Life-course models of how the social environment affects childhood respiratory risk.

Understanding the social and physical contributors to asthma risk is an important undertaking, and the article by Sternthal et al makes several very significant contributions toward this goal. In this study the authors recruited a cohort of women during pregnancy and followed the children through to age 2 years. Five hundred ten women participated in this study in which they were asked about their childhood socioeconomic status (SES), were administered psychosocial questionnaires about stress, and had dust samples taken to assess allergen exposure, and air pollution estimates were calculated based on residence. In children cord blood was used to assess IgE levels, and maternal reports of wheezing were obtained every 3 months from birth through 2 years. The authors found that lowmaternal childhood SESwas related to childhood wheezing through adult SES, prenatal stress, and prenatal pollution exposure and that low maternal childhood SES was related directly to increased cord blood IgE levels. One of the most novel aspects of this article is that it raises the notion that the factors that contribute to a child’s health might not be limited to experiences during a child’s life or even prenatally but that certain social experiences that far predate the child might nonetheless still exert effects on the child himself or herself. That is, the authors demonstrate that the family SES of a mother when she was a child is linked to her child’s cord blood IgE levels and likelihood of wheezing. These findings are groundbreaking in raising the possibility that experiences or exposures in one generation (eg, parent) can be transmitted to another generation (offspring). The findings from this study are consistent with other research that has documented that a parent’s childhood SES also predicts the offspring’s cardiovascular risk (blood pressure and C-reactive protein level) in a sample of healthy adolescents. Taken together, these studies argue for the need to broaden our models about how SES across time can affect health outcomes. There are a number of models that have been proposed for how to understand the effects of SES across the life course. These include theories about how low SES has cumulative effects over a lifetime on health (accumulation models); how low SES during certain stages of life, such as early childhood, has particularly potent effects on later