摘要：Objectives. We examined the associations of fast food restaurant (FFR) availability with dietary intake and weight among African Americans in the southeastern United States. Methods. We investigated cross-sectional associations of FFR availability with dietary intake and body mass index (BMI) and waist circumference in 4740 African American Jackson Heart Study participants (55.2 ±12.6 years, 63.3% women). We estimated FFR availability using circular buffers with differing radii centered at each participant's geocoded residential location. Results. We observed no consistent associations between FFR availability and BMI or waist circumference. Greater FFR availability was associated with higher energy intake among men and women younger than 55 years, even after adjustment for individual socioeconomic status. For each standard deviation increase in 5-mile FFR availability, the energy intake increased by 138 kilocalories (confidence interval [CI] = 70.53, 204.75) for men and 58 kilocalories (CI = 8.55, 105.97) for women. We observed similar associations for the 2-mile FFR availability, especially in men. FFR availability was also unexpectedly positively associated with total fiber intake. Conclusions. FFR availability may contribute to greater energy intake in younger African Americans who are also more likely to consume fast food. The ecological determinants of the obesity epidemic have received increased attention over the past decade. 1 – 4 Obesogenic environments are thought to promote high energy intake through the greater availability and low price of energy-dense foods, 4 , 5 to discourage physical activity through the lack of resources for exercise and because of safety concerns, 6 – 7 and to contain urban design and transportation features that limit opportunities to walk in daily life. 8 , 9 The local food environment, 10 – 14 particularly the availability of inexpensive, energy-dense, high-fat, and low dietary micronutrient (e.g., fiber, magnesium, and potassium) foods, as proxied by the availability of fast food, 13 – 16 is 1 aspect that has received increasing attention, especially in low-income and minority communities. There is growing evidence that Americans are consuming increasing numbers of meals away from home. 17 Many of these meals are fast food. US fast food sales have grown 7-fold, from $16.2 billion in 1975 to an estimated $110 billion in 2004. 18 Increased consumption of fast foods has been linked to an unhealthy diet 15 , 16 , 19 – 25 and higher weight and body mass index (BMI). 15 , 16 , 20 , 26 – 29 A number of epidemiological studies have demonstrated that the availability of fast food restaurants (FFRs) is cross-sectionally associated with weight outcomes, after adjusting for demographic characteristics, socioeconomic status (SES), and behavioral factors. 13 , 14 , 30 – 33 However, findings have been inconsistent; some studies have reported no association between FFR availability and BMI, 15 , 34 , 35 and at least 1 has reported an inverse association of the availability of FFRs with BMI. 36 Differences in the geographic areas for which FFR availability is measured (ranging from buffer zones centered at residential locations 15 to counties and states 30 , 33 ) and in the measures of FFR availability (ranging from simple counts within buffer zones 15 to state-level density measures 30 , 33 ) make comparisons across studies difficult. Moreover, a few studies have been ecological and, thus, not able to account for individual-level confounders. 30 , 33 Mississippi is the US state with the highest obesity prevalence. 37 High levels of poverty and the high proportion of African American residents (both factors associated with higher obesity rates 2 , 4 ) make it an ideal setting in which to examine associations of FFR availability with dietary and weight outcomes. African Americans often live in areas with high exposure to fast food. 38 – 41 The low cost of fast food and its practicality, palatability, and convenience makes it an attractive option. However, few studies of FFR availability, dietary intake, and weight have included large representations of African Americans or have specifically focused on high-risk areas such as Mississippi. To examine the cross-sectional associations of FFR availability with dietary intake, BMI, and waist circumference, we used data from the Jackson Heart Study (JHS), a large population-based cohort study of more than 5000 African Americans with a high prevalence of obesity and related disorders.
