Table 2 Socio-demographic characteristics, exposure and health characteristics of participants of the study according to the season
| Variables |
Season 2014–2015 n (%) |
Season 2015–2016 n (%) |
Season 2016–2017 n (%) |
|---|---|---|---|
| Socio-demographic characteristics | |||
| Gender (m.d. = 0) | |||
| Female | 2326 (60%) | 2942 (60%) | 3113 (60%) |
| Male | 1579 (40%) | 1964 (40%) | 2051 (40%) |
| Age (m.d. = 18) | |||
| [0–10[ | 98 (3%) | 188 (4%) | 175 (3%) |
| [10–15[ | 104 (3%) | 128 (3%) | 115 (2%) |
| [15–60[ | 1970 (50%) | 2541 (52%) | 2660 (52%) |
| > 60 | 1732 (44%) | 2042 (42%) | 2205 (43%) |
| Household composition (m.d. =49) | |||
| Living alone | 614 (16%) | 765 (16%) | 838 (16%) |
| Living with ≥1 child | 1219 (31%) | 1590 (33%) | 1634 (32%) |
| Living with adults only | 2059 (53%) | 2532 (52%) | 2675 (52%) |
| Main activity (m.d. = 258) | |||
| Working | 1822 (48%) | 2320 (48%) | 2453 (48%) |
| Student | 344 (9%) | 487 (10%) | 456 (9%) |
| Unemployed | 109 (3%) | 133 (3%) | 128 (3%) |
| Retired | 1411 (37%) | 1702 (35%) | 1846 (36%) |
| Stay at home/Sick leave | 148 (4%) | 171 (4%) | 187 (4%) |
| Level of education (m.d. = 90) | |||
| Middle school diploma | 613 (16%) | 707 (15%) | 814 (16%) |
| High school diploma | 696 (18%) | 861 (18%) | 944 (18%) |
| Higher education | 2223 (57%) | 2807 (58%) | 3043 (59%) |
| Not concerneda | 336 (9%) | 498 (10%) | 343 (7%) |
| Place of residency (m.d. = 0) | |||
| Urbain | 3145 (81%) | 3973 (81%) | 4161 (81%) |
| Rural | 760 (19%) | 933 (19%) | 1003 (19%) |
| Exposure | |||
| Use of public transportation (m.d. = 0) | |||
| Yes | 605 (15%) | 770 (16%) | 813 (16%) |
| No | 3300 (85%) | 4136 (84%) | 4351 (84%) |
| Contacts (m.d. = 0) | |||
| Contact with patients | 388 (10%) | 476 (10%) | 555 (11%) |
| Contact with elderly | 401 (10%) | 486 (10%) | 537 (10%) |
| Contact with a group of people (≥10) | 1230 (31%) | 1533 (31%) | 1677 (32%) |
| Contact with children | 952 (24%) | 1213 (25%) | 1223 (24%) |
| Pets at home (m.d. = 22) | |||
| None | 2127 (55%) | 2711 (55%) | 2851 (55%) |
| At least one | 1774 (45%) | 2187 (45%) | 2303 (45%) |
| Health characteristics | |||
| Common colds frequency (m.d. = 358) | |||
| Never | 1749 (45%) | 2079 (44%) | 2248 (44%) |
| Rare | 1401 (36%) | 1740 (37%) | 1890 (37%) |
| Often | 698 (18%) | 898 (19%) | 914 (18%) |
| Smoking status (m.d. = 16) | |||
| Non smoker | 3492 (90%) | 4377 (89%) | 4597 (89%) |
| Smoker | 406 (10%) | 525 (11%) | 562 (11%) |
| Comorbidities (m.d. = 0) | |||
| No comorbidities | 3094 (79%) | 3827 (78%) | 4066 (79%) |
| At least one comorbidityb | 811 (21%) | 1079 (22%) | 1098 (21%) |
| Treated asthma | 219 (6%) | 319 (7%) | 303 (6%) |
| Treated diabetes | 139 (4%) | 184 (4%) | 203 (4%) |
| Treated heart condition | 397 (10%) | 501 (10%) | 502 (10%) |
| Treated kidney condition | 22 (1%) | 36 (1%) | 29 (1%) |
| Treated immunosuppression | 109 (3%) | 144 (3%) | 133 (3%) |
| Treated pulmonary condition | 102 (3%) | 139 (3%) | 124 (2%) |
| Respiratory allergy (m.d. = 0) | |||
| None | 2609 (67%) | 3267 (67%) | 3378 (65%) |
| At least one | 1296 (33%) | 1639 (33%) | 1786 (35%) |
| Pregnancy (m.d. = 67) | |||
| Yes | 39 (1%) | 56 (1%) | 50 (1%) |
| No | 660 (17%) | 871 (18%) | 962 (19%) |
| Not concernedc | 3191 (82%) | 3943 (81%) | 4136 (80%) |
| BMI (m.d. = 229) | |||
| Underweight (< 18.5) | 185 (5%) | 207 (4%) | 231 (5%) |
| Normal weight ([18.5–25[) | 2208 (57%) | 2791(58%) | 2911 (57%) |
| Overweight ([25–30[) | 1027 (27%) | 1292 (27%) | 1368 (27%) |
| Obese (> 30) | 424 (11%) | 526 (11%) | 576 (11%) |