Mean No of pelican crossings/street | Odds ratio* | 95% CI |
---|---|---|

*Calculations with “conditional logistic regression” (SAS: PROC PHREG) with matching variable age and sex (170 cases and 168 controls). Baseline category: mean number of pelican crossings per street >3. | ||

0–1 | 2.3 | 1.2 to 4.5 |

>1–2 | 2.4 | 1.3 to 4.3 |

>2–3 | 1.1 | 0.6 to 1.9 |

>3 | 1.0 | — |