The impact of birth weight on life: constructing twin data

There is a risk that babies born with a low birth weight may die during the first month of life and for those that survive, potential lifelong consequences include increased risk of stunted growth, lower IQ and conditions like obesity and diabetes later in life. Therefore, preventing low birth weight is important. There has been little research on the impact of low and high birth weight on overall quality of life and, specifically, marriage and happiness. Assistant Professor Chisako Yamane, Faculty of Economics, Hiroshima University of Economics, Japan, is seeking to fill this research gap by providing insights into the wider aspects of birth weight that will help give researchers a deeper understanding of the potential negative impacts and encourage policy makers to introduce initiatives to prevent incidence of low birth weight in Japan and beyond. Yamane and the team are using the 'twin effect model' which is a method based on the premise that unobservable factors are almost the same for twins to identify the causal relationship between birth weight and subsequent life. Japan has the highest proportion of low-birth-weight babies among OECD countries and Yamane and the team are working to better understand this phenomenon. The researchers suspect cultural elements such as a desire to be skinny among women and children are at play here. The team therefore want to convey the health risks associated with being underweight both for individuals and their offspring.