Table 1. Demographic characteristics of ESCC cases and matched controls.
| ESCC cases | Matched controls | |
|---|---|---|
| N (%) | N (%) | |
| Total | 300 (100) | 571 (100) |
| Age (years) | ||
| ⩽50 | 32 (11) | 61 (11) |
| 51–60 | 81 (27) | 144 (25) |
| 61–70 | 86 (29) | 177 (31) |
| >70 | 101 (34) | 189 (33) |
| Gender | ||
| Male | 150 (50) | 278 (49) |
| Female | 150 (50) | 293 (51) |
| Place of residence | ||
| Urban | 82 (27) | 150 (26) |
| Rural | 218 (73) | 421 (74) |
| Ethnicity | ||
| Turkmen | 171 (57) | 312 (55) |
| Non-Turkmen | 129 (43) | 259 (45) |
ESCC=oesophageal squamous cell carcinoma.
Although cases and controls were individually matched, the percentages of cases and controls are not necessarily equal in each age, gender, or place of residence category, because some cases have one matched control and others have two matched controls.