Are price discounts on sugar-sweetened beverages (SSB) linked to household SSB purchases? – a cross-sectional study in a large US household and retail scanner database

Table 4 Association between sugar sweetened beverages annual price promotion and per capita purchase ^a

	Association between annual promotion frequency × 10 and annual per capita purchase ^d		Association between annual promotion magnitude × 100 and annual per capita purchase ^e
Section A. Overall association between price promotion and per capita purchase
	Exp Estimate (95% CI)	P-value	Exp Estimate (95% CI)	P-value
Overall	1.137 (1.123–1.151)	<0.0001	1.153 (1.137–1.169)	<0.0001
Section B. Association between price promotion and per capita purchase stratified by income per capita, female head education and race
	Exp Estimate (95% CI)	Interaction P-value	Exp Estimate (95% CI)	Interaction P-value
Income per capita ^b
≤ $15,000	1.127 (1.096–1.160)	0.7777	1.138 (1.102–1.175)	0.7517
$15,001 - $30,000	1.144 (1.122–1.167)		1.156 (1.131–1.182)
$30,001 - $50,000	1.141 (1.115–1.168)		1.162 (1.132–1.193)
≥ $50,000	1.129 (1.100–1.159)		1.147 (1.112–1.182)
Female head education ^b,c
High School or Less	1.148 (1.119–1.179)	0.4783	1.168 (1.135–1.201)	0.2954
Some College	1.139 (1.113–1.166)		1.147 (1.117–1.178)
College Grad	1.127 (1.106–1.147)		1.141 (1.118–1.165)
No Female Head	1.157 (1.116–1.199)		1.186 (1.137–1.237)
Race ^b
White	1.138 (1.122–1.153)	0.9963	1.148 (1.131–1.165)	0.2625
Black	1.138 (1.093–1.185)		1.191 (1.129–1.257)
Other	1.135 (1.089–1.184)		1.184 (1.121–1.250)

^aOrdinary least squares linear regression was used. The outcome, annual per capita purchase, was log transformed. Models adjusted for household size, household income per capita, male head age, female head age, male head education, female head education, presence of children, race, male head occupation, female head occupation, region, and urban/rural setting.
^bEstimates were obtained using the main effect (e.g., promotion magnitude) and interaction terms.
^cEducation was specific to female-head and male-head. Female head education was selected as a socioeconomic status indicator because women are typically the primary grocery shoppers and food preparers. (Citation: Crane et al. Nutr Educ Behav. 2019;51 (2):199–204.)
^dAnnual promotion frequency was calculated as: $ \frac{Weeks\ experiencing\ge 5\% magnitude\ of\ price\ promotion\ for\ the\ household}{Number\ of\ weeks\ in\ 2016} $. An exponentiated coefficient of 1.137 can be interpreted as 10 percentage points increase in annual promotion frequency is associated with 13.7% higher annual per capita purchase.
^eAnnual promotion magnitude was calculated as: $ \frac{\sum_{i=1}^{number\ of\ weeks\ in\ 2016} Promotion\ magnitude\ for\ the\ household\ in\ week\ i}{Number\ of\ weeks\ in\ 2016} $. An exponentiated coefficient of 1.153 can be interpreted as a 1 percentage point increase in annual promotion magnitude is associated with 15.3% higher annual per capita purchase.

ISSN: 1475-2891