OBJECTIVETo investigate the association between occupational psychological stress and metabolic syndrome (MS) in Hui and Han populations in Ningxia, China.

METHODSA 1:1 matched case-control study was performed. A total of 600 unrelated patients aged from 20 to 60 years who were clearly diagnosed with MS in General Hospital of Ningxia Medical University and Wuzhong People's Hospital from October 2011 to October 2012 were collected as the case group (MS group). A total of 600 healthy people who underwent a regular health examination in the same hospital during the same period were selected as the control group with matched gender, nationality, and age (≤ ± 3 years). The self-designed questionnaire was used to investigate the general situations and do the physical examination, and the fasting venous blood samples were collected for laboratory biochemical blood tests. The Occupational Stress Inventory (OSI) was used to investigate the subjects' occupational stress factors and stress levels.

RESULTSWith the increase in stress levels, the levels of WC, FPG, TG, AST, and UA were increased, WHR, SBP, and DBP first increased and then decreased, and the level of HDL-C increased. There were statistically significant differences in these parameters between the two groups (P < 0.05 or 0.01). The occupational psychological stress test results showed that the total score of stress factors (t = 6.676, P < 0.05), workload (t = 10.269, P < 0.05), interpersonal relationship (t = 6.569, P < 0.05), family/work balance (t = 2.028, P < 0.05), cognitive load (t = 8.714, P < 0.05), and other scores (t = 2.838, P < 0.05) in the MS group were all significantly higher than those in the control group, but there were no significant differences in the scores of management role, work responsibilities, and organizational climate between the MS group and the control group (P>0.05). There were no significant differences in the total score of stress factors and the score of each factor between Hui and Han groups (P>0.05). The relative risks of MS in the people with moderate stress exposure were 2.325 and 2.331 times those in the people with mild stress exposure before and after adjustment for age, gender, education level, marriage status, smoking, and drinking, and the relative risks for MS in the people with severe stress exposure were 3.000 and 3.126 times those in the people with mild stress exposure. There were significant differences in the detection rates of abdominal obesity, high TG, low HDL-C, hypertension, hyperglycemia, and diabetes between the sub-groups with different stress levels in the MS group (χ² = 17.636, 8.514, 14.640, 14.280, and 33.323, P < 0.01). The results of multivariate conditional logistic regression analysis showed that the risk factors for MS were SBP, TG, LDL-C, UA, BMI, fasting blood glucose, family history of hypertension, family history of diabetes, and the level of psychological stress in Ningxia, and the protective factor for MS was HDL-C.

CONCLUSIONThe occupational psychological stress is closely associated with MS, and it is an environmental risk factor for MS. With the increase in the stress level, the detection rates of MS components and the relative risk for MS are significantly increased. And there is no significant difference in the level of occupational psychological stress between the Hui and Han nationality groups.