Estimation of the metabolic syndrome prevalence in the general population in Germany

Aim  The purpose of this study was to estimate the order of magnitude of the metabolic syndrome (MetS) prevalence in Germany despite a lack of sufficient fasting participants in representative national studies. Subjects and methods  This analysis was based on 6,666 participants of the National Health Examination Survey (NHIES) 1998 aged 18–79, using the criteria of the National Cholesterol Education Program (NCEP), hemoglobin A_1c (HbA_1c), non-fasting triglycerides and fasting time. Results  Among 6,666 participants, 26.3% were fasting for at least 8 h and an additional 60.4% could be classified according to the NCEP criteria based on their waist circumference, HDL cholesterol and blood pressure alone (if all three parameters were above or all below the NCEP thresholds). MetS determination in the remaining 13.3% of the sample according to the NCEP criteria would have required fasting glucose and triglyceride values that were not available (inconclusive cases). The metabolic syndrome prevalence in the overall sample was therefore estimated to be at least 13.6%, if all inconclusive cases did not have the MetS, and at most 26.9%, if all inconclusive cases had the MetS. We narrowed down this range by classifying the inconclusive cases stepwise, first by adding information on HbA_1c with cutoffs >6.1% and >6.0% and then by including information on non-fasting triglycerides with three different cutoffs (≥250 mg/dl, ≥200 mg/dl and ≥75th percentile of the population distribution stratified by fasting time). Based on these different cutoffs, the prevalence of the MetS in adults aged 18–79 in Germany was estimated to lie between 20.0 to 22.5%. Using one of the more conservative scenarios (HbA1c >6.1% and triglycerides ≥75th population percentile), the presence of the MetS was associated with living in East compared to West Germany (OR 1.4, 95% CI 1.2–1.6), with lower education (OR 1.7, 95% CI 1.4–2.0 compared to higher education) and with male sex (OR 1.5, 95% CI 1.3–1.7) in an analysis additionally adjusting for age, current daily smoking and non-HDL cholesterol. Conclusions  Despite imperfect data for prevalence estimation, a high prevalence and an uneven East-West and socioeconomic distribution of the MetS phenotype in Germany can be shown and should be used in order to improve national preventive strategies.