Table 2.
Cross-sectional analyses of inactivity and education at each survey. Proportions of inactivity and means of education years in 1981 by leisure-time physical activity (LTPA) and the associations of each year of additional education (Odds Ratios [OR] and 95 % Confidence Intervals [95 % CI]) with being physically inactive at the survey in all participants and in twin pairs discordant for LTPA
| LTPA status at survey | % (n) | Education years in 1981 | All participants (n = 5254)* | Discordant twin pairs ** a | |||
|---|---|---|---|---|---|---|---|
| Age- and sex-adjusted model | Multivariate model b | All pairs | DZ pairs | MZ pairs | |||
| Mean (95 % CI) | OR (95 % CI) | OR (95 % CI) | OR (95 % CI) | OR (95 % CI) | OR (95 % CI) | ||
| 1981 | |||||||
| Active | 53 (2762) | 9.19 (9.08, 9.32) | 1.00 (reference) | 1.00 | 1.00 | 1.00 | 1.00 |
| Inactive | 47 (2492) | 8.68 (8.57, 8.79) | 0.95 (0.93, 0.96) | 0.95 (0.93, 0.97) c | 0.94 (0.88, 1.00) | 0.93 (0.87, 1.00) | 0.94 (0.80, 1.09) |
| 1990 | |||||||
| Active | 66 (3446) | 9.13 (9.03, 9.23) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Inactive | 34 (1808) | 8.61 (8.48, 8.74) | 0.95 (0.93, 0.97) | 0.96 (0.94, 0.99) d | 0.92 (0.87, 0.98) | 0.93 (0.87, 1.00) | 0.85 (0.73, 0.99) |
| 2011 | |||||||
| Active | 64 (3339) | 9.18 (9.08, 9.30) | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| Inactive | 36 (1915) | 8.55 (8.41, 8.67) | 0.94 (0.92, 0.96) | 0.97 (0.95, 0.99) e | 0.94 (0.89, 1.00) | 0.95 (0.89, 1.02) | 0.86 (0.72, 1.03) |
LTPA: leisure-time physical activity; inactive: LTPA energy cost ≤1.5 MET h/day; active (reference group): LTPA energy cost >1.5 MET h/day
*Logistic regression model, ** Conditional logistic regression model
a) Twin pairs discordant for LTPA (active vs. inactive) at each survey. Numbers of discordant pairs in the basic models (age and sex automatically adjusted in the same-sexed twin pairs) were 671 in 1981 (424 DZ and 213 MZ pairs), 664 in 1990 (404 DZ and 226 MZ pairs) and 632 in 2011 (401 DZ and 198 MZ pairs)
b) Sex, age at the survey, Body Mass Index in 1975, working status in 1975, marital status in 1975, alcohol use (g /day) in 1975 and smoking status in 1975 were included as covariates
c) In addition to other covariates, LTPA status in 1975 has been included as a covariate
d) In addition to other covariates, LTPA status from 1975 to 1981 has been included as a covariate
e) In addition to other covariates, LTPA status from 1975 to 1981 and LTPA status in 1990 has been included as covariates