Trends and risk factors of cutaneous melanoma in Europe

This thesis presents studies on different aspects of the epidemiology of melanoma: variations in disease frequency in time and place, determinants of melanoma incidence and variation in prognostic factor

IMPACT STRENGTH OF 3D-PRINTED POLYCARBONATE

A vertical wall printed by Fused Filament Fabrication consists of a ribbed surface profile, due to the layer wise deposition of molten plastic. The notches between the printed layers act as stress concentrators and decrease its resistance to impact. This article shows the relation between impact strength and layer height by experimental data and finite element simulations of the stress intensity factor and the plastic zone near the tip of the notch. The impact resistance increased from 6 to 32 kJ/m2, when the layer height was decreased from 1.8 to 0.2 mm. When notches were removed by sanding, the samples did not fail any more during impact testing, resembling the behavior of smooth molded test bars. Tensile strength values up to 61 MPa were measured independent of layer height. Birefringence measurements were done to determine the actual stress levels, which ranged from 2 to 5 MPa

Immuundeficiëntie bij kinderen en de rol van de arts-microbioloog

Met name jonge kinderen hebben vaak (luchtweg)infecties, meestal zelflimiterend. Wanneer is dit ‘niet meer normaal’? Kennis over het normale patroon van infecties en verwekkers, gerelateerd aan de leeftijd, is daarbij behulpzaam. Daarbij kan een arts-microbioloog een belangrijke rol spelen. Een voldragen kind heeft een volledig maar onrijp immuunsysteem. Vandaar dehogere infectiefrequentie bij jonge kinderen. Bij primaire immuundeficiëntie (PID) faalt het immuunsysteem intrinsiek. De ‘typische’ PID-patiënt heeft te veel, te ernstige, te therapieresistente infecties. Ook auto-immuniteit en maligniteit kunnen aanwezig zijn of zelfs op de voorgrond staan. Antistofdeficiënties komen het meeste voor; iedere arts microbioloog komt deze patiënten tegen. Ook worden bij kinderen toenemend biologicals gebruikt, waarbij ernstigeinfecties vaker voorkomen; ook minder ernstige infecties kunnen vaker optreden en voor het kind toch een grote belasting zijn. Er is weinig bekend over het effect van biologicals op het microbioom, zeker bij kinderen, er zijn wel aanwijzingen dat biologicals veranderingen in het microbioom induceren, wat weer zou kunnen bijdragen aan het vaker optreden van infecties

Immunophenotyping of lymphocytes in healthy and immunodeficient children

This thesis describes the use of immunophenotyping of lymphocytes in healthy as well as immunodeficient children. Part I describes the applied techniques (Chapters 2 and 3). The experimental work in healthy children is described in Part II (Chapters 4-7) and Part III describes the experimental work in immunodeficient children (Chapters 8-13). A summary and discussion of the work is given in Part IV

Migration and cancer mortality among Colombian migrants in the USA: a death certification study

Este estudo teve como objetivo comparar padrões de mortalidade por câncer entre os imigrantes colombianos nos EUA e colombianos em sua terra natal. Dados de 2008 a 2012 foram coletados, e foram calculadas taxas de mortalidade por câncer de colombianos residindo em seu país natal e colombianos residindo em Califórnia, Flórida e Nova York, bem como taxas específicas de mortalidade por idade e sexo por cada 100.000 pessoas. Para comparar as duas populações, tanto antes como após a correção pela escolaridade, as razões de taxas de mortalidade (MRR) foram estimadas por modelo de regressão binomial negativa. Foi descoberto que colombianos em sua terra natal apresentam taxas de mortalidade por câncer mais altas quando comparados aos que residem nos EUA (MRR masculino 1,4 (IC 95%: 1,2-1,5), MRR feminino 1,5 (IC 95%: 1,3-1,7)). Essas diferenças persistem para a maioria dos tipos de câncer, mesmo após correção pela escolaridade. Os colombianos em sua terra natal apresentaram taxa de mortalidade por câncer gástrico (MRR masculino 2,6; feminino 2,8) e cervical (MRR 5,0) significativamente mais alta em comparação com os que residem nos EUA. As desigualdades educacionais na mortalidade por câncer foram mais acentuadas para aqueles que moram em sua terra natal. A menor taxa de mortalidade por câncer observada entre os colombianos nos EUA, porém, não pode ser atribuída às diferenças de escolaridade, um indicador de status socioeconômico. Em vez disso, provavelmente ocorre devido à maior acessibilidade aos serviços de saúde preventivos e curativos nos EUA.We aim to compare cancer mortality rates of USA Colombian migrants (USA Colombians) to Colombians in their country of origin (CO Colombians). Using Colombian national mortality data and data on cancer deaths among Colombians residing in the states of California, Florida, and New York (USA Colombians) for the period 2008-2012, we estimated sex-specific and age-standardized mortality rates (ASMR), expressed per 100,000 persons. For comparisons between the two populations before and after adjustment for educational level, negative binomial regression models were used to compute Mortality Rate Ratios (MRR). CO Colombians had higher cancer mortality rates compared with USA Colombians (male MRR 1.4 [95%CI: 1.2-1.5], female MRR 1.5 [95%CI: 1.3-1.7]). These differences persisted for most cancers even after adjustment for education. CO Colombians had significantly higher mortality from gastric (MRR 2.6 in males and 2.8 in females) and cervical cancer (MRR 5.0) compared with US Colombians. Educational inequalities in cancer mortality were more pronounced among CO Colombians than among USA Colombians. Lower cancer mortality observed among USA Colombians cannot be attributed to differences in education, an indicator of socio-economic status. Rather, it is likely due to better access to preventive and curative healthcare in the USA

Planning is for doing: implementation intentions go beyond the mere creation of goal-directed associations

Studies on implementation intentions so far have mainly pointed towards strengthened cue-behavior associations as the mechanism underlying the effectiveness of this self-regulatory tool. However, we propose that because it triggers people to look into the future and to mentally simulate their future behavior, planning by means of implementation intentions might go beyond the creation of goal-directed associations and thus lead to more enduring effects on behavior. We tested this hypothesis in an experiment using a longitudinal design, where participants formed an intention for a behavior that deviates from their routine, and furnished it either with associative learning of cue and behavior, forming implementation intentions, or nothing at all. Results showed that initially, learning cue-behavior associations led to the same rate of goal completion as forming implementation intentions. However, only the effect of implementation intentions was maintained at the second measurement one week later. These findings suggest that planning does more than merely create goal-directed associations, which might offer a new perspective on the workings and use of this important tool for behavior change

Respiratory symptoms in post-infancy children:A Dutch pediatric cohort study

Aim: To study the pattern of respiratory symptoms in children in the general population. Method: We followed a cohort of children for up to 2 years through parents completing weekly online questionnaires in the Child-Is-Ill study (“Kind-en-Ziekmeting” in Dutch); the study was running 2012–2015. Inclusion criteria were “an ordinary child” (according to the parents) and <18 years old at inclusion. We especially encouraged participation of post-infancy children. Age at inclusion, sex, smoking exposure, allergy in the family, and frequent infections in the family were noted. Pearson's correlation, principal component analysis, latent class analysis, latent profile analysis, linear regression, and linear mixed effects regression were used in the statistical analyses. Results: Data were collected on 55,524 childweeks in 755 children (50% girls; median age, 7 years; interquartile range, 4–11 years, 97% ≥2 years at inclusion), with reported symptom(s) in 8,425 childweeks (15%), leading to school absenteeism in 25%, doctor's visits in 12%, and parental sick leave in 8%; symptoms lasting ≥3 weeks were rare (2% of episodes). Linear mixed effects regression showed significant, but only limited, effects of season on the proportion of “symptom(s) reported” per individual child. Only runny nose showed a significant, but very small, age effect. However, the variability between the children was considerable. There were no obvious subgroups of children with specific symptom combinations. Conclusion: In any randomly chosen week, the vast majority of children (85%) in our—mainly—post-infancy cohort derived from the general population did not have any symptom, even in the younger age group, even in winter. The children showed considerable variability; no clear subgroups of symptom patterns could be identified, underlining the difficult position of healthcare providers. These results support our opinion that post-infancy children in the general population should not be evaluated as if they are infants when they have recurrent respiratory symptoms. If they clearly deviate from the above-described most common pattern, it is wise to keep an eye on potential, maybe even rare, serious underlying causes

Time trends in educational inequalities in cancer mortality in Colombia, 1998-2012

Objectives: To evaluate trends in premature cancer mortality in Colombia by educational level in three periods: 1998-2002 with low healthcare insurance coverage, 2003-2007 with rapidly increasing coverage and finally 2008-2012 with almost universal coverage (2008-2012). Setting: Colombian population-based, national secondary mortality data. Participants: We included all (n=188 091) cancer deaths occurring in the age group 20-64 years between 1998 and 2012, excluding only cases with low levels of quality of registration (n=2902, 1.5%). Primary and secondary outcome measures: In this descriptive study, we linked mortality data of ages 20-64 years to census data to obtain age-standardised cancer mortality rates by educational level. Using Poisson regression, we modelled premature mortality by educational level estimating rate ratios (RR), relative index of inequality (RII) and the Slope Index of Inequality (SII). Results: Relative measures showed increased risks of dying among the lower educated compared to the highest educated; this tendency was stronger in women (RRprimary1.49; RRsecondary1.22, both p<0.0001) than in men (RRprimary 1.35; RRsecondary 1.11, both p<0.0001). In absolute terms (SII), cancer caused a difference per 100 000 deaths between the highest and lowest educated of 20.5 in males and 28.5 in females. RII was significantly higher among women and the younger age categories. RII decreased between the first and second periods; afterwards (2008-2012), it increased significantly back to their previous levels. Among women, no significant increases or declines in cancer mortality over time were observed in recent periods in the lowest educated group, whereas strong recent declines were observed in those with secondary education or higher. Conclusions: Educational inequalities in cancer mortality in Colombia are increasing in absolute and relative terms, and are concentrated in young age categories. This trend was not curbed by increases in healthcare insurance coverage. Policymakers should focus on improving equal access to prevention, early detection, diagnostic and treatment facilities

Oral and oropharyngeal cancer in Colombia : an experience in a middle-income country cancer institute (2004-2013)

Artículo original19-26Abstract Aims To provide demographical and clinical characteristics and estimations of 2-year overall survival (OS) of oral and oropharyngeal cancer (OOC) patients treated in the Colombian National Cancer Institute (INC) between 2004 and 2013. Methods All 1108 patients frst treated at INC for OOC in the three periods, without a prior cancer diagnosis, were included in this study. The INC hospital-based cancer registry was cross-linked with governmental databases to obtain follow-up information on all patients. Probability of surviving 24 months since the date of entry at INC was estimated using Kaplan–Meier methods, using the log-rank test to evaluate diferences between groups. In order to evaluate the relative efect of age, sex, clinical stage, anatomical site and type of health insurance on survival, we constructed a multivariate Cox proportional hazard model. Results The overall survival probability at 24 months was 48.2% (95% CI 45.3; 51.1), which was stable over time. Advanced age and clinical stage substantially afected overall survival, being 30.3% (95% CI 25.2; 35.4) for age > 70 and 34.7% (95% CI 29.4; 40.0) for stage IV disease. Hazard ratios were signifcantly higher for patients aged 70 and over [HR 1.99 (95% CI 1.41–2.79)] and advanced stage cancers [HR 2.16 (95% CI 1.55–3.01)], whereas patients with cancers of the tonsils or salivary glands had a strongly reduced risks compared to tongue and oral cavity cancer [HR 0.56 (95% CI 0.43–0.72)]. Conclusions Oral and oropharyngeal cancer has a very poor prognosis which was stable over time. Considering the late stage at diagnosis, much can be gained by improving early detection and treatment