Table 5.
Multiple regressions for menstrual cycle length computed against potential confounders (Model 1) and also against the contaminant principal component (PC) analysis scores (Model 2). The regression coefficient (B) is the coefficient of the slope for predictor variables. The PC scores used in Model 2 are generated from organohalogens and elements detectable in ≥70% of the sample population. *Regression coefficient slope B and model are significant (p<0.05).
| Menstrual Cycle Length | ||||
|---|---|---|---|---|
| Regression Coefficient (B) | t-statistic | p-value1 | ||
| Model 1 | Mean Raw1 (95% C.I.) | Standardized | ||
| Constant | 33.46 (27.40—41.58) | 9.988 | 0.001* | |
| Age (y) | −0.21 (−0.37—0.08) | −0.493 | −2.678 | 0.011* |
| Alcohol (Y/N) | −0.38 (−3.37—2.10) | −0.066 | −0.341 | 0.766 |
| Caffeine (Y/N) | 1.28 (−1.82—5.38) | 0.186 | 1.052 | 0.424 |
| Model 1 significance: F = 3.045, p = 0.046*; r2 = 0.253 | ||||
| Model 2 | ||||
| Constant | −32.56 (−219.93—247.94) | 10.861 | 0.773 | |
| Age (y) | −0.25 (−0.40—0.04) | −0.594 | −3.317 | 0.023* |
| Alcohol (Y/N) | −0.28 (−2.15—2.01) | −0.049 | −0.326 | 0.788 |
| Caffeine (Y/N) | 2.98 (−0.08—5.69) | 0.443 | 2.751 | 0.073 |
| PC-1 | 1.01 (−0.22—2.09) | 0.364 | 2.508 | 0.073 |
| PC-2 | 0.17 (−0.75—1.26) | 0.062 | 0.500 | 0.728 |
| PC-3 | −1.37 (−2.39—0.58) | −0.496 | −3.602 | 0.011* |
| PC-4 | −0.36 (−1.40—0.61) | −0.129 | −0.878 | 0.421 |
| PC-5 | 0.37 (−0.89—1.27) | 0.134 | 1.038 | 0.512 |
| PC-6 | 0.83 (−0.10—1.69) | 0.300 | 2.073 | 0.086 |
| Model 2 improvement over Model 1: F ratio change = 4.749; p = 0.003*; r2 = 0.683. | ||||
1
results from Bootstrap procedure, n=1000 samples.