gms | German Medical Science

There has been a steady increase in life expectancy over the last few decades. However, this does not automatically mean that these added years are spent in good health. Therefore, the research focus of the University Medical Center Groningen is on Healthy Ageing. The ambition is to contribute to the EU-goal of "an increase of the average health span by two years" as formulated by the European Innovation Partnership on Active and Healthy Ageing. Healthy ageing is considered a lifelong process that starts even before conception, with parents who pass on their genes and provide environments containing challenges and opportunities to achieve a healthy life course, or one that is characterized by a relatively late onset of disease. Life course epidemiology is the principle scientific discipline for the study of healthy aging. Amongst others, it addresses long term effects of genetic predisposition, physical or environmental exposures like lifestyle or dietary intake on later health or disease risks and emphatically includes psychosocial mechanisms. As the life course commonly includes periods of (chronic) disease, the domain of life course epidemiology comprises both the general population and clinical populations, thereby including the study of prognosis and its determinants.

This area of research raises some typical analytical and practical issues. One of the major challenges is the inference of causality of risk factors mediating health outcomes based on observational data. The current tutorial will briefly introduce the conceptual framework of life course epidemiology, give an overview of different statistical methods investigating causality such as structural equation models, propensity scoring and mediation analysis after which we will focus in-depth on challenges of applications of mediation analysis to observational data based on a running example of a published study investigating whether the effect of maternal smoking on birth weight is mediated by methylation markers.