Table shows that in all LSOAs, the rates for fast food outlets and supermarkets were generally positively associated with area deprivation, higher in the more deprived areas than least deprived areas (with a tail-off for supermarkets in the most deprived areas). In contrast, the rates for outdoor physical activity facilities were higher in the least deprived areas than more deprived areas. A gradient was not observed for the relationship between indoor physical activity facilities and area deprivation quintiles, but these were less common in the most deprived areas. As Whites lived in all LSOAs, these patterns hold for the White group but not necessarily for the other ethnic groups.
Mean number of facilities per 10,000 population (95% Confidence interval) by area deprivation quintile
Table shows ethnic population sizes and ethnic concentration tertiles by area deprivation quintiles. Regardless of concentration tertile, ethnic minorities were least likely to be in the less deprived quintiles 1 and 2 than in the other deprivation quintiles. Clustering in the most deprived quintile was greatest for Bangladeshis, Pakistanis, Black African and Black Caribbeans in each concentration tertile.
Percentages of ethnic population by ethnic concentration tertile and area deprivation quintile
Table shows the rates of provision for fast food outlets, supermarkets, indoor and outdoor physical activity facilities by ethnic concentration tertile. For the White British group, the rate of provision of fast food outlets decreased while that of indoor and outdoor physical activity facilities increased with increasing concentration. Generally for ethnic minority groups, the rates for fast food outlets, supermarkets, outdoor and indoor physical activity facilities increased with ethnic concentration. There was one exception; the rates for supermarkets did not vary by Black Caribbean concentration levels. There were two exceptions to these patterns when counts were based on resident and contiguous LSOAs (table not shown). For Black Caribbeans, the rates of fast food outlets did not vary by ethnic concentration, and for Chinese the rate of fast food outlets were highest in the moderate concentration areas. The mean number of fast food outlets /10,000 population for low, moderate and high Black Caribbean concentration areas were respectively: 5.2 (95% confidence interval 4.9-5.4); 5.6(5.3-5.8), 5.3 (5.0-5.5) and for Chinese 4.7 (4.5-5.0), 5.6(5.3-5.9), 5.0(4.8-5.2).
Mean number of facilities per 10,000 population (95% Confidence Interval) by ethnic concentration tertile
In high ethnic concentration areas, the rates for fast food outlets, supermarkets and indoor physical activity areas were generally greater for ethnic minority groups than for the White British group. This pattern was also largely consistent for fast food outlets at moderate ethnic minority concentrations. Among the South Asian groups (Indians, Pakistanis, Bangladeshis) the rate for fast food outlets in high concentration areas was greatest for Bangladeshis. In every concentration tertile, rates for outdoor physical activity facilities were generally lower for ethnic minority groups than the White British group.
Table shows rate ratios for facilities by ethnic concentration (low ethnic concentration
baseline rate), adjusted for clustering of LSOAs within local authorities, population size and area deprivation. The patterns largely correspond with those in Table . For ethnic minority groups, rate ratios for both fast food outlets and supermarkets increased with increasing ethnic concentration. The relative difference between low and high own concentration tertiles appeared largest for the Chinese and smallest for Black Caribbeans. For Whites, after adjustment for area deprivation, supermarkets were more likely and fast food outlets less likely, to be present in the moderate and high concentration areas than in low concentration areas. Adjusting for urban rural classification did not change these results (results not presented).
Rate ratios (95% Confidence Interval) of facilities by ethnic concentration adjusted for area deprivationb
For physical activity facilities, multilevel modelling (accounting for clustering of LSOAs within LA) changed the direction of the results shown in table . Table shows that for indoor physical activity facilities, there was no association between density of facilities and ethnic concentration among the White British, Black Caribbean and Bangladeshis. For outdoor physical activity facilities, there was no association between density of facilities and Indian concentration, but facilities were less likely to be found in high than low ethnic concentration areas for Black Caribbeans, Pakistanis and Bangladeshis. Differences in the distribution of the facilities within LSOAs, and across LSOAs within LAs were, therefore, an important influence. For some ethnic groups variation in the outdoor/indoor physical activity facilities in the LSOAs may be due more to the level of provision throughout the LAs rather than ethnic concentration in specific LSOAs. Table shows the corresponding rate ratios using a count of food outlets and PA facilities in the resident and contiguous LSOAs. The trends in rate ratios were similar to those in Table . The notable exceptions were for the White group and for outdoor PA. The density of supermarkets decreased, and the density of outdoor PA did not increase linearly with White concentration. For the Black African, Chinese and Irish groups, the density of outdoor physical activity decreased with increasing ethnic concentration.
Rate ratio (95% Confidence Interval) adjusted for area deprivation, using counts in resident and contiguous LSOAsb
There was some area variation at local authority level for fast food outlets, indoor and outdoor physical activity facilities, ranging from 0.04, 95% confidence interval, 0.03-0.05 (MRR
1.22) for indoor physical activity facilities among White British to 0.36, 0.29-0.42 (MRR
1.76) for outdoor physical activity facilities among Bangladeshis. However, there was no significant area variation associated with supermarkets.
After adjusting for ethnic concentration, area deprivation remained independently and positively associated with fast food outlets and supermarkets across all ethnic groups (Additional file 1
: Table S1). It was inversely associated with outdoor physical activity facilities across all ethnic groups. In contrast to the descriptive patterns in table , it was also independently and inversely associated with indoor physical activity facilities for all ethnic groups but Whites.
Interactions between deprivation and ethnic concentration were examined for all facilities (data not shown). Although the prevalence of fast food outlets increased with increasing deprivation among Black Caribbeans, Indians, Bangladeshis and Irish groups, there was no clear pattern by ethnic concentration in the least deprived 80%. In the most deprived quintile there were clear gradients with about twice as many fast food outlets per head of population in high concentration areas relative to low concentration areas. Similarly, in the most deprived quintile, supermarkets were more prevalent in areas with high concentration than with moderate or low concentration of Black Africans, Bangladeshis or Irish.
We conducted a sensitivity analysis to examine if the selection of specific food outlets underestimated the exposure to fast food outlets or supermarkets. Using the Points of Interest data for London, we examined the density of all fast food outlets and ‘take aways’, shops that were labeled as selling ‘Fried Chicken’, and all supermarkets, by ethnic concentration. The variation of the rates by ethnic concentration tertiles were similar to those shown in Table . For example, the mean number/10,000 population of fast food outlets and ‘take aways’ for low and high concentration were respectively: White British 12.01 (95% confidence interval 10.98- 13.05), 11.90 (9.98- 13.81); Black Africans 8.55 (7.65- 9.45), 13.59 (11.77-15.42); Black Caribbean 10.29 (9.12-11.46), 12.72(10.93-14.50); Indian 8.97 (8.13-9.82), 14.09(12.25-15.94); Pakistani 10.25 (9.06-11.44), 14.82 (12.74-16.89); Bangladeshi 10.49 (9.32-11.66), 15.05(12.68-17.41); Chinese 10.49 (9.32- 11.66), 15.05 (12.68- 17.41), and Irish 9.55 (8.64-10.47), 13.38 (11.51-15.25).