Correlation of cervical cancer mortality with reproductive and dietary factors, and serum markers in China.

BACKGROUND: Cervical cancer is the second leading cause of cancer death among Chinese women. Within China, a considerable geographical variation in mortality rates has been observed, but the reasons are not well understood.
METHODS: Cervical cancer rates were examined in relation to indices of reproductive factors, dietary habits, and selected serum biomedical markers in 65 rural Chinese counties.
RESULTS: Cervical cancer mortality rates correlated positively and significantly with antibodies to herpes simplex virus type 2 (HSV-2) (r = 0.40, P < 0.01), serum levels of ferritin (r = 0.33, P < 0.01), body mass index (BMI) (r = 0.42, P < 0.01) and cigarette smoking (r = 0.51, P < 0.05) and negatively and significantly with age at first birth (r = -0.51, P < 0.01), consumption of green vegetables (r = -0.40, P < 0.01) and animal foods (r = -0.40, P < 0.01), and serum levels of selenium (r = -0.26, P < 0.05). When these variables were considered in the multiple regression analysis, early age at first birth and higher BMI were positively associated with cervical cancer mortality, while consumption of green vegetables and animal foods were negatively correlated. In the serum model, infection with HSV-2 and low levels of sex hormone binding globulin (SHBG) were positively related to cervical cancer mortality. No relation was found for consumption of fruits.
CONCLUSIONS: Although limitations of these ecologic data preclude causal inferences, findings in this study, including associations with HSV-2 infection, early age at first birth, consumption of green vegetables and animal foods, may provide clues to cervical cancer aetiology.