OBJECTIVES

The prevention of metabolic syndrome (MetS) is one of the main targets of health promotion activities in the workplace. The present study aimed to clarify the incidence of MetS and associated lifestyle factors in a worksite male population.

METHODS

The study subjects consisted of 948 working men (mean age: 44 yr old) who did not meet the Japanese criteria for MetS during the annual health examination at a precision instrument development plant in Kanagawa, Japan, 2005. New-onset MetS was followed using the health examination data from 2006 to 2009. The incidence of MetS according to the combination of the presence of abdominal obesity and the number of other components of MetS (elevated blood pressure, dyslipidemia, and elevated fasting glucose) at baseline were calculated. The incidence of MetS was also compared among the groups with regard to differences in lifestyles (dietary habits, smoking status, sleep duration, exercise habits, and alcohol intake). A Cox proportional hazard model was used to identify independent factors contributing to an increased risk of MetS.

RESULTS

New-onset MetS was observed in 76 subjects during a mean follow-up period of 3.7 yr. The incidence of MetS was 2.2/100 person-years and the 4-year incidence of MetS according to Kaplan-Meier analysis was 8.5%. The highest 4-year incidence of MetS was found in the group without abdominal obesity but with two or more components of MetS (37.9%) and the second highest incidence was found in the group with abdominal obesity and one other component of MetS (24.6%). The presence of abdominal obesity and each increase in the number of other components of MetS had an increased age-adjusted hazard ratio for an increased risk of MetS (5.23 and 4.79, respectively, both p<0.001). Similarly, sleep duration 5 h or less, current smoking, and ethanol intake 300 g/wk or more had an increased age-adjusted hazard ratio for an increased risk of MetS.

CONCLUSIONS

The present study showed a high incidence of MetS in not only the group with abdominal obesity, but also the group without abdominal obesity but with two or more components of MetS. Sleep deprivation, current smoking, and excess alcohol intake were found to be factors contributing to an increased risk of MetS among several lifestyle factors examined. The usefulness of health promotion activities that preferentially target subjects who have such medical conditions and/or lifestyles are therefore expected to reduce the incidence of MetS in the workplace, from a high-risk strategy viewpoint.