LC Mitchell, LCK Low, J Karlberg

Abstract

The aim was to examine how well short-term growth in lower leg length (LLL) and total body length are correlated with weight gain in early life in healthy infants. This is an observational study with weekly follow up for 2 to 13 weeks for ages between birth and 21 weeks. The study was done at the Mother's Choice Adoption Center, Hong Kong. Weekly measurement of lower leg length (LLL), total body length and weight were made in 22 healthy full term Hong Kong Chinese infants (12 boys and 10 girls). The sample represents all new infants coming to the adoption center during the reqruitment period, January to May 1994. The technical error of LLL was 0.53 mm, which corresponds to 20% of the weekly growth rate in early life. In comparison, the technical error for length was 2.8 mm, or around 40% of the mean weekly growth rate in length. The main finding was a significant correlation between the gain in LLL and weight for short-term growth in early life in normal healthy babies: over 2, 3 and 4 week intervals the correlation were 0.32, 0.40 and 0.51, respectively. On the other hand the correlation coefficients between the gain in length and in weight were much lower for intervals below 4 weeks. We conclude that LLL and not length can be recommended for short-term growth studies in early life for intervals shorter than 4 weeks; the shortest interval seems to be 2 weeks in normal children, but possibly shorter under catch up growth. For intervals of 4 weeks or longer no recommendation can be made at present. LLL measurements may be useful in nutritional, hormonal and/or metabolic studies in early life by adding reliable information about longitudinal bone growth.

本文目的在於探討短期下肢小腿長度與身長的生長與同期體重增長的關係。觀察對象從出生隨訪至21周，每周一次，隨訪時間2至13周不等。本研究在香港母親的抉擇中心進行。對22例足月健康華人新生兒（男12例，女10例）每周作下肢小腿長度、身長和體重測量。此樣本代表1994年1月至5月期間所有進入領養中心的新生兒。測量下肢小腿長度技術誤差為0.53 mm，相當於同期每周生長速度數植的20%。與之相比，測量身長的技術誤差為2.8 mm，大約相當於身長生長速度均值的40%。本研究的主要發現是：早期正常嬰兒下肢小腿長度生長與體重增長之間存在相關關係，以2、3和4周為間隔時間，其相應的相關系數分別為0.32、0.40和0.51。另外，如果間隔時間短於4周，則身長與體重增長之間的相關系數就很小。就此我們得出以下結論：（1）下肢小腿長度與非身長可推薦用於間隔時間小於4周的嬰兒早期生長的短期研究；（2）對於正常嬰兒，間隔時間可選2周，但對於那些出現追上生長的嬰兒，間隔時間可進一步縮短。我們不推薦用4周或更長的間隔時間。通過引入有關骨骼生長的可靠數據，下肢小腿長度在營養、激素和/及代謝研究中心將會成為一個有用的指標。