Reduced tibial speed of sound in Chinese infants at birth compared with Caucasian peers: the effects of race, gender, and vitamin D on fetal bone development.
CONCLUSIONS
This study compared bone status between Chinese and Caucasian infants at birth, showing that Chinese neonates have lower tibial speed of sound, which is influenced by gender, gestational age, season of birth, and maternal vitamin D status. The effects of these factors on fetal bone development were discussed.


BACKGROUND
We compared the differences of speed of sound (SOS) accessed by quantitative ultrasound between Chinese and Caucasian infants at birth and explored the relationship between the concentrations of serum 25-hydroxyvitamin D [25(OH)D] and bone SOS in maternal-infant pairs.


METHODS
SOS for the tibial bone was measured at birth in 267 Chinese infants. We used the Z-scores for the direct comparisons which were available from the instrument based data of gender and age-matched Caucasian peers. The concentrations of serum 25(OH)D and bone SOS in 32 maternal-infant pairs were measured at birth in winters.


RESULTS
the Chinese infants had lower SOS demonstrated by the Z-scores. Significant differences of SOS and Z-scores were found between genders, gestational ages, birth weight, and seasons of birth. The differences of Z-scores negatively decreased with gestational age, suggesting that the bone status of Chinese infants lags behind that of the Caucasian infants during the last trimester of pregnancy in utero. The tibial SOS of infants born in winters was 2.0% higher than those born in summers after adjustment. The infant SOS correlated with maternal serum 25(OH)D (r = 0.399, P = 0.024) and infant serum 25(OH)D (r = 0.394, P = 0.026).


CONCLUSIONS
Chinese neonates have lower SOS which is influenced by gender, gestational age, season of birth, and maternal vitamin D status. It is inferred that, in pace with gestational age, race and gender effects on fetal bone development are modified by materno-fetal vitamin D status.
Xinhua Hospital, Shanghai Institute for Pediatric Research, Shanghai Key Laboratory of Children's Environmental Health, Shanghai Jiao Tong University School of Medicine, 1665 Kong Jiang Road, Shanghai, 200092, China. lxp4848@yahoo.com.cn
X P
XP
Liao
W L
WL
Zhang
C H
CH
Yan
X J
XJ
Zhou
P
P
Wang
J H
JH
Sun
X D
XD
Yu
M Q
MQ
Wu
D000886:Anthropometry / Q000379:methods; D044466:Asian People / Q000706:statistics & numerical data*; D001724:Birth Weight / Q000502:physiology; D001846:Bone Development / Q000502:physiology*; D005260:Female; D047109:Fetal Development / Q000502:physiology; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D039382:Maternal Nutritional Physiological Phenomena / Q000502:physiology; D012621:Seasons; D012727:Sex Characteristics; D013977:Tibia / Q000000981:diagnostic imaging / Q000196:embryology / Q000502:physiology*; D014463:Ultrasonography; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D044465:White People / Q000706:statistics & numerical data
D014807:Vitamin D; C104450:25-hydroxyvitamin D