Welcome to the March 2019 DRB! The Bulletin delivers a brief synopsis of the most current Human, Animal, and Environmental dairy research that is going on in the World, and also that which is of special interest to California dairy producers and consumers alike.

If you would like to peruse the most pertinent dairy research from months past, then visit the Dairy Research Bulletin Archive


Selected Publications on Animal Health, Food Safety, and Sustainability

Invited review: Examining farmers’ personalities and attitudes as possible risk factors for dairy cattle health, welfare, productivity, and farm management: A systematic scoping review. Adler F, Christley R, Campe A. J Dairy Sci. 2019 Mar 6. pii: S0022-0302(19)30210-3

  • Good stockmanship is necessary for optimization of health, welfare, husbandry, and management, thereby affecting physical and financial performance in animal production. This influence on animal performance in general can occur indirectly by management decisions determining the conditions under which animals live or directly through certain human-animal relationships.
  • The researchers aimed to determine how research regarding farmers’ personalities and attitudes as risk factors is reported and to explore evidence for the effect of farmers’ attitudes and personalities on dairy cattle health, welfare, productivity, and management.
  • The researchers conducted a systematic review of studies on personality and attitude as risk factors for dairy cattle health, welfare, productivity, and farm management. 38 manuscripts were finally included in the review.
  • The findings highlight the importance of the effect of personality and attitude on outcomes. Farmers’ personality and attitudes are associated with dairy cattle health, welfare, productivity, and management. “Agreeableness” and “conscientiousness” were shown to promote better farm performance, whereas “neuroticism” had a negative effect.
  • In general, attitudes indicating higher degrees of technical knowledge, affection with problems, perceived responsibility, perception of control of a situation, a better human-animal relationship, or a positive evaluation of the benefits of management decisions tended to affect outcomes in a beneficial way.
  • Therefore, further research on attitude and personality and their consideration by professionals and decision-makers within the dairy sector and politics is strongly recommended. This might provide the chance to better understand the needs of dairy farmers and therefore develop tailored advice and support strategies to improve both satisfactory and constructive cooperation.

Factors associated with dairy farmers’ satisfaction and preparedness to adopt recommendations after veterinary herd health visits. Ritter C, Adams CL, Kelton DF, Barkema HW. J Dairy Sci. 2019. Mar 6. pii: S0022-0302(19)30225-5.

  • Herd health and production consultancy are important aspects of modern dairy veterinary practice; therefore, veterinary farm visits will likely be more successful if veterinary practitioners communicate effectively and meet farmers’ expectations.
  • The study objectives were to assess dairy farmers’ satisfaction with veterinary advisors and their perceived preparedness to adopt veterinary advice. Furthermore, the researchers assessed whether farmers’ satisfaction and preparedness to adopt advice were associated with specific predictor variables; that is, general (demographic) factors of veterinarians or farmers, communication tools used by veterinarians, and veterinarians’ affective attributes during the farm visit.
  • Overall, farmers were satisfied with their veterinarian’s communication during farm visits and 58% of farmers felt “absolutely” prepared to follow veterinary recommendations. Based on multivariable regression analysis, farmers’ satisfaction was positively associated with their level of education and the amount of talk the veterinarian dedicated to counseling the farmer.
  • However, satisfaction was negatively association with the ratio between veterinarian talk and farmer talk. Other predictor variables for farmers’ preparedness to follow recommendations included increased veterinary counseling and frequent herd data discussions, whereas there was a negative relationship between number of farmer questions and dominance of the veterinarian during the farm visit.
  • Identification of factors influencing farmers’ satisfaction and preparedness to adopt advice will make veterinary communication more effective and could inform training of veterinarians in communication.

NMR-Based Μetabolomics of the Lipid Fraction of Organic and Conventional Bovine Milk. Tsiafoulis CG, Papaemmanouil C, Alivertis D, Tzamaloukas O, Miltiadou D, Balayssac S, Malet-Martino M, Gerothanassis IP. Molecules. 2019 Mar 18;24(6). pii: E1067. 

  • Origin and quality identification in dairy products is an important issue and also an extremely challenging and complex experimental procedure.
  • The objective of the present work was to compare the metabolite profile of the lipid fraction of organic and conventional bovine milk using NMR metabolomics analysis.
  • For this purpose, 14 organic and 16 conventional retail milk samples were collected monthly, and 64 bulk-tank (58 conventional and 6 organics) milk samples were collected over a 14-month longitudinal study.
  • The results showed a organic samples had significantly increased % content of conjugated (9-cis, 11-trans)18:2 linoleic acid (CLA), α-linolenic acid, linoleic acid, allylic protons and total unsaturated fatty acids (UFA) and decreased % content for caproleic acid compared to the conventional samples.
  • The present work confirms that lipid profile is affected by contrasting management system (organic vs. conventional), and supports the potential of NMR-based metabolomics for the rapid analysis and authentication of the milk from its lipid profile.

Freestall Farms – Associations between on-farm animal welfare indicators and productivity and profitability on Canadian dairies: I. On freestall farms. Villettaz Robichaud M, Rushen J, de Passillé AM, Vasseur E, Orsel K, Pellerin D. J Dairy Sci. 2019 Mar 14. pii: S0022-0302(19)30241-3. 

  • Motivating dairy producers to financially invest in the improvement of their animals’ comfort and welfare can pose some challenges, especially when financial returns are uncertain. Economic advantages for dairy producers associated with increased animal welfare are likely to come from either a premium paid for the milk or increased productivity.
  • The aim of the current study was to evaluate the associations between measures of herd productivity and farm profitability and animal-, management-, and resource-based indicators of cow welfare and comfort.
  • The cow welfare measures were collected during a cow comfort assessment conducted on 130 Canadian freestall dairy farms, including 20 using an automatic milking system.
  • Increased yearly corrected milk production was associated with reduced prevalence of cows with knee lesions, dirty flanks, and lameness. The farms’ economic margin per cow, calculated over replacement costs, was associated with the within farm average lying time standard deviation, percent of stalls with dry bedding, and prevalence of cows with knee lesions.
  • Some of the relationships found were complex, including several interactions between the animal-, management-, and resource-based measures. Overall, the results suggest that improved cow comfort and welfare on freestall farms is associated with increased herd productivity and profitability, when the latest is calculated by the margins over the replacement costs.

Tiestall Farms – Associations between on-farm cow welfare indicators and productivity and profitability on Canadian dairies: II. On tiestall farms. Villettaz Robichaud M, Rushen J, de Passillé AM, Vasseur E, Haley D, Pellerin D. J Dairy Sci. 2019 Mar 6. pii: S0022-0302(19)30209-7. 

  • The use of tiestall housing for dairy cows is often criticized due to the reduced freedom of movement it offers for the animals. Maximizing comfort is especially important in tiestall farms to ensure an acceptable level of cow welfare.
  • The aim of this study was to evaluate the existence of associations between on-farm animal welfare and indicators of farm productivity and profitability in tiestall farms.
  • The prevalence of animal-, resource-, and management-based welfare indicators was collected on 100 Canadian tiestall farms during a cow comfort study.
  • Increased yearly average corrected milk production was associated with longer average lying time and a higher proportion of cows fitting the tie-rail height. Lower yearly average somatic cell count was associated with lower percentages of stalls mostly soiled with manure and a lower proportion of cows with body condition score ≤2.
  • The average margin per cow over replacement costs was positively associated with average lying time, percent of stall not soiled with manure, and the frequency of scheduled hoof trimming per year.
  • Some of the relationships found included interactions between animal- and management-based welfare measures. For example, the relationship between lameness prevalence and average milk production was modified through the milk production genetic index.
  • Overall, the results show that improved cow comfort and welfare on tiestall farms is associated with increased productivity, cow longevity, and profitability when estimated through margins calculated over the replacement costs. Producers should aim to optimize all aspects of stall comfort to enhance their cows’ productivity.

Short communication: Composition of coproduct streams from dairy processing: Acid whey and milk permeate. Menchik P, Zuber T, Zuber A, Moraru CI. J Dairy Sci. 2019 Mar 14.

  • The last decade was defined by a very high interest in high-protein foods, which resulted in the surge of high-protein dairy products such as Greek-style yogurt or beverages fortified with proteins obtained by membrane fractionation of milk or cheese whey.
  • During the manufacture of such products, a significant portion of the water and water-soluble components in milk such as lactose and minerals are being removed as either whey or permeate. In the past, these streams were deemed as byproducts, and often times they were disposed as waste. However, such streams can present a huge environmental concern.
  • This article provides composition information for 3 abundantly available but little characterized dairy coproduct streams: acid whey from Greek yogurt (GAW), acid whey from cottage cheese (CAW), and milk permeate (MP).
  • Three replicate samples obtained on different dates from several dairy processors were analyzed.
    • The main component in all streams was lactose, with up to 3.5% in Greek yogurt acid whey, 2.1% in cottage cheese acid whey, and 11.9% in milk permeate.
    • Crude protein content ranged from 1.71 to 3.71 mg/g in Greek yogurt acid whey, 1.65 to 5.05 mg/g in cottage cheese acid whey, and 3.2 to 4.35 mg/g in milk permeate
    • pH ranged from 4.21 to 4.48 in Greek yogurt acid whey, 4.35 to 4.51 in cottage cheese acid whey, and 5.4 to 6.37 in milk permeate.
    • Chemical oxygen demand varied from 52,400 to 62,400 mg/L for Greek yogurt acid whey, 31,900 to 40,000 mg/L for cottage cheese acid whey, and 127,000 to 142,000 mg/L for milk permeate.
    • Biochemical oxygen demand ranged from 45,800 to 50,500 mg/L for Greek yogurt acid whey, 32,700 to 40,000 mg/L for cottage cheese acid whey, and 110,000 to 182,000 mg/L for milk permeate.
  • Overall, the Greek yogurt acid whey had the lowest pH and highest mineral content of all streams. These data will assist processors and researchers in developing value-added uses of these dairy coproducts.

Comparison of gene editing versus conventional breeding to introgress the POLLED allele into the US dairy cattle population. Mueller ML, Cole JB, Sonstegard TS, Van Eenennaam AL. J Dairy Sci. 2019 Mar 6. pii: S0022-0302(19)30227-9. 

  • Disbudding and dehorning are commonly used cattle management practices to protect animals and humans from injury. They are unpleasant, costly processes subject to increased public scrutiny as an animal welfare issue.
  • Horns are a recessively inherited trait, so one option to eliminate dehorning is to breed for polled (hornlessness). However, due to the low genetic merit and scarcity of polled dairy sires, this approach has not been widely adopted. In March 2018, only 3 Holstein and 0 Jersey active homozygous polled sires were registered with the National Association of Animal Breeders.
  • Alternatively, gene editing to produce high-genetic-merit polled sires has been proposed. To further explore this concept, introgression of the POLLED allele into both the US Holstein and Jersey cattle populations via conventional breeding or gene editing (top 1% of bulls/year) was simulated for 3 polled mating schemes and compared with baseline selection on lifetime net merit alone, over the course of 20 years.
  • The results showed that gene editing resulted in significantly higher net merit after 20 years compared with conventional breeding for both breeds. Additionally, the gene editing scenarios of both breeds used a significantly greater number of unique sires compared with either the conventional breeding or baseline scenarios.
  • Overall, our simulations show that, given the current genetic merit of horned and polled dairy sires, the use of conventional breeding methods to decrease the frequency of the HORNED allele will increase inbreeding and slow genetic improvement.
  • Furthermore, this study demonstrates how gene editing could be used to rapidly decrease the frequency of the HORNED allele in US dairy cattle populations while maintaining the rate of genetic gain, constraining inbreeding to acceptable levels, and simultaneously addressing an emerging animal welfare concern.


Selected Articles on Sustainable Nutrition

Carbon footprint of self-selected US diets: nutritional, demographic, and behavioral correlates. Rose D, Heller MC, Willits-Smith AM, Meyer RJ. Am J Clin Nutr. 2019 Mar 1;109(3):526-534

  • A substantial portion of greenhouse gas emissions (GHGE) has been attributed to the food sector, but little is known about the association between the carbon footprint of individual self-selected diets in the United States and nutritional quality.
  • The aims of this study were to assess the GHGE from individual self-selected diets in the United States and examine their association with nutritional quality of the diets, demographic patterns, and food-related behaviors.
  • The dietary GHGE from US adults (N = 16,800) in the 2005-2010 National Health and Nutrition Examination Survey (NHANES) were calculated by linking all foods consumed in their 24-h recall diets to our new database of food environmental impacts. Diets were ranked by GHGE/1000 kcal.
  • Diets in the bottom quintile accounted for one-fifth the total emissions (GHGE/1000 kcal) of those in the top quintile yet had significantly higher Healthy Eating Index scores.
  • Low-GHGE diets contained higher amounts of fiber and vitamin E and lower amounts of sodium and saturated fats, whereas high-GHGE diets contained higher amounts of vitamins A and D, choline, calcium, iron, and potassium.
  • Low-GHGE diets had less meat, dairy, and solid fats, and more poultry, plant protein foods, oils, whole and refined grains, and added sugars.
  • Food patterns responsible for lower GHGE had a better overall diet quality and were more nutritious on several key dimensions, although not all. These results can inform dietary guidance and other policies that seek to address the goals of improved dietary intakes and reduced food-related emissions.

Diets containing the highest levels of dairy products are associated with greater eutrophication potential but higher nutrient intakes and lower financial cost in the United Kingdom. Hobbs DA, Durrant C, Elliott J, Givens DI, Lovegrove JA. Eur J Nutr. 2019 Mar 29.

  • Previously, the nutritional contribution, environmental and financial costs of dairy products have been examined independently.
  • The aim of this paper was to determine the nutritional adequacy, financial cost and environmental impact of UK diets according to dairy content.
  • In this cross-sectional study of adults (19-64 years) from the UK National Diet and Nutrition Survey years 1-4 (n = 1655), dietary intakes assessed from 4-day estimated food diaries were organized into quartiles (Q) total grams of dairy (milk, cheese, yogurt, dairy desserts).
  • The data was analyzed controlling for age, sex and energy intake with Bonferroni post hoc test for nutritional adequacy, Alternative Healthy Eating Index (AHEI-2010), environmental impact [greenhouse gas emissions (GHGE), eutrophication and acidification potentials], financial cost, markers of health and cardio-metabolic diseases.
  • Nutritional adequacy, particularly for protein, calcium and iodine and AHEI-2010 were significantly higher and systolic blood pressure was significantly lower for the higher-dairy diets, compared with diets containing lower dairy.
  • Diets in highest in dairy had lower financial cost (- 19%) and the greatest eutrophication potential, compared with diets lowest in dairy (+ 29%). Yet the environmental (GHGE) and financial costs per unit nutrient (riboflavin, zinc, iodine, magnesium, calcium, potassium) were lower in the highest consumers than the lowest.
  • In conclusion, diets with the highest dairy content had higher nutrient composition, better diet quality, were associated with lower blood pressure and financial cost, but they had higher eutrophication potential.

Environmental and Economic Effects of Changing to Shelf-Stable Dairy or Soy Milk for the Breakfast in the Classroom Program. Beckerman JP, Blondin SA, Richardson SA, Rimm EB. Am J Public Health. 2019 Mar 21:e1-e3.

  • US schools have offered liquid dairy milk in the national school meal programs for nearly a century. Much of this milk ends up unopened and/or thrown away. This unused milk has substantial economic and global warming effects.
  • Reducing food waste in national school meal programs is a national priority; the 2016 National Environmental Policy Act (NEPA) mandates that all federal agencies, including the USDA, incorporate environmental considerations in their planning and decision-making.
  • To objective of this study was to estimate the economic and environmental effects of reducing milk waste from the US Breakfast in the Classroom (BIC) School Breakfast Program by replacing conventional milk with shelf-stable dairy or soy milk.
  • The results showed that replacing conventional dairy milk with shelf-stable dairy or soy milk would reduce milk-associated GHGE by 28.5% (0.133 kg CO2e) or 79.8% (0.372 kg CO2e) per student per meal, respectively. Nationally, this equates to driving 248 million or 693 million fewer miles annually, respectively.
  • This change would increase milk costs 1.9% ($0.005) or 59.4% ($0.163) per student per meal, respectively.
  • Replacing conventional milk with shelf-stable dairy or soy milk could substantially reduce waste and concomitant GHGE in BIC; switching to shelf-stable dairy has low net costs.

Do Europeans consider sustainability when making food choices? A survey of Polish city-dwellers. Rejman K, Kaczorowska J, Halicka E, Laskowski W. Public Health Nutr. 2019 Mar 12:1-10.

  • Previous studies show that people present positive attitude towards sustainable diet while their everyday food choices do not follow sustainable diet rules.
  • The objective of this study was to obtain a better insight into the conceptualization of sustainable consumption among consumers with special focus on food choice determinants.
  • A structured questionnaire was designed, and data were collected among a random group (n 600) of city-dwellers.
  • The results showed that most consumers are not familiar with the concept of sustainability and are not able to define it adequately. Only 6 % of the studied population indicated that sustainable consumption is connected with nutrition.
  • Three segments of consumers were distinguished regarding their attitude to food choice determinants adequate to sustainable diet: Non-Adopters (17 %), Emergents (32 %), Adopters (51 %). Desire to improve health by decreasing body weight was the main driver for sustainable food choices, while prices were the main limitation.
  • Knowledge dissemination on sustainability issues is needed to empower consumers to make more sustainable food choices and to make public health and food policy measures more effective.


Selected Articles on Dairy Intake and Human Health

Human Gut Microbiome Response Induced by Fermented Dairy Product Intake in Healthy Volunteers. Volokh O, Klimenko N, Berezhnaya Y, Tyakht A, Nesterova P, Popenko A, Alexeev D. Nutrients. 2019 Mar 4;11(3). pii: E547.

  • Accumulated data suggests that the gut microbiome can rapidly respond to changes in diet. Consumption of fermented dairy products fortified with probiotic microbes may be associated with positive impact on human health. However, the extent and details of the possible impact of FDP consumption on gut community structure tends to vary across individuals.
  • The purpose of the study was to assess the gut microbial composition before and after fermented dairy product consumption in healthy adults (n= 150).
  • The researchers used microbiome analysis to characterize changes in gut microbiota composition after 30 days of oral intake of a yogurt fortified with Bifidobacterium animalislactis BB-12.
  • Paired comparison of gut microbial content demonstrated an increase in presence of potentially beneficial bacteria, particularly, Bifidobacteriumgenus, as well as Adlercreutzia equolifaciens and Slackia isoflavoniconvertens. 
  • At a functional level, an increased capacity to metabolize lactose and synthesize amino acids was observed accompanied by a lowered potential for synthesis of lipopolysaccharides. Cluster analysis revealed that study volunteers segregated into two groups with post-intervention microbiota response that was dependent on the baseline microbial community structure.

A multicenter, double-blind, randomized, placebo-controlled trial to evaluate the effect of consuming Growing Up Milk “Lite” on body composition in children aged 12-23 mo. Wall CR, Hill RJ, Lovell AL, Matsuyama M, Milne T, Grant CC, Jiang Y, Chen RX, Wouldes TA, Davies PSW. Am J Clin Nutr. 2019 Mar 1;109(3):576-585. 

  • Growing Up Milk (GUM) was developed to assist young children in meeting their nutritional requirements during the second year of life. However, there is limited evidence that GUM improves nutritional status and growth in young children.
  • The purpose of this study was to evaluate the effect of consuming Growing Up Milk “Lite” (GUMLi) (reduced protein cow’s milk with synbiotics and micronutrients added) compared with standard cow milk as part of a whole diet for 1 y on body composition at 2 y of age.
  • The GUMLi Trial was a multicenter, double-blind, randomized placebo-controlled trial conducted in Auckland and Brisbane. Healthy 1-y-olds were recruited and randomly assigned to receive either GUMLi or standard cow milk for 12 months as part of a whole diet. The primary outcome was percentage body fat at 2 years of age.
  • 160 children (80 per group) were randomly assigned, and 134 (67 per group) were included in the modified intention-to-treat analyses.
  • The mean percentage body fat at 12 months was 23.3% in the GUMLi group and 25.7% in the cow milk group. After adjusting for baseline outcome and study location, the estimated mean difference in percentage body fat between the intervention and control at 12 months was -2.19%.
  • Both fat mass and the fat mass index were significantly lower in the GUMLi group at 12 months than in the cow milk group. At 2 years of age, children who consumed Growing Up Milk with a lower protein content than cow milk over 12 months had a lower percentage of body fat. 

Nutritional status of iodine in children: When appropriateness relies on milk consumption and not adequate coverage of iodized salt in households. García Ascaso MT, Pérez PR, Alcol EC, López AL, de Lucas Collantes C, Santos IM, Tessier E, Segura SA. Clin Nutr ESPEN. 2019 Apr;30:52-58.

  • Iodine deficiency inhibits the normal development of human beings and is the leading cause of preventable mental retardation.
  • This study aims to update the urinary iodine concentrations and the intake of iodized salt in children in Madrid (Spain).
  • A cross-sectional study was designed where 217 children aged 3-14 years old were studied. A nutritional survey including the intake of iodized salt and other iodine-rich foods was performed. In addition, the urinary concentration of iodine was determined in each patient.
  • Near 60% of the surveyed households routinely used iodized salt. Significant differences in age, sex, country of birth, or country of birth and parents educational levels and iodized salt consumption were not found.
  • The median of the urinary iodine level was significantly higher in boys than girls and more elevated in younger children. Iodized salt and milk consumption significantly increased the concentration of urinary iodine.
  • Children who drank less than two glasses of milk per day and did not consume iodized salt have four times the risk of iodine deficiency compared to children who daily drank at least two glasses of milk and consumed iodized salt.

Substitutions between dairy products and risk of stroke: Results from the EPIC-NL cohort. Laursen ASD, Sluijs I, Boer JMA, Verschuren WMM, van der Schouw YT, Jakobsen MU. Br J Nutr. 2019 Mar 14:1-21. 

  • The association between intake of different dairy products and the risk of stroke remains unclear.
  • The researchers therefore investigated substitutions between dairy product subgroups and risk of stroke in a high dairy consuming population.
  • This study included 36,886 Dutch men and women. Information about dairy product intake was collected through a food frequency questionnaire. Dairy products were grouped as low-fat milk, whole-fat milk, buttermilk, low-fat yogurt, whole-fat yogurt, cheese and butter.
  • During a median follow-up of 15.2 years, there were 884 stroke cases (503 ischemic and 244 hemorrhagic).
  • Low-fat yogurt substituted for whole fat yogurt was associated with a higher rate of ischemic stroke. Whole fat yogurt as a substitution for any other subgroup was associated with a lower rate of ischemic stroke. The researchers did not observe any associations for hemorrhagic stroke.
  • In conclusion, whole-fat yogurt as a substitution for low-fat yogurt, cheese, butter, buttermilk or milk regardless of fat content was associated with a lower rate of ischemic stroke.

Dose-response relationships between dairy intake and chronic metabolic diseases in a Chinese population. Guo P, Zhu H, Pan H, Feng R, Chen Y, Wang Y, Wang X, Li Y, Yang L, Zhou B, Wang X, Zhao Y. J Diabetes. 2019 Mar 22. 

  • The main causes of chronic metabolic diseases including obesity, diabetes, fatty liver, hypertension and cardiovascular diseases are largely relative to lifestyle, i.e. unhealthy diet, physical inactivity, tobacco and alcohol abuse.
  • Dairy intake has been associated with reduced the risks of obesity, diabetes, cardiovascular disease and metabolic syndrome in developed countries.
  • To purpose of this study was to investigate the associations between dairy intake and chronic metabolic diseases and evaluate the possible dose-response relationships in Chinese.
  • This cross-sectional study included 6,073 adults aged ≥18 years, enrolled from China.
  • The results showed significant inverse associations between dairy intake and overweight/obesity, central obesity and hyperlipidemia. Chronic metabolic disease risk prevention different by dairy subgroup (e.g. yogurt, milk) and by the consumer’s age.
  • In conclusion, dairy intake, especially yogurt, was inversely associated with the prevalence of overweight, obesity, central obesity and hyperlipidemia and these optimal ranges were different among young, middle-age and old participants.

Higher frequency of dairy intake is associated with a reduced risk of breast cancer: Results from a case-control study in Northern and Eastern China. Yu L, Liu L, Wang F, Zhou F, Xiang Y, Huang S, Yin G, Zhuo Y, Ma Z, Zhang Q, Yu Z. Oncol Lett. 2019 Mar;17(3):2737-2744. 

  • The association between dairy intake and breast cancer risk has not been well investigated, especially in the Chinese population.
  • This study aimed to examine the association between the weekly frequency of dairy intake and the risk of breast cancer among women in Northern and Eastern China, and to investigate whether the association varied by hormone receptor status.
  • A total of 1,286 cases of breast cancer and 1,461 controls were enrolled in this study. Dairy intake was obtained using a food-frequency questionnaire (FFQ). Frequency of dairy intake per week was divided into four categories (<1 day/week, 1-2 days/week, 3-4 days/week and 5-7 days/week).
  • This analysis revealed that weekly frequency of dairy intake was strongly inversely associated with breast cancer risk, with the most significant findings in individuals with an intake of 5-7 days/week. In the stratified analyses, women who consumed dairy 5-7 days/week had a lower risk of breast cancer in urban areas, in the group 45-59 years old, and in the group educated to senior high school or above. There was also an inverse association between the weekly frequency of dairy intake and the risk of ER+, PR+, and ER+PR+breast cancer.
  • These results indicated that the weekly frequency of dairy intake was inversely associated with the risk of breast cancer among women in Northern and Eastern China.