Dr Iris van Rooij, reproductive epidemiologist and assistant professor at the Department for Health Evidence, Radboud Institute for Health Sciences, looks back at the statements belonging to her PhD thesis.

The statements belonging to my thesis are from 2003, a long time ago, but I still know most of them by memory. My thesis was entitled ‘Etiology of Orofacial Clefts, gene-environment interactions and folate‘. Four statements were derived from the contents of my thesis. Most of these statements still hold today, but about one I start to have my doubts.
The statement was (translated into English): ‘Daily use of a folic acid supplement in the periconceptional period does not only reduce the chance of a child with a neural tube defect, but also of a child with an orofacial cleft’. I am still convinced that my data showed this result correctly, but there was recently published a Dutch article that stated the opposite (1).
One of our interns (Sander Groen in ‘t Woud) also found a negative association between the intake of folic acid supplements periconceptionally and the occurrence of kidney and urinary tract malformations and a few others found similar kind of results. Still, these studies stay rather alone in the literature on folic acid use and birth defects, but it is an interesting issue to follow up: is it a methodology design issue or the ‘truth’?

I also proposed a statement that research into gene-environment interactions needed a hypothesis to get relevant knowledge about the pathogenesis of a disease. Of course a hypothesis would help to get to know more about the pathobiology of a disease, but nowadays genome-wide arrays can be used quite easily and this hypothesis-free method can be combined with environmental risk factors to more and more explore potential pathways for disease development.

My statement ‘A decision about wanting to get pregnant implicitly involves the acceptation of a child with an anomaly’ got the most attention in newspapers. It was published in the ‘Gelderlander’ twice in the period of my defense. At the time I was writing my thesis I was thinking about the implications of my type of research. It would be good to provide useful advice to couples wanting to get pregnant to prepare themselves for a good environment for their unborn baby, as described in my statement 6. However, I am not in favor of a ‘makeable’ world in which everyone can decide whether they want their baby or not. It was and is a very personal statement and in principle I still stand behind my statement, but meanwhile getting older and having more life experience I know that sometimes these essential life issues are very complex.

One last statement I want to recall is the last one: ‘From an international solidarity perspective it is morally unacceptable that only 10% of the global expenses for research and development are spend to illnesses for which 90% of the world population carry the burden, such as malaria, tuberculosis and HIV/AIDS.’ I guess the percentages mentioned in this statement are a little bit different since Bill Gates spend part of his enormous income to research for poorer people, but how typical it is that now the Ebola disaster seems to enter the Western World more money is spend to research and vaccination possibilities than before.

(1) Rozendaal AM, van Essen AJ, te Meerman GJ, Bakker MK, van der Biezen JJ, Goorhuis-Brouwer SM, Vermeij-Keers C, de Walle HE.Periconceptional folic acid associated with an increased risk of oral clefts relative to non-folate related malformations in the Northern Netherlands: a population based case-control study. Eur J Epidemiol. 2013; 28:875-87.(http://www.ncbi.nlm.nih.gov/pubmed/24092049)
Iris van Rooij