Table 2.
Adjusteda models of maternal perfluoroalkyl substance serum concentrations (ng/mL) and absolute gestational weight gain, stratified by under-/normal weight pre-pregnancy BMI and overweight/obese pre-pregnancy BMI, in the Avon Longitudinal Study of Parents and Children sub-study population (N = 905).
| Model | Coefficientb | 95% CI | Heterogeneity p-valuec |
I2 statisticc | |
|---|---|---|---|---|---|
| PFOA | Under-/normal weight | 0.01 | −0.08, 0.09 | 0.67 | 0.0% |
| overweight/obese | −0.20 | −0.41, 0.02 | 0.40 | 0.0% | |
| PFOS | Under-/normal weight | −0.03 | −0.11, 0.06 | 0.85 | 0.0% |
| Overweight/obese | −0.12 | −0.30, 0.06 | 0.99 | 0.0% | |
| PFHxS | Under-/normal weight | 0.00 | −0.05, 0.05 | 0.26 | 19.8% |
| Overweight/obese | 0.02 | −0.08, 0.11 | 0.66 | 0.0% | |
| PFNA | Under-/normal weight | 0.09 | 0.02, 0.16 | 0.04 | 75.3% |
| Overweight/obese | −0.12 | −0.31, 0.07 | 0.98 | 0.0% |
Abbreviations: N, number; CI, confidence interval.
Adjusted for maternal education, prenatal smoking, maternal age at delivery, parity, pre-pregnancy BMI, gestational age at delivery, and gestational age at sample.
Coefficient representing a 10% increase in the PFAS of interest.
The I2 statistic indicates the percentage of variance in a meta-analysis that is attributable to study heterogeneity rather than chance. It is calculated using 100% × (Q − df)/Q where Q is the Cochran’s heterogeneity statistic, which is chi-square distributed [45].