Association of weight gain since age 20 with non-alcoholic fatty liver disease in normal weight individuals.

BACKGROUND AND AIMS

Interventions for lifestyle diseases including non-alcoholic fatty liver disease (NAFLD) have focused on overweight and obese populations. The impact of adult weight gain on NAFLD development among normal weight individuals remains unclear.

METHODS

In this cross-sectional study, we collected data from participants presenting to a health check-up program. Ultrasound-diagnosed NAFLD prevalence was examined over 1-kg increments of weight change since age 20. Relative risks were calculated in men and women stratified by current weight (normal, overweight, and obese). Logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) adjusting for potential confounders.

RESULTS

Among 21 496 participants, 3498 cases of NAFLD (16.3%) were observed. Prevalence of NAFLD increased with weight gain since age 20; among the 10.1-11.0 kg weight gain group, 41.6% of men and 24.8% of women had NAFLD. Multivariate analysis by quartiles showed that weight change was significantly associated with NAFLD risk in men and women. Risk of NAFLD associated with weight change (10-kg increments) was significantly higher in normal weight individuals (men: OR 7.53, 95% CI: 4.99-11.36, women: OR 12.20, 95% CI: 7.45-19.98) than overweight (men: OR 1.61, 95% CI: 0.91-2.85, women: OR 2.90, 95% CI: 0.99-8.54) and obese (men: OR 4.0, 95% CI: 2.97-5.39, women: OR 2.68, 95% CI: 2.00-3.60).

CONCLUSIONS

NAFLD is robustly associated with weight change since age 20. This effect appears particularly strong in individuals at normal weight, suggesting an important role for early and longitudinal weight monitoring, even among healthy individuals at normal weight.