Objective-We investigated whether dietary factors explain higher plasma fibrinogen levels in Japanese emigrants living a Western lifestyle in Hawaii compared with Japanese in Japan. Methods and Results-Plasma fibrinogen and nutrient intakes were examined by standardized methods in men and women 40 to 59 years of age from a Japanese-American sample in Hawaii (100 men and 106 women) and 4 population samples in Japan (569 men and 567 women). Multiple linear regression models were used to examine the relationship between dietary factors and the plasma fibrinogen difference between Hawaii and Japan. Average plasma fibrinogen was significantly higher in Hawaii compared with Japan (PϽ0.001 in both genders). In multiple linear regression analyses with each dietary variable considered separately, body mass index reduced the plasma fibrinogen difference between Hawaii and Japan by 20.4%; iron intake (mg/1000 kcal) and estimated total sugar intake (%kcal) reduced this difference by 30.0% and 14.4%, respectively. In a model that included body mass index, iron, estimated total sugars, and caffeine (also age and gender), this difference was reduced by 61.3% (from 42.2 to 16.3 mg/dL). Conclusions-Higher intake of iron, sugar, and caffeine, in addition to obesity, account largely for higher fibrinogen levels Key Words: fibrinogen Ⅲ nutrition Ⅲ iron Ⅲ sugar Ⅲ caffeine Ⅲ obesity Ⅲ population study J apanese living in Japan have lower rates of coronary heart disease (CHD) than people in the United States and other Western countries, 1,2 including Japanese-Americans living in Hawaii. 3,4 In recent decades, these trends appear to have continued despite higher smoking rates, higher blood pressure levels, and increasing serum cholesterol levels in Japan with a more Westernized lifestyle. 1,5 Investigation of factors possibly affecting the CHD risk difference among genetically similar Japanese populations living in Japan and Hawaii is of interest in understanding these differences.Elevated plasma fibrinogen level has been identified as a risk factor for CHD and stroke in both Western and Japanese populations. 6 -8 A previous study found plasma fibrinogen levels among 75-to 93-year-old Japanese men living in Japan to be significantly lower than those among Japanese of similar age living in Hawaii. 9 Factors contributing to this difference remain unclear; few data are available on the role of dietary factors.Here we report standardized comparisons of plasma fibrinogen and dietary factors between Japanese living in Japan and Japanese-Americans living a primarily Western lifestyle in Hawaii, from the INTERLIPID study, an ancillary investigation of the INTERMAP study on diet and blood pressure. We assessed whether dietary factors account for the difference in fibrinogen levels.
MethodsINTERMAP is an international cooperative study on relationships between multiple dietary factors and blood pressure among 4680 participants 40 to 59 years of age from 17 diverse population samples in China, Japan, the United Kingdom, and the United States. INT...