Association between serotonin transporter gene polymorphisms and depressed mood caused by job stress in Japanese workers

To estimate the genetic factors influencing depressed mood caused by job stress, a total of 243 employees at a manufacturing company and a local hospital in Japan (mean age 40.8±10.3 years) were recruited with informed consent. The Brief Job Stress Questionnaire was used to assess the present status of stress. Alcohol consumption and smoking were assessed as lifestyle factors. DNA samples were prepared to detect gene polymorphisms of serotonin transporter (5HTT), aldehyde dehydrogenase 2, D2 dopamine receptor, and cytochrome p450 2A6. The relationship between job stress, lifestyle factors and these polymorphisms was assessed for each gender. The level of depressed mood for female subjects was significantly higher among the carriers of two short (s/s) alleles of the 5HTT regulatory region compared with the carriers of one (s/l) or two (l/l) long alleles (Mann-Whitney U test, p<0.05). The odds ratio of depressed mood also confirmed this relationship for the female subjects, whereas there was no relationship for the male subjects. When social support was taken into consideration, the depressed mood score for those who had high support was significantly lower than for those who had low support, irrespective of 5HTT polymorphisms and gender. Job stress may elicit biological responses that contribute to depressed mood in relation to 5HTT polymorphisms, and social support may reduce depressed mood irrespective of 5HTT polymorphisms.