Table 3.
Associations Between Lagged Market-Level Instrumental Variables and Lagged Outcomes and Exposures in Single-Person Adult Households That Comprised the Study Population, Homescan Survey, 2000–2010a
| Lagged Instrumental Variableb | Lagged Endogenous Exposuresb in the Dynamic Panel Models, servings/day |
Lagged Outcome Variablesb in the Dynamic Panel Models, kcal/day |
||||
|---|---|---|---|---|---|---|
| LCS Beverages | CS Beverages | Total Energy | Total Energy Excluding LCS/CS Beverages | Total Beverages Excluding LCS/CS Beverages | Total Energy From Food | |
| Average prices, $ | ||||||
| Food price index per 100 g | −0.00090 (0.00087) | −0.00080 (0.00077) | −1.46138 (0.99770) | −1.37329 (0.96991) | −0.75704 (0.22817)c | −0.61481 (0.89496) |
| LCS beverage price per 100 mL | 0.52942 (0.34428) | 0.14600 (0.30687) | 333.84320 (395.64580) | 219.28940 (384.62350) | 109.74910 (90.48177) | 110.63400 (354.90260) |
| CS beverage price per 100 mL | −0.29223 (0.96174) | 0.61266 (0.85719) | 1506.79700 (1105.16800) | 1167.58100 (1074.37500) | 657.44210 (252.73670)c | 504.60710 (991.35250) |
| P valued,e | 0.150 | 0.777 | 0.504 | 0.569 | 0.011 | 0.924 |
| Average household purchases/year, $ | ||||||
| Total food | −0.00004 (0.00003) | −0.00010 (0.00003)c | 0.08474 (0.03846)c | 0.09587 (0.03738)c | −0.01517 (0.00879) | 0.11114 (0.03449)c |
| Total beverages | −0.00022 (0.00011)c | 0.00012 (0.00010) | −0.22801 (0.12904) | −0.21344 (0.12542) | 0.11441 (0.02947)c | −0.32580 (0.11572)c |
| Total LCS/CS beverages | 0.00117 (0.00025)c | 0.00047 (0.00022)c | 0.14505 (0.28738) | 0.12068 (0.27935) | −0.18146 (0.06566)c | 0.30224 (0.25774) |
| P valued,e | 0.001 | 0.006 | 0.086 | 0.034 | 0.004 | 0.001 |
| Average no. of household grocery trips/year | 0.00126 (0.00067) | −0.00019 (0.00060) | 3.46010 (0.76735)c | 3.44305 (0.74592)c | 1.03024 (0.17536)c | |
| P valued,f | 0.059 | 0.755 | <0.001 | <0.001 | <0.001 | 0.005 |
| % of market sales | ||||||
| LCS beverage purchases | 0.00565 (0.00108)c | −0.00064 (0.00096) | 0.53795 (1.24340) | 0.69859 (1.20873) | −0.17449 (0.28431) | 0.87125 (1.11531) |
| CS beverage purchases | 0.00071 (0.00110) | 0.00261 (0.00098)c | 0.79737 (1.26644) | 0.51711 (1.23114) | 0.44346 (0.28957) | 0.07739 (1.13599) |
| P valued,g | <0.001 | <0.001 | 0.820 | 0.846 | 0.015 | 0.575 |
| P valueh,i | <0.001 | 0.003 | 0.002 | <0.001 | <0.001 | 0.002 |
Abbreviations: CS beverages, beverages flavored with caloric sweeteners; LCS beverages, beverages flavored with low-calorie sweeteners.
a Values are expressed as β (standard error) and were obtained from longitudinal random-effects models that were adjusted for year, market, sex, age, race/ethnicity, educational level, and income.
b The first lagged value was used.
c Significant at P < 0.05.
d P value for the χ2 joint test of significance for each group of instrumental variables.
e Three degrees of freedom.
f One degree of freedom.
g Two degrees of freedom.
h P value for the χ2 joint test of significance for all instrumental variables.
i Nine degrees of freedom.