Impact of brown adipose tissue vascular density on body adiposity in healthy Japanese infants and children

BACKGROUND AND OBJECTIVE: The importance of brown adipose tissue (BAT) is well recognized in healthy infants and children. However, information regarding age‐related changes in BAT vascular density (BAT‐d) and the impact of BAT‐d on body adiposity are lacking. This study aimed to evaluate the normal values of BAT‐d, factors influencing BAT‐d, and the impact of BAT‐d on body adiposity in healthy infants and children. METHODS: This study included 240 participants (127 girls and 113 boys) aged 1 month to 5 years. The tissue total hemoglobin concentration in the supraclavicular region adjusted according to the subcutaneous adipose tissue thickness (SAT) ([total‐Hb‐Adj](sup)) as BAT‐d. SAT in the deltoid and interscapular regions (SAT(del+int)), the Kaup index (body weight [g]/height or length [cm]/height or length [cm] × 10) as body adiposity, and fertilization season were also measured. RESULTS: The [total‐Hb‐Adj](sup) of boys was higher than that of girls (r = 0.277, p = 0.009). Younger children had a significantly higher Kaup index (r = 0.495, p < 0.001) and SAT(del+int) (r = 0.614, p < 0.001) than older children. Children who had higher [total‐Hb‐Adj](sup) had a significantly lower Kaup index (r = 0.495, p = 0.037) and SAT(del+int) (r = 0.614, p < 0.001). CONCLUSION: The [total‐Hb‐Adj](sup), as a parameter of BAT‐d, is negatively correlated with body adiposity in children aged 1 month to 5 years, and BAT might affect human obesity to a much greater extent than expected. To prevent or treat obesity in early childhood, the level of BAT‐d should be considered when using a dietary intervention.