Bivariate and multivariable analyses of different levels of physical activity as predictor of the 2-year incidence of spinal pain
| Spinal pain (SP) status at follow-up | ||||||
|---|---|---|---|---|---|---|
| Proportion of the day spent at different levels of physical activity | No SP (n=47) n (%) | SP (n=97) n (%) | Crude RR (95% CI) | Adjusted PA* RR (95% CI) | Adjusted full model† RR (95% CI) | |
| Sedentary activity, dichotomised at the | ||||||
| 90th centile | Below | 41 (87.2) | 88 (90.7) | Ref. | Ref. | Ref. |
| Above | 6 (12.8) | 9 (9.3) | 0.83 (0.54 to 1.29) | 0.86 (0.55 to 1.32) | 0.82 (0.52 to 1.28)‡ | |
| 75th centile | Below | 36 (76.6) | 72 (74.2) | Ref. | Ref. | Ref. |
| Above | 11 (23.4) | 25 (25.8) | 1.04 (0.70 to 1.55) | 1.02 (0.79 to 1.33) | 1.02 (0.78 to 1.32)§ | |
| 50th centile | Below | 20 (42.6) | 52 (53.6) | Ref. | Ref. | Ref. |
| Above | 27 (57.5) | 45 (46.4) | 0.81 (0.65 to 1.02) | 0.84 (0.66 to 1.06) | 0.83 (0.66 to 1.04)¶ | |
| Moderate-to-vigorous physical activity, dichotomised at the | ||||||
| 90th centile | Below | 42 (89.4) | 87 (89.7) | Ref. | Ref. | Ref. |
| Above | 5 (10.6) | 10 (10.3) | 0.93 (0.64 to 1.37) | 0.97 (0.65 to 1.44) | 1.04 (0.66 to 1.63)** | |
| 75th centile | Below | 37 (78.7) | 71 (73.2) | Ref. | Ref. | Ref. |
| Above | 10 (21.3) | 26 (26.8) | 1.04 (0.81 to 1.32) | 1.11 (0.84 to 1.47) | 1.22 (0.89 to 1.67)§ | |
| 50th centile | Below | 25 (53.2) | 47 (48.5) | Ref. | Ref. | Ref. |
| Above | 22 (46.8) | 50 (51.6) | 1.00 (0.80 to 1.25) | 1.07 (0.82 to 1.41) | 1.18 (0.87 to 1.59)§ | |
| Vigorous physical activity, dichotomised at the | ||||||
| 90th centile | Below | 45 (95.7) | 84 (86.6) | Ref. | Ref. | Ref. |
| Above | 2 (4.3) | 13 (13.4) | 1.26 (1.00 to 1.58) | 1.35 (1.06 to 1.70) | 1.44 (1.09 to 1.91)†† | |
| 75th centile | Below | 38 (80.9) | 70 (72.2) | Ref. | Ref. | Ref. |
| Above | 9 (19.2) | 27 (27.8) | 1.09 (0.86 to 1.38) | 1.17 (0.90 to 1.52) | 1.31 (0.97 to 1.78)‡‡ | |
| 50th centile | Below$ | 25 (53.2) | 47 (48.5) | Ref. | Ref. | Ref. |
| Above | 22 (46.8) | 50 (51.6) | 1.00 (0.80 to 1.25) | 1.05 (0.80 to 1.38) | 1.15 (0.88 to 1.50)§ | |
Statistically significant at 95% level RRs in bold.
*Adjusted for the counts per minute (cpm) for the time spent at other activity levels, that is, for sedentary activity: adjustment for cpm for the time spent in light, moderate and vigorous activity.
†Adjusted for all variables that changed the regression coefficient of the exposure variable in the bivariate analysis by more than 10%.
‡Adjusted for: sex, height, BMI, Handgrip strength test, Andersen test.
§Adjusted for: sex, weight2, height, BMI, waist-to-height ratio, contact/collision sport, 10×5 m shuttle run test, Handgrip strength test, Andersen test.
¶Adjusted for: sex, Handgrip strength test.
**Adjusted for: sex, height, BMI, waist-to-height ratio, 10×5 m shuttle run test, Handgrip strength test, Andersen test.
††Adjusted for: sex, BMI, 10×5 m shuttle run test, Andersen test.
‡‡Adjusted for: sex, weight, height, BMI, waist-to-height ratio, contact/collision sport, 10×5 m shuttle run test, Andersen test.
BMI, body mass index; Cpm, counts per minute; PA, physical activity; RR, relative risk.