The NHANES are ongoing repeated cross-sectional surveys conducted by the US National Center for Health Statistics (NCHS). The NCHS Research Ethics Review Board approved the NHANES protocol and consent was obtained from all participants [30, 31]. Data collection on demographic, diets, and behaviours occurred through questionnaires administered during home visits, while anthropometrics and biomarkers data were collected by trained staff using mobile examination units [30, 32]. The interview consisted of questions on socio-demographic characteristics (age, gender, education, race/Hispanic origin, and health insurance) and questions on previously diagnosed medical conditions. More detailed information on the NHANES protocol is available elsewhere [30, 33, 34]. This study was based on analysis of data from the 1999-2002 NHANES cycles. Analyses were restricted to participants aged 18 years and older. Fasting blood glucose (FBG), total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), triglycerides (TG) levels and telomere length were assayed using methods described in the NHANES Laboratory/Medical Technologists Procedures Manual [30, 35, 36]. Complete laboratory procedures for collection, storage, calibration and quality control of blood samples for determination of hsCRP and other inflammatory markers are available elsewhere.  Creatinine was measured by the Jaffe reaction and standardized by methods described previously . A random urine specimen was collected from participants, and urinary creatinine was measured by the Jaffe rate reaction, urinary albumin was measured by solid-phase fluorescent immunoassay . Albuminuria was measured by urinary albumin-creatinine ratio (ACR) . Glomerular filtration rate [eGFR, (ml/min/1.73m2)] was estimated using the CKD Epidemiology Collaboration (CKD-EPI) equation. CKD was defined as eGFR less than 60 (ml/min/1.73m2) .