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Insulin resistance, cystatin C, and mortality among older adults.

Abstract

OBJECTIVE
Insulin resistance is a risk factor for cardiovascular and noncardiovascular diseases. Impaired kidney function is linked with insulin resistance and may affect relationships of insulin resistance with health outcomes.
RESEARCH DESIGN AND METHODS
We performed a cohort study of 3,138 Cardiovascular Health Study participants (age ≥ 65 years) without diabetes. Insulin sensitivity index (ISI) was calculated from fasting and 2-h postload insulin and glucose concentrations. Associations of ISI and fasting insulin concentration with all-cause mortality were tested using Cox proportional hazards models, adjusting for demographic variables, prevalent cardiovascular disease, lifestyle variables, waist circumference, and LDL cholesterol. Subsequent models were additionally adjusted for or stratified by glomerular filtration rate estimated using serum cystatin C (eGFR).
RESULTS
A total of 1,810 participants died during the 14.7-year median follow-up. Compared with the highest quartile of ISI, the lowest quartile (most insulin resistant) was associated with 21% (95% CI 6-41) and 11% (-3 to 29) higher risks of death without and with adjustment for eGFR, respectively. Compared with the lowest quartile of fasting insulin concentration, the highest quartile was associated with 22% (4-43) and 4% (-12 to 22) higher risks of death without and with adjustment for eGFR, respectively. Similar attenuation by eGFR was observed when blood pressure, triglycerides, HDL cholesterol, and C-reactive protein were included in models.
CONCLUSIONS
Insulin resistance measured as ISI or fasting insulin concentration is associated with increased risk of death among older adults, adjusting for conventional confounding characteristics. Impaired kidney function may mediate or confound this relationship.

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  • Authors

    de Boer IH, Katz R, Chonchol MB, Fried LF, Ix JH, Kestenbaum B, Mukamal KJ, Peralta CA, Siscovick DS

    Source

    Diabetes care 35:6 2012 Jun pg 1355-60

    MeSH

    Aged
    Aged, 80 and over
    Blood Glucose
    Blood Pressure
    C-Reactive Protein
    Cardiovascular Diseases
    Cholesterol, HDL
    Cholesterol, LDL
    Cohort Studies
    Cystatin C
    Fasting
    Female
    Glomerular Filtration Rate
    Humans
    Insulin Resistance
    Life Style
    Male
    Mortality
    Predictive Value of Tests
    Proportional Hazards Models
    Renal Insufficiency
    Risk Factors
    Triglycerides
    Waist Circumference

    Pub Type(s)

    Journal Article
    Research Support, N.I.H., Extramural

    Language

    eng

    PubMed ID

    22432118