Table 3. Relative versus absolute risk reduction across BMI categories.

Measure	Non-overweight (BMI < 25 kg/m2)	Overweight (25 ≤ BMI < 30 kg/m2)	Obese (BMI ≥ 30 kg/m2)
Relative odds ratio, from Mendelian randomization (β)	1.31 (1.11, 1.53)	1.36 (1.28, 1.45)	1.25 (1.20, 1.31)
Diabetes prevalence (P), from Public Health England [34]	2.40%	5.20%	12.40%
Prevalence after 1-kg/m2 BMI reduction (P/β)	1.8% (1.6, 2.2)	3.8% (3.6, 4.1)	9.9% (9.5, 10.3)
Absolute risk reduction: Reduction in prevalence after 1-kg/m2 BMI reduction (~P − P/β)	0.6% (0.2, 0.8)	1.4% (1.1, 1.6)	2.5% (2.1, 2.9)

Absolute risk reduction for a 1-kg/m² reduction in BMI is estimated from the baseline diabetes prevalence (P) and Mendelian randomization odds ratio (β) as P − P/β. 95% confidence intervals are indicated in parentheses.