Does childhood BMI influence risk of IBD in adulthood?

Takeaway

• BMI in childhood is positively associated with risk of Crohn’s disease (CD) up to age 30 years.
• Childhood underweight is found to be a risk factor for development of ulcerative colitis (UC) in adulthood.

Why this matters 

• Results add to known consequences of overweight and underweight and suggest new routes for prevention of inflammatory bowel disease (IBD).

Study design

• A population-based cohort study of 316,799 participants from the Copenhagen School Health Records Register.
• Funding: Aase and Ejnar Danielsen’s foundation.

Key results

• During the follow-up of 10 million person-years, 4232 participants were diagnosed with IBD, including 1500 participants diagnosed with CD and 2732 participants diagnosed with UC.
• Mean BMI increased from 15.5 kg/m² at 7 years to 18.2 kg/m² at 13 years for boys, whereas it increased from 15.4 kg/m² at 7 years to 18.7 kg/m² at 13 years for girls.
• Risk for CD significantly increased with increase in BMI before the age of 30 (HR, ~ 1.2), and 1 unit increase in BMI z-score was associated with a significantly decreased risk for UC (HR, ~0.9).

Limitations

• Only participants of Danish origin were included.