Lin et al. BMC Public Health 2010, 10:747 http://www.biomedcentral.com/1471-2458/10/747 Variable* Age (years) Body mass index (kg/m2) Waist (cm) Systolic blood pressure (mmHg) Diastolic blood pressure(mmHg) Fasting blood sugar (mg/dl) Triglyceride (mg/dl) HDL cholesterol (mg/dl) Alanine aminotransferase (U/l) g-Glutamyl transferase (U/l) Uric acid (mg/dl) Insulin (μU/ml) Adults having MetS component (count ≤ 2) Male gender Ever been a smoker (≥ 6 cigarettes/day for ≥1 year) Regular alcohol consumption (≥ 1 day/week) Taking exercise ≥ 3 days/week) Having snacks before sleeping (≥ 3 days/week) Having snacks between meals (≥ 3 days/week) HBV carrier HCV carrier Sonographic fatty liver 32.3 ± 6.5 23.0 ± 3.0 75.6 ± 8.6 117.0 ± 14.3 71.7 ± 9.2 94.3 ± 13.2 102.5 ± 78.0 50.5 ± 11.8 27.2 ± 26.6 33.4 ± 24.7 6.6 ± 1.6 8.2 ± 5.7 811 (58.6%) 996 (72.0%) 361 (26.1%) 100 (7.2%) 444 (32.1%) 644 (46.5%) 546 (39.5%) 256 (18.5%) 16 (1.2%) 349 (27.4%) 32.1 ± 6.5 22.6 ± 2.9 74.4 ± 8.2 116.0 ± 14.1 71.0 ± 9.0 93.7 ± 12.0 97.3 ± 77.3 51.2 ± 11.7 25.5 ± 25.8 31.0 ± 22.2 6.5 ± 1.6 7.8 ± 5.0 657 (54.3%) 855 (70.7%) 312 (25.8%) 77 (6.4%) 389 (32.2%) 568 (47.0%) 473 (39.1%) 221 (18.3%) 13 (1.1%) 278 (23.0%) Table 1 Baseline characteristics for Taiwanese adult workers not fulfilling metabolic syndrome (MetS) criteria initially Overall N = 1384 2002 baseline data, divided by MetS outcome in 2007** Without MetS outcome n = 1209 With MetS outcome n = 175 * The upper rows are means and standard deviation (mean ± SD), and the lower rows are proportions (numbers and proportions,%). Abbreviations: HDL cholesterol, high-density lipoprotein cholesterol. ** t-tests for continual variables between groups with/without MetS outcome; c2 tests were conducted for categorical variables between groups with/without MetS outcome Table 5 indicates all the ORs (from 59.6 to 3.9, all p < 0.05) of two-component combinations were greater than the ORs of single components except for COB-alone (OR, 9.1, p < 0.01). Among the two-component combi- nations, synergistic effects on MetS development were found in following combinations: HBP-plus-Low-HDL with OR of 11.7(p < 0.01), and HBP-plus-hyperglycemia with OR of 7.9 (p < 0.01) for MetS development com- pared with the adults having zero MetS component count, synergistic indexes were 4.7 (95% CI, 2.1-10.9) and 2.7 (95% CI, 1.2-6.4), respectively. Discussion and Conclusions At the baseline screening for MetS among our middle- aged working population, 84% (1384 from 1640) of the employees did not fulfill MetS criteria. However, within five years, a considerable number (13%, 175 from 1384) of the middle-aged workers fulfilled criteria of MetS. The incidence of MetS in our middle-aged working population was as high as reported in a survey for Chi- nese middle-aged adults [18]. Risk evaluations for MetS development in general population had attracted attentions of public health professionals [4-7]; further- more, risk assessments for MetS development are also necessary for all middle-aged adults, including the early- middle-aged adults potentially at risk, but not yet fulfill- ing MetS criteria at screening. In a previous worksite MetS research, applying a health promotion program for high-risk persons, Richard V. and colleagues obtained decreased total health risk as well as markedly reduced medical claim costs; and finally, over half of all baseline high-risk persons were converted to low-risk statuses [19]. In terms of health management, our results can help use the readymade screening records to identify high-risk adults and start intervention as soon as possible. Initially, over half of the adults from our sample popu- lation had at least one MetS component (58.6%, Table 1; 36.9% with single and 21.7% with two components, Table 2). Our follow-up survey demonstrated a signifi- cant correlation between the baseline MetS component count and MetS development. The middle-aged adults having one or two MetS components had respectively 2.8-fold and 7.3-fold increased risks for developing MetS 33.3 ± 6.6 25.8 ± 2.5 83.3 ± 7.4 124.2 ± 14.2 76.4 ± 9.0 97.8 ± 19 6 137.9 ± 73.3 46.0 ± 12.0 38.5 ± 29.3 49.7 ± 33.3 7.2 ± 1.5 11.1 ± 8.9 154 (88.0%) 141(80.6%) 49 (28.0%) 23 (13.1%) 55 (31.4%) 76 (43.4%) 73 (41.7%) 35 (20.0%) 3 (1.7%) 101 (57.7%) Page 4 of 8 P 0.04 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01 0.55 0.01 0.84 0.38 0.51 0.59 0.53 <0.01