| Abstract: | BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is a major cause of liver diseases worldwide and lifestyle and diet are significant factors in its development. Recent studies have suggested that dietary fat quality is associated with the development of NAFLD. OBJECTIVES: Our purpose was to investigate the cross-sectional and longitudinal associations of serum n-3 and n-6 polyunsaturated fatty acids (PUFA) with NAFLD among middle-aged and older males and females from Eastern Finland. We also investigated the associations of estimated delta-5-desaturase and delta-6-desaturase activities, enzymes involved in PUFA metabolism, with NAFLD. DESIGN: After exclusions the cross-sectional analyses included 1533 males examined in 1984-1989 and 674 males and 870 females examined in 1998-2001 in the Kuopio Ischaemic Heart Disease Risk Factor Study. The longitudinal analyses included 520 males examined in 1991-1993 and 301 males and 466 females examined in 2005-2008. Fatty liver index (FLI) was used as a surrogate for NAFLD. Hepatic steatosis was defined as FLI > 60. ANCOVA and logistic regression were used for analyses. RESULTS: In the longitudinal analyses, participants with higher serum concentrations of total n-6 PUFA and linoleic acid, the major n-6 PUFA, had markedly lower FLI and lower odds for hepatic steatosis (e.g., odds ratios for incident hepatic steatosis in the highest vs lowest quartiles were ≤ 0.41), whereas serum GLA concentration was associated with a higher FLI and higher odds for hepatic steatosis. The associations with the other PUFA were generally weaker and nonsignificant. In the cross-sectional analyses, also the long-chain n-3 PUFA had inverse associations. In most analyses, high estimated delta-5-desaturase activity was associated with lower risk and high estimated delta-6-desaturase activity with higher risk for NAFLD. CONCLUSION: In middle-aged and older Finnish adults, higher serum concentrations of total n-6 PUFA and linoleic acid were associated with lower odds for future NAFLD. Clinical trial registration: https://clinicaltrials.gov/ct2/show/NCT03221127. |
