The demographics of the census tracts included in this study (Table ) resulted in near identical averages for African Americans (29%; standard deviation [SD]

=

32), Hispanics (28%; SD

=

31), and White residents (33%; SD

=

32). The socioeconomic characteristics of the tracts were as follows: male unemployment rate of 6%, household poverty rate of 21%, households receiving public assistance of 7%, and median household income of $35,632. These rates differ from the average demographic characteristics of census tracts in Los Angeles County and New Orleans Metropolitan Statistical Areas (MSA) substantially. More modest differences were observed between sample census tract averages and socioeconomic characteristics of the populations in Los Angeles County and the New Orleans MSA.
Descriptive statistics on alcohol shelf space, outlet, and price availability and community characteristics are reported in Table . Total shelf space availability varied substantially by census tract with a low of 5 ft in one tract and to a high of 397 ft. On average, a plurality of shelf space availability was accounted for by regular beer, followed by distilled spirits, and malt liquor. For outlet availability, on average, there was one outlet for every 2 roadway miles.
| TABLE 2Shelf space and outlets per tract alcohol availability for study census tracts (n = 187) |
In bivariate analyses that examined the associations between community characteristics and various alcohol availability levels, a large number of statistically significant associations were observed (Table ). Total shelf space availability was inversely associated with socioeconomic measures (percentages of families in poverty, households receiving public assistance, and male unemployment rates). On the other hand, as percent White and median household income increased, so did shelf space. Reflecting in part that shelf space is dominated by beer beverages, the associations between beer shelf space and socioeconomic and sociodemographic measures were the same as those observed for total shelf space with the exception that percent Hispanic was also inversely associated with beer shelf space. In contrast, malt liquor shelf space tended to increase as socioeconomic conditions worsened. Demographically, as malt liquor shelf space increased, so too did the percent African American whereas percent White was inversely associated with malt liquor shelf space. For distilled spirit shelf space, only one community variable, percent African American, was associated with this measure.
| TABLE 3Pearson’s correlations coefficients of alcohol availability measures by census tract level community sociodemographic and socioeconomic characteristics (n = 187) |
We also examined per capita shelf space. We found that per capita (per thousand) shelf space was associated only with percent household receiving public assistance. Differences in beverage type shelf space availability were also found with per capita beer shelf space being inversely associated with percent of households receiving public assistance and percent Hispanic, but being positively associated with percent White. In contrast, malt liquor shelf space was positively associated with percent of families in poverty and percent African American, and inversely associated with median income and percent White. No community characteristics predicted distilled spirit availability.
In bivariate analyses of outlet availability, we found that outlets per roadway mile were positively associated with percent of families in poverty, male unemployment rate, households receiving public assistance, and Hispanic population. Outlets per roadway mile declined as median household income and percent White increased. For outlets per capita, percent of families in poverty and percent African American were positively associated with per capita outlets, whereas median household income and percent Hispanic were inversely associated with per capita outlets. For the total number of outlets, percent of families in poverty and percent African American were positively associated with number of outlets, and median household income was inversely associated with this measure.
In terms of least price, we found that beer prices were inversely associated with percent African American only. Malt liquor prices were also inversely associated with percent African American, but positively associated with percent White. For wine price, percent Hispanic was positively associated with wine price whereas percent African American were inversely associated with wine price. No community characteristics were associated with distilled spirit prices. We next constructed multivariate models for the dependent variables that seemed most promising—total shelf space measures, beverage-specific shelf space, outlets per roadway mile, and beverage-specific least prices. In models that controlled for state and considered community characteristics (excluding household receiving public assistance and median household income because of collinearity), relatively few significant associations were found (Table ). For instance, male unemployment rate was inversely associated with total shelf space (
b
=

−3.41;
p
=

0.03) and distilled spirit shelf space (
b
=

−4.02;
p
=

0.05). For malt liquor, percent White was inversely associated with malt liquor shelf space (
b
=

−0.89;
p
=

0.02). For outlets per roadway mile, we found that percent of families in poverty was positively associated with more outlets (
b
=

1.06;
p
<

0.0001), whereas African American percent was inversely associated with outlets (
b
=

−0.35;
p
=

0.03). Figures and show the plots for male unemployment rate by total shelf space (Figure ) and percent households in poverty by outlets per roadway mile with regression lines (Figure ) to better illustrate these key associations.
| TABLE 4Coefficients and p value of community characteristics by alcohol availability types at the census tract level using linear regression with multiple imputation |
In terms of price, no community characteristics were associated with least price, although California was associated with lower beer shelf space (
b
=

−0.44;
p
=

0.02) and higher wine prices (
b
=

0.46;
p
<

0.01). In separate analyses by state, beer price in California was found to have a significant association with any community characteristic (percent White,
b
=

0.37;
p
=

0.05; data not shown). In Louisiana, distilled spirit least price was positively associated with male unemployment rate (
b
=

2.93;
p
=

0.02; data not shown).