母親の喫煙による子どもの出生時および出生後の身体計測値への影響—4か月児健康診査のデータベースの分析から

Effect of Maternal Smoking on Anthropometric Measurements at Birth and on Postnatal Growth: Analysis of Infant Health Check-Up Results

要旨

　研究目的：本研究では，4か月児健康診査のデータベースの分析から，母親の喫煙が児の出生時の身体計測値（体重，身長，頭囲，胸囲）ならびに出生後の発育にどのように影響するかを明らかにすることを目的とした．

　方法：本研究で用いたデータベースは，4か月児健康診査を受診した児の健診データのうち，個人情報を全て除外し，連結不可能匿名化したデータファイルを用いた．統計解析には，母親の喫煙と児の身体計測値を重回帰分析等を用いて分析した．

　結果：3494人の単胎児のデータを分析対象とした．妊娠中に喫煙をしていた母親は全体の2.9%であった．妊娠中の母親の喫煙は，他の要因の影響を調整しても，出生体重，出生身長，出生頭囲と有意な関連が認められた．さらに，4か月児健康診査時の身長および頭囲においても関連が認められ，喫煙していた母親から出生した児は，喫煙していなかった母親から出生した児よりも有意に身長および頭囲が小さく，他の要因を調整しても有意であった．

　結論：妊娠中の母親の喫煙は，出生時の身体計測値のみならず，4か月児健康診査時の身長や頭囲にも影響していることが明らかとなり，禁煙支援のための対策をさらに強化する必要性が示された．

　Objectives: To investigate the effect of maternal smoking on anthropometric measurements (body weight, height, head circumference, and chest circumference) of newborns and their postnatal growth, with the aim of obtaining fundamental data for future considerations on maternal and child health.

　Methods: A database containing the results of health checkups for four-month-old infants in A City was analyzed by removing personal information.

　Results: A total of 3,494 infants were analyzed. The rate of maternal smoking during pregnancy was 2.9%, while that of paternal smoking was 34.9%. Maternal smoking during pregnancy affected all anthropometric measurements of infants at birth: newborns of smoking mothers were significantly lighter (P=0.013) and shorter (P＜0.001) and had a significantly smaller head circumference (P＝0.004) and a significantly smaller chest circumference (P＝0.045) than those of non-smoking mothers. Differences in newborn size without chest circumference between the two groups remained significant after adjusting for factors influencing the above measurements. Maternal smoking during pregnancy affected height and head circumference measured at the four-month-old checkup: infants of smoking mothers were significantly shorter (P＝0.004) and had a significantly smaller head circumference (P＝0.023). Differences in infant size between the two groups remained significant after adjusting for factors influencing the above measurements.

　Conclusion: Maternal smoking during pregnancy affects body weight, height, head circumference, and chest circumference of newborns, as well as height and head circumference of infants at four months old. These results demonstrate the necessity for stronger guidance on smoking cessation during pregnancy.