Fig. 1

a Box-and-whiskers plots of BMI across 13 years follow-up period. The boxes at each score extend from the 25th percentile (× [25]) to the 75th percentile (×[75]) [i.e., the interquartile range (IQ)]; the lines inside the boxes represent the median values. The line emerging from the boxes (i.e., the “whiskers”) extend to the upper and lower adjacent values. The upper adjacent value is defined as the largest data point × [75] + 1.5 × IQ, and the lower adjacent value is defined as the smallest data point × [25] – 1.5 × IQ. Observed values more extreme than the adjacent values, if any, are individually plotted (circles). BMI (Kg/m²): body mass index. b Box-and-whiskers plots of CDAI across 13 years follow-up period. The boxes at each score extend from the 25th percentile (× [25]) to the 75th percentile (× [75]) [i.e., the interquartile range (IQ)]; the lines inside the boxes represent the median values. The line emerging from the boxes (i.e., the “whiskers”) extend to the upper and lower adjacent values. The upper adjacent value is defined as the largest data point × [75] + 1.5 × IQ, and the lower adjacent value is defined as the smallest data point × [25] – 1.5 × IQ. Observed values more extreme than the adjacent values, if any, are individually plotted (circles). CDAI: Crohn’s disease activity index