Risk factors for focal nodular hyperplasia of the liver: An Italian case-control study

OBJECTIVES: Risk factors for focal nodular hyperplasia (FNH) of the liver are largely unknown, except for a possible role of female hormones. We evaluated the role of tobacco smoking and some lifestyle and dietary factors in its etiology. METHODS: A hospital-based case-control study was conducted in Italy between January, 1999 and February, 2000 on 28 patients with histologically confirmed FNH of the liver and 115 controls in the hospital for acute, nonneoplastic, non-liver related diseases. Odds ratios (OR) and 95% confidence intervals (CI) were computed using multiple logistic regression equations. RESULTS: Compared to those who never smoked the multivariate ORs were 1.9 (95% CI = 0.6-6.0) in ex-smokers and 3.5 (95% CI = 1.2-9.7) in current smokers, and the risk increased with number of cigarettes smoked to 8.0 (95% CI = 1.7-37.4) for ≥20 cigarettes/day. Intake of wholegrain foods was inversely related to risk, with an OR of 0.3 (95% CI = 0.1-0.7) in consumers versus nonconsumers. No significant association was observed with education, alcohol drinking, and selected indicator foods. CONCLUSIONS: This study indicates that cigarette smoking is an indicator of elevated risk for FNH of the liver, whereas whole grain and, possibly, vegetable intake seems to be a favorable indicator.