eTable 2. Description of the 16 study areas of the German National Cohort and the frequency of SARS-CoV-2 testing as reported in the COVID-NAKO questionnaire.
| Study region characteristics | Sample characteristics | SARS-CoV-2 infections | |||||||||||||
| # counties | Inhabitants in 1000 *1 | urban | rural | COVID-19 cases per 100 000 inhabitants *2 | Baseline | COVID-19 Follow-up | % women | Age. years mean | SARS-CoV-2 Tested | # observed positive | # expected*3 | p-value*4 | |||
| all | Age range 15–79y | all | Age range 15–79y | ||||||||||||
| All study centers | 205 219 | 113 928 | 51,8 | 50 | 5245 | 344 | 257 | < 0.001 | |||||||
| Neubrandenburg | 1 | 259 | 190 | x | 47 | 57 | 22 006 | 7433 | 51,2 | 49,5 | 277 | 9 | 4 | 0,02 | |
| Leipzig | 2 | 846 | 627 | x | x | 88 | 117 | 10 874 | 5968 | 52,7 | 50,5 | 277 | 13 | 7 | 0,02 |
| Kiel | 3 | 649 | 488 | x | x | 100 | 120 | 9504 | 5641 | 52,1 | 50,4 | 253 | 9 | 7 | 0,46 |
| Halle | 2 | 424 | 310 | x | x | 109 | 124 | 10 139 | 5346 | 53,6 | 50,2 | 362 | 12 | 7 | 0,05 |
| Essen | 1 | 583 | 435 | x | 145 | 163 | 10 623 | 5382 | 51,4 | 48,8 | 155 | 15 | 9 | 0,05 | |
| Augsburg | 3 | 680 | 517 | x | x | 170 | 178 | 20 621 | 11 740 | 50,5 | 50,2 | 400 | 40 | 22 | < 0.001 |
| Mannheim | 1 | 309 | 240 | x | 156 | 186 | 10 287 | 5521 | 50 | 49,2 | 321 | 17 | 10 | 0,03 | |
| Berlin *5 | 3 | 4040 | 3064 | x | x | 186 | 215 | 31 202 | 19 650 | 52,6 | 50,1 | 916 | 53 | 42 | 0,08 |
| Hanover | 1 | 1158 | 863 | x | x | 211 | 242 | 10 049 | 4686 | 50,8 | 50,4 | 177 | 12 | 11 | 0,83 |
| Bremen | 1 | 569 | 427 | x | 227 | 259 | 10 486 | 6150 | 51,1 | 50 | 266 | 13 | 15 | 0,66 | |
| Münster | 1 | 314 | 246 | x | 226 | 268 | 10 031 | 6514 | 52,1 | 50,7 | 309 | 23 | 18 | 0,24 | |
| Düsseldorf | 1 | 619 | 471 | x | 231 | 272 | 9146 | 5253 | 53,2 | 49,7 | 250 | 21 | 14 | 0,06 | |
| Hamburg | 1 | 1841 | 1399 | x | 277 | 315 | 10 083 | 5300 | 52,4 | 49,1 | 256 | 11 | 17 | 0,15 | |
| Saarbrücken | 2 | 472 | 355 | x | x | 294 | 345 | 10 038 | 5992 | 52,3 | 50,4 | 345 | 26 | 21 | 0,29 |
| Regensburg | 2 | 346 | 268 | x | x | 329 | 373 | 10 030 | 6545 | 49,9 | 50,3 | 302 | 34 | 24 | 0,04 |
| Freiburg | 2 | 396 | 304 | x | x | 367 | 399 | 10 100 | 6807 | 51,9 | 50 | 379 | 36 | 29 | 0,18 |
*1 The numbers of inhabitants in the respective districts were obtained from the official records of the Federal Statistical Office (www.genesis.destatis.de/genesis/online). Numbers are given for all inhabitants (as of 31 December 2018). as well as for all inhabitants in the age range of 15–79 years (as of 31 December 2019) (see eTable 4).
*2 The numbers of COVID-19 cases per 100 000 inhabitants in the period 1–30 March 2020 were obtained from the official data of the Robert Koch Institute [https://npgeo-corona-npgeo-de.hub.arcgis.com/. 02.06.2020]. The cumulative incidences were calculated as arithmetic mean of all age groups. as well as averaged based on the age groups 15–34 years. 35–59 years and 60–79 years. weighted by the number of inhabitants in the respective age group in the counties (see eTable 4).
*3 The number of expected positive tests/SARS-CoV-2 infections was calculated as weighted mean. based on the number of participants and the cumulative COVID-19 incidence. for the total population and for the age groups 15–34 years. 35–59 years and 60–79 years. weighted by the number of participants in the respective age group in each district (see eTable 4).
*4 Comparison of numbers of expected vs observed SARS-CoV-2 infections. based on a goodness-of-fit chi-squared test for probabilities. with the probabilities given by the expected number of infections. Since the absolute numbers of cases are sometimes very small. the resulting p-values have to be interpreted with caution. *5 Three NAKO study centers jointly cover the Berlin NAKO study region.