We investigate conditions sufficient for identification of average treatment effects using instrumental variables. First we show that the existence of valid instruments is not sufficient to identify any meaningful average treatment effect. We then establish that the combination of an instrument and a condition on the relation between the instrument and the participation status is sufficient for identification of a local average treatment effect for those who can be induced to change their participation status by changing the value of the instrument. Finally we derive the probability limit of the standard IV estimator under these conditions. It is seen to be a weighted average of local average treatment effects.

Evolution and Rationality Some Recent Game-Theoretic Results. Identification and Estimation of Local Average Treatment Effects

The saimie paper suggests how susceptible individuals could reduce their total intake of aluminium. In presenting the cpidemiological evidence for a link betveen aluminium and Alzheimcr's, Nart'n suggests that although definite proof is still lacking, there is more than enough positixe evidence to fuel further epidemiological investigation. It states that such investigations might specificallx address the issue of the confounding cffect of silicon and an assessment of exposure to spccific

https://jech.bmj.com/content/jech/47/6/511.4.full.pdf

Methodology for Genetic Studies of Twins and Families

Ample data indicate that mutant p53 proteins not only lose their tumour suppressive functions, but also gain new abilities that promote tumorigenesis. Moreover, recent studies have modified our view of mutant p53 proteins, portraying them not as inert mutants, but rather as regulated proteins that influence the cancer cell transcriptome and phenotype. This influence is clinically manifested as association of TP53 mutations with poor prognosis and drug resistance in a growing array of malignancies. Here, we review recent studies on mutant p53 regulation, gain-of-function mechanisms, transcriptional effects and prognostic association, with a focus on the clinical implications of these findings.

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When mutants gain new powers: news from the mutant p53 field

There is now strong evidence that mutation not only abrogates p53 tumor-suppressive functions, but in some instances can also endow mutant proteins with novel activities. Such neomorphic p53 proteins are capable of dramatically altering tumor cell behavior, primarily through their interactions with other cellular proteins and regulation of cancer cell transcriptional programs. Different missense mutations in p53 may confer unique activities and thereby offer insight into the mutagenic events that drive tumor progression. Here we review mechanisms by which mutant p53 exerts its cellular effects, with a particular focus on the burgeoning mutant p53 transcriptome, and discuss the biological and clinical consequences of mutant p53 gain of function.

/pdf/mutant-p53-one-name-many-proteins-l5xr8vi271.pdf

Mutant p53: one name, many proteins

Adults with higher educational attainment live healthier and longer lives compared with their less educated peers. The disparities are large and widening. We posit that understanding the educational and macrolevel contexts in which this association occurs is key to reducing health disparities and improving population health. In this article, we briefly review and critically assess the current state of research on the relationship between education and health in the United States. We then outline three directions for further research: We extend the conceptualization of education beyond attainment and demonstrate the centrality of the schooling process to health; we highlight the dual role of education as a driver of opportunity but also as a reproducer of inequality; and we explain the central role of specific historical sociopolitical contexts in which the education-health association is embedded. Findings from this research agenda can inform policies and effective interventions to reduce health disparities and improve health for all Americans.

/pdf/the-relationship-between-education-and-health-reducing-1uw4f5unz9.pdf

The Relationship Between Education and Health: Reducing Disparities Through a Contextual Approach

Schooling generally is positively associated with better health-related outcomes—for example, less hospitalization and later mortality—but these associations do not measure whether schooling causes better health-related outcomes. Schooling may in part be a proxy for unobserved endowments—including family background and genetics—that both are correlated with schooling and have direct causal effects on these outcomes. This study addresses the schooling-health-gradient issue with twins methodology, using rich data from the Danish Twin Registry linked to population-based registries to minimize random and systematic measurement error biases. We find strong, significantly negative associations between schooling and hospitalization and mortality, but generally no causal effects of schooling.

/pdf/does-more-schooling-reduce-hospitalization-and-delay-58qydyu74p.pdf

Does More Schooling Reduce Hospitalization and Delay Mortality? New Evidence Based on Danish Twins

Background. p53 accumulation and TP53 mutations are known prognostic markers for breast cancer. To clarify their interrelationship and the importance of different TP53 mutation types, these markers were investigated in tumours from 630 patients with breast cancer. Materials and methods. Tumour sections were stained for p53 and scored based on staining intensity and percentages of invasive tumour cells with nuclear staining. TP53 mutations were identified by sequencing. Patient cohorts were from the DBCG (Danish Breast Cancer Cooperative Group) protocols DBCG82 and DBCG89. Results. TP53 was mutated in 29% of the patients. The disease-specific survival (DSS) at 15 years of follow-up for patients with missense mutations directly involved in DNA or zinc binding was 21±8%. Patients with the remaining missense mutations within the structural/conserved domains and patients with null mutations had a DSS of 36±6% and 31±17%, respectively. For patients without TP53 mutations and patients with mutations affecting am...

A comparison between p53 accumulation determined by immunohistochemistry and TP53 mutations as prognostic variables in tumours from breast cancer patients.

Evidence of a positive association between birthweight and IQ has been established in several studies. Analyses of within twin pair differences in birthweight and IQ have been used to shed light on the basis of the association. The strength of this approach is the possibility of controlling for both unmeasured common childhood-environmental factors as well as genetic factors shared by the co-twins. Two twin studies suggest the existence of genetic mediation between birthweight and IQ, that is, common genetic factors influence both fetal growth and IQ in childhood, while two other twin studies find no evidence of such mediation. In the present study we use a large population-based national register study of 2,413 Danish twin-pairs from birth cohorts 1986-1990, of which we have zygosity information on 74%. We perform individual level as well as intra-pair analyses of birthweight and school achievements at age 16. For both sexes we observed a monotonic increase in academic performance with increasing percentiles of birthweight. However, we did not find that this association is due to genetic mediation.

/pdf/no-evidence-of-genetic-mediation-in-the-association-between-apgkn0qavf.pdf

No evidence of genetic mediation in the association between birthweight and academic performance in 2,413 Danish adolescent twin pairs.

This paper is concerned with the relationship between class size and the student outcome - length of time in post-compulsory schooling. Research on this topic has been problematic partly because omitted unobservables, like parents' incomes and education levels, are likely to be correlated with class size. Two potential ways to resolve this problem are to exploit either experimental or instrumental variation. In both cases, the methods require that the variation in both class size and the outcome should not be contaminated by other unobservable factors that affect the outcome, like family background. An alternative approach, which we pursue here, is to take advantage of variation in class size between siblings which allows unobservable family effects to be differenced out. Our aim is to provide estimates of the effect of class size and use these to conduct an evaluation of the costs and benefits of a reduction in class sizes.

/pdf/the-effects-of-school-class-size-on-length-of-post-4qnml3ckqa.pdf

The effects of school class size on length of post-compulsory education: some cost-benefit analysis

This paper is concerned with the relationship between class size and the student outcome – length of time in post-compulsory schooling. Research on this topic has been problematic partly because omitted unobservables, like parents’ incomes and education levels, are likely to be correlated with class size. Two potential ways to resolve this problem are to exploit either experimental or instrumental variation. In both cases, the methods require that the variation in both class size and the outcome should not be contaminated by other unobservable factors that affect the outcome – like family background. An alternative approach, which we pursue here, is to take advantage of variation in class size between siblings which allows unobservable family effects to be differenced out. Our aim is to provide estimates of the effect of class size and use these to conduct an evaluation of the costs and benefits of a reduction in class sizes.

Vibeke Myrup Jensen

Papers

Does More Schooling Reduce Hospitalization and Delay Mortality? New Evidence Based on Danish Twins

A comparison between p53 accumulation determined by immunohistochemistry and TP53 mutations as prognostic variables in tumours from breast cancer patients.

No evidence of genetic mediation in the association between birthweight and academic performance in 2,413 Danish adolescent twin pairs.

The effects of school class size on length of post-compulsory education: some cost-benefit analysis

The Effects of School Class Size on Length of Post-Compulsory Education: Some Cost-Benefit Analysis