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The relationships of growth with nutrition and serum growth factors in early life

by Tam, Y. M

Abstract (Summary)
(Uncorrected OCR) Abstract of thesis entitled

The relationship of growth with nutrition and serum growth factors in the early life Submitted by

Selene Y. M. Tam

for the degree of Doctor of Philosophy at the University of Hong Kong

in August 1999

The aim of this thesis is to explore the relationship of growth with nutrition, serum growth factors, infections, socioeconomic status in Hong Kong Chinese infants in the first two years of life. Forty-eight healthy full-term infants were carefully followed up prospectively to document their growth, nutritional intake, general health and serum growth factors concentrations longitudinally from birth to two years of life. The mean change in weight, length and head circumference of these infants were not significantly different from the National Center for Health Statistics (NCHS) reference mean except for a significant lower weight-for-age values from 10-15 months of age. As compared to the Hong Kong Chinese infants in the 1967 study who were found to have significant growth faltering between 6-24 months of age, an obvious improvement in growth of the infants in our study has been observed and this is related to an improvement in the nutrition, socioeconomic and health status of the population over the past 30 years. Growth faltering previously observed is likely to be due to socioeconomic rather than ethnic influence. The change in body mass index (BMI) in the first two years of life in the infants of the present study and those based on five Chinese cohorts reported in five literatures were different as compared to that observed in five groups of Caucasian children base on previous publications including the NCHS reference; the mean BMI of the Chinese cohorts was higher in the first 4 months of life and then followed by lower values thereafter when compare with that observed in the Caucasian cohorts. Our results suggest that linear growth would be better for the assessment of health and nutrition in infancy and early childhood in different communities; if BMI were to be used, then an ethnic specific and population

years of life. The mean daily energy intake of the infants was close to the revised 1985 WHO recommendation by Butte (1996) and by Torun et al (1996) except with significantly lower intake from 10-15 months in boys, and 8-15 months in girls. This result reinforces the previous finding from other studies that the 1985 WHO recommendation is too high. The mean daily protein intake was 2.0-3.4 gmlkg body weight throughout the first two 2 years which was significantly higher than the safe protein level recommended by the WHO and also the revised WHO recommendation by Dewey et al (1996) except the value at 2-months of age. The long term consequences of high protein intake in early life are still unknown. The intakes of calcium, vitamin D and iron were still subnormal at certain periods during the first two years of life and this should be addressed. There was significant correlation of the mean weight and BMI gain with the mean daily energy intake in the first six months of life. Weight gain in the second year was related to energy intake, living condition and infections while length gain in the second year was related to living conditions and infections in the multiple regression analyses.

Only two infants (4.2%) in our study were found to have a delay in the onset of childhood phase of growth (> 12 months of age). This was in contrast to the findings in the 1967 cohort when 49.2% of boys and 26.4% of girls had a delay in the onset of the childhood phase of growth. In the present study, the onset age was significantly negatively correlated with the length gain from 6 to 12 months of life. Both the length gain from 10 to 12 months (16.3 ?4.7 em/year vs 8.8 ?4.3 em/year, p 10 months of age). The infants with an earlier onset had a significantly higher mean serum insulin-like growth factor (IGF)-I values at 10 months as compared to that of the late onset group (8.8 ?5.8 nmol/L vs 4.9 ?3.1 nmol/L, p<0.05) but no difference was found in the serum IGF binding protein-3 levels. In the multiple regression analysis, the mean length gain from 6-12 months was significantly associated with the mean change in IGF-I, and was negatively significantly associated with the mean change in IGF binding protein-3 from 6-12 months and the onset of childhood phase after the adjustment for gender. The results give indirect support to our hypothesis that the onset of the childhood phase of growth represents the time when GH exerts a significant effect on growth in postnatal life.

Bibliographical Information:

Advisor:

School:The University of Hong Kong

School Location:China - Hong Kong SAR

Source Type:Master's Thesis

Keywords:growth factors serum infants china hong kong nutrition longitudinal studies

ISBN:

Date of Publication:01/01/2000

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