Published papers

Background: Recent Western studies show an inverse association between milk and dairy product intake and cardiovascular disease (CVD). We studied the association between consumption of milk and dairy products and CVD death in Japan. Methods: Men and women aged 30 years or older were followed for 24 years. All had participated in a national nutrition survey in 300 health districts throughout Japan in 1980. The Cox proportional hazards model was used to assess mortality risk according to tertiles of milk and dairy product intake, with the high consumption group as reference. Hazard ratios (HRs) per 100-g/day increase in consumption were also estimated. Results: During the 24-year follow-up period, there were 893 CVD deaths, 174 deaths from coronary heart disease (CHD), and 417 stroke deaths among 9243 participants. For women, the HRs for death from CVD, CHD, and stroke in the low consumption group were 1.27 (95% CI: 0.99-1.58; P for trend = 0.045), 1.67 (0.99-2.80; P = 0.02), and 1.34 (0.94-1.90; P = 0.08), respectively, after adjustment for age, body mass index, smoking status, alcohol drinking habits, history of diabetes, use of antihypertensives, work category, and total energy intake. With each 100-g/day increase in consumption of milk and dairy products, HRs tended to decrease for deaths from CVD (HR, 0.86; 95% CI, 0.74-0.99), CHD (0.73; 0.52-1.03), and stroke (0.81; 0.65-1.01) in women. No significant association was observed in men. Conclusions: Consumption of milk and dairy products was inversely associated with CVD death among women in Japan. © 2012 by the Japan Epidemiological Association.

Associations between dietary fatty acid intakes and risk of coronary heart disease (CHD) are not entirely consistent in prospective studies in the U.S. and Europe. Such studies in Japan are rare. The objective of this study was to examine the association between dietary total, saturated (SFA), and polyunsaturated (PUFA) fatty acids, cholesterol intake and CHD mortality using the dataset of NIPPON DATA90. At the baseline in 1990, we performed blood biochemical measurements and a nutritional survey on participants from 300 randomly selected districts. After exclusion of participants with a history of CHD and/or stroke at the baseline, we followed 7,819 community residents (3,254 men and 4,565 women, age ≥ 30) for 15 years. We estimated individual nutrient intakes among family members by weighed food records in three consecutive representative days. During the follow-up, there were 42 CHD deaths in men and 30 in women. Mean daily SFA and PUFA % calorie intakes were 5.90±1.36%, and 5.59±1.30%, respectively in men, and 6.48±1.53%, and 6.08±1.14% in women. A Cox analysis adjusted for age, vegetable and fruit intakes, and other confounders in women found that SFA intake was significantly associated with CHD mortality (hazards ratio per one quintile increment=1.34, 95% confidence intervals: 1.02-1.74, P=0.03), while no such association was noted in men. No associations were found between other fat intakes and CHD mortality in men or women. In conclusion, SFA intake was positively associated with CHD mortality independent of confounders in women, but not in men. © 2013 Bentham Science Publishers.

Objective: The clustering of cardiovascular disease (CVD) risk factors is a serious threat for increasing medical expenses. The age-specific proportion and distribution of medical expenditure attributable to CVD risk factors, especially focused on the elderly, is thus indispensable for formulating public health policy given the extent of the ageing population in developed countries. Design: Cost analysis using individuals' medical expenses and their corresponding health examination measures. Setting: Shiga prefecture, Japan, from April 2000 to March 2006. Participants: 33 213 participants aged 40 years and over. Main outcome measures: Mean medical expenditure per year. Methods: Gamma regression models were applied to examine how the number of CVD risk factors affects mean medical expenditure. The four CVD risk factors analysed in this study were defined as follows: hypertension (systolic blood pressure ≥140 mm Hg or diastolic blood pressure ≥90 mm Hg), hypercholesterolaemia (serum total cholesterol ≥240 mg/dl), high blood glucose (casual blood glucose ≥200 mg/dl) and smoking (current smoker). Sex-specific and age-specific investigations were carried out on the elderly (aged 65 and over) and nonelderly (aged 40-64) populations. Results: The mean medical expenditure (per year) for the no CVD risk-factor group was only 110 000 yen at age 50 (men, 110 708 yen; women, 107 109 yen), but this expenditure was 6-7 times higher for 80-year-olds who have three or four CVD risk factors (men, 603 351 yen; women, 765 673 yen). The total overspend (excess fraction) was larger for the non-elderly (men, 15.4%; women, 11.1%) than that for the elderly (men, 0.1%; women, 5.2%) and largely driven by people with one or two CVD risk factors, except for elderly men. Conclusions: The age-specific proportion and distribution of medical expenditure attributable to CVD risk factors showed that a high-risk approach for the elderly and a population approach for the majority are both necessary to reduce total medical expenditure in Japan.

Background: Cigarette smoking is a risk factor of coronary heart disease. Vascular calcification such as coronary artery calcium (CAC) and aortic calcium (AC) is associated with coronary heart disease. The authors hypothesised that cigarette smoking is associated with coronary artery and aortic calcifications in Japanese and Koreans with high smoking prevalence. Methods: Random samples from populations of 313 Japanese and 302 Korean men aged 40e49 years were examined for calcification of the coronary artery and aorta using electron beam CT. CAC and AC were quantified using the Agatston score. The authors examined the associations of cigarette smoking with CAC and AC after adjusting for conventional risk factors and alcohol consumption. Current and past smokers were combined and categorised into two groups using median pack-years as a cut-off point in each of Japanese and Koreans. The never-smoker group was used as a reference for the multiple logistic regression analyses. Results: The ORs of CAC (score $10) for smokers with higher pack-years were 2.9 in Japanese (p<0.05) and 1.3 in Koreans (non-significant) compared with neversmokers. The ORs of AC (score $100) for smokers with higher pack-years were 10.4 in Japanese (p<0.05) and 3.6 in Koreans (p<0.05). Conclusion Cigarette smoking with higher pack-years is significantly associated with CAC and AC in Japanese men, while cigarette smoking with higher pack-years is significantly associated with AC but not significantly with CAC in Korean men.

Background: We recently reported that Japanese had higher liver fat at a lower level of BMI compared with non-Hispanic whites (NHW). Objective: We hypothesize that ethnic difference in fat storage capacity contributes to this ethnic difference in liver fat. Design: To examine this, we assessed liver fat among 244 Japanese-American aged 40-49, using regional computed-tomography images, along with metabolic variables. Results: Despite the similar BMI between Japanese-Americans and NHW men, Japanese-Americans had more liver fat (liver to spleen attenuation ratio: 1.03 ± 0.22 for Japanese-Americans, and 1.07 ± 0.15 for NHW men; p < 0.05) and tended to have a greater disposition for fatty liver with an increase in BMI than NHW, indicating a clear difference between the two groups. In addition, liver fat is less in Japanese-Americans compared with Japanese men (1.03 ± 0.22 vs. 1.01 ± 0.16; p < 0.05), despite of a much higher BMI. These ethnic differences support the hypothesis that higher fat storage capacity indeed seems to be associated with less liver fat. In all the groups, liver fat content strongly correlated with triglycerides, homeostasis model assessment-insulin resistance, and C-reactive protein (CRP). Nevertheless, these metabolic variables were worse in Japanese-Americans, despite of less liver fat, compared with Japanese. Moreover, CRP levels were least among Japanese with highest liver fat, and highest among NHW men with least liver fat, despite of a strong positive association between CRP and fatty liver within each population. Conclusions: Fat content in the liver is intermediate for Japanese-Americans compared with Japanese and NHW men, which supports the hypothesis of less fat storage capacity among Japanese, closely linked to ethnic difference in predisposition to fatty liver. © 2011 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.