Araújo Cora L P, Dutra Carmem L C, Hallal Pedro C
Faculdade de Medicina, Universidade Federal de Pelotas, Pelotas, Brasil.
Cad Saude Publica. 2007 Oct;23(10):2421-7. doi: 10.1590/s0102-311x2007001000017.
Birth weight has short and long-term effects on health. Some studies have used retrospective data on birth weight, reported by the subject or by the parents. This paper compares data on birth weight measured by the research team in 1993 with birth weight reported by the mother in 2004-2005, using data from the 1993 Pelotas Birth Cohort Study, Rio Grande do Sul State, Brazil. We also evaluate the role of misclassification when exploring the effect of birth weight on a given outcome. Mean difference between the two variables was 20g (SD = 288.3). Agreement for detecting low birth weight was 95.2% in the sample as a whole (kappa = 0.73), but was lower among low-schooling mothers. Mothers of children weighing less than 3,500g at birth tended to overestimate the child's birth weight. Inversely, mothers of heavier children tended to underestimate the values. One out of four mothers reported a difference of at least 200g in birth weight as compared to that measured in 1993. Use of reported birth weight diluted the magnitude of the association with body mass index at 11 years in comparison with measured birth weight. Reported birth weight should be used with great caution, if at all.
出生体重对健康有短期和长期影响。一些研究使用了由受试者本人或其父母报告的出生体重回顾性数据。本文利用巴西南里奥格兰德州1993年佩洛塔斯出生队列研究的数据，比较了研究团队在1993年测量的出生体重数据与母亲在2004 - 2005年报告的出生体重数据。在探讨出生体重对特定结局的影响时，我们还评估了错误分类的作用。两个变量之间的平均差异为20克（标准差=288.3）。在整个样本中，检测低出生体重的一致性为95.2%（kappa系数=0.73），但在受教育程度低的母亲中该一致性较低。出生时体重不足3500克的儿童的母亲往往会高估孩子的出生体重。相反，孩子体重较重的母亲往往会低估数值。四分之一的母亲报告的出生体重与1993年测量的体重相比差异至少为200克。与测量的出生体重相比，使用报告的出生体重会削弱11岁时与体重指数之间关联的强度。如果要使用报告的出生体重，应极其谨慎。
