Table 1 Association of family average income and conventional potential confounders
Characteristic | Family Average Income (n, %*) | p value** | ||
|---|---|---|---|---|
| Â | Lower (N = 9689) | Middle (N = 8991) | Higher (N = 10660) | Â |
Age group(yrs) | Â | Â | Â | Â |
   35–49 | 4127 (42.6) | 4880 (54.3) | 4205 (39.4) | < 0.001 |
   50–64 | 3142 (32.4) | 2696 (30.0) | 4115 (38.6) |  |
   65+ | 2420 (25.0) | 1415 (15.7) | 2340 (22.0) |  |
Gender | Â | Â | Â | Â |
   Female | 5063 (52.3) | 4436 (49.3) | 5243 (49.2) | 0.581 |
   Male | 4626 (47.7) | 4555 (50.7) | 5417 (50.8) |  |
Area | Â | Â | Â | Â |
   Rural | 6469 (66.8) | 2624 (29.2) | 386 (3.6) | < 0.001 |
   Urban | 3220 (33.2) | 6367 (70.8) | 10274 (96.4) |  |
Education (yrs) | Â | Â | Â | Â |
   0–9 | 9018 (93.1) | 6872 (76.4) | 3947 (37.0) | < 0.001 |
   10–12 | 641 (6.6) | 1770 (19.7) | 3070 (28.8) |  |
   13+ | 30 (0.3) | 349 (3.9) | 3643 (34.2) |  |
Occupation†|  |  |  |  |
   Blue collar | 7585 (78.3) | 5538 (61.6) | 2742 (25.7) | < 0.001 |
   Service people | 1681 (17.3) | 1326 (14.7) | 652 (6.1) |  |
   White collar | 423 (4.4) | 2127 (23.7) | 7266 (68.2) |  |
BMI (kg/m2) | Â | Â | Â | Â |
   24- | 6761 (69.8) | 5366 (59.7) | 5967 (56.0) | < 0.001 |
   24–28 | 2362 (24.4) | 2834 (31.5) | 3757 (35.2) |  |
   28+ | 566 (5.8) | 791 (8.8) | 936 (8.8) |  |
Cigarette Smoking | Â | Â | Â | Â |
   Never | 6393 (66.0) | 6060 (67.4) | 7994 (75.0) | < 0.001 |
   Ex/Current | 3296 (34.0) | 2931 (32.6) | 2666 (25.0) |  |
Alcohol consumption | Â | Â | Â | Â |
   No | 7468 (77.1) | 7099 (79.0) | 9003 (84.5) | < 0.001 |
   Ex/Current | 2221 (22.9) | 1892 (21.0) | 1657 (15.5) |  |
Diabetes | Â | Â | Â | Â |
   No | 9640 (99.5) | 8844 (98.4) | 10227 (95.9) | < 0.001 |
   Yes | 49 (0.5) | 147 (1.6) | 433 (4.1) |  |
High blood pressure | Â | Â | Â | Â |
   No | 6505 (67.1) | 6108 (67.9) | 6987 (65.5) | 0.013 |
   Yes | 3184 (32.9) | 2883 (32.1) | 3673 (34.5) |  |
Occupational physical activity | Â | Â | Â | Â |
   Light | 4292 (44.3) | 6242 (69.4) | 9761 (91.6) | < 0.001 |
   Moderate | 1125 (11.6) | 1157 (12.9) | 643 (6.0) |  |
   Vigorous | 4272 (44.1) | 1592 (17.7) | 256 (2.4) |  |
Leisure-time physical activity | Â | Â | Â | Â |
   Light | 7281 (75.1) | 7502 (83.4) | 8957 (84.0) | < 0.001 |
   Moderate | 2089 (21.6) | 1374 (15.3) | 1643 (15.4) |  |
   Vigorous | 319 (3.3) | 115 (1.3) | 60 (0.6) |  |