Table 1 Distribution of the design variables
20-44 yrs | 45-64 yrs | p-value | ||
|---|---|---|---|---|
N° of eligible subjects* | 9739 | 3480 | - | |
N° of responders (response rate, %) | 5162 (53.0) | 2167 (62.3) | <0.001 | |
Season at the time of response, % | Spring | 46.2 | 51.5 | <0.001 |
Summer | 15.2 | 8.6 | ||
Autumn | 32.0 | 30.9 | ||
Winter | 6.6 | 9.0 | ||
Telephone interview, % | 11.6 | 9.6 | 0.012 | |
Females, % | 53.6 | 52.1 | 0.267 |