The contribution of the environment (especially diet) to breast cancer risk

Environmental factors play an important role in breast carcinogenesis. Opportunities for prevention are limited, however, because most of the known or suspected risk factors are not targets for modification. Dietary factors have generally not emerged as crucial contributors to mammary tumor causation. We still appear to be missing a critical piece of the breast cancer puzzle because we can only explain a moderate proportion of international and national variation in breast cancer rates. Research needs to pursue new avenues, focusing on exposure windows that have not yet been sufficiently explored, such as events between conception and adolescence, and on modifiable risk factors that show large variation within or between populations

Health differentials in the older population of England: An empirical comparison of the materialist, lifestyle and psychosocial hypotheses

BACKGROUND: In developed countries with old age structures most deaths occur at older ages and older people account for the majority of those in poor health, which suggests a particular need to investigate health inequalities in the older population. METHODS: We empirically compared the materialist, psychosocial and lifestyle/behavioural theoretical mechanisms of explanation for socio-economic variation in health using data from two waves of the English Longitudinal Study of Ageing (ELSA), a nationally representative multi-purpose sample of the population aged 50 and over living in England. Three dimensions of health were examined: somatic health, depression and well-being. RESULTS: The materialist and lifestyle/behavioural paths had the most prominent mediating role in the association between socio-economic position and health in the older population, whereas the psychosocial pathway was less influential and exerted most of its influence on depression and well-being, with part of its effect being due to the availability of material resources. CONCLUSIONS: From a policy perspective there is therefore an indication that population interventions to reduce health differentials and thus improve the overall health of the older population should focus on material circumstances and population based interventions to promote healthy lifestyles

Lifelong socio economic position and biomarkers of later life health: testing the contribution of competing hypotheses

The relative contribution of early or later life Socio Economic Position (SEP) to later life health is not fully understood and there are alternative hypotheses about the pathways through which they may influence health. We used data from the English Longitudinal Study of Ageing with a formal approach for the identification of mediating factors in order to investigate alternative hypotheses about life course influences on biomarkers of later life health. We found that early life SEP predicts physical health at least 65 years later. However, a more complicated pattern of associations than that implied by previous findings was also observed. Age group specific effects emerged, with current SEP dominating the effect on later life physical health and fibrinogen levels in participants under 65, while early life SEP had a more prominent role in explaining inequalities in physical health for men and women over 75. We extend previous findings on mid adulthood and early old age, to old age and the beginnings of late old age. The complexity of our findings highlights the need for further research on the mechanisms that underlie the association between SEP and later life health

Birth Order, Birth Weight and Asthma: how to assess mediation and the presence of Unmeasured Confounding

If the goal is to measure the causal relation between two variables when a third is involved and plays the role of mediator, it is essential to explicitly define the relational assumptions among these and others relevant variables. However if any of this assumptions are not met, estimates of mediated effects may be affected by bias. One example where this occurs is the widely discussed situation known as the Birth Weight paradox which arises when birth weight is the mediator of interest and unmeasured confounders affect the mediator-outcome relation. In this paper we will focus on a setting where such paradox might arise where birth order act as the exposure for childhood asthma (by age 1.5). After estimating the direct and indirect effects, we give a plausible graphical explanation of the empirical results and explore the magnitude of the causal relations using sensitivity analysis

Venous thromboembolic disease in people with chronic obstructive pulmonary disease (COPD): a matched case-control study

Background People with chronic obstructive pulmonary disease (COPD) are at increased risk of vascular disease, including venous thromboembolism (VTE).1 While some researchers have tested the hypothesis that within COPD certain subgroups of patients, in particular frequent exacerbators, are at even greater risk of cardiovascular disease, no large-scale investigations of the relationship between exacerbation frequency or disease severity and VTE risk have been undertaken. Methods 3,594 COPD patients recording a first VTE event during the period 1 January 2004 to 31 December 2013 were identified from the Clinical Practice Research Datalink (CPRD GOLD) dataset (cases) and matched (1:3) on age, sex and GP practice to 10,782 VTE-free COPD patients (controls). COPD severity was categorised by degree of airflow limitation (i.e. GOLD stage) and by COPD medication history (very severe, severe, moderate/mild). Patients were classed as “frequent exacerbators” if they experienced ≥ 2 exacerbations per year and as “infrequent exacerbators” otherwise. Analyses were conducted in STATA using conditional logistic regression to account for the study design. Results After controlling for smoking and BMI, as well as the matching variables, there was an association between increased disease severity and VTE when severity was measured in terms of lung function impairment (ORmoderate/mild = 1.16; 95% CIs: 1.03, 1.32; p = 0.018) and also in terms of medication history (ORsevere/moderate+mild = 1.17; 95% CIs: 1.06, 1.26; p = 0.001). There was no evidence to suggest that that frequent exacerbators were at greater risk of VTE than infrequent exacerbators (OR = 1.06; 95%: CIs 0.97, 1.15; p = 0.18). Conclusion Severity of disease but not frequent exacerbation appears to be associated with VTE events in COPD patients