Table 2. Interrupted time series for change in mean calories and mean nutrients purchased per transaction after franchise calorie labeling implementation (April 2017) and after nationwide calorie labeling implementation (May 2018).
| β (95% CI)1 | |||||||
|---|---|---|---|---|---|---|---|
| Nutrient | Baseline level | Baseline trend2 | Franchise level change3 | Franchise trend change4 | Nationwide level change5 | Nationwide trend change6 | Estimated change at end of study7 |
| Calories per transaction | 1,443 (1,411, 1,474) | 2.1 (1.5, 2.7) | −54 (−67, −42) | 3.3 (2.5, 4.1) | −82 (−88, −76) | −2.1 (−2.9, −1.3) | −73 (−81, −65) |
| Absolute nutrient content per transaction | |||||||
| Fat (g) | 62.3 (60.7, 63.9) | 0.0 (0.0, 0.1) | −1.2 (−2.0, −0.5) | 0.1 (0.1, 0.2) | −2.5 (−2.8, −2.2) | −0.1 (−0.2, −0.1) | −1.9 (−2.3, −1.5) |
| Carbohydrates (g) | 175.9 (172.6, 179.3) | 0.4 (0.4, 0.5) | −10.1 (−11.3, −9.0) | 0.5 (0.4, 0.5) | −9.7 (−10.4, −9.0) | −0.2 (−0.3, −0.1) | −9.9 (−10.8, −8.9) |
| Protein (g) | 48.6 (47.3, 49.9) | 0.0 (0.0, 0.1) | −0.1 (−0.6, 0.5) | 0.0 (−0.1, 0.0) | −2.5 (−2.8, −2.3) | 0.1 (0.1, 0.1) | −2.6 (−2.9, −2.3) |
| Saturated fat (g) | 20.2 (19.7, 20.8) | 0.0 (0.0, 0.0) | −0.4 (−0.7, −0.1) | 0.1 (0.1, 0.1) | −1.5 (−1.6, −1.4) | 0.0 (0.0, 0.0) | −0.4 (−0.5, −0.2) |
| Sugar (g) | 65.0 (63.6, 66.5) | 0.2 (0.1, 0.2) | −1.9 (−2.4, −1.4) | 0.0 (−0.1, 0.0) | −1.1 (−1.4, −0.7) | −0.1 (−0.1, 0.0) | −5.1 (−5.5, −4.7) |
| Fiber (g) | 15.7 (15.4, 16.0) | 0.0 (0.0, 0.1) | −0.5 (−0.7, −0.4) | 0.0 (0.0, 0.0) | −0.9 (−0.9, −0.8) | 0.1 (0.1, 0.1) | −0.8 (−0.9, −0.7) |
| Sodium (mg) | 2747 (2671, 2823) | 4.8 (3.1, 6.5) | −84 (−117, −50) | 0.5 (−1.8, 2.9) | −210 (−225, −195) | 9.6 (7.6, 11.7) | −151 (−168, −134) |
1Adjusted for season and holidays (spring [ref], summer, fall, holidays [week of Thanksgiving to week of New Year’s], winter).
2Baseline trend (per 4-week period from April 2015 to April 2017).
3Level change after franchise labeling in April 2017.
4Trend change (per 4-week period) after franchise labeling in April 2017.
5Level change after nationwide labeling in May 2018.
6Trend change (per 4-week period) after nationwide labeling in May 2018.
7To estimate the overall association at the end of the study, we calculated the predicted counterfactual value in the last week (i.e., a model that included only the baseline level, baseline trend, and seasonal covariates), subtracted this from the predicted actual value in the last week (i.e., a model that included the baseline level, baseline trend, all level and trend changes, and seasonal covariates), and calculated 95% CIs from 1,000 bootstrapped samples.
CI, confidence interval.