Intergenerational influences on birth outcomes


Dr. Patricia Reagan, Department of Economics
Rank at time of award: Professor
Dr. Elizabeth Cooksey, Department of Sociology
Rank at the time of Award: Associate Professor
Dr. Pamela Salsberry, College of Nursing
Rank at time of award: Associate Professor
Dr. Bo Lu, College of Public Health, Biostatistics
Rank at time of award: Assistant Professor


Background: Over the past decade research has highlighted the importance of investigating health outcomes within the context of a life course framework. In particular, the work of Barker and others (Barker, 2003; Eriksson, Forsen, Tuomilehto, Osmond, & Barker, 2000; Rautanen, Eriksson, Kere, Andersson, Osmond, Tienari et al., 2006) provides evidence that the intrauterine environment  is linked to disease development in midlife. It is also widely recognized that the intrauterine environment is influenced by a complex set of biological, social, and behavioral determinants, with some of the most powerful factors occurring before the pregnancy begins (Lu & Halfon, 2003; Misra, Guyer, & Allston, 2003). A handful of recent studies completed with European cohorts have examined intergenerational  processes that may influence birth outcomes in subsequent generations (Hypponen, Power, & Smith, 2004). For example, a longitudinal study of parents and children in the UK finds a link between Type 2 diabetes in grandparents and birth weight in the subsequent two generations  (McCarron, Davey Smith, & Hattersley, 2004). A recent study from Sweden shows evidence of an intergenerational  effect of reduced intrauterine growth, but no effect of preterm birth (Selling, Carstensen, Finnstrom, & Sydsjo, 2006). Finally, in a British-based study, smoking in grandmothers is associated with birth weights of grandchildren in models without controls for the mother's own smoking, but this effect was eliminated when maternal smoking was included (Hypponen, Smith, & Power, 2003).

There are several reasons why adverse birth outcomes may be correlated across generations (McCarron, Davey Smith, & Hattersley, 2004). First, a shared environment may encourage a maternal behavior to be adopted by her children. If this behavior has birth outcome effects (e.g., smoking during pregnancy) then this would show up as an intergenerational effect. Second, socioeconomic factors (e.g., poverty, inadequate nutrition) may influence birth outcomes in one generation and because such socioeconomic conditions are likely to continue in subsequent generations, similar birth outcomes are likely to be seen in the next generation.  Third, genetic factors may influence birth outcomes across generations.  For example, there is evidence of genetic effects on glucose intolerance and infant birth weight (Hattersley, Beards, Ballantyne, Appleton, Harvey, & Ellard, 1998; Terauchi, Kubota, Tamemoto, Sakura, Nagai, Akanuma et al., 2000). Finally, the intrauterine environment may play a role. Sibling studies in which one sibling is exposed to diabetes in utero and another is not provide evidence for this pathway (Aerts, Holemans, & Van Assche, 1990; Holemans, Aerts, & Van Assche, 2003).

Specific Aims: In this pilot project our aim is to test whether clinically relevant adverse birth outcomes such as being small for gestational age (SGA) in the mother is correlated with the same adverse birth outcome in her offspring. We will also quantify the roles of genetics and shared behaviors (eg. smoking during pregnancy) between the mother and the grandmother, in the intergenerational link between adverse birth outcomes.