| Physical activity from adolescence to adulthood and health-related fitness at age 31: Cross-sectional and longitudinal analyses of the Northern Finland birth cohort of 1966 | ||
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At age 31 the mean BMI was 25.2 kg/m2 in males and 24.2 kg/m2 in females, and the mean WC was 88.9 cm in males and 78.8 cm in females. The prevalence of overweight was higher in males than in females at age 31 (41 vs. 22%), but obesity was equally prevalent in both genders (8%). The prevalence of mild abdominal obesity was 18% in both genders, and the prevalence of severe abdominal obesity was 9% in males and 18% in females.
Most subjects, 60% of males and 55% of females, were classified as persistently active, and a small group, 7% of males and 9% of females, were classified as persistently inactive between adolescence and adulthood. More females (21%) than males (10%) had become active and more males (23%) than females (15%) had become inactive during the transition from youth to adulthood. The prevalence of overall and abdominal obesity was highest among those who had been persistently inactive or had become inactive between adolescence and adulthood (Table 9).
In males, becoming inactive between adolescence and adulthood was associated with overall obesity (OR 1.53, CI 0.99–2.37), while being persistently inactive was not associated with overall overweight or obesity (Table 9). In females, becoming inactive and being persistently inactive were associated with overall obesity in unadjusted analyses, but an adjustment for confounding factors made the associations weaker and the CIs wider (OR 1.51, CI 0.94–2.44). This was mainly due to adjustment for the level of education in the case of becoming active, and to adjustment for BMI at 14 years in the case of being persistently inactive.
In males, being persistently inactive was first associated with severe abdominal obesity, but not after adjustment for the level of education and BMI at 14 years (Table 9). Becoming inactive was associated with severe abdominal obesity in unadjusted analyses, and also after adjustment for potential confounders, while the associations disappeared after adjustment for BMI at 31 years. In females, becoming inactive was associated with severe abdominal obesity after adjustment for potential confounders and for BMI at 31 years (OR 1.80, CI 1.13–2.86). Being persistently inactive was first associated with severe abdominal obesity, but the association disappeared after adjustment for BMI at 31 years. Becoming active between adolescence and adulthood was not associated with overall or abdominal obesity in either gender, when being persistently active was the reference group (Table 9).
Table 9. Logistic regression of overall and abdominal obesity at 31 years on the change in the level of physical activity between the ages of 14 and 31. Odds ratios (OR) and 95 % confidence intervals (CI).
| Change in the level of physical activity between 14 and 31 years | Obesity at 31 years a | Abdominal obesity at 31 years b | ||||||
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| Prevalence of obesity % | Unadjusted OR (CI) | Adjusted* OR (CI) | Prevalence of abdominal obesity % | Unadjusted OR (CI) | Adjusted* OR (CI) | Adjusted** OR (CI) | ||
| Males | ||||||||
| Persistently active | 7.6 | 1.00 | 1.00 | 7.6 | 1.00 | 1.00 | 1.00 | |
| Become active | 7.1 | 1.01 (0.60–1.69) | 0.62 (0.30–1.28) | 9.4 | 1.27 (0.80–2.01) | 1.10 (0.63–1.91) | 1.17 (0.54–2.50) | |
| Become inactive | 10.4 | 1.64 (1.17–2.29) | 1.53 (0.99–2.37) | 13.1 | 1.95 (1.43–2.64) | 1.85 (1.31–2.63) | 1.43 (0.83–2.44) | |
| Persistently inactive | 8.6 | 1.14 (0.65–2.01) | 0.66 (0.27–1.59) | 12.3 | 1.82 (1.12–2.95) | 1.38 (0.75–2.55) | 1.78 (0.76–4.13) | |
| Females | ||||||||
| Persistently active | 7.9 | 1.00 | 1.00 | 16.2 | 1.00 | 1.00 | 1.00 | |
| Become active | 7.6 | 0.95 (0.66–1.38) | 0.70 (0.41–1.18) | 16.5 | 1.01 (0.77–1.32) | 0.83 (0.61–1.14) | 0.95 (0.59–1.51) | |
| Become inactive | 12.0 | 1.64 (1.16–2.32) | 1.51 (0.94–2.44) | 23.8 | 1.68 (1.29–2.19) | 1.64 (1.21–2.22) | 1.80 (1.13–2.86) | |
| Persistently inactive | 15.5 | 2.24 (1.49–3.38) | 1.55 (0.86–2.77) | 22.9 | 1.58 (1.12–2.23) | 1.47 (0.99–2.19) | 0.92 (0.48–1.76) | |
| a Body mass index (BMI) ≥ 30 vs. < 25.0 kg/m2.b Waist circumference ≥ 102.0 cm vs. < 94.0 cm in males, and ≥ 88.0 cm vs. < 80.0 cm in females.*Adjusted for occupational physical activity, vocational education, alcohol consumption, smoking, BMI at 14 years, maternal BMI, and in females for parity.** Additionally adjusted for BMI at 31 years. | ||||||||