Hospital use and cancer treatment by age and socioeconomic status in the last year of life: A Norwegian population-based study of patients dying of cancer

INTRODUCTION

Cancer is the leading cause of death in Norway. In this nationwide study we describe the number and causes of hospital admissions and treatment in the final year of life for patients who died of cancer, as well as the associations to age and socioeconomic status (SES).

MATERIALS AND METHODS

From nationwide registries covering 2010-2014, we identified all patients who were diagnosed with cancer 12-60 months before death and had cancer as their reported cause of death. We examined the number of overnight hospital stays, causes of admission, and treatment (chemotherapy, radiotherapy, surgical procedures) offered during the last year of life by individual (age, sex, comorbidity), cancer (type, stage, months since diagnosis), and socioeconomic variables (co-residential status, income, education).

RESULTS

The analytical sample included 17,669 patients; 8,247 (47%) were female, mean age was 71.7 years (standard deviation 13.7). At diagnosis, 31% had metastatic disease, while 29% had an intermediate or high comorbidity burden. Altogether, 94% were hospitalized during their final year, 82% at least twice, and 33% six times or more. Patients spent a median of 23 days in hospital (interquartile range 11-41), and altogether 38% died there. Younger age, bladder and ovarian cancer, not living alone, and higher income were associated with having ≥6 hospitalizations. Cancer-related diagnoses were the main causes of hospitalizations (65%), followed by infections (11%). Around 51% had ≥1 chemotherapy episode, with large variations according to patient age and SES; patients who were younger, did not live alone, had high education, and high income received more chemotherapy. Radiotherapy was received by 15% and declined with age, and the variation according to SES characteristics was minor. Of the 12,940 patients with a cancer type where surgery is a main treatment modality, only 835 (6%) underwent surgical procedures for their primary tumor in the last year of life.

DISCUSSION

Most patients who die of cancer are hospitalized multiple times during the last year of life. Hospitalizations and treatment decline with advancing age. Living alone and having low income is associated with fewer hospitalizations and less chemotherapy treatment. Whether this indicates over- or undertreatment across various groups warrants further exploration.

A review of the epidemiological and laboratory evidence of the role of aluminum exposure in pathogenesis of cardiovascular diseases

The objective of the present study was to review the epidemiological and laboratory evidence on the role of aluminum (Al) exposure in the pathogenesis of cardiovascular diseases. Epidemiological data demonstrated an increased incidence of cardiovascular diseases (CVD), including hypertension and atherosclerosis in occupationally exposed subjects and hemodialysis patients. In addition, Al body burden was found to be elevated in patients with coronary heart disease, hypertension, and dyslipidemia. Laboratory studies demonstrated that Al exposure induced significant ultrastructural damage in the heart, resulting in electrocardiogram alterations in association with cardiomyocyte necrosis and apoptosis, inflammation, oxidative stress, inflammation, and mitochondrial dysfunction. In agreement with the epidemiological findings, laboratory data demonstrated dyslipidemia upon Al exposure, resulting from impaired hepatic lipid catabolism, as well as promotion of low-density lipoprotein oxidation. Al was also shown to inhibit paraoxonase 1 activity and to induce endothelial dysfunction and adhesion molecule expression, further promoting atherogenesis. The role of Al in hypertension was shown to be mediated by up-regulation of NADPH-oxidase, inhibition of nitric oxide bioavailability, and stimulation of renin-angiotensin-aldosterone system. It has been also demonstrated that Al exposure targets cerebral vasculature, which may be considered a link between Al exposure and cerebrovascular diseases. Findings from other tissues lend support that ferroptosis, pyroptosis, endoplasmic reticulum stress, and modulation of gut microbiome and metabolome are involved in the development of CVD upon Al exposure. A better understanding of the role of the cardiovascular system as a target for Al toxicity will be useful for risk assessment and the development of treatment and prevention strategies.

Slow gut transit increases the risk of Alzheimer's disease: An integrated study of the bi-national cohort in South Korea and Japan and Alzheimer's disease model mice

INTRODUCTION

Although the association between Alzheimer's disease (AD) and constipation is controversial, its causality and underlying mechanisms remain unknown.

OBJECTIVES

To investigate the potential association between slow gut transit and AD using epidemiological data and a murine model.

METHODS

We conducted a bi-national cohort study in South Korea (discovery cohort, N=3,130,193) and Japan (validation cohort, N=4,379,285) during the pre-observation period to determine the previous diagnostic history (2009-2010) and the follow-up period (2011-2021). To evaluate the causality, we induced slow gut transit using loperamide in 5xFAD transgenic mice. Changes in amyloid-beta (Aβ) and other markers were examined using ELISA, qRT-PCR, RNA-seq, and behavioral tests.

RESULTS

Constipation was associated with an increased risk of AD in the discovery cohort (hazard ratio, 2.04; 95% confidence interval [CI], 2.01-2.07) and the validation cohort (hazard ratio; 2.82; 95% CI, 2.61-3.05). We found that loperamide induced slower gut transit in 5xFAD mice, increased Aβ and microglia levels in the brain, increased transcription of genes related to norepinephrine secretion and immune responses, and decreased the transcription of defense against bacteria in the colonic tissue.

CONCLUSION

Impaired gut transit may contribute to AD pathogenesis via the gut-brain axis, thus suggesting a cyclical relationship between intestinal barrier disruption and Aβ accumulation in the brain. We propose that gut transit or motility may be a modifiable lifestyle factor in the prevention of AD, and further clinical investigations are warranted.

Wastewater-based epidemiology revealed in advance the increase of enterovirus circulation during the Covid-19 pandemic

Wastewater-based epidemiology (WBE) was conducted to track Enteroviruses (EVs) circulation in the Milan metropolitan area (Northern Italy) during Covid-19 pandemic (March 2020-December 2022). 202 composite 24-hour wastewater samples (WWSs) were collected weekly from March 24, 2020, to December 29, 2022 at the inlet of two wastewater treatment plants (WWTP) in Milan (1.5 million inhabitants). EV-RNA was quantified and molecular characterization of non-polio EVs (NPEV) was performed by Sanger sequence analysis. Data from WWS were matched with virological data collected in the framework of Influenza-Like Illness (ILI) surveillance in the same place and time. EV-RNA was identified in 88.2 % of WWSs. The peak in EVs circulation was observed in late August 2020 (upon conclusion of the first national lockdown), in late August 2021, and in mid-April 2022. EV-RNA concentration in WWS (normalized as copies/d/1000 people) at peak of circulation presented a yearly increase (2020: 2.47 × 1010; 2021: 6.81 × 1010; 2022: 2.14 × 1011). This trend overlapped with trend in EV-positivity rate in ILI cases, expanded from 21.7 % in 2021 to 55.6 % in 2022. EV trends in WWS preceded clinical sample detections in 2021 and 2022 by eight and five weeks, respectively, acting as an early warning of outbreak. Although sequencing of EV-positive WWSs revealed the presence of multiple EV strains, typing remained inconclusive. Molecular characterization of EVs in clinical samples revealed the co-circulation of several genotypes: EV-A accounted for 60 % of EVs, EV-B for 16.7 %, EV-D68 for 23.3 %. EVs were circulating in Milan metropolitan area between March 2020 and December 2022. The epidemiological trends unfolded the progressive accumulation of EV transmission in the population after removal of Covid-19 restrictions. The increased circulation of EVs in 2021-2022 was identified at least 35 days in advance compared to the analysis of clinical data. The inconclusive results of Sanger sequencing lookout for improvement and innovative molecular approaches to deepen track EVs.

Estimating disease incidence rates and transition probabilities in elderly patients using multi-state models: a case study in fragility fracture using a Bayesian approach

BACKGROUND

Multi-state models are complex stochastic models which focus on pathways defined by the temporal and sequential occurrence of numerous events of interest. In particular, the so-called illness-death models are especially useful for studying probabilities associated to diseases whose occurrence competes with other possible diseases, health conditions or death. They can be seen as a generalization of the competing risks models, which are widely used to estimate disease-incidences among populations with a high risk of death, such as elderly or cancer patients. The main advantage of the aforementioned illness-death models is that they allow the treatment of scenarios with non-terminal competing events that may occur sequentially, which competing risks models fail to do.

METHODS

We propose an illness-death model using Cox proportional hazards models with Weibull baseline hazard functions, and applied the model to a study of recurrent hip fracture. Data came from the PREV2FO cohort and included 34491 patients aged 65 years and older who were discharged alive after a hospitalization due to an osteoporotic hip fracture between 2008-2015. We used a Bayesian approach to approximate the posterior distribution of each parameter of the model, and thus cumulative incidences and transition probabilities. We also compared these results with a competing risks specification.

RESULTS

Posterior transition probabilities showed higher probabilities of death for men and increasing with age. Women were more likely to refracture as well as less likely to die after it. Free-event time was shown to reduce the probability of death. Estimations from the illness-death and the competing risks models were identical for those common transitions although the illness-death model provided additional information from the transition from refracture to death.

CONCLUSIONS

We illustrated how multi-state models, in particular illness-death models, may be especially useful when dealing with survival scenarios which include multiple events, with competing diseases or when death is an unavoidable event to consider. Illness-death models via transition probabilities provide additional information of transitions from non-terminal health conditions to absorbing states such as death, what implies a deeper understanding of the real-world problem involved compared to competing risks models.

The effect of age on specialized palliative care use in the last year of life for patients who die of cancer: A nationwide study from Norway

INTRODUCTION

Specialized palliative care (SPC) is beneficial towards end of life because of its holistic approach to improve quality of life and comfort of patients and their families. Few studies have described how patient age, sex, comorbidities, and socioeconomic status (SES) are associated with SPC use in nonselective populations who die of cancer. This study aimed to evaluate the use of SPC in the year preceding death by all Norwegian individuals with a recent cancer diagnosis who died of cancer.

MATERIALS AND METHODS

From nationwide registries, we identified patients with a recent (<5 years) cancer diagnosis who died during 2010-2014. Using binary logistic regression models, we estimated the probability of receiving hospital-based SPC during the last year of life according to individual (age, sex, comorbidity), cancer (stage, type, and months since diagnosis), and SES (e.g., living alone, household income, and education) characteristics.

RESULTS

The analytical sample contained 45,521 patients with a median age at death of 75 years; 46% were women. The probability of receiving hospital-based SPC in the total cohort was 0.43 (95% confidence interval [CI] 0.42-0.43). Use of SPC was higher if patients were younger, female, had limited comorbidity, metastatic disease, had one the following cancer types: colorectal, pancreatic, bladder, kidney, or gastric, were diagnosed more than six months before death, and had higher SES. Adjusted model results suggested that the probability of using SPC in the last year of life for patients aged 80-89 years was 0.31 (95% CI 0.30-0.32), compared to a probability of 0.63 (95% CI 0.61-0.65) for patients aged 50-59 years. For patients ≥90 years, the probability was 0.16 (95% CI 0.15-0.18).

DISCUSSION

Less hospital-based SPC use among older patients, males, and those with lower SES indicates possible under-treatment in these groups. Future studies should be designed to determine the underlying reasons for these observed differences.

Toxic chemicals from uncontrolled e-waste recycling: Exposure, body burden, health impact

Uncontrolled electronic-waste (e-waste) recycling processes have induced serious environmental pollution and human health impacts. This paper reviewed studies on the wide range of toxic chemicals through the use of primitive recycling techniques, their transfer to various ecological compartments, and subsequent health impacts. Results indicated that local food items were heavily polluted by the pollutants emitted, notably heavy metals in vegetables, rice, fish and seafood, and persistent organic pollutants (POPs) in livestock. Dietary exposure is the most important exposure pathway. The associations between exposure to e-waste and high body burdens of these pollutants were evident. It seems apparent that toxic chemicals emitted from e-waste activities are causing a number of major illnesses related to cardiovascular, digestive and respiratory systems, according to the information provided by a local hospital (Taizhou, an e-waste recycling hot spot in China). More epidemiological data should be made available to the general public. It is envisaged that there are potential dangers of toxic chemicals passing on to the next generation via placental transfer and lactation. There is a need to monitor the development and health impacts of infants and children, born and brought up in the e-waste sites.

Understanding the cycles of COVID-19 incidence: Principal Component Analysis and interaction of biological and socio-economic factors

The incidence curve of coronavirus disease 19 (COVID-19) shows cyclical patterns over time. We examine the cyclical properties of the incidence curves in various countries and use principal components analysis to shed light on the underlying dynamics that are common to all countries. We find that the cyclical series of 37 countries can be summarized in four principal components which explain over 90% of the variation. We also discuss the influence of complex interactions between biological viral natural history and socio-political reactions and measures adopted by different countries on the cyclical patterns exhibited by COVID-19 around the globe.

Low dose ionizing radiation effects on the immune system

Ionizing radiation interacts with the immune system in many ways with a multiplicity that mirrors the complexity of the immune system itself: namely the need to maintain a delicate balance between different compartments, cells and soluble factors that work collectively to protect, maintain, and restore tissue function in the face of severe challenges including radiation damage. The cytotoxic effects of high dose radiation are less relevant after low dose exposure, where subtle quantitative and functional effects predominate that may go unnoticed until late after exposure or after a second challenge reveals or exacerbates the effects. For example, low doses may permanently alter immune fitness and therefore accelerate immune senescence and pave the way for a wide spectrum of possible pathophysiological events, including early-onset of age-related degenerative disorders and cancer. By contrast, the so called low dose radiation therapy displays beneficial, anti-inflammatory and pain relieving properties in chronic inflammatory and degenerative diseases. In this review, epidemiological, clinical and experimental data regarding the effects of low-dose radiation on the homeostasis and functional integrity of immune cells will be discussed, as will be the role of immune-mediated mechanisms in the systemic manifestation of localized exposures such as inflammatory reactions. The central conclusion is that ionizing radiation fundamentally and durably reshapes the immune system. Further, the importance of discovery of immunological pathways for modifying radiation resilience amongst other research directions in this field is implied.

Focusing on foot drop: Results from a patient survey and clinical examination

BACKGROUND

Epidemiological data concerning the symptom 'foot drop' are scarce in the literature. However, everyday practice shows that this symptom is frequent, and that patients who suffer from it are significantly disabled.

METHODS

A special 'foot-drop consulting hour' to examine and advise people with foot drop was founded. Over 18 months we collected data from 65 patients who consulted us: this included patient-related items, diagnoses and treatment.

RESULTS

People of all ages were affected by foot drop. Left and right sides were affected with equal frequency. Spinal lumbar nerve root damage and peroneal nerve compression were the most frequent causes, followed by polyneuropathy and nerve trauma. In 18% of patients more than one pathological condition was found that might have led to foot drop. In 14% no reason could be determined. 45% of patients with foot drop subsequently received surgical treatment.

CONCLUSION

Epidemiological data and details of patients affected by foot drop can help to raise awareness of this frequent symptom and to suggest specific therapy.

Is the press properly presenting the epidemiological data on COVID-19? An analysis of newspapers from 25 countries

We conducted a cross-sectional study to assess how the top 3 highest circulation newspapers from 25 countries are comparing and presenting COVID-19 epidemiological data to their readers. Of 75 newspapers evaluated, 51(68%) presented at their websites at least one comparison of cases and/or deaths between regions of their country and/or between countries. Quality assessment of the comparisons showed that only a minority of newspapers adjusted the data for population size in case comparisons between regions (37.2%) and between countries (25.6%), and the same was true for death comparisons between regions (27.3%) and between countries (27%). Of those making comparisons, only 13.7% explained the difference in the interpretation of cases and deaths. Of 17 that presented a logarithmic curve, only 29.4% explained its meaning. Although the press plays a key role in conveying correct medical information to the general public, we identified inconsistencies in the reporting of COVID-19 epidemiological data.

Trends in the epidemiology of thyroid diseases in Bulgaria since the year 2000-a review of the literature

This review attempts to summarize data on the prevalence of thyroid pathology in the Bulgarian population over a period of 20 years. Thyroid dysfunction was studied in two population-based studies (2006 and 2012). In the first, hypothyroidism was found in 6.3% and hyperthyroidism in 3.7% of the participants. The second study found overt and subclinical hypothyroidism in 3.2% and 4.5%, respectively, of females, and in 1.1% and 2% of males. TPOAb levels were elevated in 23% of females and in 9.6% of males. Nodules were found using ultrasound (US) in 23.4% of the participants in the 2006 study (in 30.1% of females and 15.0% of males), while the 2012 study showed 24.4% (32.1% of females and 15.7% of males). Recent data regarding prevalence of thyroid carcinoma in the Bulgarian population are lacking. Between 4 and 6% of thyroid biopsies produce results which have markers for malignancy. Four studies were carried out to address urinary iodine excretion levels in schoolchildren and three for those in pregnant women. Although median urinary iodine was in the iodine-sufficient range, a rising proportion of women had low urinary excretion. In the studies involving schoolchildren, excessive iodine excretion was also observed. The major strength of this review is the combination of data from different publications to give an overall baseline of thyroid epidemiology in Bulgaria. Further work is needed to map the recent trends regarding thyroid pathology in Bulgaria and the complete epidemiological dataset.

Cutaneous lymphoma in Japan, 2012-2017: A nationwide study

BACKGROUND

The types of cutaneous lymphoma (CL) and their incidences can vary among geographic areas or ethnic groups.

OBJECTIVE

This study aimed to investigate the incidence of various CL types in Japan using epidemiological data from a nationwide registration system for CL.

METHODS

A questionnaire was sent to participating hospitals, all of which had been approved to conduct residency programs for board-certified dermatologists by the Japanese Dermatological Association. Data from patients newly diagnosed with CL were collected electronically.

RESULTS

Between 2012 and 2017, 2547 new patients with CL from the dermatological institutes were registered. In total, 2090 patients had primary CL and 453 had secondary CL. Those with primary CL included 1609 (77.0 %) patients with mature T- and natural killer (NK)-cell neoplasms, 442 (21.1 %) with B-cell neoplasms, and 39 (1.9 %) with blastic plasmacytoid dendritic cell neoplasms. Mycosis fungoides (MF) was the most common CL subtype in the present study (1003 patients, 48.0 %), and 72.4 % of MF patients had early-stage disease, similar to observations in previous studies on other cohorts. Primary cutaneous CD30+ T-cell lymphoproliferative disorders and adult T-cell leukemia/lymphoma were the second and third most common subtypes, respectively.

CONCLUSION

Compared to that in our previous cohort (2007-2011), the number of registered T- and NK-cell CL cases decreased, whereas that of B-cell CL cases increased from 44.8-73.7 patients/year. These results provide insight into CL trends within the Japanese population, which might contribute to a better understanding of the disease.

Data of a sub-analysis of the DEMDATA study: characteristics of Austrian and Czech nursing homes residents

Objectives

The aim of this data paper is to provide the data set of a sub-analysis of the DEMDATA study data. In the DEMDATA study, epidemiological data on the prevalence and severity of dementia, as well as functioning, behavioral problems and other health related factors in residents living in Austrian and Czech nursing homes were collected. The DEMDATA project further provides information on relatives’ perception of the life Quality of residents, care team burden as well as environmental factors. Participating nursing homes were randomly drawn and stratified. Inclusion criteria for participation were that the resident was living permanently in the institution and that he/she and/or a legal representative (where relevant) had signed an informed consent.

Data description

This paper provides data of cognitive, functional and behavioral assessments as well as other health related information of 1085 residents living in Austrian and Czech nursing homes. For each resident, several measurements on his or her cognitive, functional, and behavioral status are available. Also further health-related factors such as quality of life, pain, numbers of falls and hospital stays are provided.

Epidemiology of Granulomatosis with Polyangiitis in Poland, 2011-2015

Granulomatosis with polyangiitis (GPA) is a form of vasculitis that affects small- and medium-sized vessels in many organs. The aim of the study was to describe the epidemiology of GPA in Poland in 2011-2015, including the incidence and prevalence rates. The authors conducted a retrospective, population-based study, using hospital discharge records with GPA diagnosis. GPA incidence was estimated on the basis of the data from the Polish hospital morbidity study carried out by the National Institute of Public Health. The final study group consisted of 1491 patients (749 females, 742 males) who were first time hospitalized with the diagnosis of GPA. The average annual incidence of GPA in Poland was 7.7/1,000,000 (95% CI, 4.1-11.4), and the point prevalence at the end of 2015 was 36/1,000,000. A statistically significant decrease in the GPA incidence was noticed in this study. A 1-year survival rate for GPA was 94%. In conclusion, the incidence and prevalence rates of GPA in Poland are similar to that reported in other European countries. The study provides recent epidemiological data on GPA in Poland, which may be useful for comparisons with other geographical regions.

Scarlet Fever Epidemic in China Caused by Streptococcus pyogenes Serotype M12: Epidemiologic and Molecular Analysis

From 2011, Hong Kong and mainland China have witnessed a sharp increase in reported cases, with subsequent reports of epidemic scarlet fever in North Asia and the United Kingdom. Here we examine epidemiological data and investigate the genomic context of the predominantly serotype M12 Streptococcus pyogenes scarlet fever isolates from mainland China. Incident case data was obtained from the Chinese Nationwide Notifiable Infectious Diseases Reporting Information System. The relative risk of scarlet fever in recent outbreak years 2011–2016 was calculated using the median age-standardised incidence rate, compared to years 2003–2010 prior this outbreak. Whole genome sequencing was performed on 32 emm12 scarlet fever isolates and 13 emm12 non-scarlet fever isolates collected from different geographic regions of China, and compared with 203 published emm12 S. pyogenes genomes predominantly from scarlet fever outbreaks in Hong Kong (n = 134) and the United Kingdom (n = 63). We found during the outbreak period (2011–2016), the median age-standardised incidence in China was 4.14/100,000 (95% confidence interval (CI) 4.11-4.18), 2.62-fold higher (95% CI 2.57-2.66) than that of 1.58/100,000 (95% CI 1.56-1.61) during the baseline period prior to the outbreak (2003 − 2010). Highest incidence was reported for children 5 years of age (80.5/100,000). Streptococcal toxin encoding prophage φHKU.vir and φHKU.ssa in addition to the macrolide and tetracycline resistant ICE-emm12 and ICE-HKU397 elements were found amongst mainland China multi-clonal emm12 isolates suggesting a role in selection and expansion of scarlet fever lineages in China. Global dissemination of toxin encoded prophage has played a role in the expansion of scarlet fever emm12 clones. These findings emphasize the role of comprehensive surveillance approaches for monitoring of epidemic human disease.

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The study used all epidemiological data from 1950 to 2016, and describe increased incidence levels for the current outbreak.

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Using global emm12 scarlet fever isolate genome sequences, the multiclonal nature of the outbreak was confirmed.

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Global surveillance of GAS toxin and drug resistance mobile genes in the scarlet fever outbreak is necessary.

Our study provides a detailed report of scarlet fever epidemiology and genomic analysis for mainland China since the 2011 outbreak began. We also provide a comprehensive comparison of the genomic relationship of scarlet fever outbreak emm12 isolates from China, Hong Kong and the United Kingdom, countries experiencing an unparalleled re-emergence of scarlet fever. Our observations implicate an important role for GAS toxin and drug resistance related mobile genes in the outbreak and reveal different evolutionary patterns, and identify common themes relating to the acquisition of toxin carrying prophage elements. This work emphasizes the importance of comprehensive nationwide surveillance to track scarlet fever, GAS emm types, exotoxin-encoding prophage and antibiotic resistance genes in a global context.

Epidemiological and outcome data in Japanese patients with deep vein thrombosis with and without malignancy

There are very few epidemiological studies on Japanese patients with deep vein thrombosis (DVT). In particular, mortality rate differences in Japanese DVT patients with and without malignancy have rarely been evaluated. To elucidate these differences, we enrolled 211 patients who had been diagnosed with de-novo acute DVT of the pelvis or lower extremities between January 2012 and December 2015. The clinical characteristics, treatment information, and follow-up data were retrospectively assessed. We compared these variables in patients with (n = 120) and without (n = 91) concomitant malignancies. The median age of patients was 67 years, 33.7% were male, and 82.9% patients were treated with oral anticoagulants including direct oral anticoagulants. The clinical characteristics and treatment provided were almost identical in the two groups with some exceptions. Three-year survival rates of the total population, patients with malignancy, and patients without malignancy were 80.6, 67.6, and 97.6%, respectively (log-rank p < 0.001). Multivariable Cox regression analysis demonstrated that malignancy was independently associated with high risk of 3-year all-cause mortality with an adjusted hazard ratio of 9.1 (95% confidence interval; 2.1-39.0, p = 0.003). Bootstrap validation demonstrated an acceptable index corrected slope of 0.766 without significant overfitting in a multivariable model. In conclusion, we analyzed epidemiological data on Japanese patients with DVT. Malignancy was independently associated with increased 3-year all-cause mortality.

Worldwide malaria incidence and cancer mortality are inversely associated

Background

Investigations on the effects of malaria infection on cancer mortality are limited except for the incidence of Burkitt’s lymphoma (BL) in African children. Our previous murine lung cancer model study demonstrated that malaria infection significantly inhibited tumor growth and prolonged the life span of tumor-bearing mice. This study aims to assess the possible associations between malaria incidence and human cancer mortality.

Methods

We compiled data on worldwide malaria incidence and age-standardized mortality related to 30 types of cancer in 56 countries for the period 1955–2008, and analyzed their longitudinal correlations by a generalized additive mixed model (GAMM), adjusted for a nonlinear year effect and potential confounders such as country’s income levels, life expectancies and geographical locations.

Results

Malaria incidence was negatively correlated with all-cause cancer mortality, yielding regression coefficients (log scale) of −0.020 (95%CI: −0.027,-0.014) for men (P < 0.001) and-0.020 (95%CI: −0.025,-0.014) for women (P < 0.001). Among the 29 individual types of cancer studied, malaria incidence was negatively correlated with colorectum and anus (men and women), colon (men and women), lung (men), stomach (men), and breast (women) cancer.

Conclusions

Our analysis revealed a possible inverse association between malaria incidence and the mortalities of all-cause and some types of solid cancers, which is opposite to the known effect of malaria on the pathogenesis of Burkitt’s lymphoma. Activation of the whole immune system, inhibition of tumor angiogenesis by Plasmodium infection may partially explain why endemic malaria might reduce cancer mortality at the population level.

Electronic supplementary material

The online version of this article (doi:10.1186/s13027-017-0117-x) contains supplementary material, which is available to authorized users.