The Association of Diet With High Phosphatemic Index With Odds of Nonalcoholic Fatty Liver Disease

Aim: A high intake of dietary phosphorus with an effect on the serum phosphorus level may affect the health status and predict the occurrence of some clinical disorders. Therefore, in the current study, we aimed to determine phosphatemic index (PI) according to serum levels of phosphorus after intake of different foods and assess its association with the odds of nonalcoholic fatty liver disease (NAFLD).

Methods: The current study was conducted with case-control design on 225 newly diagnosed NAFLD cases and 450 controls aged 20–60 years. Dietary intake data were collected by a validated food frequency questionnaire. The PI was calculated as the area under the curve (AUC) of serum phosphorus after eating test food divided by the AUC for the food supply containing an equal quantity of phosphorus. Multivariable logistic regression models were used to evaluate the NAFLD odds according to tertiles of the PI score.

Results: The median (IQR) of dietary PI in participants of case and control groups was 83.9 (55.8–114.2) and 82.1 (52.6–119.6), respectively. In the age and sex-adjusted model, there was no statistically significant association between PI and the odds of NAFLD (OR = 1.47; 95% CI: 0.98–2.19, P_trend = 0.065). However, in fully adjusted model, after controlling the effects of age, sex, waist-to-hip ratio, smoking, dietary intake of energy, dietary fiber, physical activity, and socioeconomic status, the odds of NAFLD increased across tertiles of PI (OR = 1.97; 95% CI: 1.08–3.58, P_trend = 0.028).

Conclusions: Our results suggested that a diet with a higher PI score may contribute to an increase in the odds of NAFLD independent of common confounders.