Table 1

Characteristics of participants by BMI trajectory groups in the Melbourne Collaborative Cohort Study

BMI trajectory groups
TR1 lower-normal stableTR2 higher-normal stableTR3 normal to overweightTR4 chronic borderline obesityTR5 normal to class I obesityTR6 overweight to class II obesity
N=5748N=11 229N=8130N=933N=2893N=948
Baseline age, mean (SD)54.3 (8.9)55.3 (8.7)54.7 (8.3)55.2 (8.5)53.8 (8.1)52.3 (8.0)
BMI age 18–21 kg/m2, mean (SD)20.1 (2.0)21.5 (2.3)22.2 (2.3)28.8 (2.6)22.8 (2.5)25.3 (3.9)
BMI 1990–1994, kg/m2, mean (SD)21.8 (1.4)25.1 (1.5)28.5 (1.8)30.5 (2.4)32.6 (2.2)37.5 (2.7)
BMI 1995–1998, kg/m2, mean (SD)22.4 (1.4)25.8 (1.5)29.3 (1.7)31.0 (2.2)33.6 (2.1)38.8 (2.4)
BMI 2003–2007, kg/m2, mean (SD)22.0 (1.7)25.7 (1.6)29.5 (1.8)31.0 (2.3)34.1 (2.2)39.0 (2.7)
Sex, N (%)
 Male1443 (25.1)5027 (44.8)3936 (48.4)535 (57.3)995 (34.4)218 (23.0)
 Female4305 (74.9)6202 (55.2)4194 (51.6)398 (42.7)1898 (65.6)730 (77.0)
Country of birth, N (%)
 Australia/New Zealand/Northern Europe5388 (93.7)9282 (82.7)5640 (69.4)564 (60.5)1832 (63.3)605 (63.8)
 Southern Europe360 (6.3)1947 (17.3)2490 (30.6)369 (39.5)1061 (36.7)343 (36.2)
SEIFA quintiles N (%)
 1 (east advantaged)724 (12.6)1734 (15.4)1554 (19.1)205 (22.0)672 (23.2)235 (24.8)
 2912 (15.9)2143 (19.1)1814 (22.3)242 (25.9)690 (23.9)233 (24.6)
 3843 (14.7)1749 (15.6)1354 (16.7)141 (15.1)480 (16.6)181 (19.1)
 41177 (20.5)2211 (19.7)1515 (18.6)151 (16.2)525 (18.1)143 (15.1)
 5 (most advantaged)2092 (36.4)3392 (30.2)1893 (23.3)194 (20.8)526 (18.2)156 (16.5)
Level of education, N (%)
 Primary or lower290 (5.0)1374 (12.2)1844 (22.7)281 (30.1)791 (27.3)261 (27.5)
 Some high/technical school2245 (39.1)4341 (38.7)3024 (37.2)326 (34.9)1142 (39.5)405 (42.7)
 Comepleted high/technical school1335 (23.2)2536 (22.6)1654 (20.3)173 (18.5)549 (19.0)163 (17.2)
 Completed tertiary education1878 (32.7)2978 (26.5)1608 (19.8)153 (16.4)411 (14.2)119 (12.6)
Mediterranean Diet Score 1990–1994, N (%)
 0–31753 (30.5)3645 (32.5)2763 (34.0)358 (38.4)1024 (35.4)318 (33.5)
 4–63238 (56.3)6090 (54.2)4373 (53.8)481 (51.6)1578 (54.5)541 (57.1)
 7–9757 (13.2)1494 (13.3)994 (12.2)94 (10.1)291 (10.1)89 (9.4)
Mediterranean Diet Score 2003–2007, N (%)
 0–3956 (23.1)1732 (23.1)1241 (24.3)125 (24.2)425 (24.4)151 (26.6)
 4–62515 (60.9)4626 (61.8)3181 (62.3)328 (63.4)1134 (65.1)360 (63.5)
 7–9660 (16.0)1128 (15.1)681 (13.3)64 (12.4)182 (10.5)56 (9.9)
Physical Activity Score 1990–1994, N (%)
 0866 (15.1)2061 (18.4)1985 (24.4)243 (26.0)859 (29.7)318 (33.5)
 >0 and <41065 (18.5)2193 (19.5)1647 (20.3)172 (18.4)643 (22.2)239 (25.2)
 ≥4 and <62079 (36.2)4026 (35.9)2844 (35.0)338 (36.2)975 (33.7)280 (29.5)
 ≥61738 (30.2)2949 (26.3)1654 (20.3)180 (19.3)416 (14.4)111 (11.7)
METs 2003–2007, median (IQR)21.5 (9.9–40.0)19.3 (8.3–36.7)15 (6.2–29.8)14 (5.0–31.4)11 (3.7–24.4)9.3 (2.8–19.8)
Drinking status 1990–1994, N (%)
 Lifetime abstainers1437 (25.0)2691 (24.0)2275 (28.0)287 (30.8)1060 (36.6)429 (45.3)
 Ex-drinkers195 (3.4)376 (3.3)315 (3.9)58 (6.2)121 (4.2)43 (4.5)
 Current (1–39 g (male) 1–19 (female))3460 (60.2)6995 (62.3)4734 (58.2)516 (55.3)1498 (51.8)429 (45.3)
 Current (≥40 (male), ≥20 (female))656 (11.4)1167 (10.4)806 (9.9)72 (7.7)214 (7.4)47 (5.0)
Smoking status at last BMI measurement, N (%)
 Never3585 (62.4)6547 (58.3)4504 (55.4)488 (52.3)1749 (60.5)602 (63.5)
 Former1710 (29.7)3905 (34.8)3004 (36.9)359 (38.5)941 (32.5)274 (28.9)
 Current453 (7.9)777 (6.9)622 (7.7)86 (9.2)203 (7.0)72 (7.6)
Had angina before 1990–1994, N (%)141 (2.5)391 (3.5)308 (3.8)38 (4.1)106 (3.7)48 (5.1)
Had heart attack before 1990–1994, N (%)103 (1.8)289 (2.6)228 (2.8)30 (3.2)75 (2.6)21 (2.2)
Had stroke before 1990–1994, N (%)37 (0.6)124 (1.1)94 (1.2)13 (1.4)25 (0.9)12 (1.3)
Had diabetes before 1990–1994, N (%)75 (1.3)253 (2.3)326 (4.0)69 (7.4)147 (5.1)58 (6.1)
Birth cohort, N (%)
 Before 19301250 (21.7)2725 (24.3)1659 (20.4)233 (25.0)479 (16.6)117 (12.3)
 After 1930, before 19401674 (29.1)3662 (32.6)2908 (35.8)307 (32.9)1028 (35.5)310 (32.7)
 After 1940, before 19501999 (34.8)3513 (31.3)2639 (32.5)298 (31.9)1033 (35.7)370 (39.0)
 After 1950825 (14.4)1329 (11.8)924 (11.4)95 (10.2)353 (12.2)151 (15.9)
  • BMI, body mass index;MET, metabolic equivalent; SEIFA, Socio-Economic Indexes for Areas.