Person:

Ding, Ming

Background: Limited evidence has been provided on the trajectories of length, weight, and bone mineral density (BMD) among preterm infants in early life in Asian countries. Methods: We conducted a longitudinal study, which included 652 late preterm (gestational age: 34–36.9 weeks), 486 moderate preterm (32–33.9), 291 very preterm (28–31.9), 149 extremely preterm infants (≤28.9) and 1434 full-term peers (≥37) during the first 12 months of corrected age in Wuhan, China. Weight and length were measured at birth, once randomly before term, and every month thereafter. BMD was examined at 3, 6, 9 and 12 months using dual-energy X-ray absorptiometry. Results: From birth to 12 months of corrected age, growth peaks in length and weight were observed at 1–3 months among preterm infants. No catch-up growth in length, weight, and BMD was observed among preterm infants. However, accelerated growth in length, weight, and BMD was found. Among extremely preterm infants, relative to full-term infants, length was −6.77 cm (95 % CI: −7.14, −6.40; P for trend < 0.001) lower during the first 12 months; weight was −1.23 kg (−1.33, −1.13; P for trend < 0.001) lower; and BMD was −0.070 g/cm2(−0.087, −0.053; P for trend < 0.001) lower; however, average growth rates of these measures were higher (Ps < 0.05). Small gestational age and low birth weight were independently associated with lower length, weight, and BMD. Conclusion: Growth peaks in length and weight among preterm infants were observed at 1–3 months. No catch-up growth in length, weight, and BMD was observed, however, there was accelerated growth in length, weight, and BMD. Electronic supplementary material The online version of this article (doi:10.1186/s12887-015-0396-6) contains supplementary material, which is available to authorized users.

Background: Bone mineral density (BMD) increases progressively during childhood and adolescence and is affected by various genetic and environmental factors. The aim of this study was to establish reference values for lumbar BMD in healthy Chinese infants and young children and investigate its influencing factors. Methods and Findings: Healthy children aged 0 to 3 years who underwent regular physical examinations at the Child Health Care Clinic of Hubei Maternal and Child Health Hospital (N = 11,898) were recruited for this study. We also chose 379 preterm infants aged 0 to 1 years to preliminarily explore the development of BMD in this special population. BMD (g/cm2) measurements of the lumbar spine (L2–L4) were carried out with dual-energy X-ray absorptiometry and a questionnaire was administered to full-term children's parents to gather information on various nutritional and lifestyle factors as well as mothers' nutritional supplement use during pregnancy. Lumbar BMD significantly increased with age among both boys and girls (p<0.05), with fastest growth observed during the first postnatal year. There was no significant difference in lumbar BMD between boys and girls of similar age (p>0.05), either among healthy reference children or preterm infants. However, BMD values in preterm infants were significantly lower than those in term infants 3 to 8 months old (p<0.05) after adjustment for gestational age. Multivariable linear regression analysis indicated significant positive associations between lumbar BMD of healthy children and the child's age and current weight, mother's weight gain during pregnancy, birth weight, children's outdoor activity duration and children's physical activity duration. Conclusion: Our study provides reference values of lumbar BMD for healthy Chinese children aged 0 to 3 years and identifies several influencing factors.

Background: The nutrition and epidemiologic transition has been associated with an increasing incidence of preterm birth in developing countries, but data from large observational studies in China have been limited. Our study was to describe the trends and factors associated with the incidence of preterm birth and infant mortality due to prematurity in Hubei Province, China. Methods: We conducted a population-based survey through the Maternal and Child Health Care Network in Hubei Province from January 2001 to December 2012. We used data from 16 monitoring sites to examine the trend and risk factors for premature birth as well as infant mortality associated with prematurity. Results: A total of 818,481 live births were documented, including 76,923 preterm infants (94 preterm infants per 1,000 live births) and 2,248 deaths due to prematurity (2.75 preterm deaths per 1,000 live births). From 2001 to 2012, the incidence of preterm birth increased from 56.7 to 105.2 per 1,000 live births (P for trend < 0.05), while the infant mortality rate due to prematurity declined from 95.0 to 13.4 per 1,000 live births (P for trend < 0.05). Older maternal age, lower maternal education, use of assisted reproductive technology (ART), higher income, residence in urban areas, and infant male sex were independently associated with a higher incidence of preterm birth (all p values < 0.05). Shorter gestation, lower birth weight, and lower income were associated with a higher mortality rate, while use of newborn emergency transport services (NETS) was associated with a lower preterm mortality rate (all p values < 0.05). Conclusion: An increasing incidence of preterm birth and a parallel reduction in infant mortality due to prematurity were observed in Hubei Province from 2001 to 2012. Our results provide important information for areas of improvements in reducing incidence and mortality of premature birth. Electronic supplementary material The online version of this article (doi:10.1186/s12884-015-0767-x) contains supplementary material, which is available to authorized users.