Prevalence and Determinants of Metabolic Syndrome Among Male Stainless Steel Factory Workers

Objectives: With the aim to provide framework for workplace health management strategy, this study tried to identify the prevalence of metabolic syndrome among male workers in a stainless factory, and to analyze possible correlation between workplace hazards and metabolic syndrome.
Methods: We recruited 908 male subjects out of 1472 workers in a stainless factory into this study when they visited our hospital for annual health examination from July 2005 to September 2005. With written informed consents, participants were asked to fill out a standard questionnaire. Information of shift work, health behavior, and demographic data were collected. Workplace exposures to noise and heat were determined based on company records of exposure survey. Data on BMI (body mass index), blood pressure, fasting blood sugar, serum lipids profile, hypertension and diabetes were collected in annual health examination. Fisher’s exact test, t-test, ANOVA, and chi-square were used for analysis of correlation. The influencing factors such as age, education, marital status, regular leisure time physical activities, smoking, alcohol consumption, betel nut chewing, workplace hazards of noise, heat, and dust were explored for correlation with metabolic syndrome by multiple logistic regression.
Results: The mean age of study subjects was 34.8(±5.8) years. Among them 474 workers were in day time work, 148 workers were in shift work for less than 6 years, 286 workers were in shift work for more than 6 years, 692 workers exposed to noise hazard, 116 workers were exposed to both noise and high temperature hazards. The prevalence of obesity (BMI≧27) of study subjects was 22.7%(206), with no significant differences among the subgroups, but betel nut chewing was a strong risk with adjusted odds ratio of 3.03. The prevalence of high blood pressure (systolic ≧130mmHg or diastolic ≧85mmHg or under medication with normal BP) was 39.5%(359) , with no significant differences among the subgroups. The prevalence of low HDL-Cholesterol (＜40mg/dl) was 14.9% (135), with alcohol drinking more than 1-2 times a month as protecting factor, the adjusted odds ratio was 0.51 compared to nondrinker. Betel nut chewing was a strong risk for low HDL level with adjusted odds ratio of 2.35 compared to non chewer. The prevalence of high fasting blood sugar (≧110mmHg or under medication with normal blood sugar) was 24.6%(223). Age was a risk factor of high fasting blood sugar, comparing to workers aged less than 30 years old, the adjusted odds ratio of workers aged between 30-40 years old was 2.35, and the adjusted odds ratio of workers aged between 30-40 years old was 4.73. Shift work was a risk factor of high fasting blood sugar, comparing to day time workers, the adjusted odds ratio of workers on shift work for less than 6 years and more than 6 years was 2.38, and 1.54. The prevalence of high fasting Triglyceride (≧150mmHg) was 36% (327). Age was a risk factor of high fasting Triglyceride, comparing to workers aged less than 30 years old, the adjusted odds ratio of workers aged between 30-40 years old and more than 40 years old was 1.87 and 2.29. Smoking was a risk factor of high fasting Triglyceride, the adjusted odds ratio of daily smoker (>10 cigarette/day) was 1.7 compared to non smoker. Betel nut chewing was a strong risk for high fasting Triglyceride with adjusted odds ratio of 3.21 compared to non chewer. The prevalence of metabolic syndrome (workers with more than 3 risk factors) was 19.2%(174), betel nut chewing was a strong risk for metabolic syndrome with adjusted odds ratio of 3.21 compared to non chewer. The adjusted odds ratio of workers on shift work for more than 6 years was 1.59 compared to day time workers.
Discussion: The high prevalence of metabolic syndrome among subjects warrants recognition as key issue in workplace health promotion. Duration of shift work and betel nut chewing are strong determinants of risk for metabolic syndrome among male workers in stainless steel factory. Health promotion activity aiming at establishing healthy life style for employee working on shift should be a priority for health management.
There are several limitations of this study. Duration of shift work is measured by self administered questionnaire, there might be recall bias. Incomplete information was obtained concerning exposure to workplace noise more than one year prior to the health examination, use of personal protective devices, or noise exposure outside the occupational setting. Possibility of healthy workers’ effect could not be ruled out. To avoid labor dispute during the process for workers health management regarding workplace hazards, more comprehensive records for hazards exposure such as noise, high temperature and shift work will provide better discretion for decision making with evidence-based information.