Association between dietary intake of n-3 polyunsaturated fatty acids and risk of colorectal cancer in the Japanese population: The Japan Collaborative Cohort Study.

BACKGROUND: Epidemiological studies of the dietary intake of specific n-3 polyunsaturated fatty acids (PUFA) and anatomical subsite-specific colorectal cancer (CRC) are limited. We examined the prospective associations of total n-3 PUFA, marine-derived n-3 PUFA [combined eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA)], and alpha-linolenic acid (ALA) as plant-derived n-3 PUFA with the risk of CRC by subsite in the Japan Collaborative Cohort Study. METHODS: The participants completed a self-administered food frequency questionnaire and had no prior history of CRC. Cox proportional hazards model was used to determine the associations between n-3 PUFAs intake and CRC risk overall and by anatomical subsite. RESULTS: During the median 13.8-year follow-up period, 699 of the 42,536 participants aged 40-79 years developed incident CRC. An inverse association was found between dietary ALA intake and the risk of distal colon cancer; the multivariable hazard ratios and 95% confidence intervals for the highest quartiles (Q4) were 0.41 (0.21-0.81; p trend = 0.01) compared with the lowest quartiles (Q1). Marine n-3 PUFA intake was not associated with CRC risk in the overall or anatomical subsite-specific analyses. CONCLUSION: Our findings suggest that higher ALA intake may be beneficial for lowering the risk of distal colon cancer.

Low Periconceptional Dietary Intakes among Japanese Women: The Japan Environment and Children's Study (JECS).

Pregnancy is usually associated with dietary imbalances. We aim to assess the changes in Japanese women's diet and nutritional adequacy before and during pregnancy. In the Japan Environment and Children's Study (JECS), we recruited a large cohort of pregnant women (>100,000) from 15 Japanese communities. We assessed their diet before and during pregnancy by a food frequency questionnaire. The before and during pregnancy intakes of energy, macronutrients, and micronutrients were lower than the recommended level for Japanese women by 1% to 49%. The dietary intakes of pregnant women were lower than their intakes before pregnancy, except for milk, dairy products, and calcium. The daily during pregnancy intake of energy, carbohydrate, fat, protein, folic acid, and iron decreased by 85 kcal, 11.6 g, 2.3 g, 2.8 g, 20 µg, and 0.5 mg than the before pregnancy intake. Pregnant women's declined food and nutrients intakes were moderately correlated to their dietary intakes before pregnancy; the correlation coefficient ranged between 0.47 and 0.67. The inter-individual variability was greater than the intra-individual variability of the dietary intakes. Almost half of the pregnant women remained in the same intake quartile for all nutrients and food groups as before pregnancy. Yet, approximately 10% of pregnant women changed their pregnancy intake by ≥50% (≥2 quartiles up or down) compared to before pregnancy. In conclusion, the study identified low periconceptional dietary intakes among Japanese pregnant women. The low dietary intake of essential nutrients, such as folate, requires revising the Japanese national periconceptional dietary and supplementation guidelines.

Engaging in musical activities and the risk of dementia in older adults: A longitudinal study from the Japan gerontological evaluation study.

AIM: Leisure cognitive activities are suggested to reduce the risk of dementia. Herein, we aimed to investigate the prospective association between engaging in different musical activities and the risk of dementia among Japanese older adults. METHODS: Longitudinal data of 52 601 participants aged ≥65 years from the Japan Gerontological Evaluation Study were analyzed. Musical activities in the form of playing a musical instrument, practicing karaoke and choir or folk singing were assessed using a questionnaire, while dementia was diagnosed using the standardized dementia scale of the long-term care insurance system. The Cox regression was used to obtain the hazard ratios and 95% confidence intervals (CIs) for incident dementia according to engagement in musical activities. RESULTS: Compared with engaging in no musical activities at all, the hazard ratios engaging in one and more than one musical activity, after 5.8 years of a median follow-up period, were 0.94 (95% CI 0.82-1.07) and 0.59 (95% CI 0.32-1.10) in men versus 0.79 (95% CI 0.69-0.90) and 0.89 (95% CI 0.63-1.26) in women, respectively. Playing a musical instrument and practicing karaoke, compared with no musical activities at all, were associated with a faintly decreased risk of dementia in men and a significantly decreased risk of dementia in women; hazard ratios 0.70 (95% CI 0.45-1.02) and 0.90 (95% CI 0.79, 1.04) in men versus 0.75 (95% CI 0.58-0.98) and 0.77 (95% CI 0.68-0.89) in women, respectively. CONCLUSION: Engaging in musical activities, especially playing a musical instrument and practicing karaoke, was associated with a reduced risk of dementia among Japanese older women. Geriatr Gerontol Int 2021; 21: 451-457.

Plasma levels of n-3 fatty acids and risk of coronary heart disease among Japanese: The Japan Public Health Center-based (JPHC) study.

BACKGROUND AND AIMS: Higher intake of fish or n-3 polyunsaturated fatty acids (PUFAs) has been associated with reduced risk of coronary heart disease (CHD). However, it is unclear whether increased blood levels of n-3 PUFAs are associated with reduced risk of CHD in the Japanese population. METHODS: The relationship between circulating levels of n-3 PUFAs (eicosapentaenoic acid + docosapentaenoic acid + docosahexaenoic acid) and risk of CHD was examined in a nested case-control study among participants in the Japan Public Health Center (JPHC)-based Study Cohort. Plasma n-3 PUFA phospholipid levels were measured at baseline by gas chromatography in 209 cases with CHD and 418 controls matched for sex, age, date of blood draw, time elapsed since last meal before blood collection, and study location. The CHD cases (n = 209) comprised 168 cases of myocardial infarction and 41 of sudden cardiac death, otherwise classified as 157 non-fatal and 52 fatal coronary events, respectively. Mean duration of follow-up was 13.5 years. RESULTS: Multivariate conditional logistic analysis showed no significant association between n-3 PUFAs and risk of total CHD. The odds ratio (OR) for the highest versus lowest quartiles of plasma n-3 PUFAs was 0.79 (95% confidence interval [95% CI]: 0.41-1.51, p for trend = 0.51). Subtype analysis of CHD revealed that the multivariate ORs for the highest versus lowest quartiles for n-3 PUFAs were 0.91 (95% CI: 0.43-1.89, p for trend = 0.90) for myocardial infarction, 0.08 (95% CI: 0.01-0.88, p for trend = 0.04) for sudden cardiac death, 0.89 (95% CI: 0.42-1.89, p for trend = 0.97) for nonfatal coronary events, and 0.12 (95% CI: 0.02-0.75, p for trend = 0.03) for fatal coronary events. CONCLUSIONS: Plasma n-3 PUFA levels were not associated with risk of total CHD but were inversely associated with risks of sudden cardiac death and fatal coronary events among middle-aged Japanese individuals.