Breastmilk contains many important nutrients, anti-inflammatory agents, and immunomodulators. It is the preferred nutrition source for infants. However, the association of the duration of exclusive breastmilk feeding (BMF) with asthma development is unclear. Data on children from the United States who participated in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2014 were obtained. We examined the association between the duration of exclusive BMF and asthma in 6000 children (3 to 6 years old). After calculating the duration of exclusive breastfeeding according to answers to NHANES questionnaires, the estimated duration of exclusive BMF was divided into five categories: never breastfed or BMF for 0 to 2 months after birth; BMF for 2 to 4 months after birth; BMF for 4 to 6 months after birth; and BMF for ≥6 months after birth. The overall prevalence of asthma in children aged 3 to 6 years was approximately 13.9%. The risk of asthma was lower in children with an exclusive BMF duration of 4 to 6 months (aOR, 0.69; 95% CI, 0.48–0.98), after adjustment for potentially confounding factors. Subgroup analysis revealed that children of younger ages (3 to 4 years old) benefited most from the protective effects of exclusive BMF for 4 to 6 months (aOR, 0.47; 95% CI, 0.27, 0.8). We found that exclusive BMF, especially BMF for 4 to 6 months, is associated with a decreased risk of asthma in preschool-age children. The protective effect appeared to be diminished in older children. The potential mechanism needs further investigation.

Transcutaneous bilirubinometer devices are widely applied to assess neonatal hyperbilirubinemia. However, the optimal skin site and timing of transcutaneous bilirubin (TCB) measurements for the strongest correlation with total serum bilirubin (TSB) levels after phototherapy are still unclear. We conducted a retrospective observational study evaluating the correlation of TCB and TSB levels in neonates postphototherapy. The TCB measurements on the forehead and mid-sternum at 0 and 30 min postphototherapy were assessed by using a JM-103 bilirubinometer. Paired TCB and TSB measurements were assessed by Pearson correlation and Bland–Altman plots. We analyzed 40 neonates with 96 TSB and 384 TCB measurements. The TSB level correlated moderately with the forehead TCB level at 30 min postphototherapy (r = 0.65) and less strongly with the midsternum TCB level at 0 min postphototherapy (r = 0.52). The forehead at 30 min after cessation of phototherapy was the best time point and location of TCB measurement for the assessment of neonatal jaundice status. The reliability of TCB measurements varied across skin sites and durations after phototherapy. The effectiveness of TCB measurement to assess neonatal hyperbilirubinemia is much better on covered skin areas (foreheads) 30 min postphototherapy. The appropriate application of transcutaneous bilirubinometers could aid in clinical practice and avoid unnecessary management.