(LB03-20-26) Association of the Traditional Okinawan Diet Score With Mortality and Cancer Risk: The Multiethnic Cohort Study

Objectives: No diet score has been developed to capture the dietary pattern of long-lived Okinawan residents. Therefore, we constructed a pre-World War II Okinawan diet score in Okinawans participating in the Multiethnic Cohort (MEC).

Methods: Mean dietary intakes from 1949 Okinawan nutrition surveys archived in the US National Archives were used to develop the traditional Okinawan diet score using baseline MEC quantitative food frequency questionnaire data (1993-1998). The score was applied to MEC Japanese American participants of Okinawan (n=3,594) or mainland Japanese descent (n=19,377) aged 45-75 years. Multivariate Cox proportional hazards models estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for mortality and cancer risk.

Results: The traditional Okinawan diet score included six higher-intake foods: sweet potato, leafy greens, soy, root vegetables, fish, and seaweed; and two lower-intake foods: rice and pickled vegetables. Overall scores ranged from 3 to 62, with higher scores indicating greater alignment with target consumption. Mean scores were higher among Okinawans than mainland Japanese (32 vs. 30), and more Okinawans were in the highest quintile (24% vs. 19%). Comparing the highest to lowest quintiles, among Okinawans, higher scores were associated with lower cardiovascular disease (CVD) mortality (HR=0.60; 95% CI: 0.40–0.90; p-trend=0.04), with non-significant inverse trends for all-cause mortality (HR=0.93; 95% CI: 0.76–1.13; p-trend=0.20), colorectal cancer (CRC) risk (HR=0.70; 95% CI: 0.31–1.56; p-trend=0.29), and breast cancer risk (HR=0.76; 95% CI: 0.48–1.23; p-trend=0.19). Among mainland Japanese, higher scores were associated with lower all-cause mortality (HR=0.90; 95% CI: 0.82–0.97; p-trend=0.005) and CVD mortality (HR=0.82; 95% CI: 0.69–0.98; p-trend=0.01), but not CRC (HR=1.05; 95% CI: 0.70–1.56; p-trend=0.63) or breast cancer risk (HR=1.07; 95% CI: 0.84–1.36; p-trend=0.87).

Conclusions: A higher traditional Okinawan diet score was associated with lower mortality, particularly CVD mortality. Among Okinawans, higher scores were suggestively associated with reduced CRC and breast cancer incidence. Further evaluation of key diet score components and in other populations is warranted.

Funding Sources: NIGMS, P20GM139753; NCI, P30CA071789