Table 2. Individual and Combined Associations Between Maternal OWO Status and Maternal RBC Lead Levels, and Child BMI z Scores and Child OWO Risk (Age Range, 2-15 Years)a.
| Maternal Status by OWO and RBC Lead Level, μg/dL | Mother-Child Dyad, No. | Child BMI z Score | Child OWO | ||||
|---|---|---|---|---|---|---|---|
| Mean (SD) | β (SE) | P Value | Child OWO, No. (%) | OR (95% CI) | P Value | ||
| Non-OWO mothers | 681 | 0.40 (1.21) | 1 [Reference] | NA | 213 (31.3) | 1 [Reference] | NA |
| OWO mothers | 761 | 1.02 (1.15) | 0.53 (0.06) | <.001 | 399 (52.4) | 2.18 (1.74-2.74) | <.001 |
| <2.0 | 513 | 0.57 (1.25) | 1 [Reference] | NA | 191 (37.2) | 1 [Reference] | NA |
| 2.0 to <5.0 | 700 | 0.78 (1.20) | 0.19 (0.07) | .006 | 311 (44.4) | 1.35 (1.05-1.72) | .02 |
| ≥5.0 | 229 | 0.92 (1.16) | 0.34 (0.10) | <.001 | 110 (48.0) | 1.65 (1.18-2.32) | .004 |
| P for linear trend | NA | NA | NA | <.001 | NA | NA | .01 |
| Stratified | |||||||
| Among non-OWO mothers | |||||||
| <2.0 | 261 | 0.22 (1.17) | 1 [Reference] | NA | 65 (24.9) | 1 [Reference] | NA |
| 2.0 to <5.0 | 320 | 0.51 (1.24) | 0.29 (0.10) | .005 | 113 (35.3) | 1.65 (1.13-2.41) | .009 |
| ≥5.0 | 100 | 0.54 (1.17) | 0.32 (0.15) | .03 | 35 (35.0) | 1.81 (1.07-3.06) | .03 |
| Among OWO mothers | |||||||
| <2.0 | 252 | 0.95 (1.23) | 1 [Reference] | NA | 126 (50.0) | 1 [Reference] | NA |
| 2.0 to <5.0 | 380 | 1.00 (1.12) | 0.08 (0.09) | .40 | 198 (52.1) | 1.12 (0.80-1.57) | .52 |
| ≥5.0 | 129 | 1.21 (1.07) | 0.32 (0.13) | .01 | 75 (58.1) | 1.53 (0.96-2.44) | .07 |
| Combined | |||||||
| Non-OWO mothers | |||||||
| <2.0 | 261 | 0.22 (1.17) | 1 [Reference] | NA | 65 (24.9) | 1 [Reference] | NA |
| 2.0 to <5.0 | 320 | 0.51 (1.24) | 0.31 (0.10) | .001 | 113 (35.3) | 1.71 (1.18-2.48) | .005 |
| ≥5.0 | 100 | 0.54 (1.17) | 0.35 (0.14) | .01 | 35 (35.0) | 1.79 (1.07-3.00) | .03 |
| OWO mothers | |||||||
| <2.0 | 252 | 0.95 (1.23) | 0.65 (0.10) | <.001 | 126 (50.0) | 2.78 (1.89-4.09) | <.001 |
| 2.0 to <5.0 | 380 | 1.00 (1.12) | 0.72 (0.10) | <.001 | 198 (52.1) | 3.08 (2.14-4.44) | <.001 |
| ≥5.0 | 129 | 1.21 (1.07) | 0.94 (0.13 | <.001 | 75 (58.1) | 4.24 (2.64-6.82) | <.001 |
Abbreviations: BMI, body mass index (calculated as weight in kilograms divided by height in meters squared); NA, not applicable; OR, odds ratio; OWO, overweight or obesity; RBC, red blood cell.
SI conversion factor: To convert lead level to micromoles per liter, multiply by 0.0483.
Maternal OWO was defined as a BMI of 25 or higher. Analyses were performed by linear and logistic regression models for outcome child BMI z scores and child OWO, respectively. Adjusted for maternal educational level, race/ethnicity, smoking status, parity, diabetes, hypertensive disorder, preterm birth, fetal growth, and breastfeeding. P values for the interaction between maternal RBC lead levels and maternal OWO status were .29 for child BMI z scores and .41 for child OWO status.