Early mortality in children with cancer in Denmark and Sweden: The role of social background in a setting with universal healthcare

Socioeconomic differences in overall survival from childhood cancer have been shown previously, but the underlying mechanisms remain unclear. We aimed to investigate if social inequalities were seen already for early mortality in settings with universal healthcare. From national registers, all children diagnosed with cancer at ages 0-19 years, during 1991-2014, in Sweden and Denmark, were identified, and information on parental social characteristics was collected. We estimated odds ratios (OR) and 95% confidence intervals (CI) of early mortality (death within 90 days after cancer diagnosis) by parental education, income, employment, cohabitation, and country of birth using logistic regression. For children with acute lymphoblastic leukaemia (ALL), clinical characteristics were obtained. Among 13,926 included children, 355 (2.5%) died within 90 days after diagnosis. Indications of higher early mortality were seen among the disadvantaged groups, with the most pronounced associations observed for maternal education (ORadj_Low_vs_High 1.65 [95% CI 1.22-2.23]) and income (ORadj_Q1(lowest)_vs_Q4(highest) 1.77 [1.25-2.49]). We found attenuated or null associations between social characteristics and later mortality (deaths occurring 1-5 years after cancer diagnosis). In children with ALL, the associations between social factors and early mortality remained unchanged when adjusting for potential mediation by clinical characteristics. In conclusion, this population-based cohort study indicated differences in early mortality after childhood cancer by social background, also in countries with universal healthcare. Social differences occurring this early in the disease course requires further investigation, also regarding the timing of diagnosis.

Educational attainment in survivors of childhood cancer in Denmark, Finland, and Sweden

BACKGROUND

Survivors of childhood cancer may face difficulties at school. We investigated whether childhood cancer affects attainment of upper secondary education, in a register-based cohort study from Denmark, Finland, and Sweden, where we limit bias from selection and participation.

METHODS

From the national cancer registers, we identified all long-term survivors of childhood cancer diagnosed aged 0-14 years in 1971-2005 (n = 7629), compared them to matched population comparisons (n = 35,411) and siblings (n = 6114), using odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

Overall, 6127 survivors (80%) had attained upper secondary education by age 25, compared to 84% among comparison groups. Elevated OR for not attaining this level were mainly confined to survivors of central nervous system (CNS) tumours (ORSurv_PopComp2.05, 95%CI: 1.83-2.29). Other risk groups were survivors who had spent more time in hospital around cancer diagnosis and those who had hospital contacts in early adulthood, particularly psychiatric. Survivors of all cancer types were less likely to have attained upper secondary education without delay.

CONCLUSIONS

Although survivors of childhood cancer experienced delays in their education, many had caught up by age 25. Except for survivors of CNS tumours, survivors attained upper secondary education to almost the same extent as their peers.

Disease incidence and not case fatality drives the rural disadvantage in myocardial-infarction-related mortality in Germany

OBJECTIVE

Demographic and infrastructural developments might compromise medical care provision in rural regions, particularly for acute health conditions. Studying the case of myocardial infarction (MI), we investigated how MI-related mortality at ages 65+ varies between rural and urban regions in Germany and to what extent differences are driven by varying case fatality and disease incidence.

METHODS

The study relies on data containing all hospitalizations, cause-specific deaths and population counts for the total German population between years 2012-2018 and ages 65+. MI-related mortality, MI incidence and case fatality are compared between urban and rural regions in a population-wide analysis. The impacts of changing incidence and case fatality on rural-urban MI-related mortality differences are assessed using a counterfactual approach.

RESULTS

Rural regions in Germany show systematically higher MI-related death rates and MI incidence at ages 65+ compared to urban regions. Higher mortality is primarily the result of higher MI incidence in rural regions, while case fatality is largely similar. The rural excess in MI-related death rates would be nullified and 1 out of 6 MI-related deaths in rural regions could be prevented if rural regions in Germany would have at least the median MI incidence of urban regions.

CONCLUSIONS

MI incidence and not case fatality drives the rural disadvantage in MI-related mortality in Germany. Higher MI incidence points towards potential regional variation in the effectiveness of disease prevention. The findings highlight that improving disease prevention at the patient level carries larger opportunities for reducing regional MI-related mortality inequalities in Germany.

Heritability of nervous system tumors: a sibling-based design

Background

The contribution of genetic and environmental factors to susceptibility to nervous system tumors remains unclear. We performed a quantitative genetic study using a sibling design to estimate the heritability of nervous system tumors, as well as the proportion of the risk of these tumors, which is attributable to environmental factors.

Methods

We conducted a population-based cohort study using Swedish National Register data. All individuals born in Sweden during 1950-2010 with available information on both biological parents were included. A Multi-Generation Register was used to identify family clusters, including both full- and half-siblings. Initially, one index person was randomly selected from each cluster containing only full siblings and one sibling was randomly assigned to this index person. Subsequently, within each of the remaining clusters of full- and half-siblings, an index person was randomly selected, and a half-sibling was randomly assigned to this index person. Among the randomly selected siblings, cases of nervous system tumors were identified using the cancer registry. Quantitative genetic models were used to estimate the proportion of the variance in nervous system tumors attributable to additive genetic factors, shared environment, and individual-specific environment.

Results

The heritability of nervous system tumors was estimated to be 29% (95% confidence interval (CI) = 19%-39%), while the contribution of the non-shared environment to the variance of nervous system tumors was estimated to be 71% (95% CI = 61%-81%). The shared environmental parameter was estimated as zero in the full model.

Conclusion

The variation in susceptibility to nervous system tumors is predominantly attributable to non-shared environmental factors, followed by genetic factors.

Parental occupational exposure to metals and risk of cancer in the offspring: A register-based case-control study from Sweden

BACKGROUND

Cancer risks in the offspring of mothers and fathers exposed to metals are unknown. We estimated the relative risks of childhood cancer, overall and by type, associated with parental occupational exposure to arsenic, cadmium, chromium, nickel, and lead.

METHODS

We conducted a nested case-control study (1960-2015) of children born in Sweden aged 0-19 years diagnosed with cancer (National Cancer Register) matched 25:1 to controls on birth year and sex. We obtained parental occupational data around their birth from censuses and a nationwide register and identified exposure to each metal (yes/no, or higher/lower/no exposure) using the Swedish job-exposure matrix (SWEJEM). Adjusted odds ratios (OR) and 95% confidence intervals (CIs) were estimated separately for maternal and paternal exposures using conditional logistic regression.

RESULTS

We compared 9653 cases to 1,72,194 controls in maternal and 12,521 cases to 2,74,434 controls in paternal analyses, respectively. We found a 38% increased risk of cancer associated with maternal occupational exposure to arsenic (OR 1.38 [95% CI 1.06, 1.82]), likely driven by higher risks for lymphoma (OR 1.52 [0.73, 3.15]), central nervous system (CNS) (OR 1.49 [0.88, 2.54]) and other solid malignancies (OR 1.74 [1.14, 2.65]). There were also indications of higher risks of lymphoma in children of mothers exposed to nickel and iron, and of CNS tumours due to chromium exposure. No associations were observed from paternal occupational exposure to any of the metals.

CONCLUSIONS

We found evidence of increased risks of cancer in children of mothers but not fathers occupationally exposed to arsenic and potentially other metals.

Income disparities between adult childhood cancer survivors and their peers-A register-based cohort study from the SALiCCS research programme

BACKGROUND

Childhood cancer survivors face various adverse consequences. This Nordic register-based cohort study aimed to assess whether survivors of childhood cancer are more likely to have low income than their peers.

METHODS

We identified 17,392 childhood cancer survivors diagnosed at ages 0 to 19 between 1971 and 2009 with 83,221 age-, sex-, and country-matched population comparisons. Annual disposable income at ages 20 to 50 years was retrieved from statistical offices (for 1990-2017) and categorized into low income and middle/high income. The number of transitions between income categories were assessed using binomial regression analyses.

RESULTS

The prevalence of annual low income among childhood cancer survivors was 18.1% and 15.6% among population comparisons (risk ratio [RR] 1.17; 95% confidence interval [CI] 1.16-1.18). Compared to population comparisons, childhood cancer survivors were 10% (95% CI 8%-11%) less likely to transition from low to middle/high income and 12% (10%-15%) more likely to transition from middle/high to low income during follow-up. Among those initially in the low income category, survivors were 7% (95% CI 3%-11%) more likely to remain in the low income category. If the initial category was middle/high income, childhood cancer survivors were 10% (95% CI 8%-11%) less likely to remain in the middle/high income and 45% (37%-53%) more likely to transition to the low income category permanently.

CONCLUSIONS

Childhood cancer survivors are at higher risk for low income in adulthood than their peers. These disparities might be reduced by continued career counseling along with support in managing within the social security system.

Frailty Among Breast Cancer Survivors: Evidence From Swedish Population Data

Incidence and survival of breast cancer, the most common cancer among women, have been increasing, leaving survivors at risk of aging-related health conditions. In this matched cohort study, we examined frailty risk with the Hospital Frailty Risk Score among breast cancer survivors (n = 34,900) and age-matched comparison subjects (n = 290,063). Women born in 1935-1975, registered in the Swedish Total Population Register (1991-2015), were eligible for inclusion. Survivors had a first breast cancer diagnosis in 1991-2005 and survived ≥5 years after initial diagnosis. Death date was determined by linkage to the National Cause of Death Registry (through 2015). Cancer survivorship was weakly associated with frailty (subdistribution hazard ratio (SHR) = 1.04, 95% confidence interval (CI): 1.00, 1.07). In age-stratified models, those diagnosed at younger ages (<50 years) had higher risk of frailty (SHR = 1.12, 95% CI: 1.00, 1.24) than those diagnosed at ages 50-65 (SHR = 1.03, 95% CI: 0.98, 1.07) or >65 (SHR = 1.09, 95% CI: 1.02, 1.17) years. Additionally, there was increased risk of frailty for diagnoses in 2000 or later (SHR = 1.15, 95% CI: 1.09, 1.21) compared with before 2000 (SHR = 0.97, 95% CI: 0.93, 1.17). This supports work from smaller samples showing that breast cancer survivors have increased frailty risk, particularly when diagnosed at younger ages.

Improved prediction of 10-year risk of severe liver disease in the general population using commonly available biomarkers

BACKGROUND

Estimating the risk for cirrhosis in the general population is complex. Existing prediction tools are in general unsatisfactory.

AIMS

To explore if using commonly available biomarkers can improve the commonly used FIB-4 score in the identification of subgroups at risk of cirrhosis.

METHODS

We used laboratory and clinical data on 126,925 individuals aged 35-79 years in Stockholm, Sweden, undergoing health examinations from 1985 to 1996. We used Swedish nationwide registries to ascertain 10-year cumulative incidence of severe liver disease, a composite of diagnoses corresponding to cirrhosis and its complications. We considered combinations of biomarkers associated with severe liver disease to identify subgroups with different risk profiles.

RESULTS

During an average follow-up of 9.3 years, we ascertained 630 incident cases of severe liver disease (0.5%). Age, the FIB-4 score, diabetes or impaired glucose and gamma-glutamyl transferase (gGT) were the most relevant characteristics for classifying risk profiles. Using these factors, we identified 24 groups with a cumulative incidence of severe liver disease at 10 years ranging from 0.2% (age 35-65, low FIB-4, no diabetes or impaired glucose and normal gGT) to 32.1% (age 35-65, high FIB-4, diabetes or impaired glucose and high gGT).

CONCLUSIONS

Identification of subjects at increased risk of severe liver disease in the general population using the FIB-4 score can be substantially improved by adding age and specific biomarkers commonly available in the primary care setting. These parameters should be considered for inclusion in the development of future risk prediction models.

Occupational exposure to pesticides in mothers and fathers and risk of cancer in the offspring: A register-based case-control study from Sweden (1960-2015)

Maternal and paternal occupational exposure to pesticides was linked to leukemia in the offspring in some previous studies. Risks for other cancers, particularly from maternal exposure, are largely unknown. We examined the association between maternal and paternal exposure to pesticides and childhood cancer in a Swedish register-based case-control study (1960-2015). Cancer cases <20 years old were identified from the Cancer Register (n = 17313) and matched to controls (1:25) on birth year and sex. Employment history of each biological parent around the child's birth was retrieved from six censuses and a nationwide register, and exposure to any of herbicides, insecticides, and fungicides was evaluated using the Swedish job-exposure matrix (SWEJEM) in 9653/172194 mothers and 12521/274434 fathers of cases/controls. Adjusted odds ratios (OR) and 95% confidence intervals (CI) were estimated from conditional logistic regression models for any cancer, leukemia, lymphoma, central nervous system [CNS], and other solid tumors. We found an OR of 1.42 (95% CI 0.78, 2.57; 12 exposed cases) for lymphoma and 1.30 (95% CI 0.88, 1.93; 27 exposed cases) for other solid tumors associated with maternal occupational exposure to pesticides. No associations were observed between maternal exposure and leukemia or CNS tumors, or paternal exposure and any of the cancers examined, except for a potential association between pesticides exposure and myeloid leukemia (OR 1.15 [95% CI 0.73, 1.79; 22 exposed cases]). Although these findings merit further investigation, they indicate that parental exposure to pesticides may lead to higher risks of childhood cancer even in settings of low exposure.

Trends in Frailty Between 1990 and 2020 in Sweden Among 75-, 85-, and 95-Year-Old Women and Men: A Nationwide Study from Sweden

BACKGROUND

Aging is the primary risk factor for frailty, which is defined as an inability to respond to acute or chronic stressors. Individuals are living longer with greater multimorbidity, but there is a paucity of evidence examining frailty across birth cohorts and ages.

METHODS

We investigated frailty prevalence and its association with mortality at ages 75, 85, and 95 in the 1895-1945 birth cohorts in Sweden with data from population registries. Frailty was assessed with the Hospital Frailty Risk Score (HFRS).

RESULTS

We observed that frailty increased with increasing age and that it has become more common in more recent birth cohorts. At age 75, the percent frail in the Total Population Register increased from 1.1% to 4.6% from birth cohorts 1915-1945, corresponding to calendar years 1990-2020. At age 85, the percentage of frail increased from 3.5% to 11.5% from birth cohorts 1905-1935, and at age 95 from birth cohorts 1895-1925, from 4.7% to 18.7%. Our results show that the increase was primarily driven by an increase in the distribution of individuals with scores in the highest quartile of HFRS, while the bottom 3 quartiles remained relatively stable across birth cohorts. Women accounted for a greater distribution of the overall population and frail population, though these disparities decreased over time. Despite increasing levels of frailty, the relationship between frailty and mortality did not change over time, nor did it differ by sex.

CONCLUSION

Increased frailty with improved survival points to a chronic condition that could be intervened upon.

Maternal smoking during pregnancy and type 1 diabetes in the offspring: a nationwide register-based study with family-based designs

BACKGROUND

Maternal smoking during pregnancy was reported to be associated with a reduced risk of type 1 diabetes in the offspring. We investigated whether this association is consistent with a causal interpretation by accounting for familial (shared genetic and environmental) factors using family-based, quasi-experimental designs.

METHODS

We included 2,995,321 children born in Sweden between 1983 and 2014 and followed them for a diagnosis of type 1 diabetes until 2020 through the National Patient, Diabetes and Prescribed Drug Registers. Apart from conducting a traditional cohort study, we performed a nested case-control study (quasi-experiment) comparing children with type 1 diabetes to their age-matched siblings (or cousins). Information on maternal smoking during pregnancy was retrieved from the Swedish Medical Birth Register. Multivariable adjusted Cox proportional hazards regression and conditional logistic regression were used.

RESULTS

A total of 18,617 children developed type 1 diabetes, with a median age at diagnosis of 9.4 years. The sibling and cousin comparison design included 14,284 and 7988 of these children, respectively. Maternal smoking during pregnancy was associated with a 22% lower risk of offspring type 1 diabetes in the full cohort (hazard ratio 0.78, 95% confidence interval [CI] 0.75-0.82). The corresponding odds ratio was 0.78 (95% CI 0.69-0.88) in the sibling and 0.72 (95% CI 0.66-0.79) in the cousin comparison analysis.

CONCLUSIONS

This nationwide, family-based study provides support for a protective effect of maternal smoking on offspring type 1 diabetes. Mechanistic studies are needed to elucidate the underlying pathways behind this link.

Risk of Cancer in Children of Parents Occupationally Exposed to Hydrocarbon Solvents and Engine Exhaust Fumes: A Register-Based Nested Case-Control Study from Sweden (1960-2015)

BACKGROUND

It remains unclear whether parental occupational exposure to hydrocarbon solvents (HCS) or engine exhaust fumes (EEF) is associated with higher risks of cancer in the offspring.

OBJECTIVES

Our aim was to estimate relative risks of childhood cancers associated with maternal or paternal exposure to aliphatic/alicyclic, aromatic, or chlorinated HCS or gasoline/diesel EEF.

METHODS

We conducted a case-control study in which individuals <20y old, born 1960-2014, were identified from the Swedish National Cancer Register (1960-2015) at first cancer diagnosis and matched to population controls (1 case:25 controls) on birth year and sex. Maternal and paternal occupation around the child's birth was retrieved for 9,653 cases and 172,194 controls and 12,521 cases and 274,434 controls, respectively, using information from six censuses and a nationwide register. Using the Swedish job-exposure matrix (SWEJEM), we assessed exposure to HCS and EEF (any or higher/lower). Odds ratios (ORs) and 95% confidence intervals (CIs) of 15 childhood cancer subtypes were estimated using conditional logistic regression models adjusted for several confounders.

RESULTS

Maternal exposure to aromatic HCS was associated with non-Hodgkin lymphoma (OR=1.64; 95% CI: 1.05, 2.58), aliphatic/alicyclic HCS with germ cell tumors (OR=1.52; 95% CI: 0.89, 2.59), and gasoline/diesel EEF with astrocytoma (OR=1.40; 95% CI: 1.04, 1.88), myeloid leukemia (OR=1.53; 95% CI: 0.84, 2.81), lymphomas (OR=1.60; 95% CI: 0.85, 3.02 for Hodgkin; OR=1.44; 95% CI: 0.71, 2.91 for non-Hodgkin), and epithelial tumors (OR=1.51; 95% CI: 0.93, 2.44). Paternal exposure to gasoline EEF was associated with Hodgkin lymphoma (OR=1.21; 95% CI: 1.01, 1.44) and soft tissue sarcomas (OR=1.22; 95% CI: 1.00, 1.48). No notable difference was observed between higher and lower exposure.

DISCUSSION

Our findings suggest that occupational exposure to HCS or EEF, especially in the mother, may increase the risk of some childhood cancers. They add to the growing literature on adverse effects from HCS and EEF in the child, but replication of these associations in other populations is warranted. https://doi.org/10.1289/EHP11035.

Long-Term Risk of Hospitalization for Somatic Diseases Among Survivors of Childhood Acute Lymphoblastic Leukemia

Background

Survivors of childhood acute lymphoblastic leukemia (ALL) may be at increased long-term risk of hospitalization for somatic diseases. However, large population-based cohort studies with risk estimates for survivors successfully cured without experiencing a relapse or requiring hematopoietic stem cell transplantation (HSCT) are lacking.

Methods

Danish and Swedish patients diagnosed with ALL before age 20 years in 1982-2008 were identified in the national cancer registries. Five-year survivors and matched population comparisons without childhood cancer were followed for hospitalization for 120 somatic disease categories in the national hospital registries from 5 years postdiagnosis until 2017, and disease-specific hospitalization rate ratios (RR) were calculated. The mean cumulative count method was used to estimate the mean number of multiple and recurrent disease-specific hospitalizations per individual.

Results

A total of 2024 5-year survivors and 9797 population comparisons were included. The overall hospitalization rate was more than twice as high compared with comparisons (RR = 2.30, 95% confidence interval [CI] = 2.09 to 2.52). At 30 years postdiagnosis, the mean cumulative hospitalization count was 1.69 (95% CI = 1.47 to 1.90) per survivor and 0.80 (95% CI = 0.73 to 0.86) per comparison. In the subcohort without relapse or HSCT (n = 1709), the RR was 1.41 (95% CI = 1.27 to 1.58).

Conclusions

Survivors of childhood ALL were at increased long-term risk for disease-specific hospitalizations; however, in survivors without relapse or HSCT, the rate was only modestly higher than in population comparisons without a childhood cancer. The absolute mean numbers of multiple and recurrent hospitalizations were generally low.

Childhood cancer risk in offspring of parents occupationally exposed to dusts: A register-based nested case-control study from Sweden of 5 decades

Background

Some largely inconsistent associations between parental occupational dust exposure and childhood cancer have been reported, with maternal exposures inadequately studied. The authors examined whether maternal or paternal occupational exposure to animal, wood, textile, or paper dust around a child's birth was associated with an increased risk of childhood cancer, both overall and by type (leukemias, lymphomas, central nervous system tumors, and other cancers).

Methods

In this nationwide, register‐based, case‐control study, children who were diagnosed with cancer from 1960 to 2015 were compared with up to 25 matched controls regarding maternal and paternal occupational dust exposure (9653 cases in maternal analyses and 12,521 cases in paternal analyses). Exposures were assessed using a job‐exposure matrix and occupational information from census and register data. By using conditional logistic regression models, adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated.

Results

Neither maternal nor paternal occupational exposure to animal, wood, textile, or paper dust was associated with childhood cancer overall, leukemias, or central nervous system tumors. Maternal, but not paternal, wood dust exposure was associated with an increased risk of lymphoma (OR, 1.42; 95% CI, 1.10‐1.84), particularly non‐Hodgkin lymphoma (OR, 2.03; 95% CI, 1.21‐3.40).

Conclusions

The current study did not confirm the associations reported previously but is the first to suggest a link between maternal occupational exposure to wood dust around pregnancy and lymphoma in the offspring.

This large study does not confirm associations reported previously for leukemia and central nervous system tumors but is the first to suggest a link between maternal occupational exposure to wood dust around pregnancy and lymphoma in the offspring.

Alterations in Biomarkers Related to Glycemia, Lipid Metabolism, and Inflammation up to 20 Years Before Diagnosis of Type 1 Diabetes in Adults: Findings From the AMORIS Cohort

OBJECTIVE

Type 1 diabetes is described to have an acute onset, but autoantibodies can appear several years preceding diagnosis. This suggests a long preclinical phase, which may also include metabolic parameters. Here we assessed whether elevations in glycemic, lipid, and other metabolic biomarkers were associated with future type 1 diabetes risk in adults.

RESEARCH DESIGN AND METHODS

We studied 591,239 individuals from the Swedish AMORIS cohort followed from 1985-1996 to 2012. Through linkage to national patient, diabetes, and prescription registers, we identified incident type 1 diabetes. Using Cox regression models, we estimated hazard ratios for biomarkers at baseline and incident type 1 diabetes. We additionally assessed trajectories of biomarkers during the 25 years before type 1 diabetes diagnosis in a nested case-control design.

RESULTS

We identified 1,122 type 1 diabetes cases during follow-up (average age of patient at diagnosis: 53.3 years). The biomarkers glucose, fructosamine, triglycerides, the ratio of apolipoprotein (apo)B to apoA-I, uric acid, alkaline phosphatase, and BMI were positively associated with type 1 diabetes risk. Higher apoA-I was associated with lower type 1 diabetes incidence. Already 15 years before diagnosis, type 1 diabetes cases had higher mean glucose, fructosamine, triglycerides, and uric acid levels compared with control subjects.

CONCLUSIONS

Alterations in biomarker levels related to glycemia, lipid metabolism, and inflammation are associated with clinically diagnosed type 1 diabetes risk, and these may be elevated many years preceding diagnosis.

Late mortality among survivors of childhood acute lymphoblastic leukemia diagnosed during 1971-2008 in Denmark, Finland, and Sweden: A population-based cohort study

OBJECTIVE

Investigate all-cause and cause-specific late mortality after childhood acute lymphoblastic leukemia (ALL) in a population-based Nordic cohort.

METHODS

From the cancer registries of Denmark, Finland, and Sweden, we identified 3765 five-year survivors of ALL, diagnosed before age 20 during 1971-2008. For each survivor, up to five matched comparison subjects were randomly selected from the general population (n = 18,323). Causes of death were classified as relapse related, health related, and external. Late mortality was evaluated by cumulative incidences of death from 5-year survival date. Mortality hazard ratios (HR) were evaluated with Cox proportional models.

RESULTS

Among the survivors, 315 deaths occurred during a median follow-up of 16 years from 5-year survival date (range 0-42). The majority were attributable to relapse (n = 224), followed by second neoplasm (n = 45). Cumulative incidence of all-cause late mortality at 15 years from diagnosis decreased gradually over treatment decades, from 14.4% (95% confidence interval [CI]: 11.6-17.2) for survivors diagnosed during 1971-1981, to 2.5% (95% CI: 1.3-3.7) for those diagnosed during 2002-2008. This was mainly attributable to a reduction in relapse-related deaths decreasing from 13.4% (95% CI: 10.7-16.1) for survivors diagnosed during 1971-1981 to 1.9% (95% CI: 0.9-2.8) for those diagnosed during 2002-2008. Health-related late mortality was low and did not change substantially across treatment decades. Compared to comparison subjects, all-cause mortality HR was 40 (95% CI: 26-61) 5-9 years from diagnosis, and 4.4 (95% CI: 3.4-5.6) ≥10 years from diagnosis.

CONCLUSIONS

Survivors of ALL have higher late mortality than population comparison subjects. Among the survivors, there was a temporal reduction in risk of death from relapse, without increments in health-related death.

Employment status and occupational positions of childhood cancer survivors from Denmark, Finland and Sweden: A Nordic register-based cohort study from the SALiCCS research programme

BACKGROUND

A childhood cancer diagnosis and late effects of treatment may affect survivors' possibilities of employment or highly skilled occupations later in life. In this study, we compared the employment and occupational status of childhood cancer survivors with population comparisons and siblings.

METHODS

In a cohort study based on Nordic registers, we identified 10 461 survivors of childhood cancer diagnosed before age 20 years in Denmark, Finland and Sweden since 1971. Survivors were compared with 48 928 population comparisons matched to survivors by age, sex and geographical region and 12 605 siblings of survivors. Annual outcome information on employment, unemployment, health-related unemployment and occupational position was obtained from the statistical institutes between 1980-2017 and assessed in multivariate logistic regression analyses from age 30 onwards.

FINDINGS

By 30 years of age, 9.2% (95% CI, 8.6-9.9%) of survivors were unemployed for health reasons. Childhood cancer survivors had considerably higher odds of health-related unemployment at ages 30, 40 and 50 than population comparisons (OR_age30, 2.57; 95% CI, 2.35-2.81) and siblings (OR_age30, 2.50; 95% CI, 2.15-2.90). We observed no large difference in unemployment unrelated to health or in occupational position. Health-related unemployment was particularly pronounced among survivors of central nervous system tumours and survivors diagnosed below 15 years of age.

INTERPRETATION

Survivors at risk of health-related unemployment should be offered comprehensive survivorship care and interventions for obtaining and maintaining suitable employment.

FUNDING

NordForsk [76111], the Danish Childhood Cancer Foundation [2016-0293], Aarhus University [43239402], the Swedish Childhood Cancer Foundation [PR2020-0130] and [OB2019-0003], Tømrermester Jørgen Holm og Hustru Elisa F. Hansens Mindelegat [20088] and the Swiss National Science Foundation to LM [P2LUP3_175288].

Cohort Profile: The Socioeconomic Consequences in Adult Life After Childhood Cancer in Scandinavia (SALiCCS) Research Programme

INTRODUCTION

The growing number of survivors of childhood cancer, with many years of life ahead, demonstrates the increasing clinical and public health relevance of investigating the risks of social and socioeconomic impairment after a childhood cancer diagnosis and the life-saving treatment. To enrich understanding of the mental, social and socioeconomic difficulties that childhood cancer survivors may face during their life-course, identify particularly vulnerable survivors and overcome the limitations of previous research, we initiated the Socioeconomic Consequences in Adult Life after Childhood Cancer in Scandinavia (SALiCCS) research programme.

METHODS

This Nordic cross-border research programme is a collaboration between the Danish Cancer Society, the Finnish Cancer Registry and Karolinska Institutet to investigate a broad range of mental, social and socioeconomic conditions in long-term childhood cancer survivors in Denmark, Finland and Sweden. SALiCCS is based on a registry-based matched cohort design, comprising five-year survivors of cancer diagnosed at ages 0-19 years (1971-2008 in Denmark, 1971-2009 in Finland, 1971-2011 in Sweden), age-, sex- and country-matched population comparisons and sibling comparisons who were followed over time. Outcomes of interest included mental disorders, educational achievements, employment and profession, family life and the need of social security benefits. Individual-level data linkage among various national registries provided the data for the research programme.

RESULTS

The SALiCCS core population comprises 21,292 five-year survivors, 103,303 population comparisons and 29,644 siblings as a second comparison group. The most common diagnoses in survivors were central nervous system tumours, leukaemias and lymphomas.

DISCUSSION

SALiCCS is the largest, most comprehensive population-based research initiative in this field, based on high-quality registry data with minimal risk of bias. The findings will be informative for evidence-based survivorship care targeting not only somatic late effects but also psychosocial impairments.

Impaired fasting glucose: a risk factor for atrial fibrillation and heart failure

BACKGROUND

Dysglycaemia is associated with overall cardiovascular disease even at prediabetes levels. The aim of this study was to explore the association between glucose levels and future risk of developing atrial fibrillation and heart failure, respectively.

METHODS

In this prospective cohort study subjects from the Swedish AMORIS-cohort with fasting glucose from health examinations 1985-1996 without previous cardiovascular disease (N = 294,057) were followed to 31 December 2011 for incident atrial fibrillation or heart failure. Cox proportional hazard models with attained age as timescale and adjustments for sex, cholesterol, triglycerides, and socioeconomic status were used to estimate hazard ratios by glucose categorized groups (normal glucose 3.9-6.0 mmol/L, impaired fasting glucose; 6.1-6.9 mmol/L, undiagnosed diabetes ≥ 7.0 mmol/L, and diagnosed diabetes).

RESULTS

During a mean follow-up time of 19.1 years 28,233 individuals developed atrial fibrillation and 25,604 developed heart failure. The HR for atrial fibrillation was 1.19 (95% confidence interval 1.13-1.26) for impaired fasting glucose, 1.23 (1.15-1.32) for undiagnosed diabetes and 1.30 (1.21-1.41) for diagnosed diabetes. Corresponding figures for heart failure were; 1.40 (1.33-1.48), 2.11 (1.99-2.23), 2.22 (2.08-2.36) respectively. In a subset with BMI data (19%), these associations were attenuated and for atrial fibrillation only remained statistically significant among subjects with diagnosed diabetes (HR 1.25; 1.02-1.53).

CONCLUSIONS

Fasting glucose at prediabetes levels is associated with development of atrial fibrillation and heart failure. To some extent increased BMI may drive this association.

Impaired fasting glucose: a risk factor for atrial fibrillation and heart failure

BACKGROUND

Dysglycaemia is associated with overall cardiovascular disease even at prediabetes levels. The aim of this study was to explore the association between glucose levels and future risk of developing atrial fibrillation and heart failure, respectively.

METHODS

In this prospective cohort study subjects from the Swedish AMORIS-cohort with fasting glucose from health examinations 1985-1996 without previous cardiovascular disease (N = 294,057) were followed to 31 December 2011 for incident atrial fibrillation or heart failure. Cox proportional hazard models with attained age as timescale and adjustments for sex, cholesterol, triglycerides, and socioeconomic status were used to estimate hazard ratios by glucose categorized groups (normal glucose 3.9-6.0 mmol/L, impaired fasting glucose; 6.1-6.9 mmol/L, undiagnosed diabetes ≥ 7.0 mmol/L, and diagnosed diabetes).

RESULTS

During a mean follow-up time of 19.1 years 28,233 individuals developed atrial fibrillation and 25,604 developed heart failure. The HR for atrial fibrillation was 1.19 (95% confidence interval 1.13-1.26) for impaired fasting glucose, 1.23 (1.15-1.32) for undiagnosed diabetes and 1.30 (1.21-1.41) for diagnosed diabetes. Corresponding figures for heart failure were; 1.40 (1.33-1.48), 2.11 (1.99-2.23), 2.22 (2.08-2.36) respectively. In a subset with BMI data (19%), these associations were attenuated and for atrial fibrillation only remained statistically significant among subjects with diagnosed diabetes (HR 1.25; 1.02-1.53).

CONCLUSIONS

Fasting glucose at prediabetes levels is associated with development of atrial fibrillation and heart failure. To some extent increased BMI may drive this association.

Number of siblings and survival from childhood leukaemia: a national register-based cohort study from Sweden

BACKGROUND

Previous studies suggest worse leukaemia survival for children with siblings, but the evidence is sparse, inconsistent and does not consider clinical factors. We explored the associations between number of siblings in the household, birth order and survival from childhood acute lymphoid leukaemia (ALL) and acute myeloid leukaemia (AML).

METHODS

In this nationwide register-based study we included all children aged 1-14, diagnosed with ALL and AML between 1991-mid-2015 in Sweden (n = 1692). Using Cox regression models, we estimated hazard ratios (HRs) and 95% confidence intervals (CIs) according to number of siblings and birth order, adjusting for known prognostic and sociodemographic factors.

RESULTS

A tendency towards better ALL survival among children with one, or ≥2, siblings was observed, adjHRs (95% CI): 0.73 (0.49-1.10) and 0.63 (0.40-1.00), respectively. However, this was mainly limited to children with low risk profiles. An indication of better AML survival among children with siblings was seen, adjHRs (95% CI) 0.68 (0.36-1.29) and 0.71 (0.34-1.48) but diminished after adjusting for birth order.

CONCLUSION

Our results do not support previous findings that a larger number of siblings is associated with poorer survival. Inconsistencies might be explained by underlying mechanisms that differ between settings, but chance cannot be ruled out.

Mortality rates and cardiovascular disease burden in type 2 diabetes by occupation, results from all Swedish employees in 2002-2015

Objective

To identify occupations where employees with type 2 diabetes have a high risk of cardiovascular disease (CVD) and mortality, and their prevalence of CVD risk factors. This study can contribute in the creation of targeted interventions at the workplace.

Research design and methods

This nationwide registry-based study included all employees with type 2 diabetes born in Sweden in 1937–1979 (n = 180,620) and followed up in 2002–2015. We calculated age-standardized incidence (per 100,000 person-years) of all-cause and CVD mortality, ischemic heart disease (IHD) and stroke across the 30 most common occupations. Information on prognostic factors was retrieved from the National Diabetes Register.

Results

In males with type 2 diabetes, mortality rates were highest in manufacturing workers (1782) and machine operators (1329), and lowest in specialist managers (633). The risk of death at age 61–70 years was 21.8% in manufacturing workers and 8.5% in managers. In females with type 2 diabetes, mortality rates were highest in manufacturing workers (1150) and cleaners (876), and lowest in writers and artists (458); the risk of death at age 61–70 years was 12.4% in manufacturing workers and 4.3% in writers and artists. The same occupations also had relatively high incidences of CVD mortality, IHD and stroke. Occupational groups with poor prognosis had high prevalence of CVD risk factors including poor glycemic control, smoking and obesity.

Conclusions

Manufacturing workers, machine operators and cleaners with type 2 diabetes have two to three times higher mortality rates than managers, writers and artists with type 2 diabetes. Major health gains would be made if targeted workplace interventions could reduce CVD risk factors in these occupations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-021-01320-8.

A Dynamic Aspartate-to-Alanine Aminotransferase Ratio Provides Valid Predictions of Incident Severe Liver Disease

The aspartate-to-alanine aminotransferase ratio (AAR) is associated with liver fibrosis, but its predictive performance is suboptimal. We hypothesized that the association between AAR and liver disease depends on absolute transaminase levels and developed and validated a model to predict liver-related outcomes in the general population. A Cox regression model based on age, AAR, and alanine aminotransferase (ALT) level (dynamic AAR [dAAR]) using restricted cubic splines was developed in Finnish population-based health-examination surveys (FINRISK, 2002-2012; n = 18,067) with linked registry data for incident liver-related hospitalizations, hepatocellular carcinoma, or liver death. The model was externally validated for liver-related outcomes in a Swedish population cohort (Swedish Apolipoprotein Mortality Risk [AMORIS] subcohort; n = 126,941) and for predicting outcomes and/or prevalent fibrosis/cirrhosis in biopsied patients with nonalcoholic fatty liver disease (NAFLD), chronic hepatitis C, or alcohol-related liver disease (ALD). The dynamic AAR model predicted liver-related outcomes both overall (optimism-corrected C-statistic, 0.81) and in subgroup analyses of the FINRISK cohort and identified persons with >10% risk for liver-related outcomes within 10 years. In independent cohorts, the C-statistic for predicting liver-related outcomes up to a 10-year follow-up was 0.72 in the AMORIS cohort, 0.81 in NAFLD, and 0.75 in ALD. Area-under-the-curve (AUC) for detecting prevalent cirrhosis was 0.80-0.83 in NAFLD, 0.80 in hepatitis C, but only 0.71 in ALD. In ALD, model performance improved when using aspartate aminotransferase instead of ALT in the model (C-statistic, 0.84 for outcome; AUC, 0.82 for prevalent cirrhosis). Conclusion: A dAAR score provides prospective predictions for the risk of incident severe liver outcomes in the general population and helps detect advanced liver fibrosis/cirrhosis. The dAAR score could potentially be used for screening the unselected general population and as a trigger for further liver evaluations.

Birth month and risk of skin tumors-Follow up of six million Caucasians born from 1950 to 2014 in Sweden

BACKGROUND

Some studies hypothesize that birth month-as a proxy of exposure to ultraviolet radiation in early infancy-is associated with increased risk of skin tumors.

METHODS

We studied a national cohort of all 5 874 607 individuals born in Sweden to parents of Swedish or Nordic origin as a proxy for Caucasian origin, 1950 to 2014. The cohort was followed for incident skin tumors, including squamous cell carcinomas and melanomas but not basal cell carcinomas, through 2015 from birth up to age 65 for the oldest cohort. Cox regression estimated the association between month of birth and risk of skin tumors in models adjusted for sex, calendar period, and education. Crude observed to expected ratios were also calculated.

RESULTS

There were 33 914 cases of skin tumors, of these, 3025 were squamous cell cancer, 16 968 malignant melanoma and 8493 melanoma in situ/other and 5 428 squamous cell in situ/other in 192 840 593 person-years of follow-up. Observed to expected ratios by month of birth showed no association between month of birth and risk of skin tumors, and the same result was seen when Cox regression analysis was used. Subgroup analyses by sex, educational level, calendar period, or age at follow-up similarly showed no association.

CONCLUSION

This large register-based cohort study showed no evidence of a higher risk of skin tumors in those born during the spring. Thus, this study lends no support to the hypothesis that birth during spring is a major risk factor for later skin tumors.

No association between waiting time to surgery and mortality for healthier patients with hip fracture: a nationwide Swedish cohort of 59,675 patients

Background and purpose - Waiting time to surgery for patients with hip fractures and its potential association with mortality has been frequently studied with the hypothesis that longer waiting time is associated with adverse outcomes. However, despite numerous studies, there is no consensus regarding which time frames are appropriate, and whether some patients are more vulnerable to waiting than others. We explored the association between waiting time to surgery and short-term mortality and whether sex, age, surgical method, and comorbidity (ASA) modified this association.Patients and methods - This is a nationwide cohort study of 59,675 patients undergoing hip fracture surgery between January 1, 2013 and December 31, 2017 with a 4-month follow-up of mortality. Data were extracted from the Swedish Registry for Hip Fracture Patients and Treatment (RIKSHÖFT) and mortality was obtained from Statistics Sweden.Results - Unadjusted analyses revealed an association between waiting more than 24 hours for surgery and increased mortality, primarily for women. However, when stratifying for ASA grade, an association persisted only among patients with ASA 3 and 4. Furthermore, the absolute differences in mortality risk between those waiting less or longer than 24 hours were small. Age, fracture type, and surgical method did not modify the association between waiting time and mortality.Interpretation - This study suggests that there may be a need for new guidelines, which take into account the heterogeneity of the patient population.

Burden and prevalence of prognostic factors for severe COVID-19 in Sweden

The World Health Organization and European Centre for Disease Prevention and Control suggest that individuals over the age of 70 years or with underlying cardiovascular disease, cancer, chronic obstructive pulmonary disease, asthma, or diabetes are at increased risk of severe COVID-19. However, the prevalence of these prognostic factors is unknown in many countries. We aimed to describe the burden and prevalence of prognostic factors of severe COVID-19 at national and county level in Sweden. We calculated the burden and prevalence of prognostic factors for severe COVID-19 based on records from the Swedish national health care and population registers for 3 years before 1st January 2016. 9,624,428 individuals were included in the study population. 22.1% had at least one prognostic factor for severe COVID-19 (2,131,319 individuals), and 1.6% had at least three factors (154,746 individuals). The prevalence of underlying medical conditions ranged from 0.8% with chronic obstructive pulmonary disease (78,516 individuals) to 7.4% with cardiovascular disease (708,090 individuals), and the county specific prevalence of at least one prognostic factor ranged from 19.2% in Stockholm (416,988 individuals) to 25.9% in Kalmar (60,005 individuals). We show that one in five individuals in Sweden is at increased risk of severe COVID-19. When compared with the critical care capacity at a local and national level, these results can aid authorities in optimally planning healthcare resources during the current pandemic. Findings can also be applied to underlying assumptions of disease burden in modelling efforts to support COVID-19 planning.

Incidence and prevalence of type 2 diabetes by occupation: results from all Swedish employees

AIMS/HYPOTHESIS

The workplace is a potentially important arena for prevention of type 2 diabetes and the first step is to identify occupations where the disease is common and/or risk is high. Therefore, our aim was to analyse incidence and prevalence of type 2 diabetes across all occupational groups in Sweden.

METHODS

This nationwide study included all Swedish citizens born between 1937 and 1979 and gainfully employed between 2001 and 2013 (N = 4,550,892), and followed for a diagnosis of diabetes from 2006 to 2015 (n = 201,717) through national registers. Prevalence in 2013 (mean age 51 years; range 35-67) and age-standardised incidence (per 1000 person-years) were analysed across the 30 most common occupations among men and women. Information on BMI, physical fitness and smoking was obtained through the National Conscription (mean age 18) and Medical Birth Registers (mean age 29).

RESULTS

Prevalence of type 2 diabetes was 5.2% in men and 3.2% in women; in men it was highest among motor vehicle drivers (8.8%) and in women it was highest among manufacturing workers (6.4%). Incidence varied dramatically across occupational groups. In men, it was highest among manufacturing workers (9.41) and professional drivers (9.32) and lowest among university teachers (3.44). In women, incidence was highest in manufacturing workers (7.20) and cleaners (6.18) and lowest in physiotherapists (2.20). We found major differences in the prevalence of being overweight and smoking and in the level of physical fitness across these occupational groups even at young ages.

CONCLUSIONS/INTERPRETATION

Professional drivers, manufacturing workers and cleaners have a threefold increased risk of type 2 diabetes compared with university teachers and physiotherapists. These differences most likely reflect dramatic differences in the prevalence of lifestyle risk factors. If workplace interventions could reduce weight and increase physical activity among employees in these occupations, major health gains may be made.

Ability of Noninvasive Scoring Systems to Identify Individuals in the Population at Risk for Severe Liver Disease

BACKGROUND & AIMS

Noninvasive scoring systems are used to identify persons with advanced liver fibrosis. We investigated the ability of scoring systems to identify individuals in the general population at risk for future liver-related events.

METHODS

We collected data from the Swedish Apolipoprotein Mortality Risk cohort on persons 35 to 79 years old who had blood samples collected from 1985 through 1996. We collected APRI (n = 127,302), BARD (n = 75,303), FIB-4 (n = 126,941), Forns (n = 122,419), and the nonalcoholic fatty liver disease (NAFLD) fibrosis scores (NFS, n = 13,160). We ascertained incident cases of cirrhosis or complications by linking Swedish health data registers. Cox regression was used to estimate hazard ratios (HRs) for severe liver disease at 5, 10, and a maximum follow-up time of 27 years. The predictive ability of the scores was evaluated using area under the receiver operating characteristic (AUROC) curve and C-statistics analyses. Our specific aims were to investigate the predictive capabilities of scoring systems for fatal and nonfatal liver disease, determine which scoring system has the highest level of accuracy, and investigate the predictive abilities of the scoring systems in persons with a higher probability of NAFLD at baseline.

RESULTS

A similar proportion of individuals evaluated by each scoring system developed cirrhosis or complications thereof (1.0%-1.4%). The incidence of any outcome was increased in intermediate- and high-risk groups compared with low-risk groups, with HRs at 10 years in the high-risk group ranging from 1.67 for the BARD score to 45.9 for the APRI score. The predictive abilities of all scoring systems decreased with time and were higher in men. All scoring systems were more accurate in persons with risk factors for NAFLD at baseline, with AUROCs reaching 0.83.

CONCLUSIONS

Higher scores from noninvasive scoring systems to evaluate fibrosis are associated with an increased risk of cirrhosis in a general population, but their predictive ability is modest. Performance was better when patients were followed for shorter time periods and in persons with a higher risk of NAFLD, with AUROC values reaching 0.83. New scoring systems are needed to evaluate risk of fibrosis in the general population and in primary care.

Colon and rectal cancer risk after bariatric surgery in a multicountry Nordic cohort study

Obesity is a risk factor for colorectal cancer. Yet, some research indicates that weight-reducing bariatric surgery also increases colorectal cancer risk. Our study was undertaken because current evidence examining bariatric surgery and risk of colorectal cancer is limited and inconsistent. This population-based cohort study included adults with a documented obesity diagnosis in Denmark, Finland, Iceland, Norway or Sweden in 1980-2015. The incidence of colorectal cancer in participants with obesity who had and had not undergone bariatric surgery was compared to the incidence in the corresponding background population by calculating standardized incidence ratios (SIR) with 95% confidence intervals (CI). Additionally, operated and nonoperated participants with obesity were compared using multivariable Cox regression, providing hazard ratios (HR) with 95% CIs adjusted for confounders. Among 502,772 cohort participants with an obesity diagnosis, 49,931(9.9%) underwent bariatric surgery. The overall SIR of colon cancer was increased after bariatric surgery (SIR 1.56; 95% CI 1.28-1.88), with higher SIRs ≥10 years postsurgery. The overall HR of colon cancer in operated compared to nonoperated participants was 1.13 (95% CI 0.92-1.39) and 1.55 (95% CI 1.04-2.31) 10-14 years after bariatric surgery. Bariatric surgery did not significantly increase the risk of rectal cancer (SIR 1.14, 95% CI 0.83-1.52; HR 1.08, 95% CI 0.79-1.49), but the risk estimates increased with longer follow-up periods. Our study suggests that bariatric surgery is associated with an increased risk of colon cancer, while the support for an increased risk of rectal cancer was weaker.

Parents survive longer after stroke than childless individuals: a prospective cohort study of Swedes over the age of 65

BACKGROUND

Parents have lower mortality than childless individuals, and one possible explanation is support provided by adult children. Since stroke often results in functional limitations, support from children may be of particular importance. Here, we examine whether the presence of children matters for survival after stroke among older Swedish men and women.

METHODS

This prospective cohort study linked data from several Swedish population registers. Individuals aged 65 years and older hospitalized for their first ischemic stroke between 1998 and 2002 (33 960 men and 36 189 women) were followed 12 years for survival. Hazard ratios for all-cause mortality were calculated by number of children using Cox proportional hazard regression stratified by sex and marital status and adjusted for education, income and comorbidities.

RESULTS

Childlessness and having only one child was associated with higher mortality after stroke compared with having two children among men and women. The relative survival disadvantage of childless individuals was largest among married women [HR 1.28 (1.18-1.39)] and smallest among married men [1.09 (1.03-1.15)]. The differences in predicted median survival between childless individuals and those with two children were 4 and 7 months among married and unmarried men, and 15 and 9 months among married and unmarried women, respectively.

CONCLUSIONS

Having children is associated with a longer survival after stroke among men and women regardless of marital status. Our findings further suggest that the presence of children is especially connected to married women's survival. These results may have implications for the improvement of informal care for childless older individuals.

Suicides and deaths linked to risky health behavior in childhood cancer patients: A Nordic population-based register study

BACKGROUND

Childhood cancer survivors have been reported to be vulnerable to psychiatric morbidities and risky health behavior. Suicides, substance abuse, accidents, and violence as causes of death can be regarded as an extreme manifestation of risky health behavior. In the current study, the authors studied the risk of suicide and other risky health behavior-related deaths among childhood cancer patients in Denmark, Finland, and Sweden.

METHODS

Using linkage between national cancer, population, and cause-of-death registries, the authors investigated the causes of death in 29,285 patients diagnosed with cancer before age 20 years between 1971 and 2009 compared with a cohort of 146,282 age-matched, sex-matched, and country-matched population comparisons. Rate ratios (RRs) with 95% CIs were estimated using Poisson regression models, adjusting for demographic factors.

RESULTS

The overall risk of dying of a risky health behavior was found to be increased among childhood cancer patients (RR, 1.25; 95% CI, 1.06-1.47) when compared with population comparisons. The elevated risk was statistically significant among patients with central nervous system tumors (RR, 1.49; 95% CI, 1.08-2.05) and patients diagnosed at ages 5 to 9 years and 15 to 19 years (RR, 1.50 [95% CI, 1.01-2.24] and RR, 1.31 [95% CI, 1.03-1.67], respectively). The overall risk of suicide was found to be increased (RR, 1.37; 95% CI, 1.02-1.83), and statistically significantly so when patients were diagnosed between ages 15 and 19 years (RR, 1.61; 95% CI, 1.09-2.39).

CONCLUSIONS

Childhood cancer patients appear to have an increased risk of risky health behavior-related causes of death compared with the general population. The results of the current study suggest the importance of integrating psychosocial support into the follow-up care of these individuals.

Poor work ability increases sickness absence over 10 years

Background

Little is known about the predictive value of single items from the work ability index (WAI) on the risk of sickness absence over several years, and whether such risk varies across age groups.

Aims

The aim of the study was to investigate whether poor self-perceived physical and mental work ability among employees in the public sector are associated with long-term sickness absence over a 10-year period.

Methods

The study was based on a prospective cohort of employees within the public sector in Sweden reporting ‘good health for working’. Baseline information was collected with questionnaires from 2000 to 2003. Poor physical and mental work ability in relation to work demands were assessed with two items from the WAI. The outcome was the number of years of long-term sickness absence between 2003 and 2012. Long-term sickness absence was defined as ≥28 days of sickness and this information was retrieved from Swedish National Registers. Crude and adjusted incidence rate ratios were calculated with analyses stratified by age.

Results

Compared with those reporting very good physical work ability, employees reporting any lower grade of physical work ability had a higher risk of long-term sickness absence across all age strata, with higher risk estimates in the highest age groups and 6-fold increased risk in the oldest age group. Similar results were found for mental work ability with an almost 4-fold increased risk in the highest age group.

Conclusions

Self-reported physical and mental poor work ability are associated with long-term sickness absence during the subsequent 10 years. The risk increases with age.

"Obesity Paradox" Holds True for Patients with Hip Fracture: A Registry-Based Cohort Study

BACKGROUND

Hip fractures are associated with high mortality and reduced quality of life. Studies have reported a high body mass index (BMI) as being positively associated with survival when linked to old age and some chronic diseases. This phenomenon is called the "obesity paradox." The association between BMI and survival after hip fracture has not been thoroughly studied in large samples, nor has to what extent the association is altered by comorbidities, sex, and age. The objective of this study was to investigate the association of BMI with survival after hip fracture and with the probability of returning to living at home after hip fracture.

METHODS

This cohort study was based on data from a prospectively maintained national registry of patients with hip fracture. A total of 17,756 patients ≥65 years of age who were treated for hip fracture during the period of 2013 to 2016, and followed until the end of 2017, were included. BMI was clinically assessed at hospital admission, comorbidity was measured with the American Society of Anesthesiologists (ASA) score, and the date of death was retrieved from a national database. Self-reported data on living arrangements were assessed on admission and 4 months after fracture. Multivariable regression models were used to estimate the associations.

RESULTS

Despite ASA scores being similar among all BMI groups, obese patients had the highest 1-year survival and patients with a BMI of <22 kg/m had the lowest. Adjustment for potential confounders strengthened the associations. For the chance of returning to living at home, no advantage was seen for obese patients, but patients with a BMI of <22 kg/m had clearly worse odds compared with patients who were of normal weight, overweight, or obese.

CONCLUSIONS

The obesity paradox appears to be true for hip fracture patients aged 65 and older. Attention should be given to patients with malnutrition and underweight status rather than to those with overweight status or obesity when developing the orthogeriatric care.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Early Infection with Cytomegalovirus and Risk of Childhood Hematologic Malignancies

BACKGROUND

Congenital cytomegalovirus (CMV) infection was recently identified as a risk factor for childhood acute lymphocytic leukemia by detecting the presence of CMV sequences in neonatal blood spots. In this study, we asked whether clinically apparent CMV infection could be identified prior to hematologic malignancy, using high-quality Swedish population-based registries.

METHODS

CMV infection was identified with appropriate ICD-9 or ICD-10 codes in the Patient and Medical Birth Registries, and childhood malignancies below the age of 15 years were identified in the Cancer Registry, among 2,782,507 children born in Sweden 1987 to 2014.

RESULTS

Observing all CMV infections registered earlier than 6 months prior to malignancy diagnosis, an increased HR of CMV-related infections, adjusting for congenital malformations, deformations, and chromosome abnormalities, was detected for hematologic malignancies [HR, 11.2; 95% confidence interval (CI), 5.8-21.5], but not for central nervous system tumors.

CONCLUSIONS

Higher CMV incidence was detected for children ostensibly exposed through maternal CMV infection during pregnancy with the index child.

IMPACT

The data are compatible with a congenital infection of CMV leading to increased risk of childhood hematologic malignancies, but not tumors of the central nervous system, although a cautious interpretation is warranted because of the small numbers.

Temporal trends in incidence, recurrence and prevalence of stroke in an era of ageing populations, a longitudinal study of the total Swedish population

BACKGROUND

Stroke incidence has declined during the past decades. Yet, there is a concern that an ageing population together with improved survival after stroke will result in a raised proportion of the population who have experienced a stroke, as well as increasing incidence rate of recurrent strokes, and, absolute numbers of strokes. The objectives of this study were to investigate how the age specific incidence rates of recurrent strokes have developed in relation to the incidence rates of first strokes and how the postponement in age look like, and to see how the prevalence proportion of stroke as well as the absolute number of incident strokes has changed over time.

METHODS

This study includes the total Swedish population born 1890-1954 living in Sweden from 1987. Stroke was identified through hospital admissions and deaths in national health registers (mandatory for all hospitals in Sweden). Age specific incidence rates were calculated for first, second, all recurrent, and all strokes for each calendar year between 1994 and 2014 for each age between 60 and 104 years. The proportion in the population with a history of stroke up to 7 years back in time was also calculated for different age groups and for different calendar years.

RESULTS

Not only the incidence rate of first stroke but also of recurrent strokes have declined. The declines are evident in all ages up to 90 years of age, but not in ages above 90 years. Despite improved survival in stroke, the prevalence proportion has declined over the period and was around 3% in 2014 (somewhat higher for men than women). Even incident cases of stroke in absolute number has declined.

CONCLUSIONS

Decreasing incidence rates of stroke have offset an increase in both absolute and relative numbers of stroke that otherwise would have taken place due to improved survival and an ageing population. The decline in stroke recurrence has been as strong as the decline in first strokes.

Central nervous system tumor registration in the Swedish Cancer Register and Inpatient Register between 1990 and 2014

Background

The Swedish Cancer Register (SCR) is characterized by excellent quality and completeness overall, but the quality of the reporting may vary according to tumor site and age, and may change over time. The aim of the current study was to investigate the completeness of the reporting of central nervous system (CNS) tumor cases to the SCR.

Materials and methods

Individuals hospitalized for a CNS tumor between 1990 and 2014 were identified using the Inpatient Register; the proportion of identified cases that did not have any cancer diagnosis reported to the SCR was subsequently assessed.

Results

Between 1990 and 2014, 58,698 individuals were hospitalized for a CNS tumor, and a large proportion of them did not have any cancer diagnosis reported to the SCR (26%). This discrepancy was particularly pronounced for benign tumors and among elderly patients (over 30%). It was substantially lower for malignant brain tumors among adults (10%); moreover, no increase in the discrepancy between the two registers was observed in this group during the study period. Similar findings were found when assessing the concordance between the Cause of Death Register and the SCR. Among CNS tumor patients who were not reported to the SCR, a large proportion had only one hospital discharge diagnosis containing a CNS tumor (35%) and were less likely to be found in the Outpatient Register, which indicates that a large proportion of patients may have received an erroneous diagnosis.

Conclusion

While a large proportion of CNS tumor patients were not reported to the SCR, the discrepancy between the SCR and the Inpatient Register was relatively small for malignant brain tumors among adults and has remained stable throughout the study period. We do not recommend that data from the Inpatient Register are combined with the SCR to estimate CNS tumor incidence, without proper confirmation of the diagnoses, as a considerable proportion of CNS tumor diagnoses registered in the Inpatient Register is unlikely to reflect true CNS tumors.

Occurrence of primary brain tumors in cochlear implant patients in Sweden between 1989 and 2014

PURPOSE

Cochlear implants are widely used for hearing rehabilitation of deaf children with congenital deafness or adults with acquired severe-to-profound hearing loss. The sound processor antenna creates a radio frequency-electromagnetic field transmitting the sound signal to the implant, similar to that in a mobile phone. A recent case report suggested a relationship between cochlear implants and malignant glioma, and some epidemiological studies have suggested an increased glioma and acoustic neuroma risk associated with long hours of mobile phone use. An epidemiological study is warranted to evaluate such a relationship in patients with cochlear implants.

PATIENTS AND METHODS

To examine whether this chronic radio frequency-electromagnetic field signaling is associated with an increased brain tumor risk, a population-based cohort study was performed examining all 2,748 patients receiving a cochlear implant in Sweden during the years 1989-2014. In all, 3,169 surgeries were performed in the total cohort. The expected occurrence of glioma, meningioma, and acoustic neuroma in the patient cohort was calculated using specific national incidence rates in the Swedish population.

RESULTS

Four patients were diagnosed with a brain tumor during follow-up, three of them having meningioma compared with 0.95 expected (standardized incidence ratio =3.16, 95% CI 0.65-9.24), and one had glioma compared with 1.34 expected (standardized incidence ratio =0.75, 95% CI 0.02-4.15). No case of acoustic neuroma was observed compared with 0.09 expected.

CONCLUSION

In this study, we did not find support for concerns raised in a previous case report regarding a potentially higher risk of glioma. The number of brain tumors observed was well within the numbers expected from national incidence figures. Although this was a relatively small cohort with a limited follow-up time, it is the largest epidemiological study to date to address this concern.

Parental age and risk of genetic syndromes predisposing to nervous system tumors: nested case-control study

Purpose

Phacomatoses are genetic syndromes that are associated with increased risk of developing nervous system tumors. Phacomatoses are usually inherited, but many develop de novo, with unknown etiology. In this population-based study, we investigated the effect of parental age on the risk of phacomatoses in offspring.

Patients and methods

The study was a population-based nested case–control study. All individuals born and residing in Sweden between January 1960 and December 2010 were eligible for inclusion. Using the Patient Register, 4625 phacomatosis cases were identified and further classified as familial or nonfamilial. Ten matched controls per case were randomly selected from the eligible population. Data were analyzed using conditional logistic regression. Analyses were conducted for neurofibromatosis alone (n=2089) and other phacomatoses combined (n=2536).

Results

Compared with offspring of fathers aged 25–29 years, increased risk estimates of nonfamilial neurofibromatosis were found for offspring of fathers aged 35–39 years (odds ratio [OR]=1.43 [95% CI 1.16–1.74]) and ≥40 years (OR =1.74 [95% CI 1.38–2.19]). For other nonfamilial phacomatoses, the risk estimate for offspring of fathers aged ≥40 years was OR =1.23 (95% CI 1.01–1.50). Paternal age was not associated with familial phacomatoses, and no consistent association was observed with maternal age.

Conclusion

The findings show a consistent increase in risk of de novo occurrence of phacomatoses predisposing to nervous system tumors in offspring with increasing paternal age, most pronounced for neurofibromatosis, while maternal age did not seem to influence the risk. These findings suggest an increasing rate of new mutations in the NF1 and NF2 genes in spermatozoa of older fathers.

Life expectancy after the first suicide attempt

OBJECTIVE

To assess excess mortality among suicide attempters compared to the general population.

METHOD

Remaining life expectancy was calculated for a nationwide cohort of all 187 894 persons 18 years or older hospitalised for the first time attempted suicide in Sweden in 1971-2010.

RESULTS

Life expectancy was shortened throughout the lifespan for both men and women debuting with suicide attempt. The reduction in life expectancy for men debuting with a suicide attempt at 20 years of age was 18 years while the reduction for men debuting at 50 years of age was 10 years. For women attempting suicide, the life expectancy was shortened by 11 and 8 years respectively. The gender difference in life expectancy attenuated in patients making their first suicide attempt at age 70 years or older. Suicide deaths explained about 20% of the total mortality within 10 years of the suicide attempt and 5% in those with duration of four decades since the first suicide attempt.

CONCLUSION

The life expectancy is dramatically reduced in patients attempting suicide. With most excess deaths being due to physical health conditions, public efforts should be directed both towards improving physical health and to prevent suicide.

The Swedish cause of death register

Sweden has a long tradition of recording cause of death data. The Swedish cause of death register is a high quality virtually complete register of all deaths in Sweden since 1952. Although originally created for official statistics, it is a highly important data source for medical research since it can be linked to many other national registers, which contain data on social and health factors in the Swedish population. For the appropriate use of this register, it is fundamental to understand its origins and composition. In this paper we describe the origins and composition of the Swedish cause of death register, set out the key strengths and weaknesses of the register, and present the main causes of death across age groups and over time in Sweden. This paper provides a guide and reference to individuals and organisations interested in data from the Swedish cause of death register.

Estimating incidence and prevalence from population registers: example from myocardial infarction

AIM

To illustrate how the fundamental epidemiological measures, incidence rate and prevalence proportion, can be estimated based on Swedish population registers using acute myocardial infarction (MI) as an example, together with a discussion about the analytical decisions.

METHODS

All individuals in Sweden aged 60-89 (born 1904-1954) during the study period 1994-2014 were identified through the Total Population Register. Cases of MI were defined and identified from information on hospital admissions and causes of death. Incidence rates of all, first, and recurrent MI were calculated together with prevalence proportions.

RESULTS

The incidence rate of all, first, and recurrent MI declined over the study period. While the incidence rates of first MI are lower for women than men, the incidence rates of recurrent MI are considerably higher but similar for men and women. The prevalence calculated with duration of disease set at 28 days also declined. This was despite improved survival from MI and increased life expectancy over the same period meaning that the decline in incidence was large enough to compensate for increased survival.

CONCLUSIONS

Calculating incidence and prevalence of diseases using population registers requires detailed and well-reasoned definitions. The definitions will affect both the study population and the number of disease events and it is essential that the cases and the study population are defined in a coherent way. Different measures of disease occurrence contribute with different aspects of the disease panorama and a joint interpretation contributes to a thorough understanding of the disease development in a population.

Adult children's socioeconomic resources and mothers' survival after a breast cancer diagnosis: a Swedish population-based cohort study

OBJECTIVES

Socioeconomic inequalities in survival after breast cancer persist worldwide. We aim to determine whether adult offspring's socioeconomic resources contribute to inequalities in mothers' survival after breast cancer.

METHODS

14 231 women, aged 65-79 years, with a child aged ≥30 years and a first primary diagnosis of breast cancer in the National Cancer Register between 2001 and 2010 were followed until death, 10 years after diagnosis, or end of study (December 2015). Relative survival proportions and excess mortality within 10 years of diagnosis by strata of offspring's education level and disposable income were estimated using flexible parametric models accounting for measures of mothers' socioeconomic position and expected mortality in the general population.

RESULTS

4292 women died during 102 236 person-years of follow-up. Crude 10-year relative survival proportions for mothers of children with >14, 12-14 and <12 years of education were 0.89 (0.87 to 0.91), 0.87 (0.85 to 0.89) and 0.79 (0.76 to 0.81), respectively. Compared with mothers of children with >14 years of education, mothers of children with <12 or 12-14 years of education had substantially higher excess mortality (excess HR 1.69 (1.38 to 2.07) and 1.22 (1.00 to 1.48), respectively). Higher mortality did not differ between tertiles of offspring's disposable income.

CONCLUSIONS

Adult offspring's education level may contribute to inequalities in mothers' survival after breast cancer. Clinicians should be aware of the educational context beyond the individual and women with less educated offsprings may require extra support. This should be considered in future research, policy frameworks and interventions aimed at reducing survival inequalities.

Payback time? Influence of having children on mortality in old age

BACKGROUND

It is known that parents have lower mortality than childless individuals. Support from adult children to ageing parents may be of importance for parental health and longevity. The aim of this study was to estimate the association between having a child and the risk of death, and to examine whether the association increased at older ages when health starts to deteriorate and the need of support from a family member increases.

METHODS

In this nationwide study, all men and women (born between 1911 and 1925 and residing in Sweden), as well as their children, were identified in population registers and followed over time. Age-specific death risks were calculated for each calendar year for individuals having at least one child and for individuals without children. Adjusted risk differences and risk ratios were estimated.

RESULTS

Men and women having at least one child experienced lower death risks than childless men and women. At 60 years of age, the difference in life expectancy was 2 years for men and 1.5 years for women. The absolute differences in death risks increased with parents' age and were somewhat larger for men than for women. The association persisted when the potential confounding effect of having a partner was taken into account. The gender of the child did not matter for the association between parenthood and mortality.

CONCLUSIONS

Having children is associated with increased longevity, particularly in an absolute sense in old age. That the association increased with parents' age and was somewhat stronger for the non-married may suggest that social support is a possible explanation.

Methodological choices affect cancer incidence rates: a cohort study

Background

Incidence rates are fundamental to epidemiology, but their magnitude and interpretation depend on methodological choices. We aimed to examine the extent to which the definition of the study population affects cancer incidence rates.

Methods

All primary cancer diagnoses in Sweden between 1958 and 2010 were identified from the national Cancer Register. Age-standardized and age-specific incidence rates of 29 cancer subtypes between 2000 and 2010 were calculated using four definitions of the study population: persons resident in Sweden 1) based on general population statistics; 2) with no previous subtype-specific cancer diagnosis; 3) with no previous cancer diagnosis except non-melanoma skin cancer; and 4) with no previous cancer diagnosis of any type. We calculated absolute and relative differences between methods.

Results

Age-standardized incidence rates calculated using general population statistics ranged from 6% lower (prostate cancer, incidence rate difference: -13.5/100,000 person-years) to 8% higher (breast cancer in women, incidence rate difference: 10.5/100,000 person-years) than incidence rates based on individuals with no previous subtype-specific cancer diagnosis. Age-standardized incidence rates in persons with no previous cancer of any type were up to 10% lower (bladder cancer in women) than rates in those with no previous subtype-specific cancer diagnosis; however, absolute differences were <5/100,000 person-years for all cancer subtypes.

Conclusions

For some cancer subtypes incidence rates vary depending on the definition of the study population. For these subtypes, standardized incidence ratios calculated using general population statistics could be misleading. Moreover, etiological arguments should be used to inform methodological choices during study design.

Electronic supplementary material

The online version of this article (doi:10.1186/s12963-017-0120-x) contains supplementary material, which is available to authorized users.

Marital status, education, and income in relation to the risk of esophageal and gastric cancer by histological type and site

BACKGROUND

Marital status, income, and education might influence the risk of esophageal and gastric cancer, but the literature is limited. A large study addressing subtypes of these tumors was used to clarify these associations.

METHODS

A nationwide, Swedish population-based cohort study from 1991 to 2010 included individuals who were 50 years old or older. Data on exposures, covariates, and outcomes were obtained from well-maintained registers. Four esophagogastric tumor subtypes were analyzed in combination and separately: esophageal adenocarcinoma, esophageal squamous cell carcinoma, cardia adenocarcinoma, and noncardia gastric adenocarcinoma. Poisson regression was used to estimate incidence rate ratios (IRRs) and 95% confidence intervals (CIs). Analyses were stratified by sex and adjusted for confounders.

RESULTS

Among 4,734,227 participants (60,634,007 person-years), 24,095 developed esophageal or gastric cancer. In comparison with individuals in a long marriage, increased IRRs were found among participants who were in a shorter marriage or were never married, remarried, divorced, or widowed. These associations were indicated for each tumor subtype but were generally stronger for esophageal squamous cell carcinoma. Higher education and income were associated with decreased IRRs in a seemingly dose-response manner and similarly for each subtype. In comparison with the completion of only primary school, higher tertiary education rendered an IRR of 0.64 (95% CI, 0.60-0.69) for men and an IRR of 0.68 (95% CI, 0.61-0.75) for women. Comparing participants in the highest and lowest income brackets (highest 20% vs lowest 20%) revealed an IRR of 0.74 (95% CI, 0.70-0.79) for men and an IRR of 0.83 (95% CI, 0.76-0.91) for women.

CONCLUSIONS

Divorce, widowhood, living alone, low educational attainment, and low income increase the risk of each subtype of esophageal and gastric cancer. These associations require attention when high-risk individuals are being identified. Cancer 2016;122:207-212. © 2015 American Cancer Society.