Mean body mass index (BMI kg/m2) and prevalence (%) of low weight (BMI<20 kg/m2) and obesity (BMI≥30 kg/m2) as well as mean change in BMI (95% CI) according to 5-year birth cohorts in 4 616 men who participated in Tromsø 4 (1994–1995) and Tromsø 6 (2007–2008)
| Birth cohort | BMI | |||||||
|---|---|---|---|---|---|---|---|---|
| Tromsø 4 | Tromsø 6 | Change (95% CI) | ||||||
| n | Mean (SD) | Per cent <20 | Per cent ≥30 | Mean (SD) | Per cent <20 | Per cent ≥30 | ||
| 1965–1969 | 494 | 24.8 (3.3) | 4.1 | 6.5 | 27.1 (3.9) | 0.6 | 19.4 | 2.3 (2.1 to 2.5) |
| 1960–1964 | 342 | 24.9 (3.2) | 3.2 | 5.9 | 27.2 (3.7) | 0.3 | 19.6 | 2.3 (2.1 to 2.6) |
| 1955–1959 | 439 | 25.2 (2.8) | 0.9 | 7.3 | 27.2 (3.6) | 0.2 | 17.5 | 1.9 (1.8 to 2.1) |
| 1950–1954 | 468 | 25.7 (3.1) | 0.9 | 9.8 | 27.6 (3.7) | 0.9 | 22.4 | 1.8 (1.6 to 2.0) |
| 1945–1949 | 863 | 26.3 (3.2) | 1.2 | 12.1 | 27.7 (3.7) | 0.7 | 23.3 | 1.4 (1.3 to 1.6) |
| 1940–1944 | 878 | 26.2 (3.1) | 1.3 | 12.1 | 27.4 (3.7) | 1.1 | 22.6 | 1.2 (1.1 to 1.3) |
| 1935–1939 | 554 | 26.2 (2.9) | 0.4 | 10.8 | 27.1 (3.5) | 0.7 | 17.7 | 0.9 (0.7 to 1.1) |
| 1930–1934 | 383 | 26.0 (2.9) | 0.8 | 8.9 | 26.7 (3.5) | 1.6 | 18.3 | 0.7 (0.5 to 0.9) |
| 1925–1929 | 195 | 25.6 (2.9) | 1.0 | 9.2 | 26.4 (3.6) | 1.5 | 14.9 | 0.7 (0.4 to 1.0) |
| Total | 4616 | 25.8 (3.1) | 1.5 | 9.8 | 27.3 (3.7) | 0.8 | 20.4 | 1.5 (1.4 to 1.6) |
| P value* | <0.001 | <0.001 | 0.001 | 0.08 | 0.03 | 0.6 | <0.001 | |
*P value for linear trend over the birth cohorts.