Epstein-Barr virus and cytomegalovirus in relation to testicular-cancer risk: a nested case-control study

An infectious etiology of testicular cancer has been suggested. We have evaluated seroreactivity against cytomegalovirus (CMV) and Epstein-Barr virus (EBV) in relation to testicular-cancer risk in a case-control study, nested within a cohort of prospectively collected serum specimens from 293,692 individuals. For each of 81 cases of testicular cancer identified, 3 controls were randomly selected from the cohort. Serum IgG antibody titers against CMV and EBV were determined using enzyme-linked immunosorbent assays (ELISAs) and immunofluorescence methods. Odds ratios (OR) were obtained from conditional logistic-regression models. No association was found between CMV positivity and testicular cancer overall (OR = 1.08; 95% confidence interval 0.60-1.94); risk for testicular seminoma was increased among CMV seropositive [OR = 1.70 (0.80-3.59)], whereas seropositivity was associated with decreased risk for testicular non-seminoma [OR = 0.54 (0.19-1.56)] (p for heterogeneity, 0.09). For EBV, the risk for testicular cancer was increased among individuals seropositive for viral capsid antigen (VCA) [OR = 2.74 (0.62-12.12)]. The results lend some support to the hypothesis of an infectious etiology, and we propose that future studies should take into account age at infection.

Epstein-Barr virus and cytomegalovirus in relation to testicular-cancer risk: a nested case-control study

An infectious etiology of testicular cancer has been suggested. We have evaluated seroreactivity against cytomegalovirus (CMV) and Epstein-Barr virus (EBV) in relation to testicular-cancer risk in a case-control study, nested within a cohort of prospectively collected serum specimens from 293,692 individuals. For each of 81 cases of testicular cancer identified, 3 controls were randomly selected from the cohort. Serum IgG antibody titers against CMV and EBV were determined using enzyme-linked immunosorbent assays (ELISAs) and immunofluorescence methods. Odds ratios (OR) were obtained from conditional logistic-regression models. No association was found between CMV positivity and testicular cancer overall (OR = 1.08; 95% confidence interval 0.60-1.94); risk for testicular seminoma was increased among CMV seropositive [OR = 1.70 (0.80-3.59)], whereas seropositivity was associated with decreased risk for testicular non-seminoma [OR = 0.54 (0.19-1.56)] (p for heterogeneity, 0.09). For EBV, the risk for testicular cancer was increased among individuals seropositive for viral capsid antigen (VCA) [OR = 2.74 (0.62-12.12)]. The results lend some support to the hypothesis of an infectious etiology, and we propose that future studies should take into account age at infection.

Height, weight and cancer of the oesophagus and stomach: a follow-up study in Norway

Epidemiological studies have suggested that socioeconomic conditions, including dietary factors, can affect the risk of several gastric cancers. Anthropometric indices, such as body weight and adult height, have been considered as measurements of prevailing diet and nutrition, respectively, in early life. The objective of this study was to evaluate the association between body mass and height and the risk of cancer of the oesophagus and stomach. The analysis was based on data from a national Norwegian screening programme for tuberculosis, which ran from 1963 to 1975, screening more than 1,100,000 individuals, aged 30-69 years at the time of examination. The participants were followed until December 1989. Body weight (expressed as Quetelet's index (QI) and height records were linked with vital status data from Statistics Norway and the Cancer Registry of Norway. Individuals in the first quintile of height appear to have an increased risk of oesophageal cancer in both sexes. Low QI was found to increase the risk for oesophageal squamous cell carcinoma, whereas high QI was linked to an elevated risk of oesophageal adenocarcinoma. The analysis reveals a relationship between low QI and the risk of stomach cancer. There were no associations between stomach cancer and height. These associations indicate that prevailing and early life conditions could play a role in later cancer development; they support the hypothesis that anthropometric indices are important as markers for the risk of oesophageal cancer and, to some extent, for cancer of the stomach.

Height, weight and gastrointestinal cancer: a follow-up study in Norway

It has been suggested that components of our diet play an essential role in carcinogenesis. Anthropometric indices, such as body weight and height, have often been considered as measurements of prevailing diet and nutrition in childhood respectively. To investigate to what extent height and body weight are associated with the risk of gastrointestinal cancer, data from a Norwegian screening programme for tuberculosis were analysed. More than 1,100,000 individuals, aged 30-69 years at the time of examination, were included in the study. Body weight, expressed as Quetelet's index (QI), and height records were linked with vital status data from Statistics Norway and the Cancer Registry of Norway. The analysis shows that individuals in the first quintile of height had a lower relative risk than later quintiles for colon cancer, independent of sex and stage of disease at completion of follow-up. The association between height and rectal cancer is similar, but weaker. Men in the fifth quintile of QI have a relative risk of 1.39 for colon cancer, compared with the first quintile, and they also have a slightly elevated risk for rectal cancer. Among women, the pattern is unclear, but we observed a significant relationship between high QI and cancer of the gallbladder. Our results indicate that prevailing diet and living conditions in early life do play a role, and seem to support the hypothesis that anthropometric indices could be of importance as indirect markers for the risk of colon cancer and, to some extent, for cancer of the rectum and gallbladder.

Maternal health and pre- and perinatal characteristics in the etiology of testicular cancer: a prospective population- and register-based study on Norwegian males born between 1967 and 1995

OBJECTIVES

The aim of the present prospective study was to identify possible risk factors of testicular cancer (TC) in relation to gestation and birth.

METHODS

Based on data from compulsory birth and cancer registration in Norway, odds ratios (ORs) of TC were estimated.

RESULTS

Among 868068 males born between 1967 and 1995, 268 cases of germ cancer had developed by June 1996, 32 TCs before 5 years of age and 236 TCs thereafter, 48 cases being seminomas and 220 non-seminomas. There was a tendency of an inverse association between parity and TC. A previous finding from Sweden linking neonatal jaundice to risk of non-seminomas was confirmed (adjusted OR = 2.1, 95 percent confidence interval [CI] = 1.3-6.9). Significant associations were also seen for seminomas and TC diagnosed after 5 years of age. Maternal disease diagnosed before pregnancy increased the risk of TC significantly, particularly in the age group 0-4 years: Adjusted OR = 3.0, CI = 1.4-6.3. Retained placenta was significantly associated with both seminomas and non-seminomas and with TC diagnosed after 5 years of age.

CONCLUSIONS

The findings of this study support the existing hypothesis that pre- and perinatal risk factors are of significance for development of TC in children and in young adults, and for seminomas and non-seminomas. The hypothesis that estrogens are involved in TC development was, among other factors, supported by the association of parity to TC. Additionally, on the basis of findings in maternal diseases and complications to pregnancy, we suggest that immune reactions during foetal life may be of significance for development of TC.

Is prostatic intraepithelial neoplasia in the transition/central zone a true precursor of cancer? A long-term retrospective study in Norway

Prostatic intraepithelial neoplasia (PIN) has been considered as a precursor of prostatic cancer. Few reports have dealt with the long-term follow-up of PIN lesions, and there is still a lack of proof that PIN is a true premalignant lesion. The objective of this study was to evaluate PIN in the transition/central zone as a marker for subsequent development of prostatic cancer. The PIN status of tissue specimens from 789 men without prostate cancer was determined in 508 transurethral resections and 281 transvesical prostatic enucleations. All slides were reviewed blind and independently by two pathologists. The patients were followed for an average of 11 years, and the incidence of subsequent cancer and cause-specific survival were analysed. Thirty-six cases of clinical prostatic cancer occurred among the cohort of 789 men through follow-up. No association between the presence of PIN in the transition/central zone and subsequent cancer development was found. There was also no difference in survival related to PIN status among the subsequent cancer patients.

Intraepithelial and invasive squamous cell neoplasia of the vulva: trends in incidence, recurrence, and survival rate in Norway

OBJECTIVE

To characterize time trends in incidence of intraepithelial and invasive vulvar neoplasia, transition of intraepithelial vulvar neoplasia to invasive cancer, and survival rate based on a total population.

METHODS

The Cancer Registry of Norway was used to identify all Norwegian inhabitants diagnosed during 1956-1990 with squamous cell carcinoma of the vulva, and all those with intraepithelial vulvar neoplasia diagnosed during 1973-92.

RESULTS

The incidence rate of intraepithelial neoplasia increased three-fold from 1973-77 to 1988-92, and 3.4% changed into invasive disease. Multivariate analyses identified age as a significant variable. The age-adjusted incidence rate for squamous cell carcinoma was constant for the whole period. The ratio between recurrence and the total number of invasive cancer varied from 21% to 31%. The 5-year survival rates have not changed significantly over the period. Age was revealed as a strong prognostic factor, showing an excess death rate by increasing age.

CONCLUSION

The incidence of vulvar intraepithelial neoplasia has increased substantially over the last 40 years, but that of invasive vulvar cancer has not changed appreciably.

Breast cancer in Norway 1970-1993: a population-based study on incidence, mortality and survival

The incidence, mortality and survival of breast cancer patients from 1970 to 1993 were studied using data from the Cancer Registry of Norway. The age-adjusted incidence rate increased from 62.0 to 76.9 per 100,000 person-years during the period, and more than 2000 cases are now registered annually. The increase tends to be highest in the age group below 40 years. The increase is mainly found in cases with localized tumours at the time of diagnosis. The mortality rate has been almost unchanged in the period; the age adjusted mortality rate is 27.0 per 100,000 person-years at the end of the study period. The 5-year overall survival has increased among cases with axillary lymph node metastases at the time of diagnosis; the other stages show only little improvement.

Malignant epithelial tumours in the upper digestive tract: a dietary and socio-medical case-control and survival study

OBJECTIVE

The aim of the present study was to elucidate the influence of social, dietary and environmental factors on the incidence of malignant epithelial tumours in the upper digestive tract and on the prognosis of patients with these cancers.

DESIGN

A population-based case-control study was carried out, and the patients in the study were included in a survival analysis.

SETTING

The study was carried out at the Department of Otorhinolaryngology at Ullevål University Hospital, Oslo, Norway.

SUBJECTS

In the case-control study, 84 patients and 89 controls were included. Only the patients were included in the survival analysis.

RESULTS

Smoking showed the highest odds ratio (OR) for morbidity (OR = 29). The patients had in general a lower social status, and a higher alcohol intake (OR = 6.6). For both beta-carotene and vitamin C, the ORs decreased with increasing intake (OR = 0.2 and 0.3, respectively). Increased ORs were associated with low values for haemoglobin, iron, TIBC, folic acid, magnesium and especially for albumin (OR = 14), and with high values for ferritin, vitamin B12 and thiocyanate (a marker for smoking). Stage of the disease was an important prognostic factor. The relative risk (RR) of dying for disseminated vs localised tumours being 3.2. A poorer prognosis was linked to higher age, to smoking vs no smoking (RR = 2.3), and to lower levels of haemoglobin, albumin, magnesium and thiocyanate.

CONCLUSIONS

Strong beer, liquor, consumption of milk and table fat, low social status and smoking seemed to have a negative impact on both disease and survival. Fruit and vegetables might, however, reduce the risk. Whereas low serum albumin, iron and magnesium indicated a high OR for cancer, vitamin C and beta-carotene had the opposite implication. No significant implications on survival could be detected in blood chemistry beyond the stage of disease.

Prognosis of patients with lung cancer diagnosed in Norway, 1954-93

Lung cancer is the most common cancer in the world today, and the prognosis for lung cancer patients is poor. In the Nordic countries, the five-year relative survival was only seven percent in patients diagnosed in 1983-87. In the present study, the survival of 36,010 lung cancer patients diagnosed in Norway in 1954-93 was examined, based on data from the population-based Cancer Registry of Norway. The variation in survival by gender, age, stage, period of diagnosis, and histologic group was explored. Relative survival rates were calculated and relative risks of dying were obtained from multivariate Cox proportional hazards regression analysis. Only a slight improvement in the prognosis of lung cancer patients was observed during the 40-year study period. More than half the patients died during the first six months after diagnosis. Patients with small cell carcinoma had the lowest frequency of localized tumors and also had the poorest prognosis, even after adjustment for stage. Patients with squamous cell carcinoma had the highest frequency of localized tumors. The patients with a localized tumor also have a poor prognosis, with a crude median survival time of nine months in males and 11 months in females in 1984-93.

Long-term survival of breast cancer in Norway by age and clinical stage

In this paper 25-year survival for 8802 Norwegian women with breast cancer diagnosed during the period 1965 to 1974 is studied. It is suggested that some of the contradictory reports in the literature of the prognostic effect of age and clinical stage on long-term survival may be caused by interactions and time varying effects of covariates. When using a linear non-parametric regression model that allows the covariates to vary over time, age and clinical stage are found to be significant long-term prognostic factors. A significantly higher excess mortality for women less than 35 years at diagnosis disappeared after 8 years, while for those above 55 years an important effect of age on the long-term survival, especially for those with regional cancer, was seen. The effect of clinical stage on survival varies strongly over time, and was significant between 15 and 20 years.

Esophageal and gastric carcinoma in Norway 1958-1992: incidence time trend variability according to morphological subtypes and organ subsites

The occurrence of adenocarcinoma (AC) of the esophagus and gastric cardia has shown large increases in many but not all examined populations. This trend is in contrast with a decrease in distal gastric AC and a relative stability of esophageal squamous cell carcinoma. Our study aimed to describe esophageal and gastric carcinoma time trends in the Norwegian population between 1958 and 1992 based on data from the Cancer Registry of Norway. Estimated esophageal AC rates have accelerated over the study period, reaching average annual increases of 17% in men and 14% in women between 1983 and 1992. The occurrence of esophageal squamous cell carcinoma was relatively stable in both sexes. Proximal gastric cancer rates were stable in males and decreased somewhat in females. Distal gastric tumors showed decreases in both sexes, but were more pronounced in females. The strong increase in esophageal AC incidence parallels similar increases in the United States and some other countries. Although the observed increase may be explained to some extent by a shift in the classification of esophago-cardial adenocarcinomas, the figures are compatible with a real increase. AC of the esophagus, the proximal stomach and the distal stomach exhibit different epidemiological features, both in terms of sex ratios and time trends, suggesting risk factor differences between the subsites.

Prediagnostic level of fatty acids in serum phospholipids: omega-3 and omega-6 fatty acids and the risk of prostate cancer

Ecological and case-control studies have demonstrated a positive correlation between consumption of fat and the risk of prostate cancer. Two recent human studies have focused on alpha-linolenic acid as a risk factor for prostate cancer. Animal experiments have shown that dietary omega-6 polyunsaturated fatty acids have generally stimulated tumour development, whereas omega-3 polyunsaturated fatty acids have diminished it. The aim of our study was to investigate the association between these fatty acids and the subsequent risk of prostate cancer. Blood donors to the Janus serum data bank in Norway, who later developed prostate cancer, were matched to blood donors without prostate cancer (141 matched sets); the proportional level of fatty acids measured before diagnosis in the donors' serum was examined. The risk of later prostate cancer was analysed by conditional logistic regression. Increasing risk for prostate cancer was found with increasing quartiles of palmitoleic, palmitic and alpha-linolenic acid. An inverse risk association was found with increasing levels of tetracosanoic acid, for the ratios of linoleic to alpha-linolenic acid and arachidonic to eicosapentaenoic acid. There was no clear association between the risk effect of total omega-3 and total omega-6 fatty acids. There were no indications of a relationship between fatty acids and more aggressive cancers. Our results verify recent findings of a positive association between alpha-linolenic acid and a negative association between the ratio of linoleic to alpha-linolenic acid and the risk of prostate cancer.

Esophageal and gastric carcinoma in Norway 1958-1992: incidence time trend variability according to morphological subtypes and organ subsites

The occurrence of adenocarcinoma (AC) of the esophagus and gastric cardia has shown large increases in many but not all examined populations. This trend is in contrast with a decrease in distal gastric AC and a relative stability of esophageal squamous cell carcinoma. Our study aimed to describe esophageal and gastric carcinoma time trends in the Norwegian population between 1958 and 1992 based on data from the Cancer Registry of Norway. Estimated esophageal AC rates have accelerated over the study period, reaching average annual increases of 17% in men and 14% in women between 1983 and 1992. The occurrence of esophageal squamous cell carcinoma was relatively stable in both sexes. Proximal gastric cancer rates were stable in males and decreased somewhat in females. Distal gastric tumors showed decreases in both sexes, but were more pronounced in females. The strong increase in esophageal AC incidence parallels similar increases in the United States and some other countries. Although the observed increase may be explained to some extent by a shift in the classification of esophago-cardial adenocarcinomas, the figures are compatible with a real increase. AC of the esophagus, the proximal stomach and the distal stomach exhibit different epidemiological features, both in terms of sex ratios and time trends, suggesting risk factor differences between the subsites.

Prostatic intraepithelial neoplasia in surgical resections: relationship to coexistent adenocarcinoma and atypical adenomatous hyperplasia of the prostate

BACKGROUND

High grade prostatic intraepithelial neoplasia (PIN) is associated with coincident prostate carcinoma, and has been considered to be a precursor of prostate carcinoma. Most studies on PIN have been performed on total prostatectomy or core needle biopsy specimens. Few reports deal with the occurrence of PIN in consecutive surgical resections, which is the objective of the current study.

METHODS

A total of 1135 nonselected surgical specimens from the prostate, examined during 1974 and 1975, underwent blind review by 2 experienced pathologists. There were 79 core needle biopsies, 731 transurethral resections of the prostate and 325 transvesical prostatic enucleations. The kappa coefficient for interobserver reproducibility was 0.66 for PIN and 0.86 for carcinoma.

RESULTS

Grade 1 PIN was found in 9%, Grade 2 PIN in 32%, and Grade 3 PIN in 20% of the total cases. Atypical adenomatous hyperplasia (AAH) was found in 11% and adenocarcinoma in 27% of the cases. Grade 3 PIN was associated with coincident adenocarcinoma in 39% of the cases. The prevalence of carcinoma for cases with Grade 1 and 2 PIN did not exceed that of those with Grade 0 PIN. PIN was most commonly found in association with small carcinomas. The mean age of the entire group of patients was 70.0 years, and was 69.4 years for patients with PIN without coincident carcinoma. Patients with PIN and coincident carcinoma had a mean age of 71.7 years, similar to all PIN grades, but patients with carcinoma without PIN had the highest mean age, 73.3 years.

CONCLUSIONS

PIN is a common histologic finding in tissues from prostatic resections. In this study, Grade 3 PIN was strongly associated with coincident carcinoma, but lower grade PIN was not. There was no association between PIN and AAH. Patients with PIN did not appear to have a higher mean age than corresponding patients without PIN.

Use of multiple primary cancers to indicate associations between smoking and cancer incidence: an analysis of 500,000 cancer cases diagnosed in Norway during 1953-93

The occurrence of multiple primary cancers is relatively rare, but may provide indications of common or opposite risk factors for different types of cancer. In the present study, the occurrence of multiple primary cancers was used to indicate possible associations between smoking and the incidence of cancers other than those generally accepted as smoking-associated. All cancer cases in persons above the age of 30, registered at the population-based Cancer Registry of Norway (1953-1993), were used in the analysis. For each type of cancer, the observed occurrence of smoking-associated cancers in the patients was compared with the expected occurrence if the patients had the same risk as the general population. Similar comparisons were made for the occurrence of other cancers in patients with a smoking-associated cancer. The results were presented as standardized incidence ratio (SIR), the ratio of the observed and the expected numbers of cases. The results indicated that uterine cervical cancer may share some important risk factor(s) with the cancers generally accepted as smoking-associated. This is in accordance with the literature, where an association between smoking and uterine cervical cancer has been found consistently. In addition, the results for liver cancer and leukemia indicated that these types of cancer also share some risk factor(s) with the smoking-associated cancers.

Risk of subsequent non-germ cell cancer after treatment of germ cell cancer in 2006 Norwegian male patients

The aim of this study was to evaluate the risk of subsequent non-germ cell cancer (SNGC) among men with germ cell cancer and the significance of radiotherapy and chemotherapy as risk factors. The study group consisted of 2006 male patients treated for germ cell cancer at the Norwegian Radium Hospital from 1952 to 1990 with a mean follow-up of 12.5 years. A group of 1194 patients had received radiotherapy only, 346 patients chemotherapy only (mainly cisplatin-based), 277 patients both radiotherapy and chemotherapy (mainly cyclophosphaoffe and doxorubicin-based), and 189 patients no cytotoxic treatment. A total number of 153 SNGCs were diagnosed after a mean interval of 15.9 years. The RR was 1.65 (95% confidence interval (CI), 1.4-1.9), and the mean cumulative risk after 15 years 7.8% (95% CI, 6.2-9.5%). Significantly elevated RRs were found for gastrointestinal cancer combined, cancer of stomach, liver and biliary system, lung, melanoma, bladder and sarcoma. Significantly elevated RRs were found in patients who had received radiotherapy (with or without chemotherapy), and the trend increased with very long follow-up. Patients given both radiotherapy and chemotherapy experienced the highest risk (RR = 3.54; 95% CI, 2.0-5.8), probably due to a high cumulative dose of cytotoxic treatment. Modern chemotherapy did not seem to increase the risk of SNGC, although this study's size and follow-up period did not allow definite conclusions as regards this risk factor.

Risk of a second germ cell cancer after treatment of a primary germ cell cancer in 2201 Norwegian male patients

The aim of this study was to evaluate the risk of developing a second germ cell cancer (SGCC) among male patients with a primary germ cell cancer (PGCC). SGCCs, all metachronous, developed in 60 out of 2201 males treated for a PGCC at the Norwegian Radium Hospital in Oslo from 1953 to 1990. Further, 8 patients had synchronous germ cell cancers. The relative risk (RR) of developing an SGCC was 27.6 (95% confidence interval (CI) 21.1-35.6), and the cumulative risk at 15 years of follow-up 3.9% (95% CI 2.8-5.0%). In patients with primary non-seminoma, the cumulative risk of an SGCC at 15 years of follow-up was 5.0% and in patients with primary seminoma 3.4%. Patients less than 30 years of age had a higher cumulative risk of 7.8% compared to 2.1% in older patients at 15 years of follow-up. The RR of an SGCC, however, was equal in patients with primary seminoma and in patients with primary non-seminoma. If the interval between PGCC and SGCC was < 5 years, the PGCC was most often followed by an SGCC of same histological type. Treatment applied for the PGCC did not seem to be of significant importance for the development of SGCC. In conclusion, patients with PGCC have high RR of developing an SGCC and age group < 30 years display an especially high cumulative risk.

Blood lipid and lipoprotein levels and the risk of cancer of the colon and rectum. A prospective study of 62,173 Norwegian men and women

BACKGROUND

Concern has been raised that a low total serum cholesterol level, although beneficial for cardiovascular diseases, may increase the risk of cancer. This prospective cohort study analyses the hypotheses that a low total serum cholesterol level or its subfractions (serum low-density-lipoprotein cholesterol, high-density-lipoprotein cholesterol, and triglycerides) increase the risk of cancer of the colon and rectum.

METHODS

Between 1977 and 1983, 62,173 men and women attended a health screening carried out by the Norwegian National Health Screening Service. The screening consisted of a questionnaire, anthropometric measurements, and samples of non-fasting blood drawn for analyses of serum total cholesterol, low-density-lipoprotein cholesterol, high-density-lipoprotein cholesterol, and triglycerides.

RESULTS

During the 7- to 13-year follow-up, 186 patients were found to have colon cancer and 106 rectal cancer by linkage to the Norwegian Cancer Registry. Among men there were no associations between blood lipid and lipoprotein levels and risk of cancer of the proximal colon, distal colon, or the rectum. Among women there was a formal statistically significant inverse relationship between level of total cholesterol and low-density-lipoprotein cholesterol and risk of distal colon cancer, and a positive trend between total cholesterol level and rectal cancer.

CONCLUSIONS

The statistically significant results among women were interpreted as incidental, and we conclude that blood lipid and lipoprotein levels were not associated with the risk of colon or rectum cancer in men or women in this cohort.

A segregation analysis of testicular cancer based on Norwegian and Swedish families

Clustering of testicular cancer cases in families is well known, although the aetiology is not. We present the results of a segregation analysis performed with the algorithm Pointer on familial data on 978 Scandinavian patients with testicular cancer. The segregation analysis favoured the involvement of major gene effects over models incorporating solely polygenic effects in testicular cancer aetiology. Overall, a recessive model best fits the family observations with an estimated gene frequency of 3.8% and a lifetime risk for homozygous men of developing the disease of 43%. This implies that 7.6% of men in the general population will be carriers of the mutant allele and that 0.1% would be homozygote and are, therefore, at high risk of developing the cancer. The testicular cancer incidence has changed greatly during the last generation. Also, the lethality of the disease has changed because of the introduction of new therapy. As failure to take account of such time trends might lead to inappropriate evidence for a recessive model, the analyses were repeated under different assumptions. The analyses favoured a recessive model of inheritance under all assumptions tested. However, the assumptions underlying the analyses are complex and, as this is the first segregation analysis of testicular cancer, the results must be interpreted cautiously.

Squamous cell carcinoma of the penis and of the cervix, vulva and vagina in spouses: is there any relationship? An epidemiological study from Norway, 1960-92

Four hundred and twenty-three wives of 671 men with cancer of the penis were compared with 444 wives of 569 men who did not have this disease. The risk among the wives of patients with cancer of the penis of preinvasive and invasive cancer of the neck of the uterus was 1.75 (95% CI 0.42-7.37).

Dietary factors and risk of colon cancer: a prospective study of 50,535 young Norwegian men and women

The relationship of meat, fish, fat, fibre or calcium consumption to the risk of colon cancer was examined in a prospective study conducted by the Norwegian National Health Screening Service. Between 1977 and 1983, 50,535 Norwegian men and women aged 20-54 attended the health screening and completed a semi-quantitative questionnaire about food frequency. During a mean follow-up of 11.4 years, 143 cases of colon cancer were identified for analyses through a link with the Norwegian Cancer Registry. The relative risk of colon cancer was 3.5 (95% CI, 1.02-11.9) in women who consumed sausages as their main meal five or more times a month, compared with the risk in those who reported a consumption frequency of less than once a month. There was an increase in the relative risk with increasing frequency of consumption (P for linear trends = 0.03). Among men, the association was not statistically significant, but the trend was in the same direction as that of the women. The frequency of consuming meat meals in general, including meat stews, roasted meat, meat balls, fish or milk, was not associated with a risk of colon cancer. No trends in relative risks of colon cancer were found to be associated with intake of total energy intake or with energy-adjusted intake of total fat, saturated fat, monounsaturated fat, dietary fibre or calcium. In conclusions, this prospective study provided no evidence of association between intake of meat, fish, fat, energy, fibre or calcium and risk of colon cancer, although an increased risk with frequent consumption of sausages was suggested.

Smoking habits and risk of cancers other than lung cancer: 28 years' follow-up of 26,000 Norwegian men and women

The impact of tobacco smoking on lung cancer risk has been investigated thoroughly since the 1950s, but other types of cancer also have been associated with smoking. In the present study, the aim was to explore the variation in risk connected with cigarette, cigar, and pipe smoking of suspected smoking-associated cancers other than lung cancer. Data were obtained from a survey of a random sample of the Norwegian population. A self-administered mailed questionnaire, which included questions about smoking habits, was completed by 26,000 men and women in 1965 (response rate: 76 percent). The cohort was followed from 1966 through 1993, including registration of all incident cancer cases. A dose-response relationship of cigarette smoking to the risk of urinary bladder cancer and cancers of the upper digestive and respiratory tract was observed. For the latter forms of cancer, a dose-response relationship of pipe smoking also was observed. In cancer of the pancreas, a stronger association between cigarette smoking and cancer risk was observed when the analysis was confined to histologically confirmed cases only. Current cigarette smokers at baseline had a significantly higher risk of cervical cancer than those who never smoked cigarettes. In cancers of the stomach, colon, rectum, breast, corpus uteri, ovary, and prostate, and in leukemia, no association between smoking and cancer risk was observed.

Lifestyle changes during adolescence and risk of breast cancer: an ecologic study of the effect of World War II in Norway

There are biologic reasons to believe that the period between the larche and the first full-term pregnancy is a particularly sensitive period in a woman's life regarding the development of breast cancer. In this ecologic study, data provided by the Norwegian Cancer Registry were analyzed to compare risk of breast cancer among women who experienced this sensitive period before, during, or after World War II. An ordinary age-cohort model and a model where the cohort was described by exposure by calendar period and sensitivity to this exposure at different ages, were fitted to the data. The incidence of breast cancer was lower than expected among women who experienced puberty during the war. The estimated configuration of the exposure variable showed an increase in exposure up to the start of WWII to twice the level in 1916, dropped by 13 percent during the war, and increased again after the war. The level in 1975 was approximately 2.7 times higher than the level in 1916. The results indicate that one or more lifestyle factors that changed among adolescent women during the war, influenced their risk of breast cancer. Dietary intake of energy, fat, meat, milk, fish, fresh vegetables, and potatoes, in addition to physical activity level and height, are important factors to consider in relation to breast cancer risk.