Impact of Missing Data for Body Mass Index in an Epidemiologic Study.

Journal Article (Journal Article)

Objective To assess the potential impact of missing data on body mass index (BMI) on the association between prepregnancy obesity and specific birth defects. Methods Data from the National Birth Defects Prevention Study (NBDPS) were analyzed. We assessed the factors associated with missing BMI data among mothers of infants without birth defects. Four analytic methods were then used to assess the impact of missing BMI data on the association between maternal prepregnancy obesity and three birth defects; spina bifida, gastroschisis, and cleft lip with/without cleft palate. The analytic methods were: (1) complete case analysis; (2) assignment of missing values to either obese or normal BMI; (3) multiple imputation; and (4) probabilistic sensitivity analysis. Logistic regression was used to estimate crude and adjusted odds ratios (aOR) and 95 % confidence intervals (CI). Results Of NBDPS control mothers 4.6 % were missing BMI data, and most of the missing values were attributable to missing height (~90 %). Missing BMI data was associated with birth outside of the US (aOR 8.6; 95 % CI 5.5, 13.4), interview in Spanish (aOR 2.4; 95 % CI 1.8, 3.2), Hispanic ethnicity (aOR 2.0; 95 % CI 1.2, 3.4), and <12 years education (aOR 2.3; 95 % CI 1.7, 3.1). Overall the results of the multiple imputation and probabilistic sensitivity analysis were similar to the complete case analysis. Conclusions Although in some scenarios missing BMI data can bias the magnitude of association, it does not appear likely to have impacted conclusions from a traditional complete case analysis of these data.

Full Text

Duke Authors

Cited Authors

  • Razzaghi, H; Tinker, SC; Herring, AH; Howards, PP; Waller, DK; Johnson, CY; National Birth Defects Prevention Study,

Published Date

  • July 2016

Published In

Volume / Issue

  • 20 / 7

Start / End Page

  • 1497 - 1505

PubMed ID

  • 27029540

Pubmed Central ID

  • PMC4911272

Electronic International Standard Serial Number (EISSN)

  • 1573-6628

Digital Object Identifier (DOI)

  • 10.1007/s10995-016-1948-6


  • eng

Conference Location

  • United States