Oxidative Stress and CRP in Nondiabetic Postmenopausal Women
Oxidative Stress and CRP in Nondiabetic Postmenopausal Women
The means of the conventional cardiovascular risk factors according to the CRP quartiles (Q1–Q4), after adjustment for age and lifestyle habits, include alcohol consumption and cigarette smoking, are shown in Table 1. BMI, insulin and HOMA-IR were higher in Q2 and Q3 than in Q1. The Q4 scores were higher than the Q1, Q2 and Q3 scores. Waist circumference was higher in Q3 and Q4 than in the other quartiles. Q2 and Q4 had higher systolic blood pressure than Q1 but Q2 displayed higher diastolic blood pressure than Q1. Triglycerides were higher in Q3 and Q4 than in Q1 or Q2; however, HDL cholesterol was lower in Q3 than in Q1 and lower in Q4 than both Q1 and Q2. Q4 had higher total cholesterol than Q2 and higher LDL cholesterol than Q2 and Q3. The participants in Q4 also had the highest glucose and leucocyte numbers.
Figure 1 shows the distribution of plasma ox-LDL and urinary 8-epi-PGF2α after participants were classified according to CRP quartiles. Plasma ox-LDL was higher in Q4 than in Q1 after adjusting for age and lifestyle habits. Urinary 8-epi-PGF2α was higher in Q2 and Q3 than in Q1, and Q4 values were higher than both Q1 and Q2.
(Enlarge Image)
Figure 1.
Comparison of plasma ox-LDL and urinary 8-epi-PGF2α in 1821 nondiabetic postmenopausal women between the CRP quartiles (Q1–Q4) after adjusting for age and lifestyle. Mean ± SE., P-values derived from anova with Bonferroni correction. *P < 0·05 compared with the value in the Q1 tested by anova (Bonferroni correction). P < 0·05 compared with the value in the Q2 tested by anova (Bonferroni correction).
Table 2 displays the correlations between oxidative stress markers and factors of metabolic syndrome factors before and after age and lifestyle adjustments. Plasma ox-LDL levels positively correlated with BMI, diastolic blood pressure, triglycerides, total cholesterol, LDL cholesterol and HOMA-IR index. Urinary 8-epi-PGF2α levels positively correlated with HDL cholesterol and CRP. In addition, there was a weak negative correlation of urinary 8-epi-PGF2α with LDL cholesterol.
To evaluate the strength of the association between CRP and oxidative stress, as well as BMI, HOMA-IR and each metabolic syndrome component, multiple linear regression analyses were performed (Table 3). After adjusting for age and lifestyle habits, CRP significantly associated with urinary 8-epi-PGF2α, triglycerides, HDL cholesterol and systolic blood pressure. There was no significant association of CRP with ox-LDL or diastolic blood pressure. These variables were then adjusted with BMI and HOMA-IR, in addition to age and lifestyle. The association of urinary 8-epi-PGF2α with CRP slightly increased after adjusting for BMI and HOMA-IR but the association of CRP with triglycerides and HDL cholesterol was attenuated.
Results
Relationships Between CRP and Conventional Cardiovascular Risk Factors
The means of the conventional cardiovascular risk factors according to the CRP quartiles (Q1–Q4), after adjustment for age and lifestyle habits, include alcohol consumption and cigarette smoking, are shown in Table 1. BMI, insulin and HOMA-IR were higher in Q2 and Q3 than in Q1. The Q4 scores were higher than the Q1, Q2 and Q3 scores. Waist circumference was higher in Q3 and Q4 than in the other quartiles. Q2 and Q4 had higher systolic blood pressure than Q1 but Q2 displayed higher diastolic blood pressure than Q1. Triglycerides were higher in Q3 and Q4 than in Q1 or Q2; however, HDL cholesterol was lower in Q3 than in Q1 and lower in Q4 than both Q1 and Q2. Q4 had higher total cholesterol than Q2 and higher LDL cholesterol than Q2 and Q3. The participants in Q4 also had the highest glucose and leucocyte numbers.
Relationship Between CRP and Oxidative Stress Markers
Figure 1 shows the distribution of plasma ox-LDL and urinary 8-epi-PGF2α after participants were classified according to CRP quartiles. Plasma ox-LDL was higher in Q4 than in Q1 after adjusting for age and lifestyle habits. Urinary 8-epi-PGF2α was higher in Q2 and Q3 than in Q1, and Q4 values were higher than both Q1 and Q2.
(Enlarge Image)
Figure 1.
Comparison of plasma ox-LDL and urinary 8-epi-PGF2α in 1821 nondiabetic postmenopausal women between the CRP quartiles (Q1–Q4) after adjusting for age and lifestyle. Mean ± SE., P-values derived from anova with Bonferroni correction. *P < 0·05 compared with the value in the Q1 tested by anova (Bonferroni correction). P < 0·05 compared with the value in the Q2 tested by anova (Bonferroni correction).
Correlations Between Oxidative Stress Markers and Metabolic Syndrome Factors
Table 2 displays the correlations between oxidative stress markers and factors of metabolic syndrome factors before and after age and lifestyle adjustments. Plasma ox-LDL levels positively correlated with BMI, diastolic blood pressure, triglycerides, total cholesterol, LDL cholesterol and HOMA-IR index. Urinary 8-epi-PGF2α levels positively correlated with HDL cholesterol and CRP. In addition, there was a weak negative correlation of urinary 8-epi-PGF2α with LDL cholesterol.
CRP in Relation to Oxidative Stress, BMI and HOMA-IR
To evaluate the strength of the association between CRP and oxidative stress, as well as BMI, HOMA-IR and each metabolic syndrome component, multiple linear regression analyses were performed (Table 3). After adjusting for age and lifestyle habits, CRP significantly associated with urinary 8-epi-PGF2α, triglycerides, HDL cholesterol and systolic blood pressure. There was no significant association of CRP with ox-LDL or diastolic blood pressure. These variables were then adjusted with BMI and HOMA-IR, in addition to age and lifestyle. The association of urinary 8-epi-PGF2α with CRP slightly increased after adjusting for BMI and HOMA-IR but the association of CRP with triglycerides and HDL cholesterol was attenuated.