Exploring relationships between exposure to fast food outlets and childhood obesity at differing spatial resolutions: results from the Born in Bradford cohort study

Publication authors

Kimon Krenz, Prof Rosemary McEachan, Mikel Subiza-Pérez, Aidan Watmuff, Tiffany Yang, Prof Laura Vaughan



Exposure to fast-food outlets (FFOs) is thought to relate to childhood obesity, but evidence is mixed and might be explained by imprecision in exposure measurement. We explored the effect of these differences by using novel geospatial analysis methods to study obesity rates of children living in a multi-ethnic, deprived location in the north of England.


We included 6260 children enrolled in the Born in Bradford cohort study who had participated in the most recent follow-up (2017–20), aged 6–12 years, and had BMI measurements (n=6260), body fat percentage (BFP; n=5004), and geolocation data for their home address. Informed consent was obtained from parents, and assent from children. Secondary points of interest data were used to classify and geolocate FFOs. We calculated proximity to FFOs using four contrasting methods including street network distance incorporating distance decay. We used linear regressions controlling for socioeconomic characteristics, including sex, age, ethnicity, mother’s physical health, and perceived financial difficulties, with area-level deprivation; and built environment characteristics as controls. Complete data were available for 2883 children with BMI measurements and 2013 with BFP.


We introduced improved spatial precision in the quantification of exposure to FFOs, but this improvement did not lead to substantial differences in associations with BMI, or BFP, when comparing unadjusted associations of BFP and postcode buffers (correlation coefficient 0·08 [95% CI 0·05–0·11]) to BFP and address-based street network distance measurements (0·11 [90% CI 0·07–0·15]). After adjusting for confounders, exposure to FFOs close to home was not associated with an increase in BMI or BFP. Higher BMI was associated with increased maternal BMI (correlation coefficient 0·19 [95% CI 0·17–0·21]) and female sex (0·46 [0·22–0·70]); and comparable associations were observed for higher BFP, with an increased maternal BMI (correlation coefficient 0·40 [95% CI 0·34–0·46]), Pakistani ethnicity (2·89 [1·98–3·80]; reference white British), and female sex (2·90 [2·24–3·57]).


We found no association between proximity to FFOs and obesity in children. Maternal predisposition and behavioural and sociocultural factors have a more important role in the development of childhood obesity. More research is required into the effectiveness of policies that ban FFOs.


UK Medical Research Council, UK Economic and Social Science Research Council, British Heart Foundation, ActEarly UK Prevention Research Partnership Consortium, and the National Institute for Health and Care Research.
KK contributed to the conceptualisation and the study design, the generation of the geospatial data, the formal analysis, and the writing of the Abstract. RM and TY contributed to the study design and the reviewing of the Abstract. MS-P contributed to the reviewing of the Abstract. AW contributed to the acquisition of data and reviewing of the Abstract. LV contributed to the conceptualisation, project supervision, and the writing (reviewing and editing) of the Abstract. All authors have seen and approved the final version of the Abstract for publication.
Declaration of interests
LV is funded by the ActEarly UK Prevention Research Partnership Consortium (MR/S037527/1). RM is funded by the National Institute for Health Research and the ActEarly UK Prevention Research Partnership Consortium (MR/S037527/1). All other authors declare no competing interests.
The Born in Bradford (BiB) Growing Up follow-up was supported by a joint grant from the UK Medical Research Council and UK Economic and Social Science Research Council (MR/N024391/1), and the British Heart Foundation (CS/16/4/32482). The construction of environmental indicators for the BiB cohort was supported by the ActEarly UK Prevention Research Partnership Consortium (MR/S037527/1) and the National Institute for Health and Care Research under its Applied Research Collaboration Yorkshire and Humber (NIHR200166). BiB is only possible because of the enthusiasm and commitment of the children and parents. We thank all the participants, health professionals, schools, and researchers who have made BiB happen. We also thank Ashley Dhanani for his assistance during various stages of the project.