Objectives To investigate the association between intake of fish and n-3 polyunsaturated fatty acids (n-3 PUFA) and the risk of breast cancer and to evaluate the potential dose-response relation. Design Meta-analysis and systematic review of prospective cohort studies. Data sources PubMed and Embase up to December 2012 and references of retrieved relevant articles. Eligibility criteria for selecting studies Prospective cohort studies with relative risk and 95% confidence intervals for breast cancer according to fish intake, n-3 PUFA intake, or tissue biomarkers. Results Twenty six publications, including 20 905 cases of breast cancer and 883 585 participants from 21 independent prospective cohort studies were eligible. Eleven articles (13 323 breast cancer events and 687 770 participants) investigated fish intake, 17 articles investigated marine n-3 PUFA (16 178 breast cancer events and 527 392 participants), and 12 articles investigated alpha linolenic acid (14 284 breast cancer events and 405 592 participants). Marine n-3 PUFA was associated with 14% reduction of risk of breast cancer (relative risk for highest v lowest category 0.86 (95% confidence interval 0.78 to 0.94), I²=54), and the relative risk remained similar whether marine n-3 PUFA was measured as dietary intake (0.85, 0.76 to 0.96, I²=67%) or as tissue biomarkers (0.86, 0.71 to 1.03, I²=8%). Subgroup analyses also indicated that the inverse association between marine n-3 PUFA and risk was more evident in studies that did not adjust for body mass index (BMI) (0.74, 0.64 to 0.86, I²=0) than in studies that did adjust for BMI (0.90, 0.80 to 1.01, I²=63.2%). Dose-response analysis indicated that risk of breast cancer was reduced by 5% per 0.1g/day (0.95, 0.90 to 1.00, I²=52%) or 0.1% energy/day (0.95, 0.90 to 1.00, I²=79%) increment of dietary marine n-3 PUFA intake. No significant association was observed for fish intake or exposure to alpha linolenic acid. Conclusions Higher consumption of dietary marine n-3 PUFA is associated with a lower risk of breast cancer. The associations of fish and alpha linolenic acid intake with risk warrant further investigation of prospective cohort studies. These findings could have public health implications with regard to prevention of breast cancer through dietary and lifestyle interventions.

The connection between triglyceride-rich lipoproteins and cardiometabolic multimorbidity, characterized by the concurrence of at least two of type 2 diabetes, ischemic heart disease, and stroke, has not been definitively established. We aim to examine the prospective associations between serum remnant cholesterol, triglycerides, and the risks of progression from first cardiometabolic disease to multimorbidity via multistate modeling in the UK Biobank. We also evaluate the causality of these associations via Mendelian randomization using 13 biologically relevant SNPs as the genetic instruments. Here we show that elevated remnant cholesterol and triglycerides are significantly associated with gradually higher risks of cardiometabolic multimorbidity, particularly the progression of ischemic heart disease to the multimorbidity of ischemic heart disease and type 2 diabetes. These results advocate for effective management of remnant cholesterol and triglycerides as a potential strategy in mitigating the risks of cardiometabolic multimorbidity.

Breast milk samples and 24-hour food records were obtained from lactating mothers on day 1 (colostrum), day 14 (transitional milk) and day 42 (mature milk) from Hangzhou (n = 202), Lanzhou (n = 133) and Beijing (n = 142), China. Fatty acid methyl esters were prepared by standard methods, separated and quantified by gas chromatography. We aimed to investigate the fatty acid composition (% of total fatty acid) in human milk of three lactating stages from three regions in China and the relationship with maternal dietary intake during lactation. Present results showed that the fatty acid composition of breast milk varied with lactating period and geographical regions in China. In all the milk samples, the total saturated fatty acid (SFA) remained stable. However, C10:0 and C12:0 increased over the lactation period, total monounsaturated fatty acid (MUFA) significantly increased from colostrum (34.50%) to transitional milk (37.06%), and total polyunsaturated fatty acid (PUFA) showed its highest percentage in colostrum (29.58%). In particular, C22:6n-3 and C22:5n-3 were lowest in mature milk (0.38% and 0.41%, respectively), and C18:3n-3 (1.83%) was lowest in colostrum. There were significant differences among the three regions in total MUFA and PUFA in breast milk. The Hangzhou samples had the lowest C18:1n-9 and highest C22:6n-3. Additionally, C22:6n-3, total PUFA and n-3 PUFA were lowest in the Lanzhou samples. Different dietary habits were largely the drivers behind the different fatty acid profiles among the three regions.