Association between body mass index and liver disorders: an epidemiological study

Background/Aims: Cross-sectional studies showed an association between obesity and liver disorders. Information on incidence rates from epidemiological studies is scarce. Methods: To explore the association between body mass index (BMI) and incident liver disorders, we conducted a follow-up study with a nested case-control analysis using the UK-based General Practice Research Database. The study population encompassed normal weight (BMI <25 kg/m2), pre-obese (BMI 25–29.9 kg/m2) or obese (BMI ≥30 kg/m2) subjects aged 20–79 years, matched on age, sex and general practice attended. Results: Within the study population of 207,630 subjects, we identified 2718 cases of newly diagnosed liver disorder, of whom 1524 (56.1%) had known predisposing conditions. The incidence rates were 2.48 (95% CI 2.31–2.66)/1000 person-years (py) in normal weight, 2.91 (95% CI 2.72–3.11)/1000 py in pre-obese, and 3.83 (95% CI 3.62–4.07)/1000 py in obese subjects. In the nested case-control analysis, the adjusted odds ratio (OR) for obese, as compared to normal weight subjects, was 1.2 (95% CI 1.1–1.4). The OR for idiopathic cases (without known risk factors for liver disorders) was 1.3 (95% CI 1.1–1.6). Conclusions: The study indicates that obesity is associated with a modest increase in the incidence of newly diagnosed liver disorder.