Table 1. Sociodemographic characteristics of participants.
| Characteristics | No. of participants | % participants |
| Sex* | ||
| Male | 2049 | 38.4 |
| Female | 3261 | 61.1 |
| Age (years old) * | ||
| 60~ | 2501 | 46.8 |
| 70~ | 1912 | 35.8 |
| 80~ | 907 | 17.0 |
| Educational level* | ||
| Illiteracy | 1082 | 20.3 |
| Primary school | 3040 | 56.9 |
| Junior high school and above | 1158 | 21.7 |
| Marital status* | ||
| Married | 3971 | 74.3 |
| Widowed / Divorced / Unmarried | 1224 | 22.9 |
(N =5341).
* Variables with missing values: Sex (31/5341; 0.6%), Age (21/5341; 0.4%), Educational level (61/5341; 1.1%), and Marital status (146/5341; 2.7%).