Variables | Mean ± SD or percentage(%) | p value | |||
---|---|---|---|---|---|
Preliminary survey (2005–2007) | Follow-up surveys (2008–2010) | ||||
n | % | n | % | ||
Dependent variable | |||||
 PWI total score | 18.74 ± 8.94 | 16.70 ± 9.59 | <0.001 †| ||
 PWI high risk group | 18.9% | 15.5% | <0.001 †| ||
Lifestyle variables | |||||
 Sleep duration |  |  |  |  | 0.035* |
  6 to 9 h | 3081 | 84.9 | 3162 | 87.1 |  |
  Less than 6 h | 395 | 10.9 | 396 | 10.9 |  |
  More than 10 h | 115 | 4.3 | 73 | 2.0 |  |
 Regular exercise |  |  |  |  | <0.001* |
  Yes | 1147 | 31.6 | 1256 | 34.6 |  |
  No | 2484 | 68.4 | 2375 | 65.4 |  |
 Smoking |  |  |  |  | <0.001* |
  Non-smoker | 2211 | 60.9 | 2128 | 58.6 |  |
  Past smoker | 821 | 22.6 | 947 | 26.1 |  |
  Current smoker | 599 | 16.4 | 556 | 15.3 |  |
 Drinking alcohol |  |  |  |  | 0.103* |
  No | 2102 | 57.9 | 2041 | 56.2 |  |
  Yes | 1529 | 42.1 | 1590 | 43.8 |  |
Medical variables | |||||
 BMI (kg/m2) | 24.65 ± 3.13 | 24.30 ± 3.19 | 0.281 †| ||
 Chronic metabolic disease (number) |  |  |  |  | <0.001* |
  0 | 2622 | 72.2 | 2394 | 66.9 |  |
  1 | 802 | 22.1 | 940 | 25.9 |  |
  2 | 174 | 4.8 | 243 | 6.7 |  |
  3 or more | 33 | 0.9 | 54 | 1.5 |  |
Occupational variables | |||||
 Occupation class |  |  |  |  | 0.013* |
  Farmers, livestock farmers | 1563 | 43.0 | 1516 | 41.8 |  |
  Blue-collar | 609 | 16.8 | 587 | 16.2 |  |
  White-collar | 397 | 10.9 | 397 | 10.9 |  |
  Housewives or unemployed | 1062 | 29.3 | 1131 | 31.1 |  |
 Working hours per day |  |  |  |  | 0.021* |
  8 to 10 h | 1030 | 28.4 | 1077 | 29.6 |  |
  Less than 8 h | 529 | 14.6 | 555 | 15.3 |  |
  More than 10 h | 1150 | 31.6 | 1098 | 30.3 |  |
  None | 922 | 25.4 | 901 | 24.8 |  |
 Sedentary time at worka |  |  |  |  | <0.001* |
  Less than 1 h per day | 1018 | 39.8 | 1021 | 39.3 |  |
  1 to 5 h per day | 939 | 36.6 | 921 | 35.4 |  |
  More than 5 h per day | 603 | 23.6 | 658 | 25.3 |  |
Demographic variables | |||||
 Sex |  |  |  |  |  |
  Male | 1518 | 41.8 | 1518 | 41.8 |  |
  Female | 2113 | 58.2 | 2113 | 58.2 |  |
 Age | 55.32 ± 8.24 | 58.15 ± 8.19 | 0.011 †| ||
  40–49 years | 861 | 23.7 | 719 | 19.8 | 0.003* |
  50–59 years | 1336 | 36.8 | 1314 | 36.2 |  |
  ≥ 60 years | 1434 | 39.5 | 1598 | 44.0 |  |
 Highest level of educationb | |||||
  Lower than elementary | 1808 | 49.8 |  |  |  |
  Middle school | 650 | 17.9 |  |  |  |
  High school | 792 | 21.8 |  |  |  |
  Two-year college or higher | 381 | 10.6 |  |  |  |
 Monthly incomeb | |||||
  < 1 million won | 1565 | 43.1 |  |  |  |
  1–2 million won | 1031 | 28.4 |  |  |  |
  2–3 million won | 479 | 13.2 |  |  |  |
  > 3 million won | 556 | 15.4 |  |  |  |
 Marital status |  |  |  |  | 0.089* |
  Spouse | 3260 | 89.8 | 3210 | 88.4 |  |
  No spouse | 371 | 10.2 | 421 | 11.6 |  |