Cancer mortality and serum levels of carotenoids, retinol, and tocopherol: A population-based follow-up study of inhabitants of a rural area of Japan

A total of 3,182 subjects (1,239 males and 1,943 females) aged from 39y to 79y, were recruited from the inhabitants of a rural area in Japan who participated in health check-up programs from 1988 to 1995. During the 10.5 year follow-up, 287 deaths (175 males and 112 females) from all causes, 134 (81 males and 53 females) from cancer of all sites, 31 from lung cancer, 21 from colorectal cancer, 20 from stomach cancer, and 62 from other cancers, were identified among the cohort subjects. Fasting serum samples were taken at the time of the health check-ups, and serum levels of carotenoids, retinol and tocopherols were separately determined by HPLC. Statistical analyses were performed using Cox's proportional hazard model after adjusting for sex, age, and other confounding factors. High serum levels of α- and β- carotenes and lycopene were found to marginally significantly or significantly reduce the risk for mortality rates of cancer of all sites and of colorectal cancers. High serum levels of β-cryptoxanthin also showed an inversely relation with the risk of mortality from lung and stomach cancers, but this was not statistically significant. High intake of green-yellow vegetables contributing to serum levels of α- and β- carotenes, as well as lycopene, may reduce the risk of cancer mortality, especially from colorectal cancer, in rural Japanese.