Table 4.
The association between principal components (PCs) and menstrual overall cycle and phases length tested by simple and multiple regression analyses.
| Principal Component (PC) | Crude | Adjusted * | |||||
|---|---|---|---|---|---|---|---|
| Beta Coeff. | b Coeff. (95% CI) | p | Beta Coeff. | b Coeff. (95% CI) | Partial r Coeff. | p | |
| Overall cycle | |||||||
| PC1 traffic-related | 0.01 | 0.03 (−0.52 to 0.58) | 0.93 | 0.00 | 0.01 (−0.54 to 0.56) | 0.00 | 0.98 |
| PC2 fossil fuel-related | −0.09 | −0.32 (−0.85 to 0.21) | 0.33 | 0.00 | 0.00 (−0.53 to 0.53) | 0.00 | 0.99 |
| Follicular phase | |||||||
| PC1 traffic-related | 0.00 | 0.00 (−0.71 to 0.71) | 0.99 | 0.02 | 0.07 (−0.56 to 0.70) | 0.02 | 0.83 |
| PC2 fossil fuel-related | −0.10 | −0.41 (−1.14 to 0.32) | 0.26 | −0.03 | −0.13 (−0.74 to 0.48) | −0.04 | 0.66 |
| Luteal phase | |||||||
| PC1 traffic-related | −0.10 | −0.15 (−0.41 to 0.11) | 0.27 | −0.14 | −0.20 (−0.48 to 0.08) | −0.14 | 0.14 |
| PC2 fossil fuel-related | −0.13 | −0.18 (−044 to 0.08) | 0.16 | −0.22 | −0.32 (−0.60 to −0.04) | −0.22 | 0.02 |
* adjusted for age, menarcheal age, alcohol and caffeine intake, smoking status, usual menstrual cycle length, and PC other than estimated.