Evidence that diet is associated with breast cancer risk is inconsistent. Most of the studies have focused on risks associated with specific foods and nutrients, rather than overall diet. In this study, we aimed to evaluate the association between dietary patterns and breast cancer risk in Japanese women. A total of 49 552 Japanese women were followed-up from 1995 to 1998 (5-year follow-up survey) until the end of 2012 for an average of 14·6 years. During 725 534 person-years of follow-up, 718 cases of breast cancer were identified. We identified three dietary patterns (prudent, westernised and traditional Japanese). The westernised dietary pattern was associated with a 32 % increase in breast cancer risk (hazard ratios (HR) 1·32; 95 % CI 1·03, 1·70; Ptrend=0·04). In particular, subjects with extreme intake of the westernised diet (quintile (Q) Q5_5th) had an 83 % increase in risk of breast cancer in contrast to those in the lowest Q1 (HR 1·83; 95 % CI 1·25, 2·68; Ptrend=0·01). In analyses stratified by menopausal status, postmenopausal subjects in the highest quintile of the westernised dietary pattern had a 29 % increased risk of breast cancer (HR 1·29; 95 % CI 0·99, 1·76; Ptrend=0·04). With regard to hormone receptor status, the westernised dietary pattern was associated with an increased risk of oestrogen receptor-positive/progesterone receptor-positivetumours (HR 2·49; 95 % CI 1·40, 4·43; Ptrend<0·01). The other dietary patterns were not associated with the risk of breast cancer in Japanese women. A westernised dietary pattern is associated with an increased risk of breast cancer in Japanese women.

The relationship between different types of meat intake and the risk of type 2 diabetes remains unclear. We prospectively examined the association between total meat, total red meat, unprocessed red meat, processed meat and poultry intake and the incidence of type 2 diabetes. Subjects were 27 425 men and 36 424 women aged 45–75 years who participated in the second survey of the Japan Public Health Center-based Prospective Study, and had no history of type 2 diabetes, cancer, stroke, IHD, chronic liver disease or kidney disease. Meat intake was estimated using a validated 147-item FFQ. OR of self-reported, physician-diagnosed type 2 diabetes over 5 years were estimated using a multiple logistic regression. A total of 1178 newly diagnosed cases of type 2 diabetes were self-reported. Intakes of total meat and total red meat were associated with the increased risk of type 2 diabetes in men but not in women. The multivariate-adjusted OR for the highest quartile compared with the lowest quartile of total meat and total red meat intake were 1·36 (95 % CI 1·07, 1·73; P for trend = 0·006) and 1·48 (95 % CI 1·15, 1·90; P for trend = 0·003) for men, respectively, and 0·82 (95 % CI 0·62, 1·09; P for trend = 0·14) and 0·77 (95 % CI 0·57, 1·02; P for trend = 0·08) for women, respectively. Intakes of processed red meat and poultry were not associated with the increased risk of diabetes in either men or women. In conclusion, elevated intake of red meat is associated with the increased risk of type 2 diabetes in Japanese men but not in women.

Vegetable and fruit intake has been associated with a reduced risk of cancer and CVD, but its relationship to the risk of type 2 diabetes remains unclear. We prospectively examined the association between vegetable and fruit intake and the incidence of type 2 diabetes. Subjects were 21 269 men and 27 168 women aged 45–75 years who participated in the second survey of the Japan Public Health Center-based Prospective Study and had no history of type 2 diabetes or other serious diseases. Intake of vegetables and fruit was estimated using a validated 147-item FFQ. The OR of self-reported, physician-diagnosed type 2 diabetes over 5 years was estimated using multiple logistic regression. A total of 896 newly diagnosed cases of type 2 diabetes were self-reported. Intake of vegetables and fruit combined or fruit only was not associated with a lower risk of type 2 diabetes. However, there was an approximately 20 %, albeit not statistically significant, risk reduction associated with vegetables (men only), green leafy vegetables (men and women) and cruciferous vegetables (men only). Such risk reduction was somewhat greater among obese or smoking men than non-obese or non-smoking men. In conclusion, although a small beneficial effect of vegetables, especially green leafy and cruciferous vegetables, cannot be excluded, vegetable and fruit intake may not be appreciably associated with the risk of type 2 diabetes for Japanese adults.

The objective of the present study was to evaluate the validity of a FFQ in the estimation of dietary amino acid intake. Amino acid intake was calculated using a composition database developed based on the Standard Tables of Food Composition for amino acids in Japan. Subjects were subsampled from two populations of the Japan Public Health Center-based Prospective Study who volunteered to participate in the validation study of the FFQ. The first group was from the population the FFQ was developed for (internal population; n 215) and the second was a separate population to confirm external validity (external population; n 350). The validity of the FFQ was evaluated using 28 d weighed dietary records (DR) as a reference method. Spearman's rank correlation coefficients (CC) between amino acid intake from the FFQ and DR were calculated. The dietary intake of amino acids was slightly underestimated by the FFQ. Deattenuated CC of energy-adjusted amino acid intake according to the FFQ and corresponding amino acid intake according to the DR ranged from 0·15 to 0·52. The median CC for twenty amino acids were 0·33 for men and 0·25 for women in the internal population, and 0·40 for men and 0·30 for women in the external population. In conclusion, the validity of the FFQ in estimating amino acid intake was low to moderate.

The purpose of this study was to evaluate the effect of low Ca intake on the 10-year incidence of vertebral fractures in cohorts I and II of the Japan Public Health Centre-based Prospective Study. The baseline studies were conducted in 1990–1994, with the follow-up studies conducted after 10 years. We analysed 33 970 subjects aged 40–59 years in cohort I and 41 664 subjects aged 40–69 years in cohort II. At baseline, the intake of Ca was assessed as a predictor, using validated FFQ. A meta-analysis was performed to estimate a summary relative risk (RR) for the two cohort studies. The 10-year cumulative incidences of self-reported vertebral fractures were 0·38 % for cohort I and 0·56 % for cohort II. In women, lower Ca intake was associated with a higher incidence of vertebral fractures (P for trend = 0·001), with the lowest quartile of Ca intake having a significantly higher incidence (0·89/1000 persons per year or RR 2·10 (95 % CI 1·25, 3·55)) than that (0·42/1000 persons per year) of the highest. In addition, the RR calculated using energy-adjusted Ca intake (by the residual method) as an outcome was 1·92 (95 % CI 1·28, 2·88). However, no such association was observed in men. An increase of Ca intake should be considered as a preventive strategy for vertebral fractures in peri- and post-menopausal women with a low Ca intake.

Limited egg consumption is often recommended to reduce serum cholesterol concentration for the prevention of CHD. We examined the association of egg consumption and total cholesterol concentration with the risk of CHD. A total of 90 735 subjects (19 856 men and 21 408 women, aged 40–59 years in cohort I; 23 463 men and 26 008 women, aged 40–69 years in cohort II) were followed from 1990–4 to the end of 2001 under the Japan Public Health Center-based prospective study. Total cholesterol was obtained in 36 % of the subjects. Men and women were combined for the analyses. The subjects were categorised into four groups according to egg consumption. Subjects with total cholesterol ≥2200 mg/l were less frequent in frequent egg consumption groups in both cohorts (trend P<0·0001). Subjects with <1 d/week of egg consumption were more likely to avoid a cholesterol-rich diet. Egg consumption was not associated with the risk of CHD, although total cholesterol was significantly related to the risk of CHD. The multivariate hazard ratio of CHD in subjects with total cholesterol ≥2400 v. <1800 mg/l was 2·17 (95 % CI 1·22, 3·85; trend P=0·0018). In conclusion, eating eggs more frequently, up to almost daily, was not associated with an increase in CHD incidence for middle-aged Japanese men and women. Subjects with hypercholesterolaemia were less frequently in frequent egg consumption groups, probably because they avoided eating eggs.