Table 4.
Student- and school-level correlates of weekday composite sugar-sweetened beverage score† among secondary-school students (n 41 829) from Alberta and Ontario participating in Year 2 of the COMPASS study, Canada, 2013/14: an illustration of the block-wise modelling process‡
| Student-level control variable | Student-level control+school beverage availability variables | Student-level control+school beverage availability+school neighbourhood variables | Student-level control+school beverage availability+school neighbourhood food outlets+school-level control variables | |||||
|---|---|---|---|---|---|---|---|---|
| Characteristic | Adjusted rate§ | 95 % CI | Adjusted rate§ | 95 % CI | Adjusted rate§ | 95 % CI | Adjusted rate§ | 95 % CI |
| Student-level control variables | ||||||||
| Gender | ||||||||
| Female | 1·00 | Ref. | 1·00 | Ref. | 1·00 | Ref. | 1·00 | Ref. |
| Male | 1·13*** | 1·10, 1·16 | 1·13*** | 1·10, 1·16 | 1·13*** | 1·10, 1·16 | 1·13*** | 1·10, 1·16 |
| Grade | ||||||||
| 9 | 1·00 | Ref. | 1·00 | Ref. | 1·00 | Ref. | 1·00 | Ref. |
| 10 | 0·98 | 0·96, 1·01 | 0·98 | 0·96, 1·00 | 0·98 | 0·96, 1·00 | 0·98 | 0·96, 1·00 |
| 11 | 0·95** | 0·93, 0·98 | 0·95** | 0·93, 0·98 | 0·95** | 0·93, 0·98 | 0·95** | 0·93, 0·98 |
| 12 | 0·93*** | 0·90, 0·96 | 0·93*** | 0·89, 0·96 | 0·93*** | 0·89, 0·96 | 0·93*** | 0·90, 0·96 |
| Ethnicity | ||||||||
| White | 1·00 | Ref. | 1·00 | Ref. | 1·00 | Ref. | 1·00 | Ref. |
| Aboriginal | 1·21*** | 1·16, 1·27 | 1·21*** | 1·16, 1·26 | 1·21*** | 1·16, 1·26 | 1·21*** | 1·16, 1·26 |
| Asian | 0·92*** | 0·88, 0·97 | 0·92*** | 0·88, 0·97 | 0·92*** | 0·88, 0·97 | 0·93*** | 0·88, 0·97 |
| Black | 1·23*** | 1·18, 1·29 | 1·23*** | 1·18, 1·29 | 1·23*** | 1·18, 1·29 | 1·24*** | 1·19, 1·30 |
| Latin | 1·01 | 0·96, 1·07 | 1·01 | 0·96, 1·07 | 1·01 | 0·96, 1·07 | 1·01 | 0·96, 1·07 |
| Other | 1·09*** | 1·06, 1·12 | 1·09*** | 1·06, 1·12 | 1·09*** | 1·06, 1·12 | 1·09*** | 1·06, 1·12 |
| Weekly spending money | ||||||||
| $CAN 0 | 1·00*** | Ref. | 1·00*** | Ref. | 1·00 | Ref. | 1·00 | Ref. |
| $CAN 1–20 | 1·14*** | 1·10, 1·17 | 1·14*** | 1·10, 1·17 | 1·14*** | 1·10, 1·17 | 1·14*** | 1·10, 1·17 |
| $CAN 21–100 | 1·21*** | 1·18, 1·25 | 1·21*** | 1·18, 1·25 | 1·21*** | 1·18, 1·25 | 1·21*** | 1·18, 1·25 |
| >$CAN 100 | 1·29*** | 1·26, 1·33 | 1·29*** | 1·26, 1·33 | 1·29*** | 1·26, 1·33 | 1·29*** | 1·26, 1·33 |
| I don’t know | 1·12*** | 1·09, 1·16 | 1·12*** | 1·09, 1·16 | 1·12*** | 1·09, 1·16 | 1·12*** | 1·09, 1·16 |
| Weight status | ||||||||
| Healthy weight | 1·00 | Ref. | 1·00 | Ref. | 1·00 | Ref. | 1·00 | Ref. |
| Underweight | 1·06 | 1·00, 1·13 | 1·06 | 1·00, 1·13 | 1·06 | 1·00, 1·13 | 1·06 | 1·00, 1·13 |
| Overweight | 0·99 | 0·97, 1·02 | 0·99 | 0·97, 1·02 | 0·99 | 0·97, 1·02 | 0·99 | 0·97, 1·02 |
| Obese | 1·09*** | 1·05, 1·13 | 1·09*** | 1·05, 1·13 | 1·09*** | 1·05, 1·13 | 1·09*** | 1·05, 1·13 |
| Missing | 1·09*** | 1·07, 1·12 | 1·09*** | 1·07, 1·12 | 1·09*** | 1·07, 1·12 | 1·09*** | 1·07, 1·12 |
| Truancy | ||||||||
| Skipped 0 classes in last 4 weeks | 1·00 | Ref. | 1·00 | Ref. | 1·00 | Ref. | 1·00 | Ref. |
| Skipped 1+classes in last 4 weeks | 1·31*** | 1·28, 1·34 | 1·31*** | 1·28, 1·34 | 1·31*** | 1·28, 1·34 | 1·31*** | 1·28, 1·34 |
| Weight goal | ||||||||
| Not trying to do anything about weight | 1·00 | Ref. | 1·00 | Ref. | 1·00 | Ref. | 1·00 | Ref. |
| Gain weight | 1·03 | 1·00, 1·06 | 1·03 | 1·00, 1·06 | 1·03 | 1·00, 1·06 | 1·03 | 1·00, 1·06 |
| Lose weight | 0·95*** | 0·93, 0·97 | 0·95*** | 0·93, 0·97 | 0·95*** | 0·93, 0·97 | 0·95*** | 0·93, 0·97 |
| Stay the same weight | 0·94*** | 0·92, 0·97 | 0·94*** | 0·92, 0·97 | 0·94*** | 0·92, 0·97 | 0·94*** | 0·92, 0·97 |
| School beverage availability variables | ||||||||
| Availability of soft drinks in school vending machines | ||||||||
| Unavailable | 1·00 | Ref. | – | – | – | – | ||
| Available | 1·00 | 0·96, 1·05 | – | – | – | – | ||
| Availability of sweetened coffees and teas in school vending machines | ||||||||
| Unavailable | 1·00 | Ref. | 1·00 | Ref. | 1·00 | Ref. | ||
| Available | 1·05 | 0·99, 1·11 | 1·05* | 1·00, 1·11 | 1·08** | 1·03, 1·13 | ||
| School neighbourhood variables | ||||||||
| Access to restaurants within 1 km buffer of school | ||||||||
| No | 1·00 | Ref. | – | – | ||||
| Yes | 1·03 | 0·96, 1·10 | – | – | ||||
| Access to food store within 1 km buffer of school | ||||||||
| No | 1·00 | Ref. | – | – | ||||
| Yes | 0·99 | 0·92, 1·05 | – | – | ||||
| School-level control variables | ||||||||
| School type | ||||||||
| Public | 1·00 | Ref. | ||||||
| Private | 0·89* | 0·82, 0·98 | ||||||
| Location | ||||||||
| Rural or small population centre | 1·00 | Ref. | ||||||
| Medium urban population centre | 0·94** | 0·90, 0·98 | ||||||
| Large urban population centre | 0·94** | 0·90, 0·98 | ||||||
| Neighbourhood median annual household income | ||||||||
| $CAN 25 000–50 000 | 1·00 | Ref. | ||||||
| $CAN 50 001–75 000 | 0·94 | 0·89, 1·01 | ||||||
| $CAN 75 000+ | 0·93 | 0·86, 1·00 | ||||||
Ref., reference category; –, variable excluded to create a more parsimonious model, since it lacked significance at P<0·2 level.
*P<0·05, **P<0·01, ***P<0·001.
A composite score, ranging from 0 to 15, representing the sum of participants’ weekday rates of consuming soft drinks, sweetened coffees/teas and energy drinks.
Table omits variables that were not significantly associated with outcome in prior univariate analyses and therefore not included in the joint model; columns reflect the model after a given block of variables had been added (i.e. before those lacking significance at P<0·2 were removed).
Rates represents the exponentiated beta coefficients; rates adjusted for all other variables in the column.