Many common diseases of aging are negatively associated with socioeconomic status, and these relationships may be appreciably explained by body mass index. This presentation provides an overview of a series of papers that explore the connection between body mass index and gene expression patterns (mRNA-seq) indicative of disease. Gene expression data are strategic because they reveal disease processes perhaps decades before clinical manifestations. We are especially interested in whether body mass index at particular ages may be especially predictive of expression profiles. To examine this possibility, we draw on a commonly-used framework of life course epidemiology and five waves of data from ~4500 people who participated in Add Health. Results reveal that body mass index that is assessed contemporaneously with gene expression is usually a salient predictor, but birth weight and obesity in earlier life are often also influential.  For some expression profiles, the entire history of body mass index may be relevant.