history of hepatic disease. Among cholecystectomy patients, the risks at 5 or more years of follow-up declined for cancers of liver (SIR = 1.1) and extrahepatic bile duct (SIR = 0.7), but were elevated for cancers of ampulla of Vater (SIR = 2.0, CI = 1.0-3.7) and pancreas (SIR = 1.3, CI = 1.1-1.6). These findings confirm that gallstone disease increases the risk of gallbladder cancer, whereas cholecystectomy appears to increase the risk of cancers of ampulla of Vater and pancreas. Further research is needed to clarify the carcinogenic risks associated with gallstones and cholecystectomy and to define the mechanisms involved.

[Does psychosocial intervention in cancer patients affect survival and psychological well-being?]

We have critically reviewed the scientific literature examining the effect of psychosocial interventions on survival and well-being among adult cancer patients. Only studies using randomization and including a control-group not receiving psychosocial intervention were reviewed. Six studies examined the effect on prognosis. In four of these studies survival increased significantly in the intervention group as compared to the control group. All of these studies, however, have methodological flaws, leaving a possible prognostic effect to be clarified in larger, well-controlled future studies. The effect of psychosocial intervention on various psychosocial variables (such as anxiety and depression) was evaluated in 20 studies. Differences in patient populations, intervention strategies, and outcomes decrease the comparability of the results, and the majority of these studies suffer from methodological flaws as well. A positive effect on anxiety and depression immediately following the intervention is, however, reported in the majority of these studies. It is thus possible that the level of anxiety and depression may be decreased by integrating psychosocial intervention in the overall treatment of cancer.

Cancer risk in individuals with benign thyroid disorders

The risk of cancer was examined in a cohort of 57,326 individuals who were discharged from a Danish hospital with a diagnosis of myxedema, thyrotoxicosis, or goiter. Although the general risk of cancer was only slightly increased, the risk of several sites was significantly above expected. The risk of thyroid cancer especially, was increased with standardized incidence ratios among women of 2.1 (myxedema), 2.5 (thyrotoxicosis), and 6.6 (nontoxic goiter). The increase in risk was present even many years after discharge, indicating that surveillance was not the only explanation. Furthermore, an increased risk was noted for cancer of the kidney in women discharged with myxedema (standardized incidence ratios [SIR] = 1.8) and thyrotoxicosis (SIR = 1.3), for cancer of the bladder in women discharged with myxedema (SIR = 1.5) and nontoxic goiter (SIR = 1.3), and for cancer of the hematopoetic system in women discharged with myxedema (SIR = 1.4) and nontoxic goiter (SIR = 1.4). The findings indicate that thyroid disorders may be related to cancer risk of several specific sites other than the thyroid.

Mortality from amyotrophic lateral sclerosis, other chronic disorders, and electric shocks among utility workers

Above-average exposure to electromagnetic fields has been associated with certain nonmalignant medical conditions such as amyotrophic lateral sclerosis, other neurologic diseases, depressive symptoms, and suicide. The authors conducted a nationwide mortality study in Denmark of 21,236 men employed in utility companies between 1900 and 1993. The causes of death were ascertained for January 1, 1974, through December 31, 1993, and cause-specific mortality was analyzed by latency and estimated levels of exposure to 50-Hz electromagnetic fields. Overall, 3,540 deaths were observed as compared with 3,709 expected from national mortality rates, yielding a standardized mortality ratio of 0.96 (95% confidence interval 0.93-0.99). A slight excess in mortality from cancer was due to deaths from cancers of the lung and pleural cavity, probably because of exposure to asbestos. A twofold increase in mortality from amyotrophic lateral sclerosis and a tenfold increase in mortality from electrical accidents were seen on the basis of 14 and 10 deaths, respectively, the former increasing with time since first employment in a utility company. The excess mortality from amyotrophic lateral sclerosis seems to be associated with above-average levels of exposure to electromagnetic fields and may be due to repeated episodes with electric shocks.

Sexological problems after cystectomy: bladder substitution compared with ileal conduit diversion. A questionnaire study of male patients

A questionnaire study was carried out to compare the postoperative sexological problems after cystectomy and bladder substitution using the urethral Kock reservoir or the ileocecal reservoir with that following ileal conduit diversion. A total of 76 male patients with bladder cancer completed the questionnaire: 49 patients had a bladder substitution and 27 an ileal conduit diversion. Median follow-up was 1.3 years (range 0.5-6.4) and 4.8 years (range 2.4-14.7), respectively. Only 9% of all patients could achieve an erection at least every second time, in comparison to 82% preoperatively. Thirty-eight percent of all patients were able to achieve orgasm, and 26% were coitally active to some degree. Reasons for decrease or cessation of coitus were loss of potency among 77% and 96% respectively (p = 0.04), while those reporting decreased libido (29%), partner refusal (13%), and feeling less sexually attractive (20%) showed no between-group differences. Regression analysis showed no influence of type of operation, while age above 68 years influenced orgasmic ability and coital activity, and radiation treatment influenced whether the patient felt less sexually attractive than before surgery.

[Psychological stress, occurrence of cancer and cause-specific mortality]

Psychological stress has been claimed to contribute to the onset of cancer and to increase mortality from a number of nonmalignant diseases. We investigated the effect of a genuine psychological stressor, i.e. cancer in a child, on the incidence of cancer and mortality from nonmalignant diseases of 11,231 parents in a Danish nationwide population-based study. The children were identified from records in the Danish Cancer Registry for the period 1943-1985; their parents were identified from population registers. Overall, 1665 parental malignancies were diagnosed from the date the cancer of the child was reported through 1992, as compared with 1702 expected from national incidence rates, to yield standardized incidence ratios of 1.0 (95% confidence interval, 0.9-1.0) for all parents, 1.0 for mothers and 1.0 for fathers. No excess mortality was seen from causes associated with allergic illness, autoimmune conditions, chronic illness or changes in behaviour. Our data provide no support for the hypothesis of an association between psychological stress and the incidence of cancer or mortality from nonmalignant diseases. We conclude that the human organism is highly adaptable, even to extreme psychological stress.

Risk of cancer among Danish utility workers--a nationwide cohort study

The authors report the incidence of cancer in a large cohort of employees identified from all 99 Danish utility companies. Personal data and information on employment and exposure to magnetic fields and asbestos were obtained from manual files at the companies, the Danish Supplementary Pension Fund, and the public payroll administration. A total of 32,006 individuals with more than 3 months of employment were linked with the files of the Danish Cancer Registry. The period of follow-up for cancer occurrence among the employees was from April 1968 through December 1993 in the study conducted from 1994 to 1997. Overall, 3,008 cancers were observed, with 2,825 expected, yielding a small but significantly increased risk of 1.06 (95% confidence interval 1.03-1.10) among the utility workers in comparison with the general population. No excess was observed for all leukemias or for cancers of the brain or breast among men or women. There was no association of electromagnetic field exposure with risk of these cancers, even when the level and length of exposure to magnetic fields were taken into account. Increased risks for cancers of the lung and pleural cavity were seen mainly for workers whose jobs involved exposure to asbestos. The results from this study do not support the hypothesis of an association between occupational exposures to magnetic fields in the electric utility industry and the risk for cancer.

Cancer risk following appendectomy for acute appendicitis (Denmark)

OBJECTIVE

Epidemiologic studies have not been able definitely to exclude that appendectomy carries a cancer risk. This study was conducted to clarify whether appendectomy is associated with a subsequent increase in cancer risk, since appendectomy is frequently an elective procedure.

METHODS

The present study included more than 82,000 persons who underwent appendectomy for acute appendicitis during 1977-89 according to the nation-wide Danish Hospital Discharge Register. During a follow-up interval of up to 17 years, cancer incidence was assessed by linkage to the Danish Cancer Registry and compared with the incidence in the general population of Denmark.

RESULTS

The total number of malignancies among appendectomized persons was 1.05 times higher than expected with 95 percent confidence intervals of 0.99-1.11. There was no clear significant excess of any specific cancer type.

CONCLUSION

During a postsurgery period of nearly two decades, results of our study did not support the hypothesis that either appendectomy or acute appendicitis are likely to be associated with malignant neoplasms.

[Risk of colorectal cancer and other cancer diseases in patients with gallstones]

In a nationwide cohort of gallstone patients we evaluated the hypothesis that gall stones are associated with an increased risk of cancer of the colon. In the Danish Hospital Discharge Register we identified 42,098 patients with gallstones diagnosed in 1977-1989. These patients were linked to the Danish Cancer Registry in order to assess their risks of colorectal and other cancers during follow-up to the end of 1992. The analysis showed a modest increase in the number of cancers at all sites combined (N = 3940; RR = 1.07; 95% CI = 1.0-1.1). A weak association was found for cancer of the colon (N = 360; RR = 1.09; 95% CI = 1.0-1.2), which remained unchanged when analysed by sex, anatomical subsite and duration of follow-up. Multivariate analysis with adjustment for cholecystectomy and clinically defined obesity did not change these estimates to any significant extent. A nonsignificantly increased risk of breast cancer was seen in women five years after initial discharge for gallstones.

[Marital status and survival in colorectal cancer]

We analysed marital status and survival from colorectal cancer among 9596 patients in a nationwide Danish study with complete follow-up of 22-26 years. After exclusion of 2294 patients with missing information, adjusted survival among married patients diagnosed with colon cancer was significantly longer (RR = 0.85; 95% CI: 0.78-0.93). We conclude that marital status does indeed prognosticate long-term survival from colon cancer. These results may have implications for psychosocial intervention after surgery for colorectal cancer.

[Incidence and mortality of breast cancer among women in Denmark 1943-1992]

Nationwide incidence and mortality rates are presented for female breast cancer in Denmark from 1943 to 1992. The annual incidence rate of breast cancer has increased among Danish women from 61 in 1943-1947 to 105 per 100,000 women in 1988-1992. Mortality rates have increased to a smaller extent, from 36 to 43 per 100,000 women. We found that only a small part of the observed increase in incidence of breast cancer can be explained by the known risk factors, based on calculation of population attributable-risk per cent.

Enzymatic removal and disinfection of bacterial biofilms

Model biofilms of Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas fluorescens, and Pseudomonas aeruginosa were made on steel and polypropylene substrata. Plaque-resembling biofilms of Streptococcus mutans, Actinomyces viscosus, and Fusobacterium nucleatum were made on saliva-coated hydroxyapatite. The activity of enzymes against bacterial cells in biofilm was measured by fluorescence microscopy and an indirect conductance test in which evolution of carbon dioxide was measured. Glucose oxidase combined with lactoperoxidase was bactericidal against biofilm bacteria but did not remove the biofilm from the substrata. A complex mixture of polysaccharide-hydrolyzing enzymes was able to remove bacterial biofilm from steel and polypropylene substrata but did not have a significant bactericidal activity. Combining oxidoreductases with polysaccharide-hydrolyzing enzymes resulted in bactericidal activity as well as removal of the biofilm.

Effect of Soil Temperature on Vegetative and Reproductive Growth and Development in Three Spanish Genotypes of Peanut (Arachis hypogaea L.)

Extremes of soil temperature limit yield development of peanut. To obtain information relevant to improving yield by agronomic management and breeding, the influence of the soil temperature regimes (day/night) of 20/14 (T1), 26/20 (T2), 32/26 (T3), and 38/32 C (T4) imposed from the time of peg penetration into the soil until maturity on growth and development of three spanish genotypes of peanut (Arachis hypogaea L.) was investigated in a greenhouse. Soil temperature treatments were imposed by placing pots with individual plants in large temperature-controlled water baths. With increasing soil temperature from T1 to T3, leaves, stems and lateral roots became thinner. The leaf area increased from T1 to T3. The lateral root length increased up to maturity more at higher than at lower temperatures. The number of mature pods per plant, mature single seed mass, and therefore mature total seed mass per plant were highest at the intermediate temperature regimes, less at the warmest, and lowest at the coldest treatment. In early reproductive stages, pod inititation rate increased with decreasing soil temperature. Total pod growth and development of mature pods was lowest in T1, although pod initiation was high. Suboptimal soil temperatures slowed pod filling and maturation. At T4, one reason for the lower mature pod number compared to the intermediate temperature treatments seems to be the low pod initiation rate at early reproductive stages. These responses to temperature suggest agronomic management and genetic options for increasing yield at nonoptimal soil temperatures, such as irrigation during pod initiation stage when soil temperatures are high.

Comparison of a self-administered questionnaire and a telephone interview of 146 Danish waste collectors

Methods to collect epidemiologic data include, among other means, self-administered questionnaires and personal and telephone interviews. In some studies, these data collection methods are used simultaneously. However, little is known about the comparability of the data obtained, thus, the validity of pooling data. A self-administered questionnaire was completed by 146 waste collectors, who participated in a telephone interview 3 months later. The responses to health questions were compared. Agreement percentages and kappa values were calculated. An answer pattern shift was detected in a subgroup of questions with five answer options. Grouping the answer options diminished the shift in the answer pattern. The questions in a yes/no format generally showed no shift in the answer pattern. The study indicates that caution should be exercised when pooling data collected by self-administered questionnaire and telephone interview in epidemiological research. Some types of questions seem to be sensitive to the data collection method.

A questionnaire study of sexological problems following urinary diversion in the female patient

A questionnaire study was conducted to evaluate the sexological problems after urinary diversion, using the continent Kock reservoir or the ileal conduit diversion. Thirty-seven female patients completed the questionnaire: 17 patients had a continent and 20 an ileal conduit diversion, with a median follow-up of 0.8 year (range 0.5-4.4) and 4.6 years (range 2.8-12.0), respectively. Data from only 33 patients were eligible for analysis, but no significant between-group differences were found. Coital frequency remained unchanged or increased among 44% of patients with a continent reservoir and among 18% of ileal conduit patients (p = 0.11). Among those reporting other than unchanged/increased activity almost one-third gave physical problems or decreased desire as the reason, and 30% felt less sexually attractive, with cystectomized patients reporting a higher percentage than others. A higher frequency of dyspareunia among patients with a continent reservoir was an unexpected finding (p = 0.06), and merits further investigation in a larger sample. Here it may be due to the shorter follow-up of these patients. Thirty per cent of all patients would have like more sexological counselling.

Protamine-induced permeabilization of cell envelopes of gram-positive and gram-negative bacteria

The inhibitory effect of the cationic peptide protamine on Listeria monocytogenes, Escherichia coli, and Shewanella putrefaciens has been studied in detail. The addition of protamine (10 to 1,000 micrograms/ml) resulted in inhibition of oxygen consumption after less than 1 min and loss of intracellular carboxyfluorescein and ATP after 2 to 5 min. Maximum antibacterial activity was reached at alkaline pH and in the absence of divalent cations. The efficient permeabilization of cell envelopes of both gram-positive and gram-negative bacteria suggests that protamine causes a general disruption of the cell envelope, leading to a rapid and nonspecific efflux of low- and high-molecular-weight compounds.

Psychological stress, cancer incidence and mortality from non-malignant diseases

Psychological stress has been claimed to contribute to the onset of cancer and to increase mortality from a number of non-malignant diseases. We investigated the effect of a genuine psychological stressor, i.e. cancer in a child, on the incidence of cancer and mortality from non-malignant diseases of 11,231 parents in a Danish nationwide population-based study. The children were identified from records in the Danish Cancer Registry for the period 1943-85; their parents were identified from population registers. Overall, 1665 parental malignancies were diagnosed from the date the cancer of the child was reported until 1992, compared with 1702 expected from national incidence rates, yielding standardized incidence ratios of 1.0 (95% confidence interval, 0.9-1.0) for all parents, 1.0 for mothers and 1.0 for fathers. No statistically significant deviation of the relative risk from unity was seen for any period of follow-up after the stressful event, and no excess risk was seen for any particular type of cancer. Moreover, a total of 2137 parental deaths were observed over the period 1974-92, compared with 2333 expected from national mortality rates, giving an overall standardized mortality ratio of 0.9 (range 0.9-1.0). No excess mortality was seen from causes associated with allergic illness, autoimmune conditions, chronic illness or changes in behaviour. Our data provide no support for the hypothesis of an association between psychological stress and the incidence of cancer or mortality from non-malignant diseases. We conclude that the human organism is highly adaptable, even to extreme psychological stress.

Risk of colorectal cancer and other cancers in patients with gall stones

BACKGROUND

The occurrence of gall stones has repeatedly been associated with an increased risk for cancer of the colon, but risk associated with cholecystectomy remains unclear.

AIMS

To evaluate the hypothesis in a nationwide cohort of more than 40,000 gall stone patients with complete follow up including information of cholecystectomy and obesity.

PATIENTS

In the population based study described here, 42,098 patients with gall stones in 1977-1989 were identified in the Danish Hospital Discharge Register.

METHODS

These patients were linked to the Danish Cancer Registry to assess their risks for colorectal and other cancers during follow up to the end of 1992.

RESULTS

The analysis showed a modest increase in the number of cancers at all sites combined (n = 3940; RR, 1.07; 95% confidence intervals (CI), 1.0 to 1.1). A weak association was found for cancer of the colon (n = 360; RR, 1.09; 95% CI 1.0 to 1.2), which remained unchanged when analysed by sex, anatomical subsite, and duration of follow up. Multivariate analysis with adjustment for cholecystectomy and clinically defined obesity did not change these estimates to any significant extent. Excess risks were found for cancers of the pancreas and the small intestine. A non-significant increased risk for breast cancer was seen in women five years after initial discharge for gall stones.

CONCLUSION

A borderline significant association was seen between gall stones and cancer of the colon, and for cancer of pancreas and small intestine as well as for breast cancer in women.

Influence of marital status on survival from colon and rectal cancer in Denmark

Survival from colorectal cancer has been analysed in relation to marital status in a nationwide Danish study of 9596 patients with complete follow-up of 22-26 years. After exclusion of 2294 patients with missing information adjusted five-year survival among married patients was significantly longer (RR=0.85; 95% CI 0.78-0.93).

Changes in cell morphology of Listeria monocytogenes and Shewanella putrefaciens resulting from the action of protamine

Protamine, which is an antibacterial basic peptide, was shown to alter the cell morphology of Listeria monocytogenes and Shewanella putrefaciens. Atomic force microscopy revealed that protamine smoothed the surface of cells, formed holes in the cell envelope, and caused fusion of S. putrefaciens cells. Immunoelectron microscopy of protamine-treated cells of both L. monocytogenes and S. putrefaciens showed great damage to the cell wall and condensation of the cytoplasm. Respiration of the cells was decreased due to treatment with sublethal concentrations of protamine, probably due to leakage or loss of cell envelope potential. It was concluded that protamine disrupted the outer surface structure and condensed the cytoplasm of sensitive cells and, in sublethal concentrations, altered membrane structures, thereby eliminating respiration.

A Technique for Imposing Separate Temperature Regimes on Pods and Roots of Peanut (Arachis hypogaea L.)1

Recent studies have shown marked effects of soil temperature on growth, development, and seed composition of peanut. Knowledge about how soil temperature affects pods and roots separately could provide useful information for field management and genetic manipulation. To facilitate such investigations, a technique was developed which allows imposition of different temperature regimes to the pods and the roots separately. Pods and roots were grown in different compartments that have soil temperature controlled by separate water baths. Day/night temperature regimes of 28/22 and 40/34 C with a 12-hr ‘day’ and 12-hr ‘night’ period were imposed to the pod and root compartments separately in all four possible combinations of these temperature regimes. The temperature change between the ‘day’ and ‘night’ period occured mainly within the first 2 brand the transition to tbe final temperature required up to 5 hr. After adjustment to the ‘day’ or ‘night’ temperatures, the temperatures ranged in the 40/34 C treatment between the programmed temperature and 0.6 C less (root compartments) or 0.8 C less (pod compartments); and the maximal fluctuation in the 28/22 C treatment is ± 0.3 C (root compartments) or ± 0.6 C (pod compartments).

Antibacterial effect of protamine assayed by impedimetry

Impedimetric measurements were used to assay the antibacterial effect of protamine. A good linear correlation between the impedance detection time and the initial cell counts was obtained (r = 0.99, n = 2). As basic peptides may cause clumping of cells, this correlation curve was used when estimating the cell number after protamine treatment, rather than colony counts. Protamine from salmon killed growing Gram-positive bacteria and significantly inhibited growth of Gram-negative bacteria in Tryptone Soy Broth (TSB) at 25 degrees C. In general Gram-positive bacteria were more sensitive to protamine than Gram-negative bacteria; the minimum inhibitory concentrations (MIC) determined for Gram-positive strains varied from 20 to 1000 micrograms ml-1 and for Gram-negative strains from 500 micrograms ml-1 to more than 4000 micrograms ml-1. The effect of protamine on non-growing Listeria monocytogenes Scott A suspended in buffer was not lethal as was the effect on growing cells; however, protamine (50-500 micrograms ml-1) killed the Gram-negative fish spoilage bacteria Shewanella putrefaciens when the live cells were suspended in buffer.

Health-related quality of life after cystectomy: bladder substitution compared with ileal conduit diversion. A questionnaire survey

OBJECTIVE

To compare the health-related quality of life after bladder substitution with that following ileal conduit diversion.

PATIENTS AND METHODS

Sixty-seven male patients with bladder cancer completed the questionnaire; 38 had undergone bladder substitution and 29 ileal conduit diversion; the median follow-up was 1.0 year (range 0.5-3.0) and 4.8 years (range 1.1-15.2), respectively. Semi-structured qualitative interviews were conducted and analysed, and the questionnaire was developed based upon these results.

RESULTS

Both day- and night-time urinary leakage occurred more frequently following bladder substitution (18% against 10%, and 21% against 3%). Nevertheless, urinary leakage affected conduit patients more severely and they scored higher on a leakage distress scale. Furthermore, 58% of the ileal conduit but only 21% of the bladder substitution patients gave urinary leakage as their main concern (P = 0.04). Ileal conduit patients did not retain their body image as well as those with bladder substitution. The frequency of both sexual and non-sexual physical contacts decreased in the majority of the conduit patients but only in a minority of the bladder substitute patients. Global satisfaction was high and similar in both groups.

CONCLUSION

These results show that the health-related quality of life is retained to a higher degree after bladder substitution and supports the use of this procedure as the standard method of diversion after cystectomy for bladder cancer.

Cancer in patients with ulcerative colitis

A cohort of 5,546 ulcerative colitis patients was identified from the Danish Hospital Discharge Register for 1977-1989. Patients not included in the cohort comprised those with proctitis, those treated in outpatient clinics and those for whom follow-up was less than 1 year. The cohort was linked to the Danish Cancer Registry in order to assess the risks for colorectal and other cancers. The linkage revealed a significant increase in the number of colorectal cancers over that in the general population (RR = 1.8; n = 42; 95% CI = 1.3-2.4) with consistent relative risks during early and late follow-up. The relative risk was considerably higher among younger (20-39 years: RR = 22; n = 8; 95% CI = 9.7-44) than older patients (> or = 60 years: RR = 1.3; n = 25; 95% CI = 0.8-1.9), but the risk difference between patients and the general population was approximately constant across all ages. In addition, we observed a significant increase in the relative risk of hepatobiliary cancers (RR = 2.3; n = 9; 95% = 1.0-4.3) and a slight but significant increase in the relative risk of non-melanoma skin cancer (RR = 1.4; n = 37; 95% CI = 1.0-1.9). In summary, our population-based study confirms the increased risk of colorectal cancer among patients with ulcerative colitis and provides new leads suggesting that hepatobiliary cancer and non-melanoma skin cancer should be considered as possible sites for future patient monitoring.

[Colorectal cancer in Denmark 1943-1988]

Nation-wide incidence rates are presented of colorectal cancer in Denmark from 1943 to 1988. In Denmark notification of malignant and related diseases is mandatory. The percentage of histologically confirmed tumours is now 95. The annual incidence rate of colon cancer in Denmark has been increasing among men and women combined from 684 cases in 1943-1947 to 2020 cases in 1988. In the same period the incidence of rectal cancer has increased from 762 cases in 1943-1947 to 1108 cases in 1988. We analyzed the effects of age, calender time, and birth cohort with multiplicative Poisson models. We did not find consistent period effects in the models. We suggest an etiologic distinction between carcinoma of the rectum, the left colon and the right colon.

Age-period-cohort modelling of large-bowel-cancer incidence by anatomic sub-site and sex in Denmark

In a previous investigation, statistical modelling was used to examine the relationship between large-bowel-cancer incidence and age, time period and birth cohort by anatomic sub-site and sex, using data from the Connecticut Tumor Registry (CTR) for the period 1950 to 1984. This analysis revealed differences in age-period-cohort patterns that suggested etiologic distinctions among sub-site groupings and between the sexes. To test the generalizability of the Connecticut findings, we have conducted a similar age-period-cohort analysis using data from the Danish Cancer Registry (DCR) for the period 1953 to 1987. Cancers of the large bowel were classified into 6 anatomic sub-sites: cecum, ascending colon, transverse colon, descending colon, sigmoid colon and rectum. Data were fitted to log-linear age-period-cohort models. If we interpret differences in age-period-cohort patterns as reflecting etiologic distinctions, the Denmark analysis, in conjunction with the Connecticut findings, was consistent with there being etiologic distinctions between cancers of the colon vs. the rectum in both males and females, between cancers of the cecum and the ascending colon vs. the remainder of the colon in females and between males vs. females for cancers of the sigmoid colon and rectum. Cancers of the cecum and the ascending colon were the most similar between males and females. Due to the ambiguities of age-period-cohort modelling, these should be considered only tentative conclusions that can be tested by analytical epidemiologic studies.

Colorectal cancer in Denmark 1943-1988

Nation-wide incidence rates are presented of colorectal cancer in Denmark from 1943 to 1988. In Denmark notification of malignant and related diseases is mandatory. The percentage of histologically confirmed tumours is now 95. The annual incidence rate of colon cancer in Denmark has been increasing among men and women combined from 684 cases in 1943-47 to 2020 cases in 1988. In the same period the incidence of rectal cancer has been increasing from 762 cases in 1943-47 to 1108 cases in 1988. We analyzed the effects of age, calendar time, and birth cohort with multiplicative Poisson models. We did not find consistent period effects in the models. We suggest the trends in colorectal cancer incidence rates may be due to changes in environmental factors such as dietary habits and in physical activity. Furthermore, we suggest an etiologic distinction between carcinoma of the rectum, the left colon and the right colon.

Antibiotic prophylaxis in high risk biliary surgery: one dose of ceftriaxone compared with two doses of cefuroxime

In a controlled trial 219 high risk patients undergoing biliary surgery were allocated at random by sealed envelopes to one of two treatment groups. Group I (n = 112) received a single dose ceftriaxone 1 g intravenously at the time of skin incision, and group II (n = 107) was given cefuroxime 1.5 g intravenously at the time of skin incision, followed by a second dose eight hours later. There were no significant differences between groups in age, sex, diagnosis, or operations carried out. There were three wound infections in group I (3%) and four in group II (4%) (p = 0.65). One patient in group I and two patients in group II developed intra-abdominal abscess and septicaemia (0.9% and 1.9%, respectively). Five patients developed pneumonia postoperatively in group I (5%) and six in group II (6%) (p = 0.65). There was no significant difference of the total number of postoperative infectious complications (wound infection, intraabdominal abscess, septicaemia, and pneumonia) between the groups (p = 0.42). A single dose of ceftriaxone given intravenously at skin incision was as effective as two doses of cefuroxime for the prophylaxis of wound infection in this high risk group of patients.