Incidence rate ratios (95% confidence intervals) for the different periods of the lunar cycle, with period 5 as the reference period

Period

IRR

95%CI

P value

1

0.509

(0.414, 0 .625)

<0.001

2

0.557

(0.456, 0.680)

<0.001

3

0.606

(0.498, 0.736)

<0.001

4

0.747

(0.622, 0.897)

0.002

5

1.000

—

—

6

0.576

(0.472, 0.702)

<0.001

7

0.527

(0.430, 0.646)

<0.001

8

0.542

(0.443, 0.663)

<0.001

9

0.550

(0.450, 0.672)

<0.001

10

0.613

(0.505, 0.744)

<0.001