Incidence Of Hodgkin's Disease Research Articles

Incidence of haematological malignancies in adults in Szabolcs-Szatmár-Bereg county, Hungary. Analysis of data of a 36-year period

During a 36-year period (between January 1, 1983 and December 31, 2018), 5159 adult patients with newly diagnosed haematological malignancy were registered in the leukaemia/lymphoma registry of Szabolcs-Szatmár-Bereg county. The review of the incidence of different haematological malignancy in the authors' county, and the changes of incidence from time to time, the associated haematological malignancies, and familial occurrence of malignant haematological diseases. Detailed analysis of the data of the registry, with statistical analysis of incidence. The incidence of Hodgkin disease and non-Hodgkin's lymphoma (1.49 and 7.12 new cases, respectively/100000 inhabitants/year) was a little smaller, that of essential thrombocythaemia was larger than in the published data. The incidence of all other haematological malignancies corresponded to the data of the literature. The change of incidence of all malignant haematological diseases was similar to the published data. In the registry, there were 35 patients with two different malignant haematological diseases appearing simultaneously or successively. During the 36-year period, 88 families with haematological malignancies were recorded in the registry. With the exception of Hodgkin disease, non-Hodgkin's lymphoma, and essential thrombocythaemia, the incidence of other haematological malignancies corresponded to the data of the literature. The change of incidence in all entities was similar to that observed by other authors. The authors in their country do not know other published data related to associated malignant haematological diseases. The observed anteposition in familial haematological diseases of uncle/aunt and nephew/cousin, and anteposition in malignant haematological diseases of siblings are equally new in the literature. Orv Hetil. 2020; 161(34): 1400-1413.

Hodgkin Disease and Pregnancy - A Case Report

Abstract The article presents a case with diagnosed Hodgkin disease (HD) during pregnancy. The aim of this case study was to present diagnostic possibilities in determining HD stage during pregnancy and therapeutic dilemmas. The incidence of HD during pregnancy is 3.2% of all cases with this malignant hematological disorder. The treatment of this disease during pregnancy depends on disease-related factors, pregnancy-related factors, as well as possible implications for fetal morbidity and mortality. The need of analysis of the nature of the disease during pregnancy indicates examination of a larger series of pregnant women with HD and the drawn conclusions affect the decision whether chemotherapy treatment should start immediately or it should be postponed for after delivery.

Fertility preservation after caesarean delivery in a woman diagnosed with Morbus Hodgkin disease during pregnancy

Female fertility preservation before chemotherapy has become a common issue among postpubertal and premenopausal women who desire children. Von Wolff et al. [1] recently published a practical guideline for different fertility preservation techniques, based on data from the FertiPROTEKT network database. The published practical guideline particularly addresses women with breast cancer, Hodgkin disease, or borderline ovarian tumour. The following are the different fertility preservation techniques covered: (1) hormonal stimulation and cryopreservation of unfertilised and fertilised oocytes, (2) cryopreservation of ovarian tissue, and (3) administration of gonadotropin-releasing hormone agonists (GnRHa). There is one or more than 1 option available for cancer patients, depending on cancer type, partnership, and individual desire. The classical Hodgkin’s lymphoma presents with an enlargement of lymph nodes and unspecific symptoms like night sweats, unexplained weight loss, fatigue and others. It is classified histopathologically by the typical Sternberg-Reed-Cells and may be cured with modern polychemotherapy in more than 80 % [2]. Women with Morbus Hodgkin receiving COPP/ABVD (cyclophosphamide, vincristine [O], procarbazine, prednisolone/adriamycin, bleomycin, vinblastine, and dacarbazine) or BEACOPP (bleomycin, etoposide, adriamycin, cyclophosphamide, vincristine [O], procarbazine, and prednisolone) have a high risk of amenorrhoea after chemotherapy [1, 3, 4]. The incidence of Hodgkin disease in pregnancy is low, with an estimated prevalence of 1 per 6,000 pregnancies [5]. If the diagnosis is made during the first trimester, the pregnancy usually needs to be interrupted [5]; however, with low-risk lymphoma, the pregnancy might be prolonged until labour. Even if a woman has given birth to a healthy child, she may still have the desire for more children. Therefore, fertility preservation techniques should be considered, especially for young mothers. To the best of our knowledge, no report has been published on fertility preservation in pregnant women or women who had given birth just a few days before an anti-cancer treatment.

Breast cancer and microbial cancer incidence in female populations around the world: A surprising hyperbolic association

Current literature on cancer epidemiology typically discusses etiology of cancer by cancer type. Risks of different cancer types are, however, correlated at population level and may provide etiological clues. We showed previously an unexpected very high positive correlation between breast cancer (BC) and young-adult Hodgkin disease incidence rates. In a population-based case-control study of BC, older ages at the first Epstein-Barr virus exposure, indicated by older ages at onset of infectious mononucleosis, were associated with elevated BC risk. Here we examine BC risk in association with microbial cancer (MC) risk in female populations across the world. MC cancers are cervical, liver and stomach cancers with established causal associations with human papillomaviruses, hepatitis viruses, and helicobacter pylori, respectively. We examined age-adjusted BC and MC incidence rates in 74 female populations around the world with cancer registries. Our analysis suggests that BC and MC rates are inversely associated in a special mathematical form such that the product of BC rate and MC rate is approximately constant across world female populations. A differential equation model with solutions consistent to the observed inverse association was derived. BC and MC rates were modeled as functions of an exposure level to unspecified common factors that influence the 2 rates. In conjunction with previously reported evidence, we submit a hypothesis that BC etiology may have an appreciable link with microbial exposures (and/or immunological responses to them), the lack of which, especially in early life, may elevate BC risk.

Sperm Cryopreservation: Recent and Marked Increase in Use for Testicular Cancer Compared With Hodgkin Disease

In a public network of sperm banks, time trends in use of sperm cryopreservation by men with testicular cancer (TC) and Hodgkin disease (HD) were assessed from 1990 to 2004. During this period, overall incidence of sperm cryopreservation rose from 1.08 to 3.06 per 100 000 person-years for TC and from 0.79 to 1.20 for HD. Modeling suggests that in 2010 the expected rate will reach 5.90 per 100 000 for TC, compared with 1.39 for HD. This increase in sperm cryopreservation for TC and HD is similar to increases observed in incidence of these 2 diseases in France and other European countries. Although TC and HD are rare malignancies, they are the most common cancers in adolescents and young men (Bray et al, 2002). Recent advances in chemotherapy and/or radiotherapy treatments have improved the longterm survival of patients with these diseases (5-year survival rate is approximately 90%). Nevertheless, the side effects of treatment, especially infertility (decrease of 30%), are still a major preoccupation for these young patients who often have not yet fathered children (Huyghe et al, 2004). Accordingly, sperm cryopreservation and sperm banking are now offered to these men before treatment to preserve their capacity to conceive naturally or through assisted reproduction techniques (Hallak et al, 1999; Magelssen et al, 2005). With this aim in mind, a unique public network of sperm banks (Centre d’Etude et de Conservation des Oeufs et du Sperme [CECOS]) was created in France in 1984, and 22 centers now cover the whole country. Sperm banks appear to be increasingly used for sperm donation and to offer the possibility of preserving sperm in the event of disease or surgical treatment, especially for men with HD and TC (Agarwal, 2000). The recent and marked increase of these diseases in most industrialized countries is a major concern (Parkin et al, 1997), drawing the attention of oncologists to the need for sperm cryopreservation. Although this option is still underutilized, it is now becoming a good and safe practice to safeguard future fertility (Chung et al, 2004). The aim of this study was to assess time trends in the use of sperm banking over the period of 1990 to 2004 by men with TC or HD.

Incidence of lymphohaematopoietic cancer at a university laboratory: a cluster investigation

We investigated a suspected cluster of lymphohaematopoietic cancer in departments of biology and chemistry at a Norwegian university. A historical cohort of students and employees (n = 7,189) were followed for cancer for 96,936 person-years in the Cancer Registry of Norway. Overall, 12 cases of lymphohaematopoietic cancer were identified, which was close to the expected number (standardised incidence ratio 1.1, 95% confidence interval (CI) 0.6-1.9). The SIR for leukaemia was 1.8 (95% CI 0.6-4.2) whereas incidences for non-Hodgkin lymphoma and Hodgkin's disease incidence were close to the expected. Distinct rate differences were observed in subgroups, and the strongest adjusted associations were found for Ph.D. students (rate ratio (RR) = 4.8, 95% CI 1.1-20.3) and students who participated in basic organic chemistry laboratory course (RR = 4.4, 95% CI 1.2-18.8). The latter category was identified a priori because it was the only student activity with known use of benzene according to the university administration. This is an observational study with some limitations, and hence, caution is warranted when drawing inferences on the causal relationship between university activities and cancers under study. The study provides an example that cluster investigations can answer questions of public importance despite a more limited value regarding causal inference.

Outcomes for hematologic malignancies in the Nurses’ Health Study (NHS) as compared to the Surveillance, Epidemiology, and End Results (SEER) program

6599 Background: Health literacy, often defined as the degree to which an individual can obtain and understand information needed to make appropriate health decisions, may lead to a decreased incidence and improved mortality for some cancers by promoting risk factor modification and adherence to treatment. As a result, nurses, who presumably possess a higher level of health literacy and access to care than the general population, might be expected to manifest a lower incidence of and better survival for the hematologic malignancies. Methods: We assessed the incidence, all-cause, and cause-specific mortality for Hodgkin's disease (HD), non-Hodgkin's lymphoma (NHL), multiple myeloma (MM) and chronic lymphocytic leukemia (CLL) in the NHS, an ongoing cohort study of 121,700 female registered nurses aged 30–55 years at entry who have been followed for 30 years. We compared these outcomes to those in the SEER program of the National Cancer Institute, matching for age and race. Results: In over 2.5 million person-years, the incidence of HD in the NHS was the same as in SEER. The incidence of NHL, CLL and MM was slightly increased. All-cause mortality was better in the NHS when compared to SEER for HD (HR= 0.62, 95% CI: [0.38, 1.0]) and NHL (HR= 0.81, 95% CI: [0.71, 0.91]). There were no differences in cause-specific mortality, except for MM, which was worse in the NHS (HR= 1.27, 95% CI: [1.07, 1.52]). Conclusion: The incidence of hematologic malignancy is not reduced in nurses, possibly because preventable risk factors for these cancers have yet to be elucidated. To the contrary, the slight increase in incidence for NHL, MM and CLL may be due to higher levels of overall health vigilance and/or occupational exposures. The fact that cancer-related mortality is similar for nurses as compared to age and race-matched SEER controls casts doubt on the roles of health literacy and access to care in improving survival for these disorders. No significant financial relationships to disclose. [Table: see text]

Total Registration of Non-Hodgkin's Lymphoma and Hodgkin's Disease in Scotland: Effect of Deprivation and Caseload on Outcome

All cases ≥16 years of age with a histological diagnosis of non-Hodgkin's lymphoma (NHL) and Hodgkin's disease (HD) presented in Scotland between 1 January 1994 and 31 December 1996 were registered prospectively in the Scotland and Newcastle Lymphoma Group database by a process of total registration. The census population of Scotland in 1996-1997 was 5.1 million.One thousand seven hundred and sixty three patients were registered with NHL and 350 patients with HD. These patients have been followed up for a median of 47 months in the case of NHL and 51 months for HD cases. Actuarial 5-year survival for adult NHL was 35% and for HD, 75%. Outcome for both NHL and HD was particularly poor in the population over 60 years with median survival of 18 months for NHL and 27 months for HD. When analysis of survival was related to degree of material deprivation using the Carstairs score a significantly poorer survival was seen for NHL with increasing deprivation that could not be explained by a different pattern of age or stage at presentation. Deprivation had no impact on incidence or survival in HD. Analysis of impact of caseload of the physician initiating therapy showed no significant difference in 5-year survival.

Hodgkin's disease in the elderly: a population-based study.

This study evaluated the incidence and outcome of Hodgkin's disease (HD) in older patients using a population-based approach. In total, 102 patients (52 men, 50 women) aged >or= 60 years presented in the Northern Health Region of England (population of 3.09 million) between 1 January 1991 and 31 December 1998 and were studied prospectively. The age-specific incidence was 1.97/100,000 for those aged 60-69 years, and 2.18/100,000 for those aged 70 years or over. The median age of the cohort was 70 years (range 60-91) and the median follow up was 63 months (range 20-113). Out of 95 treated patients, 70 (74%) obtained complete or good partial (> 90% response) remissions. In the 60 to 69-year-old group, the disease-specific survival at 5 years was 100% for those presenting with early stage disease and 52% for those with advanced stage disease. In patients aged >70 years the 5 year disease-specific survival was 36% in patients with early stage and 14% for patients with advanced stage disease. The survival of patients with Epstein-Barr virus (EBV)-positive tumours was significantly poorer than that of patients with EBV-negative tumours (P = 0.007); median survival in the former group was 20 months versus undefined in the latter group. In total, 43 deaths were due to progressive HD and five were treatment-related. This study defined the incidence of HD in our population and demonstrated that the prognosis of elderly patients, particularly those with advanced stage disease, has not improved concurrently with that of patients aged < 60 years old. Novel approaches to assessment and treatment are necessary.

Lymphomas in rheumatoid arthritis patients treated with methotrexate: a 3-year prospective study in France

A national prospective study was designed to collect all cases of lymphoma appearing in patients with rheumatoid arthritis (RA) treated with methotrexate (MTX) throughout France over a period of 3 years. A total of 25 cases of lymphoma were recorded, 18 cases of non-Hodgkin lymphoma (NHL), 3 of which were associated with the presence of Epstein-Barr virus (EBV) in lymphoma cells, and 7 cases of Hodgkin disease (HD), 5 of them associated with EBV. Among the 8 patients who were treated by MTX withdrawal alone, 3 underwent remission, but 2 of them had a relapse, the third patient with clonal EBV-associated large granular lymphocytes T-cell NHL remaining alive in complete remission. The estimated annual incidence rate of NHL in RA patients treated with MTX was 33.3.10(-5) (0-80.5) among men and 16.7.10(-5) (0-33.3) among women. There was no significant excess with the French population as a comparison: the standardized mortality ratio (SMR) adjusted for age and sex was 1.07 (0.6-1.7). The estimated annual incidence rate of HD among men and women was, respectively, 27.8.10(-5) (0-70.1) and 2.8.10(-5) (0- 9.6). The incidence of HD was significantly increased compared with the French incidence, with an SMR adjusted for age and sex of 7.4 (3.0-15.3; P <.001). Thus, this 3-year prospective study indicated that, whereas the risk of NHL was not significantly increased in RA patients treated with MTX, the incidence of HD appeared to be higher in these patients compared to the French population.

Social class and risk of Hodgkin's disease in young-adult women in 1988-94.

Hodgkin's disease (HD) risk in young adults has been associated with higher childhood social class. Although recent decades have witnessed increases in both young-adult HD incidence rates and the socioeconomic affluence reported to influence risk, social class risk factors have not been reexamined. For 204 cases and 254 controls aged 19-44 years from a population-based case-control study of HD diagnosed in 1988-94 in San Francisco area females, we evaluated social class predictors of HD overall and for subgroups defined by age and by ethnicity. HD was associated weakly with a few childhood social class markers but more strongly with combinations of these variables. Risk was higher for women with family-owned than rented childhood homes; for US-born women with single vs. shared bedrooms at age 11; and for women with 2+ births who were from smaller than larger childhood households. These patterns differed by age, with risk appearing to increase over the young-adult years for some factors and to decrease for others. In whites, risk was additionally associated with having a single childhood bedroom in larger households, and with tall adult height in women from smaller childhood households. In nonwhites, risk was higher for single bedrooms at age 11 in smaller childhood households, taller height and higher maternal education. Most study findings support the hypothesis that HD development in young adults follows protection from early exposure to other children. Variation in risk by age suggests differing etiologies across young adulthood, or the importance of birth cohort-appropriate social-class measures. Negative findings for previously reported risk factors may reflect their insufficient heterogeneity of exposure or their failure to measure cohort-relevant exposures in this population.

Hodgkin's disease in Asians: incidence patterns and risk factors in population-based data

Hodgkin's disease (HD) has been reported to be rare in Asians. Data sparseness has hindered studies exploring the relative contributions of environment and heredity to HD etiology, and individual risk factors have never been studied in an Asian population. With the most recent, uniformly collected population-based data from the US and Asia, we compared HD incidence rates in Chinese, Japanese, Filipinos, and Asian Indians in the US and in Asia. HD incidence rates were quite low in all Asian subgroups, but approximately double in US Asians as in native Asians. In both, rates were lower for Japanese and Chinese than for Filipinos and Asian Indians. A modest young-adult rate peak occurred for most US Asian groups, but not for any population in Asia. In data from a population-based case–control study of HD in San Francisco area women, young-adult Asian cases, like young-adult cases of other racial/ethnic groups, had childhood social environments indicative of less early contact with children. Given environmental and lifestyle differences between the US and Asia, the consistently low rates of HD in Asians suggest genetic resistance to disease development, possibly associated with HLA type. International and inter-ethnic differences, and risk factor patterns in case–control data, implicate environmental influences in the etiology of HD.

Epidemiology of lymphomas.

Non-Hodgkin lymphoma (NHL) is the fifth most common cancer in the US, with about 55,000 new cases estimated for the year 2000. According to the new Surveillance, Epidemiology, and End Results (SEER) data from 1973 to 1997, the age-adjusted incidence rates rose by about 80%, with an annual percentage increase of nearly 3%, which is faster than for the majority of cancers. The increasing incidence of NHL is largely unexplained. AIDS-related NHL accounts for some but not all of the increase. The American Cancer Society predicts about 7,400 new cases of Hodgkin Disease (HD) in the year 2000 in the US. The incidence of HD is consistently lower than that of NHL, and has decreased about 16% since the 1970s. Only a small portion of the decrease in HD incidence can be explained by misdiagnosis of HD as NHL. Further research is needed on the cofactors that predispose AIDS cases to lymphoma, as well as other possible causes of NHL such as immunosuppression, genetics, viruses, medical conditions, pesticides, solvents, hair dyes, and diet. Further evaluation of the role of viruses, occupational exposures, and genetics in the etiology of HD should prove valuable.

Time Trends and Sex Patterns in Hodgkin’s Disease Incidence in Canada, 1970–1995

To examine time trends and sex patterns in Hodgkin's disease incidence in Canada, from 1970 through 1995. In addition to analyses of the secular trends and sex ratio in incidence rates, age-period-cohort models were fitted to estimate the effects on the trends. Age-specific male/female incidence rate ratios were examined for the disease and for its two major histologic subtypes. The overall age-adjusted incidence rate of Hodgkin's disease decreased significantly in males (3.5 per 100,000 in 1970-71 to 2.8 in 1994-95) but only slightly in females (2.4 per 100,000 to 2.3). There was a significant increase in the incidence among females aged 10-29 and among males aged 10-24, but a dramatic decrease among older ages. Age-period-cohort modelling showed that birth cohort and period effects were responsible for the observed trends in males and females, respectively. The risk factors responsible for Hodgkin's disease are different in females and males. Reproductive factors are likely to be associated with the occurrence of the disease in young women.

Advanced Hodgkin's disease in a pregnant HIV seropositive woman: Favorable mother and baby outcome following combined anticancer and antiretroviral therapy

We describe a 33 y/o HIV(+) woman who developed advanced Hodgkin's disease (HD) during the 2nd trimester of her pregnancy. Combination chemotherapy and antiretroviral treatment along with opportunistic infection prophylaxis were administered. At term, while in partial remission, she delivered by a Caesarian section a healthy baby, PCR-negative for HIV. A complete remission was later achieved upon completion of the chemotherapy regimen. Since both the incidence of HD and the proportion of young women among the HIV(+) individuals are increasing, it seems important to recognize that successful completion of pregnancy with no deterioration of accepted surrogate parameters of HIV disease progression is achievable in a carefully treated HIV(+) pregnant woman with advanced HD.

Increased incidence of Hodgkin's disease after allogeneic bone marrow transplantation.

Immune dysregulation associated with allogeneic bone marrow transplantation (BMT) is linked to an increased risk of posttransplant lymphoproliferative disorders (PTLD); however, reports of Hodgkin's disease (HD) after transplantation are rare. We evaluated the risk of HD among 18,531 persons receiving allogeneic BMT between 1964 and 1992 at 235 centers. The number of HD cases was compared with that expected in the general population. Risk factors were identified using Poisson regression and a nested case-control study. Risk of HD was increased in the postBMT population compared with the general population with an observed-to-expected incidence ratio (O/E) of 6.2 (observed cases, n = 8; 95% confidence interval [CI], 2.7 to 12). A significantly increased risk of HD remained after excluding two human immunodeficiency virus-positive patients (observed cases, n = 6; O/E = 4.7, 95% CI, 1.7 to 10.3). Mixed cellularity subtype predominated (five of eight cases, 63%). Five of six assessable cases contained Epstein-Barr virus (EBV) genome. Posttransplant HD differed from PTLD by later onset (> 2.5 years) and lack of association with established risk factors (such as T-cell depletion and HLA disparity). Patients with HD were more likely than matched controls to have had grade 2 to 4 acute graft-versus-host disease (GVHD), required therapy for chronic GVHD, or both (P =.002), although analysis included small numbers of patients. The increased incidence of HD among BMT recipients adds support to current theories which link overstimulation of cell-mediated immunity and exposure to EBV with various subtypes of HD. The long latency of HD after transplant and lack of association with risk factors for PTLD is noteworthy and should be explored further for possible insights into pathogenesis.

Advanced stage and unfavorable Hodgkin's disease in the Chinese-a 20-year experience.

We retrospectively analyzed 57 patients with advanced stage (stage III/IV) or unfavorable (presence of B symptoms or bulky disease) Hodgkin's disease from January 1977 to December 1997. There were 29 male and 28 female patients. The median age was 27 years old (range, 13-59). Lactate dehydrogenase levels ranged from 104 units/l to 2320 units/l (median, 433). Eighteen (31.6%), 13 (22.8%), and 26 (45.6%) patients had stage II bulky, stage III, and stage IV disease, respectively. Twenty-five (44%) patients had B symptoms. One (1.8%), 3 (5.3%), 36 (63.2%), and 17 (29.8%) had lymphocyte predominant, lymphocyte depleted, nodular sclerosis, and mixed cellularity histology, respectively. Chemotherapy regimens included mechlorethamine, vincristine, procarbazine, prednisone (MOPP) (n = 9), adriamycin, bleomycin, vinblastine, dacarbazine (ABVD) (n = 23), MOPP alternating with ABVD (n = 13), and COPP-ABV hybrid (n = 12). Complete remission was achieved in 47 (82.4%) patients. Eleven patients (23%) relapsed after the first complete remission and four (36%) attained a second complete remission with salvage chemotherapy. Projected overall survival was 69.0% at 10 years and 20 years. Disease-free survival rates were 71% at 10 years and 20 years. Of the potential prognostic factors analyzed (age, sex, stage, lactate dehydrogenase, serum albumin level, regimen, B symptoms and bulky disease) by using the Cox regression model, only a low albumin level was found to adversely affect overall survival (P = 0.003). In conclusion, despite the relative low incidence of Hodgkin's disease in Hong Kong Chinese, the treatment outcomes in patients with advanced stage or unfavorable Hodgkin's disease is comparable to Caucasian patients.

Expression of Epstein-Barr virus in patients with Hodgkin's disease in Taiwan.

The association of Epstein-Barr virus (EBV) with Hodgkin's disease (HD) is intimately related to socioeconomic status. The proportion of HD patients with EBV is high in developing countries but low in developed countries. The aim of this study was to delineate the association of EBV with HD in Taiwan. Tissues from 70 consecutive cases of HD were examined for the presence of EBV, for the latent membrane protein (LMP- 1) by immunohistochemistry, and for EBER-1 by in situ hybridization. There were 53 males and 17 females, with a mean age of 42 years (range, 7-75 years). Histologic subtypes included nodular sclerosis in 36 cases (51.4%), mixed cellularity in 26 (37.1%), lymphocyte predominance in 6, and lymphocyte depletion in 2. Overall, EBV was expressed in 44 cases (62.9%), with EBER-1 expression detected in 40 (57.1%) and LMP-1 detected in 38 (54.3%). The following histologic subtypes were associated with EBV: lymphocyte predominance in 1 of 6 cases (16.7%), nodular sclerosis in 23 of 36 cases (63.9%), mixed cellularity in 18 of 26 cases (69.2%), and lymphocyte depletion in 2 of 2 cases (100%). EBV association with HD is relatively high in Taiwan. Although EBV was detected in all subtypes and at all ages in this study, the low endemic incidence of HD in Taiwan suggests that other factors, besides EBV, play a role in the pathogenesis of HD.

Seasonal variation in the incidence of Hodgkin's disease

Seasonal variation in the incidence of Hodgkin's disease

Birth order, sibship size and risk of Hodgkin's disease in children and young adults: a population-based study of 31 million person-years.

It has been proposed that Hodgkin's disease (HD) may have an infectious origin and that delayed exposure to infection may increase the risk of HD in young adults. This hypothesis is addressed by studying the family structure among children and young adults. The Civil Registration System was used to establish a population-based cohort consisting of all persons whose mothers were born in Denmark since 1935. Persons who developed HD were identified by linkage with the Danish Cancer Registry. HD incidence rate ratios were estimated based on a log-linear Poisson regression model. The cohort of 2.1 million persons (aged 0-42 years) was followed for 31.1 million person years, during which period 378 cases of HD occurred. Among children (< 15 years, n = 72), the relative risk (RR) of HD tended to increase with increasing sibship size, the relative increase in risk per increase in sibship size (the trend) being 1.28 [95% confidence interval (CI) 1.00-1.63]. The trend for birth order was 1.26 (95% CI 0.92-1.73). Among young adults (> or = 15 years, n = 306) the risk of HD, on the contrary, tended to decrease with increasing sibship size [trend = 0.91 (95% CI, 0.81-1.03)] and birth order (trend = 0.85 (95% CI, 0.71-1.01). These trends among young adults were significantly different from the corresponding trends among children (p < 0.05). Siblings of cases were at increased risk of HD (RR = 18; 95% CI, 2.2-65, n = 2). Our findings are compatible with the hypothesis that delayed exposure to infection may be a risk factor for HD in young adults, and that early exposure perhaps to another infectious agent may increase the risk of HD in children.