Skip to main content
. 2015 Mar 31;181(9):661–671. doi: 10.1093/aje/kwu317

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.