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Oxidative stress is associated with C-reactive protein in nondiabetic postmenopausal women, independent of obesity and insulin resistance

Authors

  • Seonmin Park,

    1. Interdisciplinary Course of Science for Aging, Yonsei University, Seoul, South Korea
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    • These two authors contributed equally to this work.

  • Minjoo Kim,

    1. National Leading Research Laboratory for Clinical Nutrigenetics/Nutrigenomics, Department of Food and Nutrition, College of Human Ecology, Yonsei University, Seoul, South Korea
    2. Department of Food and Nutrition, Brain Korea 21 Project, College of Human Ecology, Yonsei University, Seoul, South Korea
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    • These two authors contributed equally to this work.

  • Jean Kyung Paik,

    1. Department of Food and Nutrition, Eulji University, Gyeonggi-do, South Korea
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  • Yoon-Jung Jang,

    1. Interdisciplinary Course of Science for Aging, Yonsei University, Seoul, South Korea
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  • Sang-Hyun Lee,

    1. Department of Family Practice, National Health Insurance Corporation Ilsan Hospital, Goyang-si, South Korea
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  • Jong Ho Lee

    Corresponding author
    1. National Leading Research Laboratory for Clinical Nutrigenetics/Nutrigenomics, Department of Food and Nutrition, College of Human Ecology, Yonsei University, Seoul, South Korea
    2. Department of Food and Nutrition, Brain Korea 21 Project, College of Human Ecology, Yonsei University, Seoul, South Korea
    3. Department of Food and Nutrition, Eulji University, Gyeonggi-do, South Korea
    • Interdisciplinary Course of Science for Aging, Yonsei University, Seoul, South Korea
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Correspondence: Jong Ho Lee, Department of Food & Nutrition, College of Human Ecology, Yonsei University, 134 Shinchon-Dong, Seodaemun-Gu, Seoul 120-749, South Korea. Tel.: +82 2 2123 3122; Fax: +82 2 364 9605; E-mail: jhleeb@yonsei.ac.kr

Summary

Objective

Oxidative stress is associated with obesity, metabolic syndrome and inflammation, suggesting it could be an early event in the pathology of chronic diseases. We tested the hypothesis that elevated levels of oxidative stress markers are associated with increased C-reactive protein (CRP) and that this is independent of obesity and insulin resistance.

Research design and methods

This study was cross-sectional designed and nondiabetic postmenopausal women (n = 1821) with CRP levels ≤10 mg/l was enrolled. The CRP levels were categorized into quartiles from the lowest to the highest concentrations (Q1–Q4). The degree of insulin resistance was determined using the homoeostasis model assessment of insulin resistance (HOMA-IR). We measured oxidative stress using urinary 8-epi-prostaglandin F (8-epi-PGF) and plasma oxidized low-density lipoprotein (ox-LDL).

Results

After adjustments for age and lifestyle habits, including smoking and drinking, we found higher body mass index (BMI) and HOMA-IR scores in Q2 and Q3 vs Q1. The Q4 BMI and HOMA-IR scores were higher than all other quartiles. The plasma ox-LDL was higher in Q4 than in Q1. Urinary 8-epi-PGF was higher in Q3 and Q4 than in Q1 or Q2. Urinary 8-epi-PGF positively correlated with CRP (r = 0·235, P < 0·001), whereas no correlation was found between ox-LDL and CRP. Multiple linear regression analyses of BMI and HOMA-IR showed that the association between urinary 8-epi-PGF and CRP levels remained significant (P < 0·001).

Conclusions

Oxidative stress measured by increased concentration of urine 8-epi-PGF is strongly associated with CRP levels. This finding was independent of obesity and insulin resistance in nondiabetic postmenopausal women.

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