Table 3. Interrupted time series for change in mean calories and nutrients purchased per transaction after restaurant calorie labeling implementation (April 2017) and after nationwide calorie labeling implementation (May 2018) by median income of restaurant census tracts1.
| β (95% CI)2 | |||||||
|---|---|---|---|---|---|---|---|
| Nutrient | Baseline level | Baseline trend3 | Franchise level change4 | Franchise trend change5 | Nationwide level change6 | Nationwide trend change7 | Estimated change at end of study8 |
| Calories | |||||||
| Lower income | 1,429 (1,391, 1,466) | 1.8 (1.2, 2.4) | −48 (−62, −34) | 4.0 (3.0, 5.0) | −82 (−91, −73) | −2.2 (−3.4, −1.1) | −49 (−59, −39) |
| Higher income | 1,457 (1,407, 1,507) | 2.4 (1.3, 3.5) | −60 (−81, −40) | 2.6 (1.4, 3.9) | −82 (−90, −73) | −2.0 (−3.1, −0.8) | −95 (−107, −85) |
| Fat (g) | |||||||
| Lower income | 61.4 (59.6, 63.2) | 0.0 (0.0, 0.0) | −0.6 (−1.4, 0.1) | 0.2 (0.1, 0.2) | −2.5 (−3.0, −2.0) | −0.1 (−0.2, −0.1) | −0.9 (−1.4, −0.4) |
| Higher income | 63.2 (60.6, 65.8) | 0.0 (0.0, 0.1) | −1.8 (−3.0, −0.5) | 0.1 (0.0, 0.2) | −2.4 (−2.8, −2.0) | −0.1 (−0.2, −0.1) | −2.9 (−3.5, −2.3) |
| Carbohydrates (g) | |||||||
| Lower income | 174.9 (170.7, 179.2) | 0.4 (0.3, 0.5) | −9.8 (−11.2, −8.4) | 0.6 (0.5, 0.7) | −9.3 (−10.3, −8.2) | −0.2 (−0.4, −0.1) | −6.6 (−8.0, −5.4) |
| Higher income | 177.0 (171.7, 182.3) | 0.5 (0.4, 0.6) | −10.5 (−12.3, −8.6) | 0.3 (0.2, 0.5) | −10.1 (−11.2, −9.1) | −0.1 (−0.3, 0.0) | −13.1 (−14.3, −11.8) |
| Protein (g) | |||||||
| Lower income | 47.9 (46.3, 49.5) | 0.0 (0.0, 0.1) | 0.0 (−0.6, 0.7) | 0.0 (−0.1, 0.0) | −2.7 (−3.0, −2.4) | 0.1 (0.1, 0.1) | −2.3 (−2.6, −1.9) |
| Higher income | 49.2 (47.1, 51.3) | 0.0 (0.0, 0.1) | −0.2 (−1.0, 0.7) | −0.1 (−0.1, 0.0) | −2.4 (−2.7, −2.0) | 0.1 (0.0, 0.1) | −3.0 (−3.4, −2.6) |
| Saturated fat (g) | |||||||
| Lower income | 19.9 (19.2, 20.5) | 0.0 (0.0, 0.0) | −0.2 (−0.5, 0.1) | 0.1 (0.0, 0.1) | −1.5 (−1.7, −1.4) | 0.0 (0.0, 0.0) | 0.0 (−0.2, 0.1) |
| Higher income | 20.6 (19.7, 21.4) | 0.0 (0.0, 0.0) | −0.6 (−1.2, −0.1) | 0.1 (0.0, 0.1) | −1.4 (−1.5, −1.2) | 0.0 (−0.1, 0.0) | −0.7 (−0.9, −0.5) |
| Sugar (g) | |||||||
| Lower income | 65.7 (63.5, 68.0) | 0.1 (0.1, 0.2) | −1.7 (−2.5, −0.9) | 0.0 (−0.1, 0.1) | −0.5 (−1.0, 0.0) | −0.1 (−0.2, 0.0) | −3.6 (−4.2, −2.9) |
| Higher income | 64.4 (62.5, 66.2) | 0.2 (0.1, 0.2) | −2.0 (−2.7, −1.4) | −0.1 (−0.1, 0.0) | −1.6 (−2.1, −1.1) | −0.1 (−0.1, 0.0) | −6.6 (−7.1, −6.0) |
| Fiber (g) | |||||||
| Lower income | 15.6 (15.2, 16.0) | 0.0 (0.0, 0.0) | −0.6 (−0.7, −0.4) | 0.0 (0.0, 0.0) | −0.9 (−0.9, −0.8) | 0.1 (0.0, 0.1) | −0.6 (−0.7, −0.4) |
| Higher income | 15.9 (15.4, 16.4) | 0.0 (0.0, 0.1) | −0.5 (−0.7, −0.3) | 0.0 (0.0, 0.0) | −0.9 (−1.0, −0.8) | 0.1 (0.0, 0.1) | −1.0 (−1.2, −0.9) |
| Sodium (mg) | |||||||
| Lower income | 2,698 (2,610, 2,787) | 4.5 (3.0, 5.9) | −75 (−121, −30) | 1.6 (−0.5, 3.7) | −221 (−245, −196) | 10.2 (8.0, 12.3) | −117 (−140, −95) |
| Higher income | 2,796 (2,671, 2,920) | 5.2 (2.2, 8.1) | −92 (−142, −41) | −0.5 (−4.7, 3.7) | −199 (−217, −182) | 9.1 (5.6, 12.7) | −184 (−211, −156) |
1Lower-income census tracts had a median income <$50,329, and higher-income census tracts had a median income >$50,329. In the US, a census tract is a small geographic unit (typically having a population size between 1,200 and 8,000 people) for which population-level demographic data are available [23].
2Adjusted for season and holidays (spring [ref], summer, fall, holidays [week of Thanksgiving to week of New Year’s], winter).
3Baseline trend (per 4-week period from April 2015 to April 2017).
4Level change after franchise labeling in April 2017.
5Trend change (per 4-week period) after franchise labeling in April 2017.
6Level change after nationwide labeling in May 2018.
7Trend change (per 4-week period) after nationwide labeling in May 2018.
8To 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.