Biomedical subjects

Klaus Rostgaard

Publications and source records attributed to Klaus Rostgaard.

At least 19 recordsLinked to original sources

PubMed2026

Plasma donation rates and infection risk: A multicentre observational study in Denmark.

BACKGROUND AND OBJECTIVES: The demand for plasma-derived medicinal products underscores the need to assess health effects of plasma donation. This study examines the association between plasma donation rates and infection risk in a country with voluntary, non-remunerated donation. MATERIALS AND METHODS: From 2016 to 2024, 45,615 first-time plasma donors were enrolled in a cohort study with time-varying exposure. Follow-up began 90 days after the first plasma donation, with donation rates recalculated every 90 days. Donation rates were categorized as 0, 1 (reference), 2-3, 4-5 or 6-8 donations. Infection was defined using Danish health registers. Survival models were used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs). RESULTS: The median plasma donation rate was 2 (Q1, 1; Q3, 4). During follow-up, 15,498 donors experienced an infection. A trend of decreasing HRs for infection was observed with higher donation rates compared with a single donation (0 donations: HR: 0.89, 95% CI: 0.86-0.93; 2-3 donations: HR: 0.85, 95% CI: 0.81-0.89; 4-5 donations: HR: 0.65, 95% CI: 0.59-0.72; and 6-8 donations: HR: 0.48, 95% CI: 0.36-0.62). Findings were consistent across multiple regression models. CONCLUSION: In this study, higher plasma donation rates were associated with lower infection risk. Importantly, this inverse association is likely due to bias inherent to observational designs, particularly the internal healthy donor effect, which limits interpretation. Thus, no causal relationship between plasma donation rates and infection risk can be inferred. This underscores the challenges of assessing plasma donation safety using non-randomized data.

Adult↗

PubMed2007

Atopy and risk of non-Hodgkin lymphoma.

BACKGROUND: A possible connection between allergy and cancer has been suspected, but allergy-related conditions or atopy have been inconsistently associated with reduced risks of non-Hodgkin lymphoma. We investigated this association in a population-based case-control study and in a prospective study with prediagnostic blood specimens. METHODS: We carried out a population-based study of 3055 case patients with non-Hodgkin lymphoma and 3187 control subjects in Denmark and Sweden, including questionnaire information on allergy and blood specimens, and a nested case-control study within a prospective cohort of more than 400,000 Finnish women. In the second study, serum specimens from the 198 case patients who developed non-Hodgkin lymphoma within a median of 8.9 years after the blood was drawn were matched with serum specimens from 594 control subjects. In both studies, laboratory-based evidence of allergy (atopy) was determined in serum on the basis of specific IgE reactivity to common inhalant allergens. Dissemination of disease was classified by the Ann Arbor system. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated by logistic regression. RESULTS: In the first study, ever having hay fever, but not other allergic conditions, was associated with a reduced risk of non-Hodgkin lymphoma. In particular, subjects with specific IgE reactivity in serum had a 32% (95% CI = 20% to 42%) lower risk of overall non-Hodgkin lymphoma than those without such reactivity. However, among case patients, dissemination of the disease was strongly inversely associated with specific IgE reactivity. In the second (i.e., prospective) study, no association was found between non-Hodgkin lymphoma and specific IgE reactivity, except possibly immediately before a diagnosis of non-Hodgkin lymphoma (> or = 10 years before diagnosis, OR = 1.00, 95% CI = 0.48 to 2.09; 5-9 years before, OR = 0.95, 95% CI = 0.50 to 1.84; 1-4 years before, OR = 0.33, 95% CI = 0.11 to 1.02; and < 1 year before, OR = 0.27, 95% CI = 0.03 to 2.31). CONCLUSION: Allergy may not be causally associated with the risk of non-Hodgkin lymphoma. The inverse association observed in some case-control studies may arise because non-Hodgkin lymphoma suppresses the immunologic response to allergens.

Adult↗

PubMed2007

Multiple sclerosis after infectious mononucleosis.

BACKGROUND: Infectious mononucleosis caused by the Epstein-Barr virus has been associated with increased risk of multiple sclerosis. However, little is known about the characteristics of this association. OBJECTIVE: To assess the significance of sex, age at and time since infectious mononucleosis, and attained age to the risk of developing multiple sclerosis after infectious mononucleosis. DESIGN: Cohort study using persons tested serologically for infectious mononucleosis at Statens Serum Institut, the Danish Civil Registration System, the Danish National Hospital Discharge Register, and the Danish Multiple Sclerosis Registry. SETTING: Statens Serum Institut. PATIENTS: A cohort of 25 234 Danish patients with mononucleosis was followed up for the occurrence of multiple sclerosis beginning on April 1, 1968, or January 1 of the year after the diagnosis of mononucleosis or after a negative Paul-Bunnell test result, respectively, whichever came later and ending on the date of multiple sclerosis diagnosis, death, emigration, or December 31, 1996, whichever came first. MAIN OUTCOME MEASURE: The ratio of observed to expected multiple sclerosis cases in the cohort (standardized incidence ratio). RESULTS: A total of 104 cases of multiple sclerosis were observed during 556,703 person-years of follow-up, corresponding to a standardized incidence ratio of 2.27 (95% confidence interval, 1.87-2.75). The risk of multiple sclerosis was persistently increased for more than 30 years after infectious mononucleosis and uniformly distributed across all investigated strata of sex and age. The relative risk of multiple sclerosis did not vary by presumed severity of infectious mononucleosis. CONCLUSIONS: The risk of multiple sclerosis is increased in persons with prior infectious mononucleosis, regardless of sex, age, and time since infectious mononucleosis or severity of infection. The risk of multiple sclerosis may be increased soon after infectious mononucleosis and persists for at least 30 years after the infection.

Adult↗

PubMed2006

Psychiatric hospitalizations in a cohort of Danish polio patients.

Although previous polio infection remains a considerable cause of long-term morbidity worldwide, few studies have examined the psychiatric consequences of poliomyelitis. The authors followed 4,660 polio patients hospitalized at the primary infectious disease hospital in Copenhagen, Denmark, between 1922 and 1954 as well as 19,017 age- and gender-matched Danes for psychiatric hospitalizations from January 1, 1977, to December 31, 1993. Incidence rates of all psychiatric disorders combined and of separate diagnostic groups of psychiatric diseases in the two cohorts were compared, yielding the incidence rate ratio, a measure of relative risk. Overall, polio patients had a 40% increased risk of being hospitalized for a psychiatric disorder (incidence rate ratio = 1.43, 95% confidence interval: 1.23, 1.66). Apparently, the overall increased risk of psychiatric hospitalizations could not be confined to specific groups of psychiatric disorders but seemed to be explained by slightly increased risks of several different disorders, especially milder psychiatric disorders. Finally, psychiatric morbidity did not differ between paralytic and nonparalytic polio patients. History of hospitalization for polio might be associated with subsequent risk of hospitalization for psychiatric disorders. The underlying mechanism for this association remains uncertain.

Adult↗

PubMed2006

Cancer risk among patients with multiple sclerosis: a population-based register study.

Cancer occurrence in patients with multiple sclerosis (MS) has been little studied, but associations with brain tumours, breast cancer, Hodgkin lymphoma and nasopharyngeal carcinoma have been suggested. We took advantage of population-based registers of MS and cancer to assess the risk of cancer following diagnosis of MS. Patients registered in the Danish Multiple Sclerosis Register were linked with the Danish Cancer Register to obtain information on cancer occurrence. The ratio of the observed to the number of expected cancers based on population-based incidence rates, i.e., the standardised incidence ratio (SIR), served as measure of the relative cancer risk. A database comprising all Danish women born after April 1, 1935, with information on all live-born children, was used in the analyses of breast cancer to adjust for reproductive factors. Overall 1,037 cancers were observed in 11,817 MS patients during 153,875 person-years of follow-up vs. an expected number of 1,098 (SIR = 0.94 [95% confidence interval CI: (0.89-1.00)]. The risk of brain tumours and Hodgkin lymphoma was not increased. A 16% overall reduced cancer risk in men with MS was explained by reduced numbers of cancers of the digestive, respiratory and genital organs. Though the overall cancer risk was not increased [SIR = 1.01(0.94-1.09), n = 676], female MS patients had an increased risk of breast cancer [SIR = 1.21 (1.05-1.39), n = 193]. Adjusting for parity and age at first child delivery did not change this risk estimate materially. In general MS patients are not at increased risk of cancer. Women with MS, however, seem to have a small excess risk of breast cancer, which cannot be attributed to reduced parity or delayed first child birth.

Adult↗

PubMed2006

Type 1 diabetes and multiple sclerosis: A Danish population-based cohort study.

BACKGROUND: Type 1 diabetes mellitus (T1D) and multiple sclerosis (MS) contribute considerably to the burden of autoimmune diseases in young adults. Although HLA patterns of T1D and MS are considered mutually exclusive, individual and familial co-occurrence of the 2 diseases has been reported. OBJECTIVE: To assess the co-occurrence of T1D and MS by estimating the risk for MS in patients with T1D and the risk for T1D in first-degree relatives of patients with MS. DESIGN, SETTING, AND PARTICIPANTS: Two population-based disease registers, the Danish Hospital Discharge Register and the Danish Multiple Sclerosis Register were used to identify patients with T1D, defined as patients in whom diabetes was diagnosed before age 20 years (N = 6078), and patients with MS (N = 11 862). First-degree relatives (N = 14,771) of patients with MS were identified from family information in the Danish Civil Registration System. MAIN OUTCOME MEASURE: Patients with T1D and first-degree relatives of patients with MS were followed up for occurrence of MS and T1D, respectively, and the relative risks were expressed as standardized incidence ratios, that is, ratios of observed to expected numbers of outcomes based on national age, sex, and period-specific MS and T1D incidence rates. RESULTS: Patients with T1D were at more than 3-fold increased risk for development of MS (relative risk, 3.26; 95% confidence interval, 1.80-5.88; n = 11). First-degree relatives of patients with MS were at 63% increased risk (relative risk, 1.63; 95% confidence interval, 1.26-2.12; n = 56) for development of T1D. However, adjusting for familial relationship to patients with T1D reduced the excess risk to 44% (relative risk, 1.44; 95% confidence interval, 1.11-1.88; n = 56). CONCLUSION: The present nationwide cohort study demonstrates an intraindividual and, to a lesser degree, an intrafamilial co-occurrence of MS and T1D.

Adolescent↗

PubMed2006

Do changes in lymph node status distribution explain trends in survival of breast cancer patients in Denmark?

We studied the impact on survival of changes in breast cancer patients' distribution by lymph node status at the time of diagnosis. Our study included breast cancer patients diagnosed from 1978 to 1994 in Denmark, where the treatment schemes for breast cancer patients were fairly stable, and where mammography screening was limited. We measured lymph node status by the proportion of positive lymph nodes of all excised lymph nodes, as assessed by a pathologist. This measure was available for two-thirds of the breast cancer patients. The outcome was 5-year relative survival. Changes in lymph node status distribution explained half of the improvement in 5-year relative survival, and seem to be the single most important cause behind the improved survival of breast cancer patients in Denmark.

Aged↗

PubMed2006

Preleukemic TEL-AML1-positive clones at cell level of 10(-3) to 10(-4) do not persist into adulthood.

The TEL-AML1 translocation, t(12;21)(p13;q22), is one of the most frequent genetic aberrations in childhood B-cell precursor acute lymphoblastic leukemia (ALL), where it occurs in 25% of all cases. In contrast, the translocation is seen in only 3% of adult ALL cases. Evidence suggests that the TEL-AML1 translocation occurs in utero in 1% of all newborn children at cell levels of 10 to 10. In this study, we explore the prevalence of TEL-AML1-positive cells in 2 cohorts of healthy blood donors by real-time and nested reverse transcription-polymerase chain reaction. Overall, TEL-AML1-positive cells were demonstrated in 10 of 2005 healthy donors, that is, a prevalence of 0.5% (95% confidence interval, 0.2-0.3%). The level of TEL-AML1-positive cells was estimated to 10 to 10. The observed prevalence of TEL-AML1-positive cells in healthy adults is of the same order of magnitude as the prevalence reported in healthy newborns, but the observed cell level of 10 to 10 is much lower. These data indicates that prenatal TEL-AML1 subclones does not persist throughout adult life at cell levels of 10 to 10. The findings are compatible with the risk of t(12;21)(p13;q22) ALL correlating with the total number of TEL-AML1-positive cells in peripheral blood in both childhood and adulthood.

Adult↗

PubMed2006

Incidence of non-Hodgkin's lymphoma in Sweden, Denmark, and Finland from 1960 through 2003: an epidemic that was.

BACKGROUND: Reports during the early 1990s indicated non-Hodgkin's lymphoma (NHL) as one of the most rapidly increasing malignancies. More recent trends remain poorly characterized, as do the underlying reasons for NHL time trends, in particular, the effect of changes in classification and registration of lymphoproliferative malignancies. Insights into the descriptive epidemiology of NHL may shed light upon its elusive etiology. METHODS: We used data from the Swedish, Danish, and Finnish national cancer registers to assess the incidences of NHL and other lymphoproliferative malignancies between 1960 and 2004. Using Poisson regression, we estimated the annual rate of change in NHL incidence per decade by sex, age, and country. RESULTS: In Sweden, Denmark, and Finland, the NHL incidence increased in both genders and all age categories by about 4% every year up until the early 1990s. Thereafter, the incidence increased at a slower rate (ages 60-79 years), stabilized (ages 50-59 and > or =80 years), and decreased (ages 0-49 years), respectively, similarly for males and females in the three countries. Time trends of NHL were not reciprocated and explained by trends for other lymphoproliferative malignancies nor explained by trends in NHL as secondary primaries or NHL diagnosed postmortem. CONCLUSIONS: The epidemic increase of NHL has recently subsided. Changes in the classification of lymphoproliferative malignancies, or occurrence of NHL as second primaries, only offer a marginal explanation.

Adolescent↗

PubMed2005

Familial risk of multiple sclerosis: a nationwide cohort study.

Multiple sclerosis (MS) is known to accumulate within families. The magnitude of the familial risk, however, remains uncertain. Using a nationwide MS register and other national registers, the authors estimated relative and absolute risks of MS in a population-based cohort that included 19,615 first-degree relatives of 8,205 Danish MS patients followed from 1968 to 1997. The ratio of observed to expected numbers of MS cases served as the measure of the relative risk of MS. Lifetime risks of MS in first-degree relatives were estimated as the product of the relative risk and the national lifetime risk of MS. Overall, first-degree relatives had a sevenfold increased risk of MS (relative risk=7.1, 95% confidence interval: 5.8, 8.8) (n=90) compared with the background population. By modeling the individual incidence rate of MS as the sum of a familial component and a sporadic risk component, the familial excess lifetime risk was found to be 2.5% (95% confidence interval: 2.0, 3.2) among first-degree relatives of MS patients, irrespective of the gender of the proband and the relative. This percentage should be added to a sporadic absolute risk in the general population of 0.5% in women and 0.3% for men. Spouses of MS patients did not experience an increased risk of MS, suggesting no major role for environmental factors acting in adulthood.

Denmark↗

PubMed2005

Sibship characteristics and risk of allergic rhinitis and asthma.

Studying associations between sibship characteristics and allergic diseases in detail may contribute clues to their etiology. The authors studied associations between sibship characteristics and risk of self-reported allergic rhinitis and asthma among 31,145 pregnant women participating in a nationwide study in Denmark during 1997-2000. Increasing sibship size was associated with a decreased risk of allergic rhinitis and asthma with allergic rhinitis but not with asthma without allergic rhinitis. The protective effect of having older siblings was stronger than the protective effect of having younger siblings for both allergic rhinitis and asthma with allergic rhinitis. There was no association between interval to closest older or younger sibling and risk of allergic rhinitis or asthma with allergic rhinitis, while the risk of asthma without allergic rhinitis increased with intervals of 2 or more years compared with less than 2 years to the nearest older sibling. The protective effect of having siblings on the risk of asthma with allergic rhinitis could be explained by a protective effect of siblings on the risk of allergic rhinitis alone. In conclusion, our findings suggest that different etiologic mechanisms are involved for allergic rhinitis and asthma with respect to the effect of sibship characteristics. Furthermore, the findings that allergic rhinitis was associated with the number of younger siblings but not with the age interval to younger siblings support the hypothesis of an influence of postnatal mechanisms and suggest that these mechanisms may not necessarily be operating only in early life.

Adolescent↗

PubMed2005

Ultraviolet radiation exposure and risk of malignant lymphomas.

BACKGROUND: The incidence of malignant lymphomas has been increasing rapidly, but the causes of these malignancies remain poorly understood. One hypothesis holds that exposure to ultraviolet (UV) radiation increases lymphoma risk. We tested this hypothesis in a population-based case-control study in Denmark and Sweden. METHODS: A total of 3740 patients diagnosed between October 1, 1999, and August 30, 2002, with incident malignant lymphomas, including non-Hodgkin lymphoma, chronic lymphocytic leukemia, and Hodgkin lymphoma, and 3187 population controls provided detailed information on history of UV exposure and skin cancer and information on other possible risk factors for lymphomas. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated by logistic regression. Statistical tests were two-sided. RESULTS: Multivariable-adjusted analyses revealed consistent, statistically significant negative associations between various measures of UV light exposure and risk of non-Hodgkin lymphoma. A high frequency of sun bathing and sunburns at age 20 years and 5-10 years before the interview and sun vacations abroad were associated with 30%-40% reduced risks of non-Hodgkin lymphoma (e.g., for sunbathing four times a week or more at age 20 versus never sunbathing, OR = 0.7, 95% CI = 0.6 to 0.9; for two or more sunburns a year at age 20 versus no sunburns, OR = 0.6, 95% CI = 0.5 to 0.8). These inverse associations increased in strength with increasing levels of exposure (all P(trend)< or =.01). Similar, albeit weaker, associations were observed for Hodgkin lymphoma. There were no clear differences among non-Hodgkin lymphoma subtypes, although associations were stronger for B-cell than for T-cell lymphomas. A history of skin cancer was associated with a doubling in risks of both non-Hodgkin and Hodgkin lymphoma. CONCLUSIONS: A history of high UV exposure was associated with reduced risk of non-Hodgkin lymphoma. The positive association between skin cancer and malignant lymphomas is, therefore, unlikely to be mediated by UV exposure.

Adult↗

PubMed2005

Cigarette smoking and risk of non-Hodgkin's lymphoma--a population-based case-control study.

BACKGROUND: Epidemiologic evidence of an association between tobacco smoking and non-Hodgkin's lymphoma has been conflicting. This may reflect that non-Hodgkin's lymphoma comprises several distinct disease entities with different etiologies, as some studies have indicated an association between smoking and follicular lymphoma. OBJECTIVE: To investigate the association between cigarette smoking and non-Hodgkin's lymphoma risk, overall and by subtype. METHODS: As part of a nationwide Danish-Swedish population-based case-control study, we interviewed 3,055 incident non-Hodgkin's lymphoma patients and 3,187 population controls. All lymphomas were uniformly classified according to the WHO classification. We used unconditional logistic regression to estimate adjusted odds ratios (OR) and 95% confidence intervals (95% CI) for the association between cigarette smoking and risk of non-Hodgkin's lymphoma. RESULTS: Cigarette smoking was not associated with the risk of non-Hodgkin's lymphoma overall (OR, 0.97; 95% CI, 0.87-1.08) nor with the major subgroups such as diffuse large B-cell lymphoma (OR, 0.94; 95% CI, 0.79-1.10), chronic lymphocytic leukemia (OR, 0.86; 95% CI, 0.72-1.02), or follicular lymphoma (OR, 1.03; 95% CI, 0.85-1.24). Female smokers were at a marginally increased risk of follicular lymphoma (OR, 1.41; 95% CI, 1.04-1.92). Men who had ever smoked had a significantly increased risk of T-cell lymphoma (OR, 1.67; 95% CI, 1.11-2.51). No dose-response association with cigarette smoking could be established for any lymphoma subgroup. CONCLUSION: We found little evidence of an association between cigarette smoking and non-Hodgkin's lymphoma risk overall. Although increased risks of follicular lymphoma in female smokers and of T-cell lymphoma in male smokers were suggested, no dose-response relationship was observed, leaving limited support for causality.

Adolescent↗

PubMed2004

Birth weight and risk for childhood leukemia in Denmark, Sweden, Norway, and Iceland.

BACKGROUND: Compelling evidence suggests that childhood leukemia often originates in utero. Birth weight is one of the few pregnancy-related risk factors that has been associated with leukemia risk, but the association has remained poorly characterized. We conducted a population-based case-control study in Denmark, Sweden, Norway, and Iceland to investigate the association between birth weight (and other birth characteristics) and the risk of childhood leukemia. METHODS: Overall, 1905 children (aged 0-14 years) with acute lymphoblastic leukemia (ALL) and 299 children with acute myeloid leukemia (AML) diagnosed between January 1, 1984, and December 31, 1999, were identified in the Nordic Society of Paediatric Haematology and Oncology acute leukemia database. Each case patient was matched to five population control subjects (n = 10745) on nationality, age, and sex. All live-born siblings of case patients (n = 3812) and control subjects (n = 17,937) were also identified in population registers. Information on birth weight and gestational age at birth was ascertained from the national Medical Birth Registers. The association between various birth characteristics and leukemia risk was assessed by conditional logistic regression. All statistical tests were two-sided. RESULTS: Risk of ALL overall was statistically significantly associated with birth weight (odds ratio [OR] = 1.26 per 1-kg increase in birth weight, 95% confidence interval [CI] = 1.13 to 1.41). The association was similar for B- and T-lineage ALL and across all diagnostic ages (0-14 years). However, children with ALL did not weigh more at birth than their siblings. Statistically significantly reduced risks of B-precursor ALL were observed with increasing position in the birth order (OR = 0.90 per position increase, 95% CI = 0.84 to 0.96) and increasing gestational age (OR = 0.87 per 2-week increase in gestational age, 95% CI = 0.81 to 0.94). Risk of AML did not vary monotonically with birth weight, and low birth weight (<1500 g [i.e., 3.3 pounds]) was associated with the highest risk. CONCLUSION: Our results are compatible with the hypothesis that a high birth weight is associated with an increased risk of ALL.

Adolescent↗

PubMed2004

Familial clustering of Hodgkin lymphoma and multiple sclerosis.

BACKGROUND: Epidemiologic similarities between Hodgkin lymphoma in young adults (i.e., between 15 and 44 years old) and multiple sclerosis have led to the suggestion that these diseases may have related etiologies. Previous investigations have not supported this hypothesis, but the negative results could have been caused by methodologic problems. We therefore assessed the risk of developing Hodgkin lymphoma for patients with multiple sclerosis and for their families and the risk of developing multiple sclerosis for patients with Hodgkin lymphoma and for their families. METHODS: We identified 11,790 patients with multiple sclerosis and 19,599 of their first-degree relatives in Danish population-based registers and followed them for the occurrence of Hodgkin lymphoma. Analogously, we identified 4381 patients with Hodgkin lymphoma and 7388 of their first-degree relatives and followed them for the occurrence of multiple sclerosis. The relative risks (RRs) of Hodgkin lymphoma and multiple sclerosis were expressed as standardized incidence ratios (i.e., the ratio between observed and expected numbers of outcomes based on age, sex, and period-specific incidence rates). All statistical tests were two-sided. RESULTS: Overall, six cases of Hodgkin lymphoma were identified in patients with multiple sclerosis (RR for Hodgkin lymphoma = 1.40, 95% confidence interval [CI] = 0.63 to 3.12), two of which occurred in young adults (RR = 1.59, 95% CI = 0.40 to 6.37). The risk of young-adult-onset Hodgkin lymphoma was statistically significantly increased in the first-degree relatives of patients with multiple sclerosis (RR = 1.93, 95% CI = 1.01 to 3.71; n = 9 such lymphomas). Two cases of multiple sclerosis were identified among young adult patients with Hodgkin lymphoma (RR for multiple sclerosis = 0.82, 95% CI = 0.20 to 3.27), and the risk for multiple sclerosis was statistically significantly increased in their first-degree relatives (RR = 2.76, 95% CI = 1.44 to 5.31; n = 9 such multiple sclerosis cases). CONCLUSION: The observed familial clustering of multiple sclerosis and young-adult-onset Hodgkin lymphoma is consistent with the hypothesis that the two conditions share environmental and/or constitutional etiologies.

Adolescent↗

PubMed2004

Life-long morbidity among Danes with poliomyelitis.

OBJECTIVE: To estimate long-term morbidity in a cohort of Danish poliomyelitis patients. DESIGN: A historical prospective cohort study of 27,047 persons. SETTING: Denmark. PARTICIPANTS: A total of 5421 persons hospitalized for poliomyelitis between 1919 to 1954 in Copenhagen, Denmark, and 21,626 age- and gender-matched Danes. Participants were followed up on average for 20.6 years, yielding a total of 555,884 person-years of follow-up. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The exposed (poliomyelitis) cohort and the unexposed (control) cohort were followed up for somatic hospitalization from 1977 to 1999 in the Danish Hospital Discharge Register. The incidence rate ratio (IRR) was calculated as the ratio between the incidence rate of disease in the exposed and unexposed cohorts. RESULTS: Overall, polio patients had a 1.2- to 1.3-fold increased risk of being hospitalized with pulmonary diseases, heart diseases, gastrointestinal disorders, or diseases of the locomotive apparatus. Among paralytic polio patients, long-term morbidity seems to be associated with the acute severity of poliomyelitis, as well as young age at infection. Paralytic patients, who contracted respiratory polio under the age of 5, had the highest risk of being hospitalized with lung diseases (IRR=7.26; 95% confidence interval [CI], 3.06-18.33), diseases of the locomotive apparatus (IRR=4.05; 95% CI, 1.66-9.86), heart diseases (IRR=1.70; 95% CI, 0.65-3.98), and diseases of the digestive system (IRR= 2.23; 95% CI, 1.03-4.62). Surprisingly, patients without paralyses, especially women, also had an increased morbidity. CONCLUSIONS: Overall, a history of poliomyelitis was associated with a slightly increased morbidity measured by hospitalizations. Long-term morbidity was highest among respiratory polio patients; however, patients presumably left without any residual symptoms also had an increased morbidity.

Adult↗

PubMed2003

Birth weight as a risk factor for childhood leukemia: a meta-analysis of 18 epidemiologic studies.

Evidence has emerged that childhood leukemia is initiated in utero. High birth weight is one of the few birth-related factors that has been associated with childhood leukemia, albeit not consistently. The authors conducted a meta-analysis of studies of the association between birth weight and childhood leukemia risk. Study-specific odds ratios for leukemia were calculated, using a cutoff at 4,000 g of birth weight. The authors also evaluated whether the association between birth weight and leukemia followed a log-linear dose-response-like pattern. They calculated summary estimates using weighted averages of study-specific odds ratios from dichotomous and trend analyses. Eighteen studies (published between 1962 and 2002) were included, encompassing 10,282 children with leukemia. Children weighing 4,000 g or more at birth were at higher risk of acute lymphoblastic leukemia than children weighing less (odds ratio (OR) = 1.26, 95% confidence interval (CI): 1.17, 1.37). Furthermore, data were consistent with a dose-response-like effect (OR = 1.14/1,000-g birth weight increase, 95% CI: 1.08, 1.20). Studies of acute myeloid leukemia indicated a similar increase in risk for children weighing 4,000 g or more at birth (OR = 1.27, 95% CI: 0.73, 2.20) and a dose-response-like effect (OR = 1.29/1,000 g, 95% CI: 0.80, 2.06), but results varied across studies. Our findings support a relation between birth weight and childhood acute lymphoblastic leukemia risk and emphasize the need for additional studies of the biologic mechanisms underlying this association.

Adolescent↗

PubMed2003

Age- and sex-specific incidence of childhood leukemia by immunophenotype in the Nordic countries.

BACKGROUND: Studies from various countries have found an increasing incidence of childhood leukemia in recent decades. To characterize time trends in the age- and sex-specific incidence of childhood acute leukemia during the last 20 years in the Nordic countries, we analyzed a large set of population-based data from the Nordic Society of Paediatric Haematology and Oncology (NOPHO) in their acute leukemia database covering a population of approximately 5 million children aged 0-14 years. METHODS: Temporal trends in acute myeloid leukemia and acute lymphoblastic leukemia incidence rates overall and for acute lymphoblastic leukemia immunophenotypes and for specific age groups were analyzed by Poisson regression adjusting for age, sex, and country. All statistical tests were two-sided. RESULTS: We identified 1595 girls and 1859 boys diagnosed with acute lymphoblastic leukemia between January 1, 1982, and December 31, 2001, and 260 girls and 224 boys diagnosed with de novo acute myeloid leukemia between January 1, 1985, and December 31, 2001. No statistically significant change was seen in the overall incidence rate for acute lymphoblastic leukemia during the 20-year study (annual change = 0.22%, 95% confidence interval [CI] = -0.36% to 0.80%). The incidence rate of B-precursor acute lymphoblastic leukemia remained unchanged (annual change = 0.30%, 95% CI = -0.57% to 1.18%) from January 1, 1986, through December 31, 2001. A somewhat lower incidence in the first years of the study period indicated an early increasing incidence of B-precursor acute lymphoblastic leukemia that corresponded to a simultaneous decreasing incidence of unclassified acute lymphoblastic leukemia. Incidences of T-cell acute lymphoblastic leukemia (annual change = 1.55%, 95% CI = -1.14% to 4.31%) and acute myeloid leukemia (annual change = 0.58%, 95% CI = -1.24% to 2.44%) were stable during the study period. CONCLUSION: Incidences of acute myeloid leukemia overall, acute lymphoblastic leukemia overall, and specific acute lymphoblastic leukemia immunophenotypes have been stable in the Nordic countries over the past two decades.

Adolescent↗