Division of Nutrition, Physical Activity and Obesity, National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP), Centers for Disease Control and Prevention, 4770 Buford Highway, NE, Mailstop K-26, Atlanta, GA, 30341, USA.
Matern Child Health J. 2011 Oct;15(7):851-9. doi: 10.1007/s10995-009-0544-4.
To investigate the reliability and validity of weight, height, and body mass index (BMI) from birth certificates with directly measured values from the Women, Infants, and Children (WIC) Program. Florida birth certificate data were linked and compared with first trimester WIC data for women with a live birth during the last quarter of calendar year 2005 (n = 23,314 women). Mean differences for weight, height, and BMI were calculated by subtracting birth certificate values from WIC values. Reliability was estimated by Pearson's correlation. Validity was measured by sensitivity and specificity using WIC data as the reference. Overall mean differences plus or minus standard error (SE) were 1.93 ± 0.04 kg for weight, -1.03 ± 0.03 cm for height, and 1.07 ± 0.02 kg/m(2) for BMI. Pearson's correlation ranged from 0.83 to 0.95, which indicates a strong positive association. Compared with other categories, women in the second weight group (56.7-65.8 kg), the highest height group (≥167.6 cm), or BMI < 18.5 had the greatest mean differences for weight (2.2 ± 0.08 kg), height (-2.4 ± 0.05 cm), and BMI (1.5 ± 0.06), respectively. Mean differences by maternal characteristics were similar, but statistically significant, likely in part from the large sample size. The sensitivity for birth certificate data was 77.3% (±1.42) for underweight (BMI < 18.5) and 76.4% (±0.51) for obesity (BMI ≥ 30). Specificity was 96.8% (±0.12) for underweight and 97.5% (±0.12) for obesity. Birth certificate data had higher underweight prevalence (6 vs. 4%) and lower obesity prevalence (24 vs. 29%), compared with WIC data. Although birth certificate data overestimated underweight and underestimated obesity prevalence, the difference was minimal and has limited impact on the reliability and validity for population-based surveillance and research purposes related to recall or reporting bias.
为了研究出生证明中体重、身高和身体质量指数（BMI）与妇女、婴儿和儿童计划（WIC）中直接测量值的可靠性和有效性。将佛罗里达州的出生证明数据与 2005 年最后一个季度活产妇女的 WIC 第一季度数据相联系（n=23314 名妇女）。通过从 WIC 值中减去出生证明值来计算体重、身高和 BMI 的平均差异。用皮尔逊相关系数来估计可靠性。以 WIC 数据为参考，用灵敏度和特异性来衡量有效性。总的平均差异加或减标准误差（SE）分别为体重 1.93±0.04kg，身高-1.03±0.03cm，BMI 1.07±0.02kg/m(2)。皮尔逊相关系数范围为 0.83 至 0.95，表明存在强烈的正相关。与其他类别相比，体重处于第二组（56.7-65.8kg）、身高最高组（≥167.6cm）或 BMI<18.5 的女性体重（2.2±0.08kg）、身高（-2.4±0.05cm）和 BMI（1.5±0.06）的平均差异最大。按母体特征划分的平均差异相似，但有统计学意义，部分原因可能是样本量较大。出生证明数据的灵敏度分别为 77.3%（±1.42%）和 76.4%（±0.51%），用于诊断体重不足（BMI<18.5）和肥胖症（BMI≥30）。体重不足的特异性为 96.8%（±0.12%），肥胖症的特异性为 97.5%（±0.12%）。与 WIC 数据相比，出生证明数据的体重不足患病率更高（6%比 4%），肥胖症患病率更低（24%比 29%）。尽管出生证明数据高估了体重不足，低估了肥胖症的患病率，但差异很小，对基于人群的监测和与回忆或报告偏倚相关的研究目的的可靠性和有效性影响有限。
