Higher uric acid levels positively correlated with fructose in
the overall pattern of PCOS
As stated, elevated serum uric acid levels were accompanied with
increased fructose levels in women with PCOS. Therefore, using RCS
models, we further explore the relationship between serum fructose and
uric acid levels (Figure 1a; Supplementary Figure 1). Remarkably, there
was a linear correlation between uric acid and fructose levels in women
with PCOS (P overall < 0.001,P non-linear = 0.30; Figure 1a), whereas no
correlation between serum uric acid and fructose levels in controls
(P overall = 0.712,P non-linear = 0.43; Figure 1a).
Since there is no clear cut-off value for serum fructose levels in
clinical practice, we divided women with PCOS according to the quartile
of serum fructose levels. The serum uric acid levels were substantially
higher combined with increasing quartiles of serum fructose levels and
multivariate ANOVA confirmed differences in serum uric acid levels at
different fructose levels (P < 0.001; Figure 1b).
Considering that clinical, biochemical, and endocrine characteristics
may change with age,21 we further stratified women
with PCOS by age (< 25, 25-29, 30-34, and ≥ 35 years).
Interestingly, there was no linear
or non-linear correlation between serum uric acid and fructose levels
when age was less than 25 years. In contrast, there was a non-linear
association between serum uric acid and fructose levels in women with
PCOS between 25 and 29 years of age (P overall =
0.001, P non-linear = 0. 01). After 30 years of
age, there was a significant linear correlation between serum uric acid
and fructose levels in women with PCOS (Figure 1c).