Table 3.

Combined associations of fast-food outlet exposure and genetic risk score for BMI (BMI-GRS) with risk of obesity in the Fenland Study (n = 10,798), Cambridgeshire, UK, estimated using multinomial logistic regression with a single reference group. Overweight results shown in supplementary materials

	Quartiles (Q) of fast-food outlet exposurea
	Q1 (n = 4167)		Q2 (n = 1360)		Q3 (n = 3096)		Q4 (n = 2175)
BMI-GRSb	Obese/normal weight (n), % obesec	RR (95% CI)	Obese/normal weight (n), % obesec	RR (95% CI)	Obese/normal weight (n), % obesec	RR (95% CI)	Obese/normal weight (n), % obesec	RR (95% CI)
Low (n = 5399)	392/836, 19.1	REF	122/286, 18.2	1.08d,e (0.83, 1.40)	308/620, 19.9	1.21d,e (0.99, 1.48)	179/555, 16.0	1.73d,e (1.27, 2.35)**
High (n = 5399)	559/682, 26.5	1.84d,e (1.55, 2.19)**	158/247, 22.9	1.54d,e (1.20, 1.98)*	413/493, 26.7	2.20d,e (1.81, 2.68)**	214/416, 20.3	2.70d,e (1.99, 3.66)**

*P < 0.05; **P < 0.001

^aHome neighbourhood fast-food outlet exposure, quartiles (Q): Q1 (least exposed) = 0–1 outlets; Q2 = 2; Q3 = 3–14; Q4 (most exposed) = 15–51. Quartiles are unequal in sample size due to the distribution of the underlying data

^bBMI-GRS, two groups split by sample median: low ≤ 2.29; high > 2.29

^cPercent obese as a proportion of all participants, including those normal weight, overweight, and obese

^dAdjusts for age, sex, household income, highest educational attainment, car access, smoking status, physical activity energy expenditure, counts of supermarkets in home neighbourhoods

^eRRs relative to a single reference group (REF): those least exposed to fast-food outlets (Q1) and at lower BMI-GRS (low)