Smoking, earlier menarche and low parity as independent risk factors for gynecologic cancers in Japanese: a case-control study.

During recent decades, the incidence of gynecologic cancers, i.e., cancers of the cervix, endometrium and ovary, has increased in Japan. However, risk factors of gynecologic cancers have not been fully clarified in Japan. To investigate common and site-specific risk factors among gynecologic cancers, we conducted a hospital-based case-control study. The cases, i.e., 151 cervical, 103 endometrial and 141 ovarian cancer cases and the controls (n = 2016) were selected from female patients aged 30 and over, who were admitted to a single hospital in Miyagi Prefecture from 1997 to 2003. Information on reproductive factors, exogenous hormone use, and lifestyles including smoking was collected using a self-administered questionnaire. Smoking was significantly associated with an increased risk of cervical cancer. A dose-response relationship with the number of cigarettes per day was also observed (p for trend = 0.004). Older age at menarche was associated with a decreased risk of endometrial and ovarian cancers. For these cancers, the decreased risk was detected with increasing parity number (endometrium, p for trend = 0.0001; ovary, p = 0.0002). There was no significant association between exogenous hormone use and gynecologic cancer risk. The results indicate that smoking is a major risk factor of cervical cancer. In addition, hormonal factors, which are related to early onset of menarche and low parity, are common risk factors for endometrial and ovarian cancers. The increase in female smokers and the decrease in fertility rate may contribute to the increase in gynecologic cancer incidence in Japan.

Height, urban-born and prostate cancer risk in Japanese men.

BACKGROUND: Height and early-life environments have received attention as risk factors for prostate cancer. However, the evidence is sparse in Japan. To elucidate the associations of height and early-life factors with prostate cancer risk in Japanese men, we conducted a hospital-based case-control study. In addition, to investigate whether the associations vary between prostate cancer and other major cancers, we conducted a comparative study within the same case-control study. METHODS: Study subjects consisted of 282 prostate cancer cases, 584, 461, 231, and 156 male stomach, lung, colon and rectal cancer cases, respectively, and 1730 male hospital controls, aged 50 and over admitted to a single hospital in Miyagi Prefecture from 1997 to 2003. Information on height and early-life factors including birthplace and stature at 12 years was collected using a self-administered questionnaire. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were estimated for each exposure variable. RESULTS: A significant positive association was found between height and prostate cancer risk (OR, 1.52; 95% CI, 1.00-2.31, between the highest and lowest quartiles; P for trend = 0.03). A significant association of urban-born with prostate cancer risk was also found (OR, 1.48; 95% CI, 1.03-2.13). Analyses by stage revealed that height might be more strongly associated with the risk of advanced prostate cancer. For other major cancers, no significant association with height and early-life factors was observed. CONCLUSIONS: Height and early-life factors were significantly associated with prostate cancer risk. Compared with other major cancers, these associations were specific to prostate cancer.

Assessment of DNA damage in Japanese nurses handling antineoplastic drugs by the comet assay.

To clarify genotoxic effects of occupational exposure to antineoplastic drugs in Japan, we examined DNA damage, assessed by the comet assay, in 121 female nurses and 46 female clerks working at three hospitals in the northeast of Japan. The comet assay is considered to be a sensitive and rapid method for DNA strand break detection in individual cells, and tail length and tail moment are used as the comet parameters. Concerning the basal characteristics, the 46 control subjects had higher rates of smoking and coffee-drinking habits and lower hemoglobin than the 121 nurses (p<0.05). The log-transformed tail length in the nurses was significantly longer than that in the control subjects after adjusting for possible covariates such as age and smoking habit (p<0.05). Also, the log-transformed tail length was significantly longer, in the 57 nurses who had handled antineoplastic drugs in the last six months, than that in the 46 control subjects (p<0.05); but, no significant difference in tail length or tail moment was seen between the two nurse groups with and without experience of handling hazardous drugs (p>0.05). These results suggest that Japanese nurses who have worked at hospitals using antineoplastic drugs may have a potential risk of DNA damage. To minimize this risk in Japan, use of biological safety cabinet and appropriate protective equipment, in addition to staff education and training, should be implemented in the healthcare environment.