ABSTRACT
OBJECTIVE: Observational epidemiologic studies have shown that a high intake of dietary and high serum levels of carotenoids are associated with a reduced risk of mortality from cancer and cardiovascular disease. To investigate whether high serum levels of carotenoids can reduce mortality rates, a population-based follow-up study was conducted among Japanese inhabitants. MATERIALS AND METHODS: Three thousand two hundred and fifty-four subjects (1,260 males and 1,994 females) aged from 39 to 85 years who had attended health check-up programs from 1989 to 1995 were recruited from the Japanese population. Serum levels of carotenoids, retinol and tocopherols were separately determined by high-performance liquid chromatography. Hazard ratios for serum values of carotenoids, retinol and tocopherols were estimated by Cox's proportional hazard model after adjusting for sex, age, and other confounding factors. RESULTS: During the 11.7-year follow-up period, 140 deaths (86 males and 54 females) from cancer of all sites were identified among the cohort subjects, including 41 from lung , 17 from stomach , 16 from colorectal and 12 from liver cancer, as well as 89 deaths from cardiovascular disease, including 45 from heart disease and 37 from stroke. High serum values of carotenoids including xanthophylls were apparently associated with low hazard ratios for mortality rates of cancer of all sites or of cardiovascular disease. High serum values of beta-carotene, total carotene, provitamin A and total carotenoid for colorectal cancer or stroke also appeared to be related to low hazard ratios. Those of retinol and tocopherols were not associated with any reduction in risk of mortality from cancer or cardiovascular disease. CONCLUSIONS: Our follow-up study demonstrated that a typical Japanese diet related to elevating serum levels of carotenoids with provitamin A activity may significantly reduce risk of mortality from cancer of certain sites or cardiovascular disease, especially colorectal cancer or stroke, while high serum levels of some xanthophylls, retinol and tocopherols do not.