Table 1:

Characteristics and effect sizes of studies included in the meta-analysis

Author Year		Data Collection Year	Country	Sample Size	Sample Age	Outlet Density Buffer Distance (km)	Controls	Outlet Density Measure^a	Distribution of Outlet Density^b	OR (95% CI)^c
Homes
	Novak (2006)¹⁶	1995–1999	USA	2,116	11–23^d	0.43^e	Minor status, age, race/ethnicity, gender, parental education, commercial land use, neighborhood racial composition, and neighborhood poverty	Trend	M = 7.1	1.21 (1.04, 1.40)
	Adachi-Mejia (2012)²²	2007	USA	1,263	13–18	0.80	Age, race/ethnicity, SES, sibling smoking, friend smoking, exposure to movie smoking, team sport participation, sensation seeking, tobacco outlet proximity, and proportion of community population Black, Hispanic, and families with income below the poverty level	Trend	Median =.34	1.11 (0.70, 1.79)
	Lipperman-Kreda (2014)¹⁴	2010	USA	832	13–18	1.21	Gender, race/ethnicity, age, population density, median family income, and city % of minors <18 years, % African Americans, % Hispanic, % college educated, and % unemployed	Trend	M = 3.88 SD = 5.24 Range = 0–37.20	1.08 (1.01, 1.16)
	Shortt (2016)¹⁸	2010	Scotland	20,446	13–15	0.80	Age group, sex, ethnicity, received free school meals, perceived family wealth, family structure, parental smoking status, rurality, and Carstairs deprivation score	Trend	Range = 0- >5.63	1.06 (1.00, 1.12)
Schools
	Leatherdale (2007)¹	2001–2002	Canada	19,464	14–18	1.00	Gender, age, parent smoking, older sibling smoking, ever smoked with family member, 5 closest friends smoking, and school student smoking rate	Trend	M = 6.3 Range = 1–13	1.01 (0.99, 1.03)
	McCarthy (2009)¹⁵	2003–2004	USA	19,306	M = 14.9	1.61	Age, gender, race/ethnicity, English-language use in the home, grades, peer smoking, friends’ smoking, ease of obtaining cigarettes, depressive symptoms, school type, school rurality, and school-level parental education	Trend	M = 10.8 SD = 8.9	1.11 (1.02, 1.21)
	Chan (2011)¹³	2005–2006	Canada	22,764	9–12 grade	1.00	Grade, gender, older sibling smoking, parent smoking, up to 5 closest friends smoking, and neighborhood disadvantage	Trend	M = 2.68 Range = 0–16	0.99 (0.97, 1.01)
	Adams (2013)¹⁹	2002	USA	9,704	7–10 grade	0.80	Sex, race/ethnicity, grade, illegal tobacco sales rate, median neighborhood income, and mean neighborhood density	Trend	M = 2.76 SD = 2.45 Range = 0–9	1.04 (0.95, 1.14)
	Scully (2013)²⁰	2008	Australia	2,044	12–17	0.50	Age, sex, personal spending money, perceived ease of buying cigarettes, smoking status of parents/caretakers, and neighborhood SES	Trend	M = 2.37 SD = 1.65 Range = 0–7	1.06 (0.90, 1.25)
	Lipperman-Kreda (2014)¹⁴	2010	USA	832	13–18	1.21	Gender, race/ethnicity, age, population density, median family income, and city % of minors <18 years, % African Americans, % Hispanic, % college educated, % unemployed	Trend	M = 4.97 SD = 5.45 Range = 0–44.62	1.02 (0.93, 1.11)
	Mistry (2015)²³	2010	India	1,320	8–10 grade	0.50	Age, gender, religion, monthly receipt of pocket money, hopelessness, ease of access to tobacco, parental tobacco use, peer tobacco use, and school annual fee	Low vs high density	M = 60.0 SD = 43.9 Range = 2–199	1.99 (0.92, 4.33)^f
	Marsh (2016)³	2012	New Zealand	27,238	14–15	1.00	Sex, age, ethnicity, family smoking, peer smoking, school decile, and school location	Zero vs high density	Median = 2	0.94 (0.82, 1.07)
	Shortt (2016)¹⁸	2010	Scotland	20,446	13–15	0.80	Age group, sex, ethnicity, received free school meals, perceived family wealth, family structure, parental smoking status, rurality, and Carstairs deprivation score	Trend	Range = 0- >6.72	0.98 (0.92, 1.04)

This column represents how the number of tobacco outlets was measured. Most studies used a count measure in which higher scores indicted a greater number of outlets (trend). Some studies compared zero/low vs high density areas.

These values represent descriptive statistics of tobacco outlet density provided in each study. These values may not be directly comparable due to differences in density and buffer size conceptualizations. Please refer to the “Outlet Density Buffer Distance” and “Outlet Density Measure” columns for more information about how to interpret these values.

These values represent adjusted ORs by the controls listed in the “Controls” column.

Although the age range extended beyond our initial cutoff of 18 years old, legal age to purchase cigarettes did not significantly influence the association between tobacco outlet density and current smoking.

We calculated the average census tract distance from the city in which the study was conducted to represent the outlet density catchment distance.

This study outcome included both smoked and non-smoked tobacco products.