Effect of serum uric acid to creatinine ratio on cognitive function decline in middle-aged adults: Longitudinal evidence from CHARLS.

BACKGROUND

Serum uric acid (SUA) was a predictor of cognitive function. The association of SUA/serum creatinine ratio (Scr), which represents renal function-normalized SUA and cognitive function is unknown.

OBJECTIVE

This study investigated the association of the SUA/Scr with cognitive function and the potential mediation effect of inflammation in the above relationship.

METHODS

This study used 1-5 waves of data from the China Health and Retirement Longitudinal Study. 3302 participants aged 45-60 years at baseline were included. Among them, 1129 who attended subsequent 2-3 waves were further included for cumulative exposure calculation to the SUA/Scr ratio. The Cox models were used to evaluate the impact of baseline SUA/Scr ratio and its cumulative exposure on cognitive function decline.

RESULTS

During a median follow-up of 8.6 years, there were 1512 (45.8%) cognitive function declined. After adjustment, the highest quartile of the SUA/SCr ratio was associated with the highest risk of cognitive function decline (Hazard ratio, 1.175; 95% confidence interval, 1.015-1.360). Restricted cubic spline showed a linear association between the SUA/Scr ratio and the risk of cognitive function decline (p= 0.514). There were a stronger association of cumulative SUA/Scr ratio and its exposure burden with cognitive function decline [the highest versus lowest quartile: 1.635 (1.006-2.656), the high versus low group: 1.729 (1.212-2.466), respectively]. No significant mediating effect through white blood cell count or C-reactive protein in SUA/Scr ratio-cognitive function decline was found.

CONCLUSIONS

The SUA/Scr ratio was associated with a higher risk of cognitive decline, whereas the mechanism mediated by inflammation indicators was not found.