Secker-Walker R H, Vacek P M, Flynn B S, Mead P B
Office of Health Promotion Research, University of Vermont, Burlington, USA.
J Reprod Med. 1998 Nov;43(11):967-74.
To compare the estimated effect on birth weight of reductions in maternal cigarette consumption and urinary cotinine during pregnancy.
An observational study of 641 women with complete data on cigarette consumption, urinary cotinine and infant birth weight. Correlation and regression analyses were used to examine relationships between birth weight, cigarette consumption and urinary cotinine at first and last prenatal visits.
Correlations of cigarette consumption and urinary cotinine with infant birth weight were -.23 and -.30 (first visit) and -.26 and -.31 (last visit); all P values were < .001. The regression equation relating urinary cotinine concentrations at first and last visits to infant birth weight explained a significantly larger proportion of the variability in birth weight than the equation relating cigarette consumption at these visits to infant birth weight, 11% vs. 7%, P = .04. Among continuing smokers, both equations predicted gains in birth weight in association with reductions in cigarette consumption, but quitting smoking before the first visit was associated with the most weight gain. As compared to the average infant birth weight of a woman who smoked 20 cigarettes per day throughout pregnancy, the estimated gain in birth weight would be 105 g if she cut down by 10 cigarettes per day after the first visit, 210 g if she quit after this visit and 310 g if she quit before the first visit.
For women still smoking at their first prenatal visit, infant birth weight is already compromised, but subsequent reductions in cigarette consumption are associated with gains in birth weight. For women who cannot quit smoking, these reductions need to be substantial if increases in birth weight of > 100 g are to be achieved.
比较孕期母亲减少香烟消费量和尿可替宁水平对出生体重的估计影响。
对641名妇女进行观察性研究，这些妇女有关于香烟消费、尿可替宁和婴儿出生体重的完整数据。采用相关性和回归分析来检验首次和末次产前检查时出生体重、香烟消费和尿可替宁之间的关系。
首次检查时，香烟消费和尿可替宁与婴儿出生体重的相关性分别为 -0.23和 -0.30，末次检查时分别为 -0.26和 -0.31；所有P值均<0.001。将首次和末次检查时的尿可替宁浓度与婴儿出生体重相关联的回归方程，比将这些检查时的香烟消费与婴儿出生体重相关联的方程，能解释出生体重变异性的比例显著更大，分别为11%对7%，P = 0.04。在持续吸烟的人群中，两个方程都预测随着香烟消费量的减少出生体重会增加，但在首次检查前戒烟与体重增加最多相关。与整个孕期每天吸20支烟的女性所生婴儿的平均出生体重相比，如果她在首次检查后每天减少10支烟，估计出生体重会增加105克；如果在此检查后戒烟，会增加210克；如果在首次检查前戒烟，会增加310克。
对于首次产前检查时仍在吸烟的女性，婴儿出生体重已经受到影响，但随后减少香烟消费与出生体重增加有关。对于无法戒烟的女性，如果要使出生体重增加超过100克，这些减少量需要相当大。
