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Background: Results from randomized trials indicate that treatment with tamoxifen or chemotherapy for primary breast cancer reduces the risk for contralateral breast cancer. However, less is known about how long the risk is reduced and the impact of factors such as age and menopausal status., Methods: The study included 634 women with contralateral breast cancer (case patients) and 1158 women with unilateral breast cancer (control subjects) from the Women's Environment, Cancer and Radiation Epidemiology Study. The women were younger than age 55 when they were first diagnosed with breast cancer during 1985-1999. Rate ratios (RRs) and 95% confidence intervals (CIs) for contralateral breast cancer after treatment with chemotherapy or tamoxifen were assessed by multivariable adjusted conditional logistic regression analyses., Results: Chemotherapy was associated with a lower risk for contralateral breast cancer (RR = 0.57, 95% CI = 0.42 to 0.75) than no chemotherapy. A statistically significant association between chemotherapy and reduced risk for contralateral breast cancer persisted up to 10 years after the first breast cancer diagnosis and was stronger among women who became postmenopausal within 1 year of the first breast cancer diagnosis (RR = 0.28, 95% CI = 0.11 to 0.76). Tamoxifen use was also associated with reduced risk for contralateral breast cancer (RR = 0.66, 95% CI = 0.50 to 0.88) compared with no use, and the association was statistically significant for 5 years after the first diagnosis., Conclusion: The associations between chemotherapy and tamoxifen treatment and reduced risk for contralateral breast cancer appear to continue for 10 and 5 years, respectively, after the initial breast cancer is diagnosed. Ovarian suppression may have a role in the association between chemotherapy and reduced risk for contralateral breast cancer.

Objective: To describe the incidence of malignancies in a cohort of Danish patients with Wegener's granulomatosis (WG) and to investigate the cancer risk associated with cyclophosphamide (CYC) -therapy in WG., Methods: In total, 293 patients diagnosed with WG between 1973 and 1999 were studied. Cancer incidence in the cohort was assessed through 2003 by linkage to the Danish Cancer Registry and compared to that of the general population by calculation of standardized incidence ratios (SIR). Analyses were stratified according to treatment with low cumulative CYC doses (< or = 36 g) and high doses (> 36 g, corresponding to treatment with 100 mg CYC/day for > 1 year)., Results: Fifty cancers occurred during 2121 person-years of followup (SIR of cancer of 2.1, 95% CI 1.5-2.7). Significantly increased SIR were observed for acute myeloid leukemia (AML; SIR 19.6, 95% CI 4.0-57), bladder cancer (SIR 3.6, 95% CI 1.2-8.3), and non-melanoma skin cancers (SIR 4.7, 95% CI 2.8-7.3). Leukemias and bladder cancers were diagnosed 6.9-18.5 years after initiation of CYC therapy. The risk of these malignancies was not increased for patients who never received CYC or for patients treated with cumulative CYC doses < or = 36 g. In contrast, high risks of AML (SIR 59.0, 95% CI 12-172) and bladder cancer (SIR 9.5, 95% CI 2.6-24) were observed for patients treated with cumulative CYC doses > 36 g., Conclusion: Treatment with high cumulative CYC doses implies a substantial risk of late-occurring, serious malignancies in WG. Patients with WG should be monitored for development of cancer for several decades after cessation of CYC therapy. These findings emphasize the need for development of new treatment regimens in WG.

Objective: Several chronic diseases have been hypothesized to affect the risk of subsequent gynecologic malignancies, possibly through shared hormonal mechanisms., Methods: Using record linkage techniques, we assessed the relationships between hospital and outpatient admissions for gallbladder disease, diabetes, hypertension, thyroid diseases and obesity and the subsequent development of uterine and ovarian cancers in Denmark between 1978 and 1998. Based on a subsample of more than 99,000 women, including 1398 uterine and 2491 ovarian cancers, we derived relative risks (RRs) and 95% confidence intervals (CIs) associated with overall and histology-specific cancer risks after adjustment for age, calendar time and reproductive characteristics., Results: Uterine cancers were related to previous diagnoses of thyroid diseases (RR=1.52, 95% CI 1.17-1.98) and obesity (2.05, 1.40-3.00). Associations with diabetes were confounded by obesity, but there were some elevations in risk for subjects diagnosed with obesity prior to age 45 (RRs 1.66-1.79). Although the "usual types" of endometrial cancer largely accounted for the observed associations, there was some evidence that uterine sarcomas (n=137) were related to prior diagnoses of thyroid diseases (2.78, 1.41-5.50). In contrast, ovarian cancers were not strongly related to most documented chronic diseases. Serous carcinomas were associated with gallbladder diseases of short durations, but detection bias or misdiagnosis probably accounts for this association. An association of obesity and endometrioid ovarian cancer was not identified., Conclusions: Uterine cancers, including sarcomas, appear to be influenced by selected chronic diseases. Further attention should focus on possible biologic mechanisms underlying observed associations with thyroid diseases and obesity.

Primary fallopian tube cancer (PFTC) is a rare disease, and its aetiological factors are poorly understood. Studies on PFTC in the setting of 2nd primary malignant neoplasms can provide clues on aetiology and also define the possible side effects of different treatment modalities for PFTC. A cohort of 2,084 cases with first PFTC was extracted from the data from 13 cancer registries from Europe, Canada, Australia and Singapore and followed for second primary cancers within the period 1943-2000. Standardized incidence ratios (SIRs) were calculated and Poisson regression analyses were done to find out the RRs related to age at, period of and time since the PFTC diagnosis. There were 118 cancer cases observed after first PFTC (SIR 1.4, 95%CI 1.1-1.6). Elevated SIRs were seen for colorectal cancer (1.7, 95%CI 1.0-2.6), for breast cancer (1.5, 95%CI 1.1-2.2), for bladder cancer (2.8, 95%CI 1.0-6.0), for lung cancer (1.8, 95% CI 0.9-3.2) and for nonlymphoid leukaemia (3.7, 95%CI 1.0-9.4). Significant risk increases were detected for colorectal cancer during the 2nd to 5th year after the first PFTC diagnosis, for breast cancer in follow-up 10+ and for nonlymphoid leukaemia during the 2nd to 10th year. The clustering of cancers of the lung and bladder in PFTC patients may suggest shared smoking aetiology. The excess of colorectal and breast cancers after PFTC may indicate a genetic aetiology., ((c) 2007 Wiley-Liss, Inc.)

Although several risk factors are common to endometriosis and breast cancer, the results of observational studies of an association have so far been inconsistent. We evaluated the relationship between endometriosis and breast cancer on the basis of data on selected cancers and medical histories from the Danish nationwide cancer and hospital registries used in a large case-cohort study. A total of 114,327 women were included in the study of whom 1,978 women had received a diagnosis of endometriosis and 16,983 had had a diagnosis of breast cancer between 1978 and 1998. Of the women with endometriosis, 236 subsequently received a diagnosis of breast cancer. The crude overall rate ratio for breast cancer after endometriosis was 1.00 and after adjustment for reproductive factors, calendar-period, bilateral oophorectomy and benign breast disease, the rate ratio was 0.97 (95% confidence interval, 0.85-1.11). The risk for breast cancer increased with age at diagnosis of endometriosis, so that women in whom endometriosis was diagnosed at a young age (approximately <40 years) had a reduced risk for breast cancer and women in whom endometriosis was diagnosed at older ages (approximately > or =40 years) tended to have an increased risk for breast cancer. The reduced risks observed among young women may reflect their exposure to drugs with antiestrogenic effects. The increased risk associated with endometriosis among postmenopausal women may be due to common risk factors between postmenopausal endometriosis and breast cancer or an altered endogenous estrogen., ((c) 2006 Wiley-Liss, Inc.)

Recent evidence suggests that chronic lymphocytic leukemia (CLL) might occur following a response to an infectious agent. We conducted a population-based study including 4249 CLL patients diagnosed in Denmark from 1977 to 1997 and 15 690 frequency-matched controls to quantify risk of CLL following various airway infections. Through data linkage we gathered information on hospital inpatient/outpatient discharges that listed infections present at least 1 year prior to CLL. Using logistic regression, we calculated odds ratios (ORs) and 95% confidence intervals (CIs). Personal history of pneumonia was associated with significantly increased CLL risk (OR = 1.4; 1.2-1.8); risk was restricted to 1 to 4.99 years prior to CLL diagnosis (OR = 1.6; 1.2-2.0). Individuals with 3 or more prior pneumonia events had a significant 2.5-fold (1.1-5.6) elevated CLL risk, and risk increased with the number of pneumonia episodes (P(trend) < .001). None of 9 other respiratory-tract infections was significantly associated with CLL risk. Pneumonia might be a potential CLL trigger or it could represent premalignant immune disruption preceding CLL.

Radiotherapy and chemotherapy are known risk factors for second cancers after lymphoma. The role of genetic influences, however, remains largely unknown. We assessed risk of second cancers associated with family history of any cancer in 41,181 patients with Hodgkin lymphoma (HL) (n = 7,476), non-Hodgkin lymphoma (NHL) (n = 25,941), or chronic lymphocytic leukemia (CLL) (n = 7,764), using a large population-based database. Family history of cancer was based on a diagnosis of any cancer in 110,862 first-degree relatives. We found increased relative risk (RR) (1.81, 95% confidence interval (CI): 1.04-3.16) of breast cancer among HL patient with positive (vs. negative) family history of cancer. Among CLL patients with positive (vs. negative) family history of cancer, we observed elevated risks of bladder (RR = 3.53, 95% CI: 1.31-9.55) and prostate cancer (RR = 2.15, 95% CI: 1.17-3.94). For NHL patients with positive (vs. negative) family history of cancer, we observed non-significantly increased risk of non-melanoma skin cancer (RR = 1.94, 95% CI: 0.86-4.38) and lung cancer (RR = 1.99, 95% CI: 0.73-5.39). Our observations suggest that genetic factors, as measured by positive family history of cancer, may be influential risk-factors for selected second tumors following lymphoproliferative disorders., (Copyright 2006 Wiley-Liss, Inc.)

Recently, the incidence of intrahepatic cholangiocarcinoma (ICC) has been increasing in a number of developed (Western) countries. However, risk factors in these low-risk populations are poorly understood. In this nationwide population based case-control study in Denmark, we examined the relationship between selected medical conditions and subsequent ICC risk to provide additional clues to etiopathogenesis. All histologically confirmed ICC cases diagnosed in Denmark between 1978 and 1991 were identified from the Danish cancer registry. Population controls were selected from the central population registry and were matched 4:1 to cases on sex and year of birth. Cases and controls were linked to the Danish hospital discharge registry to obtain information on prior hospital diagnoses. Odds ratios (OR) and 95% confidence intervals (95% CI) were derived using conditional logistic regression. A total of 764 ICC cases and 3,056 population controls were included in the study. Chronic liver diseases were significantly related to ICC: alcoholic liver disease (OR = 19.22, 95% CI = 5.55-66.54), unspecified cirrhosis (OR = 75.9, 95% CI 10.2-565.7). Bile duct diseases were also associated with risk: cholangitis (OR = 6.3, 95% CI = 2.3-17.5), choledocholithiasis (OR = 23.97, 95% CI = 2.9-198.9), cholecystolithiasis (OR = 4.0, 95% CI = 2.0-7.99), though gallbladder removal did not change risk (OR = 1.6, 95% CI = 0.65-3.7). Among other conditions, chronic inflammatory bowel disease (OR = 4.7, 95% CI = 1.65-13.9) was significantly associated with ICC. Diabetes was associated with risk in the year prior to diagnosis of ICC (OR = 3.02, 95% CI = 1.05-8.69). Obesity was unrelated to risk. These results confirm that prior bile duct diseases increase risk of ICC and suggest that alcoholic liver disease and diabetes may also increase risk.

Objective: To analyze whether fibromyalgia (FM) and FM-like symptoms are related to an increased incidence of cancer., Methods: We identified 1361 patients referred on suspicion of FM in the period 1984-99 from hospital records. Following the American College of Rheumatology (ACR) criteria, patients were divided into subgroups with and without confirmed FM. The cohort was followed to the end of 1999 and linked to the files of the Danish Cancer Register. Site-specific standardized incidence ratios (SIR) were calculated., Results: We found no association between FM and cancer in 1132 female patients with confirmed FM at our institution (SIR 1.2, 95% CI 0.8-1.8). In 106 women referred for muscle pain and/or tenderness who did not meet the criteria for FM, an increased overall SIR was observed (SIR 2.5, 95% CI 1.2-4.6), with increased risk for breast cancer (SIR 4.8, 95% CI 1.6-11.3) and lymphatic and hematological cancers (SIR 10.6, 95% CI 1.2-38.2). There were 4 lung cancers in 84 men with confirmed FM (SIR 12.6, 95% CI 3.4-32.4)., Conclusion: Neither confirmed FM nor those without confirmed FM predicted cancer. An increased risk of breast cancer was found among those who did not meet the ACR criteria for FM. These patients should be investigated if they develop any new or warning symptoms of malignancy, and treating physicians should be vigilant with screening procedures such as mammography.

Encounter with infectious antigens has been proposed to initiate the cascade of events associated with progression from premalignancy (monoclonal gammopathy of undetermined significance, MGUS) to multiple myeloma (MM). We conducted a population-based case-control study to evaluate risk of developing MM associated with a personal history of various respiratory tracts infections occurring >1 year prior to MM. Inpatient (1977-1997) and outpatient (1994-1997) diagnoses were obtained for all MM patients (n=4,476) diagnosed in Denmark (1977-1997) and 16,727 matched controls. A personal history of pneumonia was associated with a 1.6-fold (95%CI 1.3-2.0) increased risk of MM; the elevated risk was restricted to 1-4.99 years prior to the diagnosis of MM (OR=1.7,95%CI 1.3-2.2). Individuals with two and three or more previous episodes of pneumonia had a 1.7-fold (95%CI 1.0-3.0; p=0.05) and a 1.5-fold (95%CI 0.6-3.9) elevated MM risk, respectively. Pneumonia could be a trigger to the development of MM or a manifestation of immune disturbances in late-stage MGUS.

Background: Malignant degeneration of chronic ulcers such as nonhealed burn wounds has been described in the literature, but this phenomenon has never been quantified in an epidemiologic study. We investigated the risks for skin and other cancers among patients with a prior burn., Methods: We identified 16,903 patients from the Danish Hospital Discharge Register who had been admitted to a hospital with a thermal or chemical burn during 1978 to 1993. The cohort was followed for cancer in the Danish Cancer Registry through 2002, and the cancer incidence in the cohort was compared with that in the general population of Denmark., Results: Patients with burn had 139 skin cancers, with 189 expected, yielding a standardized incidence ratio of 0.7 (95% confidence interval = 0.6-0.9). This reduced risk was due mainly to deficits of basal cell carcinoma and malignant melanoma, whereas the number of squamous cell carcinomas observed was close to expected. We saw no consistent increases in risk for skin cancer in the subgroups of patients with the most severe injuries or with the longest periods of follow up., Conclusions: The tendency to malignant degeneration of burn scars, described in previous reports of case series, did not result in an excess of squamous cell carcinoma of the skin or of any other type of skin cancer during up to 25 years' follow up of a large unselected cohort of patients hospitalized for burn injuries.

Objective: To assess the importance of body fat mass (BFM) and fat free mass (FFM) for the established positive association between BMI and breast cancer among post-menopausal women., Research Methods and Procedures: A prospective cohort of 23,788 postmenopausal women included in the Danish study Diet, Cancer, and Health during 1993 to 1997 was linked to the Danish Cancer Registry to identify all cases of breast cancer occurring during 1993 to 2002. Breast cancer incidence rate ratios for anthropometric measurements with adjustment for known risk factors for breast cancer were calculated by Cox regression analyses., Results: Among the most commonly used anthropometric measurements, BMI was positively associated with breast cancer among never users of hormone replacement therapy (HRT). By splitting BMI into two indices, BFM index and FFM index, we found that the incidence rate ratio with each 1 kg/m(2) among never users of HRT was 0.98 (95% confidence interval, 0.93 to 1.03) for BFM index and 1.12 (95% confidence interval, 1.00 to 1.26) for FFM index after mutual adjustment., Discussion: The finding for BMI was in accordance with previous findings. Our results indicate that the FFM component of BMI may play a role for development of breast cancer among never users of HRT.

Background: Personal history of autoimmune diseases is consistently associated with increased risk of non-Hodgkin lymphoma. In contrast, there are limited data on risk of Hodgkin lymphoma following autoimmune diseases and almost no data addressing whether there is a familial association between the conditions., Methods: Using population-based linked registry data from Sweden and Denmark, 32 separate autoimmune and related conditions were identified from hospital diagnoses in 7476 case subjects with Hodgkin lymphoma, 18,573 matched control subjects, and more than 86,000 first-degree relatives of case and control subjects. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) as measures of relative risks for each condition using logistic regression and also applied multivariable hierarchical regression models. All P values are two-sided., Results: We found statistically significantly increased risks of Hodgkin lymphoma associated with personal histories of several autoimmune conditions, including rheumatoid arthritis (OR = 2.7, 95% CI = 1.9 to 4.0), systemic lupus erythematosus (OR = 5.8, 95% CI = 2.2 to 15.1), sarcoidosis (OR = 14.1, 95% CI = 5.4 to 36.8), and immune thrombocytopenic purpura (OR = infinity, P = .002). A statistically significant increase in risk of Hodgkin lymphoma was associated with family histories of sarcoidosis (OR = 1.8, 95% CI = 1.01 to 3.1) and ulcerative colitis (OR = 1.6, 95% CI = 1.02 to 2.6)., Conclusions: Personal or family history of certain autoimmune conditions was strongly associated with increased risk of Hodgkin lymphoma. The association between both personal and family histories of sarcoidosis and a statistically significantly increased risk of Hodgkin lymphoma suggests shared susceptibility for these conditions.

A population-based case-control study was conducted to evaluate risk of developing chronic lymphocytic leukemia (CLL) associated with personal and/or family history of autoimmune and related diseases. Data were obtained for all (n = 7764) patients diagnosed with CLL in Sweden and Denmark over a 40-year period and with linkable relatives, 16,658 matched control subjects, and first-degree relatives of patients (n = 17,991) and control subjects (n = 39,388). Odds ratios (ORs) were calculated to quantify risk of CLL in relation to personal/family history of 32 autoimmune and related disorders. The risk of CLL was significantly increased among subjects with a personal history of pernicious anemia (OR = 1.94; 1.18-3.18), mainly in the 0- to 1-year latency period. A significantly decreased risk of CLL was found among individuals with a personal history of chronic rheumatic heart disease (OR = 0.55; 0.33-0.93), particularly persons with a long latency (10+ years) between the 2 conditions. We found no association between personal or familial occurrence of other autoimmune or related disorders and CLL. If our results are confirmed, mechanistic studies examining how pernicious anemia might promote increased occurrence of CLL and how chronic rheumatic heart disease protects against CLL, perhaps related to long-term antibiotics use, may provide insights to the as-yet-unknown etiology of CLL.

Cancer risk in children born before term has been assessed in a large number of case-control studies but very rarely in cohort studies. We carried out a cohort study of 35 178 children with the diagnosis immaturity at birth in the Hospital Discharge Register during 1977-89. The children were followed for cancer in the Danish Cancer Registry until 1994 and comparisons were made with incidence rates for all children in Denmark. The 64 observed cases of childhood cancer in the cohort corresponded closely to the expected number {standardised incidence ratio (SIR) = 1.03; [95% confidence interval (CI) 0.80, 1.32]}. The only cancer site with an observed number that deviated significantly from the expected number was central nervous system (CNS) tumours (26 cases observed; SIR = 1.57; [95% CI 1.02, 2.30]) in particular medulloblastoma (9 cases observed; SIR = 3.1; [95% CI 1.4, 5.9]). In a nested case-control study of the CNS tumours, we found that more cases than controls had been exposed to diagnostic X-rays, but the result was not significant. Surprisingly, for those born before term, the risk of CNS tumours increased with increasing gestational age in the nested case-control data. Our results are in line with previous evidence that children born before term are not at increased risk for childhood cancer in general. An explanation behind the excess of CNS tumours could not be identified, but the effect of diagnostic X-rays in newborns may deserve further attention.

A large number of women survive a diagnosis of breast cancer. Knowledge of their risk of developing a new primary cancer is important not only in relation to potential side effects of their cancer treatment, but also in relation to the possibility of shared etiology with other types of cancer. A cohort of 525,527 women with primary breast cancer was identified from 13 population-based cancer registries in Europe, Canada, Australia and Singapore, and followed for second primary cancers within the period 1943-2000. We used cancer incidence rates of first primary cancer for the calculation of standardized incidence ratios (SIRs) of second primary cancer. Risk of second primary breast cancer after various types of nonbreast cancer was also computed. For all second cancer sites combined, except contralateral breast cancer, we found a SIR of 1.25 (95% CI = 1.24-1.26) on the basis of 31,399 observed cases after first primary breast cancer. The overall risk increased with increasing time since breast cancer diagnosis and decreased by increasing age at breast cancer diagnosis. There were significant excesses of many different cancer sites; among these the excess was larger than 150 cases for stomach (SIR = 1.35), colorectal (SIR = 1.22), lung (SIR = 1.24), soft tissue sarcoma (SIR = 2.25), melanoma (SIR = 1.29), non-melanoma skin (SIR = 1.58), endometrium (SIR = 1.52), ovary (SIR = 1.48), kidney (SIR = 1.27), thyroid gland (SIR = 1.62) and leukaemia (SIR = 1.52). The excess of cancer after a breast cancer diagnosis is likely to be explained by treatment for breast cancer and by shared genetic or environmental risk factors, although the general excess of cancer suggests that there may be additional explanations such as increased surveillance and general cancer susceptibility., (2005 Wiley-Liss, Inc.)

Objective: Although endometriosis and uterine leiomyomas are common conditions, the extent to which either is associated with certain types of malignancies remains uncertain., Methods: Using record linkage techniques, we assessed the relationships between hospital and outpatient admissions for endometriosis or leiomyomas and the development of ovarian and uterine cancers in Denmark between 1978 and 1998. Based on a population-based cohort exceeding 99,000 women, including 2,491 ovarian cancers, 860 borderline ovarian tumors, and 1,398 uterine cancers, we derived relative risks (RR) and 95% confidence intervals (95% CI) associated with overall and histology-specific tumor risks after adjustment for calendar time and reproductive characteristics., Results: Endometriosis seemed to predispose to the development of ovarian cancer, with the association restricted to endometrioid or clear cell malignancies. Five or more years after the diagnosis of endometriosis, the RRs (95% CIs) were 2.53 (1.19-5.38) for endometrioid (7 exposed cases) and 3.37 (1.24-9.14) for clear cell (4 exposed cases) malignancies. Uterine leiomyomas were associated with increases in the risk of uterine malignancies, particularly sarcomas, where the RRs (95% CIs) were 20.80 (11.32-38.22) for women with 1 to 4 years of follow-up (11 exposed cases) and 5.70 (2.27-14.32) for those with more extended follow-up (5 exposed cases)., Conclusion: In combination with clinical, pathologic, and molecular data, our results support that some endometriotic lesions may predispose to clear cell and endometrioid ovarian cancers. Uterine leiomyomas also showed a strong connection with subsequent uterine sarcomas, although it was difficult to decipher whether this reflected detection bias, shared risk factors, or an etiologic relationship.

Background: Fever of unknown origin is associated with cancer, but the tumour types most commonly involved and the prognostic implications of this relation have not been studied. We aimed to assess the risk of cancer and survival after hospital admission for fever of unknown origin in a nationwide Danish follow-up study., Methods: We linked the Danish national registry of patients and the nationwide cancer registry, and assessed cancer risk for 43,205 patients discharged for the first time from Danish hospitals after admission for fever of unknown origin during 1977-97. We compared cancer frequency with that expected on the basis of cancer incidence in the general population, and survival of patients with cancer who had had fever of unknown origin with that of controls (ie, patients with cancer matched for cancer site, age at time of cancer diagnosis, and year of cancer diagnosis)., Findings: Median follow-up was 6.3 years (IQR 2.7-12.3). During the first year of follow-up, 399 cancers were diagnosed in those who had had fever of unknown origin (standardised incidence ratio 2.3 [95% CI 2.1-2.5]). These individuals had an increased risk of developing cancer--in particular haematological malignant disease; sarcoma; and cancers of the liver, brain, kidney, colon, and pancreas. After 1 year of follow-up, individuals had an increased risk of developing haematological malignant disease and cancers of the liver, brain, and kidney. A slightly higher proportion of people diagnosed with cancer within 1 year of hospital discharge after fever of unknown origin had distant metastases compared with controls (101 [34%] of 294 vs 819 [28%] of 2907; prevalence ratio 1.2 [95% CI 1.0-1.4], and had worse survival than did controls (mortality rate ratio 1.4 [95% CI 1.2-1.6])., Interpretation: Hospital admission for fever of unknown origin is a marker of occult cancer and is associated with a poor outlook.

Although venous thromboembolism (VTE) is common in patients with cancer, it is not known if it is associated with risk of a second malignancy. Using the Danish Cancer Registry and National Registry of Patients, we studied a population-based cohort of 6285 patients with cancer who had an episode of VTE. The risk of a second cancer was compared with that among 30 713 cancer patients without VTE, matched for age, sex, cancer site and year of diagnosis. Overall, the relative risk for a second cancer diagnosis was 1.3 (95% confidence interval (CI) 1.1-1.4). However, the excess risk varied with the time from the initial cancer diagnosis to the thrombotic event. If the thrombotic episode occurred within the first year, the relative risk for a second cancer was 1.0 (95% CI 0.9-1.3), but if the VTE occurred more than 1 year after the initial cancer, the overall relative risk for a second cancer was 1.4 (95% CI 1.2-1.7), with strong associations for cancers of the digestive organs, ovary and prostate. The association between VTE and subsequent incident cancer extends to patients who already have had a cancer diagnosis.

The importance of genetic factors in the etiology of non-Hodgkin lymphoma (NHL) is suggested by case-control and cohort studies. Most previous studies have been too small to estimate accurately risks of specific categories of lymphoproliferative malignancies in relatives of NHL cases or to quantify the contribution of NHL case characteristics to familial risk. We have overcome sample size limitations and potential recall bias by using large databases from Sweden and Denmark. Diagnoses of lymphoproliferative malignancies were compared in 70,006 first-degree relatives of 26,089 NHL cases (including 7,432 with subtype information) versus 161,352 first-degree relatives of 58,960 matched controls. Relatives of NHL cases were at significantly increased risk for NHL [relative risk (RR), 1.73; 95% confidence interval (95% CI), 1.39-2.15], Hodgkin lymphoma (RR, 1.41; 95% CI, 1.0-1.97), and nonsignificantly for chronic lymphocytic leukemia (CLL; RR, 1.31; 95% CI, 0.93-1.85). No increased risk was found for multiple myeloma among case relatives. Findings with respect to siblings compared with parents and offspring or with respect to age at diagnosis of proband were inconsistent. In both populations, relatives of cases with an aggressive NHL subtype were at substantially increased risk of NHL (combined RR, 3.56; 95% CI, 1.80-7.02). We conclude that NHL has an important familial component, which is shared with Hodgkin lymphoma and CLL. We estimate that the absolute lifetime risk for a first-degree relative of an NHL case to develop NHL is 3.6% (compared with a population risk of 2.1%) and higher if the index case had an aggressive subtype of NHL.

An analysis of other primary cancers in individuals with non-Hodgkin's lymphoma (NHL) can help to elucidate this cancer aetiology. In all, 109 451 first primary NHL were included in a pooled analysis of 13 cancer registries. The observed numbers of second cancers were compared to the expected numbers derived from the age-, sex-, calendar period- and registry-specific incidence rates. We also calculated the standardised incidence ratios for NHL as a second primary after other cancers. There was a 47% (95% confidence interval 43-51%) overall increase in the risk of a primary cancer after NHL. A strongly significant (P<0.001) increase was observed for cancers of the lip, tongue, oropharynx*, stomach, small intestine, colon*, liver, nasal cavity*, lung, soft tissues*, skin melanoma*, nonmelanoma skin*, bladder*, kidney*, thyroid*, Hodgkin's lymphoma*, lymphoid leukaemia* and myeloid leukaemia. Non-Hodgkin's lymphoma as a second primary was increased after cancers marked with an asterisk. Patterns of risk indicate a treatment effect for lung, bladder, stomach, Hodgkin's lymphoma and myeloid leukaemia. Common risk factors may be involved for cancers of the lung, bladder, nasal cavity and for soft tissues, such as pesticides. Bidirectional effects for several cancer sites of potential viral origin argue strongly for a role for immune suppression in NHL.

We investigated the cancer risk of patients hospitalized for schizophrenia in a nationwide cohort study. All 22766 adults admitted for schizophrenia, ICD-8 295, in Denmark between 1969 and 1993 were followed up for cancer through 1995. The incidence of site-specific cancers was compared with national incidence rates, adjusted for sex, age and calendar time. The risk for cancer was increased for both men and women during the first year of follow-up. When the first year of follow-up was excluded, the risk for all tobacco-associated cancers and for prostate and rectal cancers was reduced for male patients with schizophrenia. The standardized incidence ratio (SIR) of lung cancer was marginally reduced (SIR, 0.86; 95% CI: 0.65, 1.02) for male patients with schizophrenia; this was due, however, to a reduction in risk for older patients. An increased risk for breast cancer found for female patients with schizophrenia (SIR, 1.20; 95% CI: 1.05, 1.38) should be interpreted with caution, given the high proportion of nulliparous women with schizophrenia in Denmark. The data might support reduced risks for prostate and rectal cancer among male patients with schizophrenia, whereas a changing smoking pattern might explain the reduced risk for tobacco-related cancers.

Genetic anticipation in familial non-Hodgkin's lymphoma, Hodgkin's lymphoma, and chronic lymphocytic leukemia (CLL) has been consistently reported in the literature. However, most of these findings were based on data from families ascertained for genetic studies. Fecundity bias, right censoring bias, and secular trends can lead to erroneous conclusions regarding the presence of anticipation. Our report investigates anticipation in four lymphoproliferative cancers, non-Hodgkin's lymphoma, Hodgkin's lymphoma, CLL, and multiple myeloma, drawn from Swedish and Danish population-based registries. We used marginal survival methods to test for a relative difference in age at diagnosis between parents and offspring and to account for other risk factors, staggered entries, censored data, and correlations among relatives. Changes in incidence rates of lymphoproliferative tumors were accommodated in the models by using time-varying covariates for different periods of diagnosis. Whereas no anticipation was observed for Hodgkin's lymphoma, CLL, and multiple myeloma, our initial model, which controlled for gender and country, suggested a significant difference (hazard ratio, 0.5; 95% confidence interval, 0.33-0.75) in age at diagnosis between the parents and offspring in the non-Hodgkin's lymphoma sample. However, once we accounted for the significant change in non-Hodgkin's lymphoma incidence over time, the statistical difference between parents and offspring disappeared (hazard ratio, 0.99; 95% confidence interval, 0.56-1.76). Our results emphasize the importance of considering secular trends when evaluating the possibility of anticipation in lymphoproliferative cancers. This is the first study to consider the changes of incidence over time as a source of bias when evaluating anticipation in lymphoproliferative cancers.

Numerous studies and meta-analyses have shown that hormone replacement therapy (HRT) for menopausal symptoms increases the risk of developing breast cancer, estimated to be 2.3% for each year of use. The influence of different oestrogen-progestin regimens has still not been fully evaluated. Using longitudinal data from the population-based prescription database of the county of North Jutland, Denmark, and the Danish Cancer Registry, we examined the risk of developing breast cancer in relation to HRT in a cohort of 78,380 women aged 40-67 years from 1989 to 2002. A total of 1462 cases of breast cancer were identified during a mean follow-up of 10 years. Use of HRT did not increase the risk of breast cancer in women aged 40-49 years. Restricting the cohort to 48,812 women aged 50 years or more at entry, of whom 15 631 were HRT users, we found an increased risk associated with current use of HRT (relative risk 1.61, 95% confidence interval 1.38-1.88). The risk increased with increasing duration of use and decreased with time since last HRT prescription, reaching unity after 5 years. No material risk difference was observed among the various HRT-regimens. This population-based cohort study provides further confirmation that HRT increases the risk of developing breast cancer in women aged 50 years or more.

An international multicentre study of first and second primary neoplasms associated with male breast cancer was carried out by pooling data from 13 cancer registries. Among a total of 3409 men with primary breast cancer, 426 (12.5%) developed a second neoplasia; other than breast cancer, a 34% overall excess risk of second primary neoplasia, affecting the small intestine (standardised incidence ratio, 4.95, 95% confidence interval, 1.35-12.7), rectum (1.78, 1.20-2.54), pancreas (1.93, 1.14-3.05), skin (nonmelanoma, 1.65, 1.16-2.29), prostate (1.61, 1.34-1.93) and lymphohaematopoietic system (1.63, 1.12-2.29). A total of 225 male breast cancers was recorded after cancers other than breast cancer, but an increase was found only after lymphohaematopoietic neoplasms. BRCA2 (and to some extent BRCA1) mutations may explain the findings for pancreatic and prostate cancers. Increases at other sites may be related to unknown factors or to chance. This large study shows that the risks for second discordant tumours after male breast cancer pose only a moderate excess risk.

First pregnancies are known to have higher oestrogen levels than later ones and first-born women are at increased breast cancer risk compared with later-born women. We hypothesized that a birth order effect might be even more evident in male breast cancer patients, in whom oestrogens in adult life are generally low. In a population-based study in Denmark involving 77 male breast cancer patients and 288 population controls, first-born men compared with later-born men had a relative risk of 1.71 for the disease (95% confidence interval (CI) 1.00-2.92). This result is in line with that seen in female breast cancer cases and indicates that male breast cancer may have roots in the intrauterine life, oestrogens being a likely mediator.

Among 14,088 patients, with a primary diagnosis of Parkinson's disease during the period 1977-98 identified from the National Register of Patients, 1282 cancers were subsequently recorded in the Danish Cancer Registry, compared with 1464 expected, with a standardised incidence ratio (SIR) of 0.88 (95% confidence interval (CI), 0.8-0.9). Significantly reduced risks were found for smoking-related cancers, for example, cancers of the lung (SIR, 0.38), larynx (0.47) and urinary bladder (0.52), although moderate reductions in risk were also seen for several nonsmoking-related cancers. In contrast, increased risks were seen for malignant melanoma (SIR, 1.95; 95% CI, 1.4-2.6), nonmelanocytic skin cancer (1.25; 1.1-1.4) and breast cancer (1.24; 1.0-1.5). The observed cancer pattern supports the hypothesis that constituents of tobacco smoke inhibit or delay the development of Parkinson's disease, but a low smoking prevalence appears to be only part of the explanation for the decreased cancer incidence. The increased relative risks of melanoma and nonmelanoma skin cancer are not likely to be artefactual, but further investigations of potential mechanisms are warranted.

Background: Studies have shown a positive association between serum insulin-like growth factor (IGF)-I and breast cancer risk in premenopausal but not postmenopausal women. IGF-II and estrogen receptor (ER) status has never been investigated. We examined the association between IGF-I, IGF-II, IGF binding protein (IGFBP)-2, IGFBP-3, and IGFBP-3 protease activity and breast cancer risk in postmenopausal women, taking ER status of the breast cancer into consideration., Methods: We conducted this case-cohort study within a Danish follow-up study based on 24,697 postmenopausal women. We identified 411 cases with breast cancer and a matched control group including 397 cohort members. We estimated breast cancer risk using Cox regression analysis with adjustment for known breast cancer risk factors., Results: We observed no association for IGF-I but a positive association between levels of IGFBP-3 and breast cancer risk. Per 500 units higher levels of IGFBP-3, an incidence rate ratio [IRR; 95% confidence interval (95% CI)] of 1.14 (1.00-1.30) was estimated. For ER-positive breast cancer, the IRR (95% CI) was 1.18 (1.05-1.33). IGFBP-3 protease activity was not associated with breast cancer risk. Per 275 units higher levels of IGF-II, an IRR (95% CI) of 1.35 (1.10-1.66) was observed for ER-positive tumors, whereas IGFBP-2 was not associated with breast cancer risk. Adjustment for potential confounders did not change the risk estimate. There was no association between IGF-I, IGF-II, IGFBP-2, or IGFBP-3 and risk of ER-negative breast cancer., Conclusion: Serum IGFBP-3 and IGF-II levels were positively associated with ER-positive breast cancer risk. This may suggest an important relationship among IGFs, IGFBPs, the ER system, and breast cancer development in postmenopausal women.

The possibility of an interaction between gender and fetal growth on the risk of Wilms tumor is poorly examined. Using nationwide population-based registries, the authors identified all children (N = 126) diagnosed with Wilms tumor in Denmark, 1973-1993, and selected 10 matched population controls per case. Data on birth weight, gestational age, and ponderal index were used to examine the association between gender, fetal growth, and risk of Wilms tumor. It was found that the risk of Wilms tumor increased with fetal growth in girls, but decreased with fetal growth in boys, although the findings did not reach statistical significance.

Background: On the basis of a population-based cohort, we assessed the cancer risk, focusing on gynaecological cancers and pre-malignant lesions, among women with a previous tubal sterilization., Methods: Using the Danish Hospital Discharge Register we identified 65 232 women who had a tubal sterilization (1977-1993). The cohort was followed for cancer occurrence, and compared with the expected number based on the national cancer incidence rates., Results: The overall risk of ovarian cancer was decreased (standardized incidence ratio [SIR] = 0.82; 95% CI: 0.6, 1.0), and it was still decreased > or =10 years after the sterilization (SIR = 0.65; 95% CI: 0.4, 1.0). The rate of endometrial cancer was also decreased (SIR = 0.66; 95% CI: 0.5, 1.0), the risk continued being moderately reduced during follow-up, although it was not statistically significant., Conclusions: In this nationwide, population-based study we find that women with tubal sterilization have a decreased risk of subsequent development of ovarian cancer. As the protective effect is not decreasing with years of follow-up, our data do not support that 'screening' bias can explain the protective effect, but indicate that the sterilization itself may convey a reduction in risk. The same pattern is found for endometrial cancer, the association being less strong.

Background: The goal of the current study was to investigate the relation between hormone replacement therapy (HRT) and breast carcinoma in a prospective study cohort. Particular attention was paid to the type of HRT used and to the association of HRT type with estrogen receptor status and tumor histology., Methods: Between 1993 and 1997, a total of 29,875 women were enrolled in the Danish Cancer Society's prospective "Diet, Cancer and Health" study. Among 23,618 women who were assumed to be postmenopausal and for whom information on HRT use was available, we identified 423 cases of breast carcinoma over a median follow-up period of 4.8 years. Statistical analyses were based on the Cox proportional hazards model, with age serving as the time parameter., Results: The breast carcinoma incidence rate ratio (IRR) was 2.22 (95% confidence interval [CI], 1.80-2.75) for users of HRT at baseline compared with women who never received HRT. Among HRT users (relative to nonusers), the IRR for estrogen receptor-positive tumors (2.38; 95% CI, 1.84-3.06) was greater than the IRR for estrogen receptor-negative tumors (1.56; 95% CI, 1.00-2.43). HRT use at baseline also was analyzed in relation to the incidence of lobular carcinoma and the incidence of ductal carcinoma; the adjusted IRR associated with HRT use was 3.53 (95% CI, 1.94-6.41) for lobular carcinoma and 2.10 (95% CI, 1.64-2.70) for ductal carcinoma. The likelihood of developing estrogen receptor-positive breast carcinoma was found to depend significantly on the type of HRT regimen used (P = 0.03), with women receiving continuous therapy having the greatest probability of developing estrogen receptor-positive disease., Conclusions: An increased breast carcinoma IRR was found to be associated with current HRT use. In addition, relative to other types of HRT regimens, continuous estrogen + progestin regimens were found to be associated with an increased risk of breast carcinoma, and particularly estrogen receptor-positive breast carcinoma., (Copyright 2004 American Cancer Society.)

Patients treated with glucocorticoids may have an increased risk of skin cancer. Using data from the population-based North Jutland Prescription Database and the Danish Cancer Registry, we compared observed and expected numbers of cases of skin cancer and non-Hodgkin lymphoma among 59 043 individuals who received prescriptions for glucocorticoids, a common immunosuppressive therapy, during an 8-year period from January 1, 1989, through December 31, 1996. The overall risks for squamous cell carcinomas and basal cell carcinomas of the skin were increased, particularly among persons who had 15 or more prescriptions (standardized incidence ratio [SIR] for squamous cell carcinomas = 2.45, 95% confidence interval [CI] = 1.37 to 4.04; SIR for basal cell carcinomas = 1.52, 95% CI = 1.09 to 2.07). An elevated risk was also found for non-Hodgkin lymphoma among those with 10-14 prescriptions (SIR = 2.68, 95% CI = 1.16 to 5.29). Our data suggest that use of glucocorticoids may be a shared risk factor for certain skin cancers and lymphomas.

Objective: This study attempted to determine whether a genetic protection against cancer might be manifest in parents of offspring with schizophrenia., Method: Using data from the Danish Central Population Registry, the authors identified 1,999,072 parents of offspring born after 1935. By linking this nationwide population-based parent cohort to the Danish Psychiatric Central Register, they identified 19,856 parents of offspring with schizophrenia. Follow-up for cancer in the Danish Cancer Registry began on the date of birth of the oldest child or April 1, 1969, and ended on the date of cancer diagnosis, death, or Dec. 31, 1997, yielding a total of 48,343,430 person-years at risk and 211,681 cases of cancer. The relative risk for cancer among parents with schizophrenic offspring compared to parents with no schizophrenic offspring was estimated by Poisson regression analysis and adjusted for age, period, and number of children., Results: The risk for all cancer was 1.01 for fathers and 1.00 for mothers of schizophrenics. Mothers of schizophrenic patients had an increased risk of 1.20 for lung cancer and a nonsignificant risk of 1.14 for tobacco-related cancers combined. Apart from a reduced risk for leukemia in both mothers and fathers of schizophrenics, there was no difference in risk for any other cancer., Discussion: This study does not confirm a previously reported reduced risk for cancer in parents of schizophrenic patients and provides no support for genetic protection against cancer in families with schizophrenia.

Using the population-based Pharmacoepidemiologic Prescription Database of North Jutland County, Denmark, we identified 113,538 persons who filled prescriptions for ibuprofen during 1989 through 1995 and determined subsequent mortality through 1996. Standardized mortality ratios [SMRs] for 25 specific causes of death were computed compared with the general population. SMRs were elevated for most causes of death, with an overall SMR of 1.21 (95% confidence interval 1.19-1.24) among persons who filled prescriptions for ibuprofen. There was a nearly threefold increase in the number of deaths from gastrointestinal bleeding within 1 year of ibuprofen prescription but no concomitant increase in hemorrhagic stroke. Elevated SMRs were seen for several cancer types, although the mortality ratios were highest within 1 year of prescription and declined with longer follow-up. For colon cancer, SMRs were below 1.0 three or more years after ibuprofen prescription. For hypertensive disease, nonhemorrhagic stroke, and diabetes, we observed slight but significant elevations of the SMRs that persisted beyond the fifth year of follow-up. Our findings indicate a slight increase in overall mortality among persons receiving ibuprofen on prescription. This excess was greatest within the first year, due partially to ibuprofen-related gastrointestinal bleeding but mostly to elevated cancer mortality among ibuprofen users. This temporal pattern is characteristic of an effect of confounding by indication, with ibuprofen being used for pain relief by patients with imminent fatal illnesses such as cancer. The slight excess mortality that persisted beyond the first few years was largely due to elevated death from hypertensive disease and diabetes, which may be explained in part by increased prescription of ibuprofen to patients with long-standing medical problems.

Background: The importance of genetic factors in the etiology of Hodgkin lymphoma (HL) has been suggested by family and population studies. However, the spectrum of malignancies associated with common genetic etiology and the effects of gender and age on familial risk have not been established., Methods: Diagnoses of lymphoproliferative malignancies were compared in 15,799 first-degree relatives of 5047 patients with HL versus 32,117 first-degree relatives of 10,078 control probands from Sweden and in 7185 first-degree relatives of 2429 patients with HL versus 27,434 first-degree relatives of 8,495 control probands from Denmark using marginal survival models., Results: The risk of HL in relatives of patients with HL was increased significantly in both populations, with relative risks of 3.47 (95% confidence interval [95% CI], 1.77-6.80) in Sweden and 2.55 (95% CI, 1.01-6.45) in Denmark and a pooled estimate of 3.11 (95%CI, 1.82-5.29). In Sweden, risks for relatives of patients also were increased significantly for chronic lymphocytic leukemia and non-Hodgkin lymphoma (in males). Relative risks were higher in males compared with females and in siblings of patients compared with parents and offspring of patients. Relatives of patients with earlier-onset disease were at higher risk for HL., Conclusions: HL has an important familial component, which is stronger in families of affected individuals age < 40 years, in males, and in siblings, and it is shared with some (but not other) lymphoproliferative malignancies. The cumulative lifetime risks are very small, however, for the development of HL de novo or in first-degree relatives of affected patients.

Background/aims: There are very limited data available regarding the prognosis of patients with fatty liver. We examined the overall and cause-specific mortality of fatty liver patients in a large Danish cohort., Methodology: In the Danish National Registry of Patients, we identified 7,372 patients discharged with a diagnosis of fatty liver from a Danish hospital between 1977 and 1993. Causes of death were identified in the Danish Death Registry. We estimated the standardized mortality ratio by comparing with the general population., Results: Most patients (76%) had alcoholic fatty liver. During follow-up, 2,914 (40%) died. The commonest cause of death was hepatobiliary disease (25% of deaths). Mortality was increased 5.4-fold (95% CI 5.2-5.6) in patients with alcoholic fatty liver, and 2.6-fold (95% CI 2.4-2.9) in patients with non-alcoholic or unspecified fatty liver. Overall, in the first year of follow-up, mortality was increased more than 7-fold, almost 5-fold in the second to fifth years, and more than 3-fold after that. Mortality was similar among genders and among diabetics and non-diabetics, and remained increased after censoring patients upon diagnosis of liver cirrhosis., Conclusions: The mortality of patients with a hospital discharge diagnosis of fatty liver was higher than that of the general population.

Background: We investigated whether children and adolescents who survive cancer are at increased risk for psychiatric hospitalization., Methods: In a nationwide, population-based, retrospective cohort study, 3710 persons who survived at least three years after a diagnosis of cancer in childhood or adolescence in the period from 1943 to 1990, and who were alive on January 1, 1970, or were born after that date, were identified in the Danish Cancer Registry. This population was followed up for psychiatric hospitalization from January 1, 1970, through 1993 by linkage with the Danish national Psychiatric Central Register. The number of expected cases was based on the national rates of hospitalization for psychiatric disease., Results: Among the 3710 survivors of cancer in childhood or adolescence, there was a total of 88 psychiatric hospitalizations. The risk of hospitalization for any psychiatric disease was higher among the survivors than in the general population, but the excess risk was restricted to survivors of brain tumor (the standardized hospitalization ratio [SHR], corresponding to the ratio of observed to expected cases of hospitalization for psychiatric disease, was 1.8; 95 percent confidence interval, 1.5 to 2.2). An increased risk of psychoses of somatic, cerebral causes (SHR, 7.7; 95 percent confidence interval, 4.1 to 13.2), psychiatric disorders in somatic disease (SHR, 5.1; 95 percent confidence interval, 2.5 to 9.1), and schizophrenia and related disorders (SHR, 2.4; 95 percent confidence interval, 1.2 to 4.4) was observed among survivors of brain tumor. There was no evidence of a significantly increased risk of major depression., Conclusions: The risk of hospitalization for a psychiatric disorder is not increased among survivors of cancer in childhood or adolescence, except among survivors of brain tumor., (Copyright 2003 Massachusetts Medical Society)

Objective: We examined overall and cause-specific mortality in a population-based cohort of individuals prescribed paracetamol. We evaluated rates of death due to liver and renal disease, cancer, and other major causes of death., Method: Using the population-based pharmacoepidemiology prescription database of North Jutland County, Denmark, we identified nearly 50,000 persons receiving prescriptions for paracetamol from 1989 to 1995 and evaluated mortality through 1996. Standardized mortality ratios (SMRs) for 18 specific causes of death were computed for persons prescribed paracetamol compared with persons among the general population of the county., Results: SMRs were elevated regardless of cause of death, with a nearly doubled overall death rate among persons prescribed paracetamol. The mortality ratios were highest within 1 year of paracetamol prescription and tended to decline with increasing follow-up, especially for cancers. The magnitudes of the excess mortality risks for liver and renal diseases were not materially higher than for other causes of death., Conclusion: Paracetamol is a first-line analgesic for patients with a wide variety of chronic or serious illnesses and therefore is associated with increased rates of nearly all causes of death. The findings are an example of confounding by indication. Paracetamol may be a drug most prone to this form of bias in pharmacoepidemiologic studies. Future observational studies reporting adverse effects of paracetamol must thoroughly evaluate confounding by indication before making causal inferences.

The authors investigated the risk for breast cancer in schizophrenia in a cohort of 1336313 Danish women born after 1935, including information on reproductive factors. In all, 7541 had been hospitalized for schizophrenia in 1970-1997 and the overall relative risk for breast cancer adjusted for age, period, age at first birth and number of births was not increased (RR, 0.91; 95% confidence interval, 0.71-1.12). Studies not taking parity into account may overestimate the risk for breast cancer in schizophrenic women.

Purpose: Infections have been hypothesized to be a risk factor for Hodgkin disease and non-Hodgkin lymphoma. Because infections usually occur seasonally, the authors looked at the seasonal pattern of occurrence of these diseases, since seasonal variation in occurrence would lend support to the hypothesis of an etiologic link between infection and lymphoma., Methods: The authors identified 575 patients with Hodgkin disease and 498 with non-Hodgkin lymphoma under the age of 20 years in the Danish Cancer Registry from 1943 to 1994. A periodic regression model was used to evaluate the seasonal distribution of month of diagnosis and month of birth., Results: For the month of diagnosis of Hodgkin disease, the peak month of occurrence was March. The peak-to-trough ratio (the estimated incidence in the month of the peak divided by the estimated incidence in the month of the trough) was 1.57. For birth date, the ratio of case births at the peak month to case births at the trough month was 1.21, with a peak in July. There was no meaningful seasonal variation in the diagnosis or month of birth of children with non-Hodgkin lymphoma., Conclusions: These data corroborate a previously reported March peak in the diagnosis of Hodgkin disease.

Goals: To examine the risk of cancer in patients with fatty liver., Background: The relation between liver disease, including fatty liver, and cancer risk is poorly understood., Study: Using the population-based National Registry of Patients, we examined the incidence of cancer in 7,326 patients discharged with a diagnosis of fatty liver from a Danish hospital during 1977-1993. Patients with a prior diagnosis of liver cirrhosis were excluded. We identified cancers through the Danish Cancer Registry. The expected number of cancers was estimated from national age-, sex-, and site-specific incidence rates., Results: Overall, 523 cancers were diagnosed during 47,594 person-years of follow-up, yielding a 1.7-fold increased risk (95% confidence interval, 1.6-1.9) compared with the Danish general population. The risk of primary liver cancer was markedly elevated in patients with alcoholic as well as nonalcoholic fatty liver with a standardized incidence ratio of 9.5 (95% confidence interval, 5.7-14.8) and 4.4 (95% confidence interval, 1.2-11.4), respectively. Patients with alcoholic fatty liver also had substantially increased risks of several types of cancer associated with alcohol and tobacco use (cancers of the lung, pharynx, larynx, esophagus, and stomach) and a moderately increased risk for cancers of the colon and breast. Among patients with nonalcoholic fatty liver, an increased risk of some alcohol- and tobacco-related cancers was seen, and there was also an increased risk of colon and pancreas cancer., Conclusions: Patients discharged with a diagnosis of fatty liver have an increased risk of cancer, in particular liver cancer, most prominently among patients with alcoholic fatty liver.

Background: Individuals with Down syndrome (DS) have a predisposition to leukemia and possibly other cancers and excess mortality from other conditions, but information on the magnitude of risk associated with specific cancers or causes of death is sparse., Methods: Mortality experience and cancer incidence were evaluated in a combined cohort of 4872 individuals with a hospital discharge diagnosis of DS in Sweden (1965-1993) or Denmark (1977-1989) by linkage to national cancer and vital statistics registries. Standardized incidence ratios (SIRs) and standardized mortality ratios (SMRs) were estimated by comparison with age, sex, and calendar-year expected values., Results: Individuals with DS had an increased risk of incident acute lymphocytic (SIR, 24.2; 95% confidence interval [CI], 15.2-36.6; n = 22) and acute nonlymphocytic (SIR, 28.2; 95% CI, 15.7-48.3; n = 14) leukemias. Risks of testicular cancer (SIR, 3.7; 95% CI, 1.0-9.4; n = 4) and liver cancer (SIR, 6.0; 95% CI, 1.2-17.5; n = 3) were also elevated. Individuals with DS also experienced elevated mortality attributed to stomach cancer (SMR, 6.4; 95% CI, 1.7-16.4; n = 4), dementia and Alzheimer disease (SMR, 54.1; 95% CI, 27.9-94.4), epilepsy (SMR, 30.4; 95% CI, 13.9-57.7), ischemic heart disease (SMR, 3.9; 95% CI, 2.7-5.4), other heart disease (SMR, 16.5; 95% CI, 11.0-23.7), cerebrovascular disease (SMR, 6.0; 95% CI, 3.5-9.6), infectious diseases (SMR, 12.0; 95% 6.0-21.4), and congenital anomalies (SMR, 25.8; 95% CI, 21.0-31.4)., Conclusions: Individuals with DS have a substantially increased risk of mortality due to specific causes and may have an elevated risk of other incident cancers in addition to leukemia. These results provide clues regarding chromosome 21 gene involvement in diseases that complicate DS and are important for disease detection and care of affected individuals.

Objective: To investigate if birth weight is associated with early-onset breast cancer. The mechanism behind an association with high birth weight could be the link between fetal growth and estrogens in utero., Methods: We conducted a population-based case-control study in Denmark including 881 women with breast cancer diagnosed before the age of 40 years and 3,423 age-matched controls. Information concerning birth weight and other birth-related variables was obtained from midwife reports., Results: The risk of early-onset breast cancer was increased 1.25 times (95% CI 1.00-2.51) for birth weights above 4,000 g and 1.59 times (95% CI 1.00-1.55) for birth weights below 2,500 g in comparison with birthweights of 3,000-3,499 g., Conclusions: The finding that high birth weight is associated with breast cancer is compatible with the hypothesis that level of estrogen during pregnancy is related to breast cancer in early adult life. The finding that low birth weight is also associated with breast cancer may indicate that other characteristics of the fetal environment may be important for breast cancer in early adult life.

Background: Selective serotonin reuptake inhibitors (SSRIs) have been suspected of increasing the risk of bleeding. We examined the risk of upper gastrointestinal tract (GI) bleeding with use of antidepressant medication., Methods: All users of antidepressants in the county of North Jutland, Denmark, from January 1, 1991, to December 31, 1995, were identified in the Pharmaco-Epidemiologic Prescription Database of North Jutland. In the Hospital Discharge Register, hospitalizations for upper GI bleeding were searched among the 26 005 users of antidepressant medications and compared with the number of hospitalizations in the population of North Jutland who did not receive prescriptions for antidepressants., Results: During periods of SSRI use without use of other drugs associated with upper GI bleeding, we observed 55 upper GI bleeding episodes, which was 3.6 times more than expected (95% confidence interval, 2.7-4.7), corresponding to a rate difference of 3.1 per 1000 treatment years. Combined use of an SSRI and nonsteroidal anti-inflammatory drugs or low-dose aspirin increased the risk to 12.2 (95% confidence interval, 7.1-19.5) and 5.2 (95% confidence interval, 3.2-8.0), respectively. Non-SSRIs increased the risk of upper GI bleeding to 2.3 (95% confidence interval, 1.5-3.4), while antidepressants without action on the serotonin receptor had no significant effect on the risk of upper GI bleeding. The risk with SSRI use returned to unity after termination of SSRI use, while the risks were similarly increased during periods of use and nonuse of non-SSRIs., Conclusion: Selective serotonin reuptake inhibitors increase the risk of upper GI bleeding, and this effect is potentiated by concurrent use of nonsteroidal anti-inflammatory drugs or low-dose aspirin, whereas an increased risk of upper GI bleeding could not be attributed to other types of antidepressants.