Characteristics of participants among four groups of BMI gain trajectories (n=14 185*)
| Loss | Stable | Moderate gain | Substantial gain | P value | |
| Participants (n) | 1052 | 5858 | 5609 | 1218 | |
| BMI measurements during follow-up | 4.5±2.03 | 4.4±2.1 | 4.5±2.1 | 4.4±2.0 | 0.361 |
| Age (years) | 40.6±14.7 | 41.6±14.9 | 41.5±15.1 | 42.0±15.0 | <0.0001 |
| Female (%) | 559 (53.1) | 3128 (53.4) | 2981 (53.2) | 670 (55.1) | 0.980 |
| Education (years) | 6.9±4.2 | 6.6±4.2 | 6.4±4.3 | 6.5±4.3 | 0.004 |
| Never | 143 (15.0%) | 935 (17.7%) | 988 (19.5%) | 197 (18.2%) | 0.066 |
| <6 | 200 (21.0%) | 1109 (21.0%) | 1078 (21.3%) | 237 (21.9%) | |
| 6–8 | 177 (18.6%) | 939 (17.8%) | 894 (17.6%) | 189 (17.4%) | |
| 9–11 | 298 (31.3%) | 1639 (31.1%) | 1467 (28.9%) | 309 (28.5%) | |
| >12 | 134 (14.1%) | 649 (12.3%) | 647 (12.8%) | 152 (14.0%) | |
| Rural (%) | 605 (57.5) | 3590 (61.3) | 3796 (67.7) | 752 (61.8) | <0.001 |
| Household income (¥) | 6460.4±7203.9 | 6459.1±10 654.2 | 6194.3±11 095.0 | 6005.3±7415.9 | 0.453 |
| Anthropometry at baseline | |||||
| Height (cm) | 161.1±8.2 | 160.4±8.5 | 160.4±8.3 | 160.9±8.3 | 0.014 |
| Weight (kg) | 58.9±10.7 | 57.4±10.2 | 57.1±10.0 | 57.9±10.3 | <0.001 |
| BMI (kg/m2) | 22.6±3.3 | 22.3±3.1 | 22.1±3.0 | 22.3±3.2 | <0.001 |
| Lean (<18.5) | 77 (7.3%) | 481 (8.2%) | 485 (8.7%) | 97 (8.0%) | 0.004 |
| Normal (18.5–23.9) | 658 (62.6%) | 3875 (66.2%) | 3802 (67.8%) | 809 (66.5%) | |
| Overweight (24–27.9) | 249 (23.7%) | 1216 (20.8%) | 1066 (19.0%) | 250 (20.5%) | |
| Obesity (≥28) | 68 (6.5%) | 286 (4.9%) | 256 (4.6%) | 61 (5.0%) | |
| Systolic BP (mm Hg) | 117.2±16.6 | 116.9±17.6 | 116.2±18.0 | 117.1±18.1 | 0.114 |
| Diastolic BP (mm Hg) | 76.3±10.5 | 76.1±10.9 | 75.6±11.4 | 76.3±11.8 | 0.029 |
| Initial health-related behavior at baseline | |||||
| Cigarette smoker (%) | 328 (31.7) | 1891 (32.8) | 1812 (32.8) | 390 (32.6) | 0.922 |
| Alcohol drinker (%) | 406 (38.8) | 2168 (37.3) | 2020 (36.2) | 413 (34.2) | 0.081 |
| Physical activities (MET-hours/day) | 6.9±10.6 | 6.6±10.7 | 6.9±11.4 | 6.7±10.5 | 0.462 |
| Dietary total energy (kcal) | 2490.5±733.3 | 2475.2±780.0 | 2481.2±746.5 | 2446.9±710.5 | 0.493 |
| Latest health-related behavior | |||||
| Cigarette smoker (%) | 286 (28.1) | 1584 (28.3) | 1541 (28.7) | 310 (26.6) | 0.509 |
| Alcohol drinker (%) | 337 (33.0) | 1808 (32.2) | 1681 (31.3) | 341 (29.3) | 0.540 |
| Physical activities (MET-hours/day) | 20.2±18.5 | 19.1±19.8 | 18.8±19.8 | 19.4±19.5 | 0.184 |
| Dietary total energy (kcal) | 2147.9±951.4 | 2096.5±949.1 | 2070.1±897.8 | 2085.5±684.0 | 0.059 |
| Change in time-varying health-related behavior | |||||
| Smoking | |||||
| Never smoking | 640 (64.6%) | 3553 (64.6%) | 3358 (63.8%) | 749 (65.8%) | 0.338 |
| Change to be a smoker | 51 (5.2%) | 238 (4.3%) | 275 (5.2%) | 41 (3.6%) | |
| Quit smoking | 76 (7.7%) | 415 (7.6%) | 421 (8.0%) | 93 (8.2%) | |
| Keep smoking | 224 (22.6%) | 1291 (23.5%) | 1211 (23.0%) | 256 (22.5%) | |
| Alcohol consumption | |||||
| Never drinking | 538 (53.0%) | 3014 (54.0%) | 2951 (55.3%) | 669 (57.8%) | 0.501 |
| Change to be a drinker | 90 (8.9%) | 538 (9.6%) | 513 (9.6%) | 104 (9.0%) | |
| Quit drinking | 141 (13.9%) | 764 (13.7%) | 714 (13.4%) | 149 (12.9%) | |
| Keep drinking | 246 (24.2%) | 1263 (22.6%) | 1161 (21.8%) | 235 (20.3%) | |
| Physical activity change (MET-hours/day) | 13.17±20.12 | 12.25±21.12 | 11.60±21.14 | 12.30±21.04 | 0.121 |
| Increase | 666 (65.1%) | 3638 (64.5%) | 3449 (63.9%) | 776 (66.3%) | 0.619 |
| Decrease | 357 (34.9%) | 2000 (35.5%) | 1946 (36.1%) | 394 (33.7%) | |
| Dietary total energy level (kcal) | −341.57±1093.37 | −380.36±1142.08 | −411.34±1079.06 | −365.65±873.41 | 0.168 |
| Increase | 341 (33.3%) | 1774 (31.5%) | 1639 (30.4%) | 372 (31.8%) | 0.130 |
| Decrease | 682 (66.7%) | 3864 (68.5%) | 3756 (69.6%) | 798 (68.2%) | |
| Type 2 diabetes | 35 (3.3%) | 190 (3.2%) | 219 (3.9%) | 54 (4.4%) | 0.067 |
| Censored | 953 (90.6%) | 5236 (89.4%) | 4952 (88.3%) | 1079 (88.7%) | |
| Competing risk (death) | 64 (6.1%) | 432 (7.4%) | 438 (7.8%) | 84 (6.9%) | |
| Duration of follow-up (years) | 11.4±6.7 | 11.0±6.8 | 11.3±6.8 | 10.9±6.7 | 0.053 |
Values in the table are mean±SD or n (%); missing data are handled in the analysis.
*448 participants were failed to be classified into BMI trajectory groups.
BMI, body mass index; BP, blood pressure; MET, metabolic equivalent.