In the United States, 1 in 9 live births are preterm, and l in 5 live births among African Americans are preterm. "There is growing evidence that fetal and early life events may result in permanent metabolic alterations, such as type 2 diabetes and metabolic syndrome [a combination of risk factors that increase the risk for heart disease, diabetes, and stroke]. Although available studies in children and adults support the hypothesis that preterm birth may result in adverse metabolic alterations, it is unclear whether the observed association between preterm birth, later insulin resistance, and type 2 diabetes stems from alterations in insulin metabolism during the in utero [in the uterus] period or in early childhood," according to background information in the article.

Guoying Wang, M.D., Ph.D., of the Johns Hopkins University Bloomberg School of Public Health, Baltimore, and colleagues tested the hypothesis that preterm birth is associated with elevated plasma insulin levels (indirect evidence of insulin resistance) at birth that persist into early childhood. The study included 1,358 children, born between 1998 and 2010, and followed-up from 2005 to 2012. Random plasma insulin levels were measured at birth and in early childhood.