Reyn van Ewijk

The effect of peer socioeconomic status on student achievement: A meta-analysis

Previous studies on the effects on students’ test scores of their peers’ socioeconomic status (SES) reported varying results. A meta-regression analysis including 30 studies on the topic shows that the compositional effect that researchers find is strongly related to how they measure SES and to their model choice. If they measure SES dichotomously (e.g. free lunch eligibility) or include several average SES-variables in one model, they find smaller effects than when using a composite that captures several SES-dimensions. Composition measured at cohort/school level is associated with smaller effects than composition measured at class level. Researchers estimating compositional effects without controlling for prior achievement or not taking into account the potential for omitted variables bias, risk overestimating the effect. Correcting for a large set of not well-thought-over covariates may lead to an underestimation of the compositional effect, by artificially explaining away the effect. Little evidence was found that effect sizes differ with sample characteristics such as test type (language vs. math) and country. Estimates for a hypothetical study, making a number of “ideal” choices, suggest that peer SES may be an important determinant of academic achievement.

Long-Term Health Effects on the Next Generation of Ramadan Fasting During Pregnancy

Each year, many pregnant Muslim women fast during Ramadan. Using Indonesian cross-sectional data and building upon work of Almond and Mazumder (2011), I show that people who were prenatally exposed to Ramadan fasting have a poorer general health than others. As predicted by medical theory, this effect is especially pronounced among older people, who also more often report symptoms indicative of coronary heart problems and type 2 diabetes. Among exposed Muslims the share of males is lower, which is most likely caused by death before birth. I show that these effects are unlikely the result of common health shocks correlated to the occurrence of Ramadan, or of fasting mainly occurring among women who would have had unhealthier children anyway.

Peer Ethnicity and Achievement: A Meta-Analysis into the Compositional Effect

This study reports a meta-analysis on the effects of ethnic minority share in school on achievement test scores. Best evidence from the studies that have appeared thus far on this topic shows that these compositional effects appear small in general, but may be larger when the ethnic minority group is African Americans in the USA than when the minority group consists of immigrants. A high share of students from an ethnic minority group seems to affect the achievement of students belonging to the same ethnic group more than the achievement of students belonging to the ethnic majority or to other ethnic minority groups. Effects of the share of immigrants on test scores of ethnic majority students even seem to be close to zero. Several robustness checks confirm our results. The review concludes with a discussion of implications for research and policy practice.

Adherence to treatment guidelines and survival in triple-negative breast cancer: a retrospective multi-center cohort study with 9156 patients

BackgroundTriple-negative breast cancer (TNBC) remains a challenging topic for clinical oncologists. This study sought to evaluate TNBC versus other breast cancer subtypes with respect to survival parameters. We evaluated possible differences in survival in TNBC by age and by the extent to which evidence-based treatment guidelines were adhered.MethodsThis German retrospective multi-center cohort study included 9156 patients with primary breast cancer recruited from 1992 to 2008.ResultsThe rates of guideline adherence are significantly lower in TNBC compared to non-TNBC subtypes. These lower rates of guideline adherence can be observed in all age groups and are most pronounced in the >65 subgroup [<50 (20.9% vs. 42.0%), 50–64 (25.1% vs. 51.1%), and >65 (38.4% vs. 74.6%)]. In TNBC patients of all age groups, disease-free survival and overall survival were associated with an improvement by 100% guideline-adherent adjuvant treatment compared to non-adherence. Furthermore, TNBC patients of all ages had similar outcome parameters if 100% guideline-adherent adjuvant treatment was applied.ConclusionThe rates of guideline-adherent treatment were significantly lower in TNBC, even though guideline adherence was strongly associated with improved survival. In the case of 100% guideline-adherent treatment, no difference in survival was observed over all the age groups examined, even in the group of >65-year-old TNBC patients.

Associations of Prenatal Exposure to Ramadan with Small Stature and Thinness in Adulthood: Results From a Large Indonesian Population–Based Study

A growing body of evidence suggests that maternal diet during pregnancy can lead to permanent alterations to the physiology of the fetus. It is unknown whether intermittent maternal fasting during Ramadan has long-term associations with the offsprings body composition. By using data from the third wave of the Indonesian Family Life Survey (2000), we compared the body mass indices (weight (kg)/height (m)(2)) of Muslims who had been in utero during Ramadan with those of Muslims who had not been in utero during Ramadan. Adult Muslims who had been in utero during Ramadan were slightly thinner than Muslims who had not been in utero during Ramadan (adjusted adult body mass index: -0.32, 95% confidence interval: -0.57, -0.06). Those who were conceived during Ramadan also had smaller stature, being on average 0.80 cm shorter than those who were not exposed to Ramadan prenatally. Among non-Muslims, no such associations were found. This study suggests that exposure to Ramadan during pregnancy may have lasting consequences for adult body size of the offspring.

Ramadan Exposure In Utero and Child Mortality in Burkina Faso: Analysis of a Population-Based Cohort Including 41,025 Children

Ramadan exposure in utero can be regarded as a natural experiment with which to study how nutritional conditions in utero influence susceptibility to disease later in life. We analyzed data from rural Burkina Faso on 41,025 children born between 1993 and 2012, of whom 25,093 were born to Muslim mothers. Ramadan exposure was assigned on the basis of overlap between Ramadan dates and gestation, creating 7 exclusive categories. We used proportional hazards regression with difference-in-differences analysis to estimate the association between Ramadan exposure at different gestational ages and mortality among children under 5 years of age. Under-5 mortality was 32 deaths per 1,000 child-years. Under-5 mortality among Muslims was 15% higher than that among non-Muslims (P < 0.001). In the difference-in-differences analysis, the occurrence of Ramadan during conception or the first or second trimester was associated with higher under-5 mortality rates among Muslims only. The mortality rates of children born to Muslim mothers were 33%, 29%, and 22% higher when Ramadan occurred during conception, the first trimester, and the second trimester, respectively, compared with children of non-Muslim mothers born at the same time (P = 0.01, P < 0.001, and P = 0.007). Having a Muslim mother was not associated with mortality when the child was not exposed to Ramadan, born during Ramadan, or exposed during the third trimester. Observance of Ramadan during early pregnancy can have detrimental consequences for the future health of the unborn child.

Radiotherapy effects on early breast cancer survival in observational and randomized studies: a systematic analysis of advantages, disadvantages and differences between the two study types

AimTreatment–outcome associations often differ substantially between observational studies (OSs) and randomized controlled trials (RCTs). We investigate causes, focusing on radiotherapy (RT) effects in early breast cancer treatment, to better understand each study type’s merits.Methods and materialsWe systematically analyzed three potential causes, by comparing data from a large OS with results from two previously published meta-analyses of RCTs: differences in patient populations combined with heterogeneous treatment effects, non-random treatment decisions in OSs, and differences in therapy administration.ResultsRT–survival associations were considerably stronger in our OS than in the RCTs, e.g., a hazard rate for overall survival after breast-conserving therapy of 0.57 in the OS vs 0.90 in the RCTs. The first proposed reason has limited relevance: patient populations differed considerably, but effect heterogeneity between patient groups was limited. The second reason does explain part of the difference: in the OS treatment decisions (being nonrandomized) and prospects differed with patient characteristics. Notably, patients with early recurrences or mortality are generally excluded from RCTs. Their inclusion in OSs leads to stronger treatment–outcome associations.ConclusionRCTs and OSs each have their own merits. While RCTs have their undisputed benefits, results from OSs that indicate that RT effects in early breast cancer are even stronger than those reported in RCTs should not be ignored.

Human CD8+ memory and EBV-specific T cells show low alloreactivity in vitro and in CD34+ stem cell–engrafted NOD/SCID/IL-2Rγcnull mice

Current strategies in cellular immunotherapy of cancer and viral infections include the adoptive transfer of T cell receptor (TCR) and chimeric antigen receptor engineered T cells. When using transient RNA expression systems in clinical studies, multiple infusions with receptor-redirected T cells appear necessary. However, in allogeneic hematopoietic stem-cell transplantation, repeated transfer of donor-derived T cells increases the risk of alloreactive graft-versus-host disease. We investigated naive-derived (TN), memory-derived (TM), and Epstein Barr virus-specific (TEBV) CD8(+) T cell subsets for alloreactivity upon redirection with RNA encoding a cytomegalovirus-specific model TCR. We observed that alloreactivity to human leukocyte antigen (HLA)-mismatched hematopoietic cells developed at much stronger levels in TN compared with TM or TEBV populations in cytokine-release and cytotoxicity assays. Cytomegalovirus-specific effector function was higher in TCR-transfected TEBV and TM over TN cells. To measure alloreactivity in vivo, we reconstituted NOD/SCID/IL-2Rγc(null) mice with human CD34(+) stem cells and adoptively transferred them with CD8(+) T cell subsets previously stimulated against cells of the HLA-mismatched stem-cell donor. TN cells showed a significant ability to eliminate CD34-derived hematopoietic cells, which was not found with TM and TEBV cells. This reduced alloreactive potential along with strong effector function upon receptor RNA engineering makes CD8(+) memory and EBV-specific T cells advantageous tools in adoptive immunotherapy after allogeneic transplantation.

The course of psychiatric co‐morbidity in patients with breast cancer – results from the prospective multi‐centre BRENDA II study

This study examined the frequency of psychiatric co‐morbidity in patients with breast cancer, its changes over time and predictors for these changes.

Early life conditions and later life inequality in health

Abstract Prenatal exposure to adverse conditions is known to affect health throughout the life span. It has also been shown that health is unevenly distributed at advanced ages. This chapter investigates whether health inequalities at old age may be partially caused by prenatal circumstances. We use a sample of people aged 71–91 from eight European countries and assess how shocks in GDP that occurred while the respondents were still in utero affect four important dimensions of later-life health: cognition, depression, functional limitations, and grip strength. We find that early-life macro-economic circumstances do not affect health at advanced ages, nor do they affect inequalities in health. In additional analyses, we show that the least healthy people may not enter our sample as the probability of dying before reaching age 71 is high, and mortality rates among those who were prenatally exposed to adverse GDP shocks are higher. We conclude that selective mortality may mask effects of early-life circumstances on health and health inequality at old age.