Our study suggested that the combined effect between HLA-Cw6 and cigarette smoking or stressful life events may play an important role in the development of psoriasis vulgaris in Han Chinese population.

The APOE4 allele and life-stress factors are associated with SRH, especially in women. Physical exercise is good for health, but benefits may be attenuated among APOE4 allele carriers. This is the first evidence associating a genetic factor and an interaction between APOE4 and physical exercise with SRH. We suggest that well studied genetic factors should be included in health research to control potential heterogeneity.