Table 2. Relative risk of overweight at the age of 9 years according to the IOTF associated with early weight and BMI measures in the NFBCC1966 and the NFBC1986.
| NFBC1966 (N = 1399) | NFBC1986 (N = 4064) | Total (N = 5463) | |||||||
| N | n(%) | RR(95%CI) | N | n(%) | RR(95%CI) | N | n(%) | RR(95%CI) | |
| Weight at 5 months (kg) | |||||||||
| <50 percentile | 685 | 55(8) | 1 | 2038 | 227(11) | 1 | 2723 | 282(10) | 1 |
| ≥50–<75 | 355 | 29(8) | 1.2(0.7–1.8) | 1013 | 192(19) | 1.9(1.6–2.2) | 1368 | 221(16) | 1.7(1.5–2.0) |
| ≥75–<90 | 215 | 20(9) | 1.4(0.9–2.4) | 610 | 129(21) | 2.2(1.8–2.6) | 825 | 149(18) | 2.0(1.7–2.4) |
| ≥90 | 144 | 23(16) | 2.6(1.6–4.1) | 403 | 125(31) | 3.2(2.6–4.0) | 547 | 148(27) | 3.1(2.6–3.7) |
| Weight at 1 year (kg) | |||||||||
| <50 percentile | 699 | 52(7) | 1 | 2031 | 210(10) | 1 | 2730 | 262(10) | 1 |
| ≥50–<75 | 345 | 27(8) | 1.2(0.7–1.8) | 1016 | 188(19) | 1.9(1.6–2.3) | 1361 | 215(16) | 1.8(1.5–2.1) |
| ≥75–<90 | 210 | 21(10) | 1.6(1.0–2.6) | 608 | 143(24) | 2.5(2.1–3.0) | 818 | 164(20) | 2.3(1.9–2.8) |
| ≥90 | 145 | 27(19) | 3.0(2.0–4.6) | 409 | 132(32) | 3.5(2.9–4.3) | 554 | 159(29) | 3.4(2.8–4.0) |
| BMI at 2 years (kg/m2) | |||||||||
| <50 percentile | 701 | 39(6) | 1 | 2036 | 196(10) | 1* | 2737 | 235(9) | 1 |
| ≥50–<75 | 353 | 31(9) | 1.6(1.0–2.6) | 1007 | 161(16) | 1.7(1.4–2.0) | 1360 | 192(14) | 1.7(1.4–2.0) |
| ≥75–<90 | 202 | 23(11) | 2.1(1.3–3.5) | 617 | 147(24) | 2.5(2.1–3.0) | 819 | 170(21) | 2.5(2.1–3.0) |
| ≥90 | 143 | 34(24) | 4.5(3.0–6.9) | 404 | 169(42) | 4.4(3.7–5.3) | 547 | 203(37) | 4.4(3.8–5.2) |
| BMI at 3 years (kg/m2) | |||||||||
| <50 percentile | 710 | 25(4) | 1 | 2028 | 141(7) | 1 | 2738 | 166(6) | 1 |
| ≥50–<75 | 345 | 32(9) | 2.7(1.7–4.5) | 1024 | 171(17) | 2.4(2.0–3.0) | 1369 | 203(15) | 2.5(2.0–3.0) |
| ≥75–<90 | 206 | 28(14) | 4.0(2.4–6.7) | 615 | 152(25) | 3.6(2.9–4.5) | 821 | 180(22) | 3.7(3.0–4.5) |
| ≥90 | 138 | 42(30) | 8.9(5.6–14.0) | 397 | 209(53) | 7.6(6.3–9.2) | 535 | 251(47) | 7.8(6.6–9.3) |
| BMI at 4 years (kg/m2) | |||||||||
| <50 percentile | 706 | 18(3) | 1 | 2030 | 83(4) | 1 | 2736 | 101(4) | 1 |
| ≥50–<75 | 341 | 19(6) | 2.3(1.2–4.3) | 1024 | 153(15) | 3.7(2.8–4.7) | 1365 | 172(13) | 3.4(2.7–4.4) |
| ≥75–<90 | 217 | 32(15) | 5.9(3.4–10.2) | 607 | 178(29) | 7.2(5.7–9.2) | 824 | 210(25) | 7.0(5.6–8.7) |
| ≥90 | 135 | 58(43) | 17.1(10.4–27.9) | 403 | 259(64) | 15.7(12.6–19.7) | 538 | 317(59) | 16.0(13.1–19.6) |
| BMI at 5 years (kg/m2) | |||||||||
| <50 percentile | 697 | 14(2) | 1 | 2038 | 62(3) | 1 | 2735 | 76(3) | 1* |
| ≥50–<75 | 348 | 24(7) | 3.5(1.9–6.7) | 1010 | 135(13) | 4.4(3.2–5.9) | 1358 | 159(12) | 4.2(3.2–5.5) |
| ≥75–<90 | 205 | 25(12) | 6.2(3.3–11.8) | 603 | 195(32) | 10.6(8.1–14.0) | 808 | 220(27) | 9.9(7.7–12.6) |
| ≥90 | 149 | 64(43) | 21.0(12.1–36.4) | 413 | 281(68) | 22.3(17.3–28.8) | 562 | 345(61) | 22.0(17.5–27.8) |
*Statistically significant difference between genders. No statistically significant differences between the cohorts found. BMI- Body mass index. IOTF – overweight/obese according to the International Obesity Task Force. NFBC1966 and NFBC1986 – Northern Finnish Birth Cohorts born in 1966 and 1986.