On 2014 Apr 09, SATISH KALHAN commented:

The interesting and provocative paper by Wang et al is significant contribution to our understanding of the physiological adaptation to preterm birth and the potential mechanism/s of the development of insulin resistance during adult life in the prematurely born infants. By using complex statistical analysis, and adjusting for pertinent perinatal variables, the authors show a strong negative correlation between cord blood insulin levels and gestational age, and tracking of plasma insulin levels from birth to early childhood. Although the authors do not discuss the biological mechanism/s for their observations, these data raise some key questions: 1. Are these data only applicable to the black and Hispanic populations? Over 75% of the study population was minority with higher incidence of obesity and insulin resistance. Examination of the data separately for the black and Hispanic group may have been useful. 2. Plasma levels of insulin respond rapidly to nutrients, are modified by the metabolic milieu and by changes in other hormones. Although the authors discuss the possible impact of such changes on the insulin levels in childhood, they ignored the impact of maternal milieu and her clinical care during labor and delivery on the cord blood insulin levels. In addition, mothers of preterm babies had higher incidence of smoking, diabetes and pregnancy related illness. The inclusion of obese subjects (BMI over 30) added additional variable to these measurements. It is interesting that all babies born before 32 weeks were classified as appropriate for gestational age. 3. The insulin tracking data are the most interesting and show that the babies with high insulin at birth also had high insulin during childhood. Since the insulin levels were not measured in the “basal” state these data show that babies who responded with higher insulin level at birth continue to be high insulin responders in childhood The study by Wang et al is laudatory for its execution and statistical analysis. However relating the levels of a substrate or hormone, that is acutely responsive to nutritional and metabolic influences, in this instance insulin, to multisystem disorder such as obesity or type 2 diabetes or body weight which are cumulative effects of a number of variables over time, although statistically feasible, may not give us useful biological insights. The present data do not exclude the possibility that interruption of pregnancy prematurely caused a metabolic insult to developing pancreas that programs the babies to develop long term consequences.

On 2014 Apr 09, SATISH KALHAN commented:

The interesting and provocative paper by Wang et al is significant contribution to our understanding of the physiological adaptation to preterm birth and the potential mechanism/s of the development of insulin resistance during adult life in the prematurely born infants. By using complex statistical analysis, and adjusting for pertinent perinatal variables, the authors show a strong negative correlation between cord blood insulin levels and gestational age, and tracking of plasma insulin levels from birth to early childhood. Although the authors do not discuss the biological mechanism/s for their observations, these data raise some key questions: 1. Are these data only applicable to the black and Hispanic populations? Over 75% of the study population was minority with higher incidence of obesity and insulin resistance. Examination of the data separately for the black and Hispanic group may have been useful. 2. Plasma levels of insulin respond rapidly to nutrients, are modified by the metabolic milieu and by changes in other hormones. Although the authors discuss the possible impact of such changes on the insulin levels in childhood, they ignored the impact of maternal milieu and her clinical care during labor and delivery on the cord blood insulin levels. In addition, mothers of preterm babies had higher incidence of smoking, diabetes and pregnancy related illness. The inclusion of obese subjects (BMI over 30) added additional variable to these measurements. It is interesting that all babies born before 32 weeks were classified as appropriate for gestational age. 3. The insulin tracking data are the most interesting and show that the babies with high insulin at birth also had high insulin during childhood. Since the insulin levels were not measured in the “basal” state these data show that babies who responded with higher insulin level at birth continue to be high insulin responders in childhood The study by Wang et al is laudatory for its execution and statistical analysis. However relating the levels of a substrate or hormone, that is acutely responsive to nutritional and metabolic influences, in this instance insulin, to multisystem disorder such as obesity or type 2 diabetes or body weight which are cumulative effects of a number of variables over time, although statistically feasible, may not give us useful biological insights. The present data do not exclude the possibility that interruption of pregnancy prematurely caused a metabolic insult to developing pancreas that programs the babies to develop long term consequences.