Relationship between cold temperature and cardiovascular mortality, with assessment of effect modification by individual characteristics: Ibaraki Prefectural Health Study.

BACKGROUND: Cold temperature has been reported to contribute to cardiovascular mortality, but it is not clear which people are more susceptible to cold temperature. METHODS AND RESULTS: The relationship between ambient temperature and mortality was examined in 3,593 subjects from the Ibaraki Prefectural Health Study who died of cardiovascular disease during a mean follow-up period of 9.7±4.0 years. Daily values of meteorological variables were obtained from the Japan Meteorological Agency. Time-stratified case cross-over analysis was used. The multivariate odds ratios (ORs; 95% confidence interval) per 1°C decrease in daily maximum temperature over the day of death and the 2 days prior to this day adjusted for relative humidity were 1.018 (1.003-1.034) for all cardiovascular deaths and 1.025 (1.003-1.048) for stroke deaths. Risk-stratified analysis showed that younger subjects aged <80 years and those with hyperglycemia were more susceptible to cold temperature. The OR of all cardiovascular deaths related to cold temperature was 1.034 (1.012-1.056) for subjects aged <80 years, and that of stroke deaths was 1.076 (1.023-1.131) for those with hyperglycemia. CONCLUSIONS: Exposure to cold temperature triggers cardiovascular deaths. Additionally, younger age and hyperglycemia could enhance susceptibility to cold temperature.

Low serum LDL cholesterol levels are associated with elevated mortality from liver cancer in Japan: the Ibaraki Prefectural health study.

Liver cancer a global public health concern and well known for poor prognosis. The association between low total cholesterol level and liver cancer has been reported. However, the association between low low-density lipoprotein (LDL) cholesterol levels and liver cancer is still unclear. The aim of this study was to examine the relationship between LDL cholesterol level and liver cancer mortality. A total of 16,217 persons (5,551 men and 10,666 women) aged 40-79 years in 1993 were followed until 2008. LDL cholesterol levels were divided into four categories (<80 mg/dl, 80-99 mg/dl, 100-119 mg/dl, and ≥120 mg/dl). Hazard ratio of LDL cholesterol level for liver cancer mortality was calculated using a multivariable Cox proportional hazards model. Covariates were age, sex, alanine transaminase, body mass index, alcohol intake and smoking status, all of which were correlated with LDL cholesterol levels. There were 51 deaths (32 men and 19 women) from liver cancer. Multivariable hazard ratios of liver cancer deaths for LDL cholesterol levels of <80 mg/dl was 4.33 (95% confident interval [CI]: 1.94, 9.68), for LDL cholesterol levels of 80-99 mg/dl was 1.03 (95% CI: 0.42, 2.53), and for LDL cholesterol levels of ≥120 mg/dl was 0.43 (95% CI: 0.20, 0.92) compared with LDL cholesterol levels of 100-199 mg/dl (p for trend<0.01). Therefore, low LDL cholesterol levels are associated with elevated risk of liver cancer mortality. Low LDL cholesterol may be a predictive marker for death due to liver cancer.

Duration of cigarette smoking is a risk factor for oropharyngeal cancer mortality among Japanese men and women: the Ibaraki Prefectural Health Study (IPHS).

PURPOSE: The relationship between duration of cigarette smoking and the risk of oropharyngeal cancer has not been studied in the general Japanese population. Thus, the aim of the present study was to examine the relationship between the duration of cigarette smoking and the risk of oropharyngeal cancer mortality in the Japanese population. METHODS: In this large cohort study, 32,989 men and 63,894 women, ages 40-79 years, who completed health check-ups in Ibaraki Prefecture, Japan, in 1993 were followed through 2008. Oropharyngeal cancer mortality was identified by death certificates. Smoking habits were divided into five categories, and years of cigarette smoking and pack-year classifications were divided into four categories. Hazard ratios and 95% confidence intervals for oropharyngeal cancer mortality were calculated by use of the Cox proportional hazards regression models. RESULTS: During the follow-up period, deaths from oropharyngeal cancer occurred in 38 of 32,989 men and 31 of 63,894 women. The multivariate hazard ratios for oropharyngeal cancer mortality were significantly greater for those subjects currently smoking for 40 years or longer (hazard ratio: 4.22, 95% confidence interval: 1.23-14.51), and they were greater with longer years of cigarette smoking among men (P for trend = .027). CONCLUSIONS: Smoking duration can be a risk factor for oropharyngeal cancer mortality in the Japanese population.