Milk, milk products and lactose intake and ovarian cancer risk: a meta-analysis of epidemiological studies

Artificial and Natural Sweeteners Biased T1R2/T1R3 Taste Receptors Transactivate Glycosylated Receptors on Cancer Cells to Induce Epithelial-Mesenchymal Transition of Metastatic Phenotype

Understanding the role of biased taste T1R2/T1R3 G protein-coupled receptors (GPCR) agonists on glycosylated receptor signaling may provide insights into the opposing effects mediated by artificial and natural sweeteners, particularly in cancer and metastasis. Sweetener-taste GPCRs can be activated by several active states involving either biased agonism, functional selectivity, or ligand-directed signaling. However, there are increasing arrays of sweetener ligands with different degrees of allosteric biased modulation that can vary dramatically in binding- and signaling-specific manners. Here, emerging evidence proposes the involvement of taste GPCRs in a biased GPCR signaling crosstalk involving matrix metalloproteinase-9 (MMP-9) and neuraminidase-1 (Neu-1) activating glycosylated receptors by modifying sialic acids. The findings revealed that most natural and artificial sweeteners significantly activate Neu-1 sialidase in a dose-dependent fashion in RAW-Blue and PANC-1 cells. To confirm this biased GPCR signaling crosstalk, BIM-23127 (neuromedin B receptor inhibitor, MMP-9i (specific MMP-9 inhibitor), and oseltamivir phosphate (specific Neu-1 inhibitor) significantly block sweetener agonist-induced Neu-1 sialidase activity. To assess the effect of artificial and natural sweeteners on the key survival pathways critical for pancreatic cancer progression, we analyzed the expression of epithelial-mesenchymal markers, CD24, ADLH-1, E-cadherin, and N-cadherin in PANC-1 cells, and assess the cellular migration invasiveness in a scratch wound closure assay, and the tunneling nanotubes (TNTs) in staging the migratory intercellular communication. The artificial and natural sweeteners induced metastatic phenotype of PANC-1 pancreatic cancer cells to promote migratory intercellular communication and invasion. The sweeteners also induced the downstream NFκB activation using the secretory alkaline phosphatase (SEAP) assay. These findings elucidate a novel taste T1R2/T1R3 GPCR functional selectivity of a signaling platform in which sweeteners activate downstream signaling, contributing to tumorigenesis and metastasis via a proposed NFκB-induced epigenetic reprogramming modeling.

Dairy intake and risk of hip fracture in prospective cohort studies: non-linear algorithmic dose-response analysis in 486 950 adults

Previous studies on the relationship between dairy consumption and hip fracture risk have reported inconsistent findings. Therefore, we aimed to conduct an algorithmically driven non-linear dose-response meta-analysis of studies assessing dairy intake and risk of developing incident hip fracture. Meta-analysis from PubMed and Google Scholar searches for articles of prospective studies of dairy intake and risk of hip fracture, supplemented by additional detailed data provided by authors. Meta-regression derived dose-response relative risks, with comprehensive algorithm-driven dose assessment across the entire dairy consumption spectrum for non-linear associations. Review of studies published in English from 1946 through December 2021. A search yielded 13 studies, with 486 950 adults and 15 320 fractures. Non-linear dose models were found to be empirically superior to a linear explanation for the effects of milk. Milk consumption was associated with incrementally higher risk of hip fractures up to an intake of 400 g/d, with a 7 % higher risk of hip fracture per 200 g/d of milk (RR 1⋅07, 95 % CI 1⋅05, 1⋅10; P < 0⋅0001), peaking with 15 % higher risk (RR 1⋅15, 95 % CI 1⋅09, 1⋅21, P < 0⋅0001) at 400 g/d versus 0 g/d. Although there is a dose-risk attenuation above 400 g/d, milk consumption nevertheless continued to exhibit elevated risk of hip fracture, compared to zero intake, up to 750 g/d. Meanwhile, the analysis of five cohort studies of yoghurt intake per 250 g/d found a linear inverse association with fracture risk (RR 0⋅85, 95 % CI 0⋅82, 0⋅89), as did the five studies of cheese intake per 43 g/d (~1 serving/day) (RR 0⋅81, 95 % CI 0⋅72, 0⋅92); these studies did not control for socioeconomic status. However, no apparent association between total dairy intake and hip fracture (RR per 250 g/d of total dairy = 0⋅97, 95 % CI 0⋅93, 1⋅004; P = 0⋅079). There were both non-linear effects and overall elevated risk of hip fracture associated with greater milk intake, while lower risks of hip fracture were reported for higher yoghurt and cheese intakes.

Prevention of Epithelial Ovarian Cancer

Given the challenges with achieving effective and durable treatment for epithelial ovarian cancer, primary prevention is highly desirable. Fortunately, decades of research have provided evidence for several strategies that can be deployed to optimize risk reduction. These include surgery, chemoprevention, and lifestyle factor modifications. These broad categories vary in terms of the magnitude of risk reduction possible, the possible short-term and long-term side effects, the degree of difficulty, and acceptability. Thus, the concept of a risk-based model to personalize preventive interventions is advocated to guide discussion between care providers and women at risk. For women with inherited major gene mutations that greatly increase risk of ovarian cancer, surgical approaches have favorable risk to benefit ratios. Chemoprevention and lifestyle factor modifications portend a lower degree of risk reduction but confer lower risk of undesirable side effects. Since complete prevention is not currently possible, better methods for early detection remain a high priority.

Milk consumption and risk of twelve cancers: A large-scale observational and Mendelian randomisation study

BACKGROUND & AIMS

Milk consumption is a modifiable lifestyle factor that has been associated with several cancer types in observational studies. Limited evidence exists regarding the causality of these relationships. Using a genetic variant (rs4988235) near the lactase gene (LCT) locus that proxies milk consumption, we conducted a comprehensive survey to assess potential causal relationships between milk consumption and 12 types of cancer.

METHODS

Our analyses were conducted using white British participants of the UK Biobank (n = up to 255,196), the FinnGen cohort (up to 260,405), and available cancer consortia. We included cancers with previous evidence of an association with milk consumption in observational studies, as well as cancers common in both UK Biobank and FinnGen populations (>1000 cases). We evaluated phenotypic associations of milk intake and cancer incidence in the UK Biobank, and then used a Mendelian randomisation (MR) approach to assess causality in the UK Biobank, FinnGen consortium, and combined analyses incorporating additional consortia data for five cancers. In MR meta-analyses, case numbers for cancers of breast, ovary, uterus, cervix, prostate, bladder and urinary tract, colorectum, and lung ranged between 6000 and 148,000 cases, and between 780 and 1342 cases for cancers of the liver, mouth, stomach and diffuse large B-cell lymphoma.

RESULTS

In observational analyses, milk consumption was associated with higher risk of bladder and urinary tract cancer (OR 1.23, 95% CI 1.03-1.47), but not with any other cancer. This association was not confirmed in the MR analysis, and genetically predicted milk consumption showed a significant association only with lower risk of colorectal cancer (0.89, 0.81-0.98 per additional 50 g/day). In the MR analyses conducted among individual cohorts, genetically predicted milk consumption provided evidence for an association with lower colorectal cancer in the FinnGen cohort (0.85, 0.74-0.97), and in the UK Biobank greater risk of female breast cancer (1.12, 1.03-1.23), and uterine cancer in pre-menopausal females (3.98, 1.48-10.7).

CONCLUSION

In a comprehensive survey of milk-cancer associations, we confirm of a protective role of milk consumption for colorectal cancer. Our analyses also provide some suggestion for higher risks of breast cancer and premenopausal uterine cancer, warranting further investigation.

Cow's Milk in Human Nutrition and the Emergence of Plant-Based Milk Alternatives

Cow's milk is considered a complete food, providing high-quality protein and essential micronutrients, including vitamins and minerals. For medical reasons or as a lifestyle choice, consumers are replacing cow's milk with plant-based milk alternatives (PBMA); some perceive them as healthier alternatives to cow's milk due to their low saturated fatty acid content and no cholesterol content. However, the nutritional composition of PBMA is quite variable between different types and even within, which makes a comparison with cow's milk a complex issue. Furthermore, the consumption of PBMA has been associated with the development of some diseases in infants and children. Meanwhile, the consumption of cow's milk in human health is a controversial issue since it has been associated with a favorable effect in some diseases (such as obesity, type 2 diabetes, and Alzheimer's) and a negative effect in others (such as prostate cancer risk and Parkinson's disease); while in some diseases, there is no consensus in the cow's milk consumption effect. The aim of this review is to make a nutritional comparison of cow's milk with PBMA and to clarify the potential health issues related to their consumption.

Epidemiology beyond its limits

In 1995, journalist Gary Taubes published an article in Science titled "Epidemiology faces its limits," which questioned the utility of nonrandomized epidemiologic research and has since been cited more than 1000 times. He highlighted numerous examples of research topics he viewed as having questionable merit. Studies have since accumulated for these associations. We systematically evaluated current evidence of 53 example associations discussed in the article. Approximately one-quarter of those presented as doubtful are now widely viewed as causal based on current evaluations of the public health consensus. They include associations between alcohol consumption and breast cancer, residential radon exposure and lung cancer, and the use of tanning devices and melanoma. This history should inform current debates about the reproducibility of epidemiologic research results.

Risk Factors for Ovarian Cancer: An Umbrella Review of the Literature

Several non-genetic factors have been associated with ovarian cancer incidence or mortality. To evaluate the strength and validity of the evidence we conducted an umbrella review of the literature that included systematic reviews/meta-analyses that evaluated the link between non-genetic risk factors and ovarian cancer incidence and mortality. We searched PubMed, EMBASE, Cochrane Database of Systematic Reviews and performed a manual screening of references. Evidence was graded into strong, highly suggestive, suggestive or weak based on statistical significance of the random effects summary estimate and the largest study in a meta-analysis, the number of cases, between-study heterogeneity, 95% prediction intervals, small study effects, and presence of excess significance bias. We identified 212 meta-analyses, investigating 55 non-genetic risk factors for ovarian cancer. Risk factors were grouped in eight broad categories: anthropometric indices, dietary intake, physical activity, pre-existing medical conditions, past drug history, biochemical markers, past gynaecological history and smoking. Of the 174 meta-analyses of cohort studies assessing 44 factors, six associations were graded with strong evidence. Greater height (RR per 10 cm 1.16, 95% confidence interval (CI) 1.11-1.20), body mass index (BMI) (RR ≥ 30 kg/m2 versus normal 1.27, 95% CI 1.17-1.38) and three exposures of varying preparations and usage related to hormone replacement therapy (HRT) use increased the risk of developing ovarian cancer. Use of oral contraceptive pill reduced the risk (RR 0.74, 95% CI 0.69-0.80). Refining the significance of genuine risk factors for the development of ovarian cancer may potentially increase awareness in women at risk, aid prevention and early detection.

Dairy Consumption and Total Cancer and Cancer-Specific Mortality: A Meta-Analysis of Prospective Cohort Studies

The association between dairy consumption and cancer mortality varies among studies and remains unclear. Thus, we conducted a comprehensive meta-analysis of prospective cohort studies to examine the association between dairy consumption and total cancer and cancer-specific mortality. We sought eligible studies in PubMed and Web of Science databases for all publications through March 2021, and pooled RRs and 95% CIs were calculated. We identified 34 prospective cohort studies including 3,171,186 participants and 88,545 deaths. Compared with low milk consumption, high milk consumption was associated with higher cancer mortality in females (RR: 1.10; 95% CI: 1.01, 1.21) and people consuming high/whole-fat milk (fat content ≥3.5%) (RR: 1.17; 95% CI: 1.07, 1.28). Increased risks of cancer-specific mortality were detected for liver (RR: 1.13; 95% CI: 1.02, 1.26), ovarian (RR: 1.32; 95% CI: 1.13, 1.55), and prostate (RR: 1.23; 95% CI: 1.02, 1.48) cancers. Also, females with high consumption of fermented milk had a lower cancer mortality risk (RR: 0.85; 95% CI: 0.77, 0.94). High cheese consumption was not associated with total cancer mortality but rather with higher colorectal cancer mortality (RR: 1.22; 95% CI: 1.02, 1.46). There was no association between butter (RR: 1.06; 95% CI: 0.70, 1.59) or total dairy product consumption (RR: 0.99; 95% CI: 0.95, 1.03) and cancer mortality. Our results imply that high milk consumption, especially high/whole-fat milk, was associated with higher cancer mortality, whereas fermented milk consumption was associated with lower cancer mortality, and this was particularly evident in females. Consequently, further studies are warranted.

Steroid Hormone Exposure as a Potential Hazard in Milk Consumers: A Significant Health Challenge in Iran

The presence of steroid hormones in milk is inevitable, and they can be considered as potential carcinogenic agents for consumers. The purpose of this study was to evaluate the level of 17β-estradiol, progesterone, and hydroxyprogesterone in sixty-nine bovine milk samples, collected from April to September 2020, in Hamadan, Iran. The milk samples were analyzed using enzyme-linked immunosorbent assay (ELISA). In this study, the mean contents of 17β-estradiol, progesterone, and hydroxyprogesterone in the milk samples were determined to be 330.5 ± 190.2 pg/ml, 3.57 ± 2.47 ng/ml, and 1.54 ± 0.41 ng/ml, respectively. However, the content of these steroid hormones in milk samples could be considered safe in children and adults, if the milk consumption is assumed to be in the reported range (175–240 ml/daily). Due to the effects of steroid hormones, especially 17β-estradiol, in the etiology of various cancers, regular monitoring of these hormones is recommended in milk and its dairy products in Iran.

High vs. low-fat dairy and milk differently affects the risk of all-cause, CVD, and cancer death: A systematic review and dose-response meta-analysis of prospective cohort studies

Considerable controversy exists regarding the association between milk and dairy consumption and mortality risk. The present systematic review and meta-analysis of prospective studies was undertaken to examine the association of high vs. low-fat dairy and milk consumption with mortality. We searched PubMed/Medline, ISI Web of Science, and Scopus databases through February 2020 for prospective cohort studies that reported the association between milk and dairy consumption and mortality risk. High-fat milk consumption was significantly associated with a greater risk of all-cause (Pooled ES: 1.15; 95% CI: 1.09-1.20, I²=24.5%, p = 0.22), CVD (Pooled ES: 1.09; 95% CI: 1.02-1.16, I²=4.5%, p = 0.38) and cancer mortality (Pooled ES: 1.17; 95% CI: 1.08-1.28, I²=30.1%, p = 0.19). However, total dairy consumption was associated with a lower risk of CVD mortality (Pooled ES: 0.93; 95% CI: 0.88-0.98, I²=59.7%, p = 0.001). Dose-response analysis revealed a significant non-linear association of total dairy consumption with all-cause and CVD mortality. Moreover, high-fat milk consumption was significantly associated with risk of cancer mortality in linear and non-linear dose-response analysis. In conclusion, we found high-fat milk consumption was associated with a higher risk of all-cause, CVD, and cancer mortality. However, total dairy consumption was associated with a lower risk of CVD mortality.

Dietary Changes and Its Impact on Quality of Life among Malay Breast and Gynaecological Cancer Survivors in Malaysia

OBJECTIVE

Fear of cancer recurrent, side effects of treatment and belief in food taboos encourage cancer survivors to make changes in their dietary practices after diagnosis of cancer. The objective of this study was to determine the impact of dietary changes on quality of life (QoL) among Malay breast and gynaecological cancer survivors.

METHODS

Questionnaire of dietary changes was modified from WHEL study and adapted to typical Malay's food intake in Malaysia. A total of 23 items were listed and categorized by types of food and cooking methods.  Four categories of changes "increased", "decreased", "no changes" or "stopped" were used to determine the changes in dietary practices. Score one (+1) is given to positive changes by reference to WCRF/AICR and Malaysia Dietary Guideline healthy eating recommendations. Malay EORTC QLQ-C30 were used to determine the QoL. Sociodemographic, clinical characteristics and anthropometric measurement were also collected.

RESULTS

The mean age of the subjects (n=77) was 50.7±7.8 years old with duration of survivorship 4.0±3.1 years. Subjects mean BMI was 27.8±4.9 kg/m2 which indicate subjects were 31.2% overweight and 32.5% obese. The percentage score of positive dietary changes was 34.7±16.4%. Positive dietary changes were increased intake of green leafy vegetable (49.4%), cruciferous vegetable (46.8%) and boiling cooking methods (45.5%). Subjects reduced their intake of red meat (42.9%), sugar (53.2%) and fried cooking method (44.2%). Subjects stopped consuming milk (41.6%), c 2008-5862 heese (33.8%) and sweetened condensed milk (33.8%). With increasing positive dietary changes, there was a significant improvement on emotional function (rs=0.27; p=0.016) and reduced fatigue symptoms (rs=-0.24; p=0.033).

CONCLUSION

Positive changes in dietary intake improved emotional function and reduced fatigue symptoms after cancer treatment. By knowing the trend of food changes after cancer treatment, enables the formation of healthy food intervention implemented more effective.

Diet and ovarian cancer risk: An umbrella review of systematic reviews and meta-analyses of cohort studies

BACKGROUND & AIMS

Diet may play an important role in the etiology of ovarian cancer (OC). We aimed to evaluate the strength and credibility of evidence pertaining to dietary risk factors for OC.

METHODS

We comprehensively searched PubMed, Web of Science, Cochrane, CINAHL, JBI Database of Systematic Reviews and Implementation Reports, PROSPERO and EMBASE databases to identify related systematic reviews and meta-analyses of prospective cohort studies. This study had been registered at PROSPERO. The registration number is CRD42020187651. For each association, we estimated the summary effect size using fixed and random effects models, the 95% confidence interval and the 95% prediction interval. We assessed heterogeneity, evidence of small-study effects, and excess significance bias.

RESULTS

A total of 22 systematic reviews and meta-analyses were included in the present study. These previous reports evaluated 184 individual studies, which proposed a total of 36 associations between dietary factors and OC risk. Out of the 36 associations, there were no strong, highly suggestive and suggestive evidence, only four (black tea, skim/low-fat milk, lactose, and calcium) were determined to be supported by weak evidence. OC risk was inversely associated with intake of black tea or calcium, and positively associated with intake of skim/low-fat milk or lactose.

CONCLUSIONS

Our studies revealed that four associations between OC risk and dietary factors (black tea, skim/low-fat milk, lactose, and calcium) were supported by weak evidence. The remaining 32 associations were not confirmed. Additional studies are needed to carefully evaluate the relationship between dietary factors and OC risk.

Children and adults should avoid consuming animal products to reduce risk for chronic disease: YES

The consumption of animal products exposes humans to saturated fat, cholesterol, lactose, estrogens, and pathogenic microorganisms, while displacing fiber, complex carbohydrates, antioxidants, and other components needed for health. In the process, consumption of animal products increases the risk for cardiovascular disease, cancer, diabetes, obesity, and other disorders. This dietary pattern also promotes the growth of unhealthful gut bacteria, fostering, among other things, the production of trimethylamine N-oxide, a proinflammatory compound associated with cardiovascular and neurological diseases. When omnivorous individuals change to a plant-based diet, diet quality as measured by the Alternate Healthy Eating Index improves, and the risk of these health problems diminishes. Planning for nutrient adequacy is important with any diet. However, a diet based on vegetables, fruits, whole grains, and legumes, supplemented with vitamin B-12, is nutritionally superior to diets including animal products and is healthful for children and adults.

Serum vitamin D deficiency and risk of epithelial ovarian cancer in Lagos, Nigeria

The studies that have evaluated the association between vitamin D and risk of ovarian cancer have reported inconsistent findings. Many of these studies were carried out in regions with relatively low sunshine all year round unlike in Africa. This study was aimed to determine the relationship between vitamin D deficiency and epithelial ovarian cancer (EOC) amongst women in Lagos, Nigeria. We conducted a case–control study involving women with histologically confirmed EOC (case group) and an equal number of healthy women without cancer (control group) treated at the gynaecological oncology units of two public tertiary hospitals in Lagos, Nigeria, between 1 August, 2016 and 31 May, 2017. Relevant information was obtained from the participants using a structured interviewer-administered questionnaire, and then, venous blood samples were collected and analysed for serum 25-hydroxyvitamin D levels using the CALBIOTECH® 25(OH) vitamin D ELISA kit. The descriptive statistics were conducted for all relevant data, and the multivariable analysis using binary logistic regression model was performed to examine the association between vitamin D deficiency and EOC after adjusting for all possible confounders. The mean age of the participants was 50.6 ± 11.1 years. There was no statistically significant association between serum vitamin D deficiency and EOC (p = 0.09). However, 10 mmol/L change in circulating vitamin D levels was associated with EOC amongst the study participants (adjusted odds ratio 0.96; 95% confidence interval 0.93–0.99; p = 0.04), but following adjustment for potential confounders in a multivariable analysis, there was no statistically significant relationship observed with EOC (adjusted odds ratio 0.99; 95% confidence interval 0.97–1.00; p = 0.06). In addition, there was no evidence of an interaction effect between these confounders and change in circulating 25(OH)D levels in relation to the risk of EOC. The study revealed no statistically significant association between the circulating levels of vitamin D and the risk of EOC. A better assessment of sun exposure in the future as well as better dietary compositional data may help to clarify whether the association between vitamin D and EOC actually exists. Therefore, the future large prospective longitudinal studies are recommended to further examine this relationship and then evaluate the possible need for vitamin D supplementation in women with an increased risk of EOC in Nigeria.

Association between dietary intake and risk of ovarian cancer: a systematic review and meta-analysis

PURPOSE

It is unclear how dietary intake influences the ovarian cancer. The present paper sets out to systematically review and meta-analyze research on dietary intake to identify cases having high- or low-risk ovarian cancer.

METHODS

Scopus, PubMed, and Wiley Online Libraries were searched up to the date November 24, 2019. Two reviewers were requested to independently extract study characteristics and to assess the bias and applicability risks with reference to the study inclusion criteria. Meta-analyses were performed to specify the relationship between dietary intake and the risk of ovarian cancer identifying 97 cohort studies.

RESULTS

No significant association was found between dietary intake and risk of ovarian cancer. The results of subgroup analyses indicated that green leafy vegetables (RR = 0.91, 95%, 0.85-0.98), allium vegetables (RR = 0.79, 95% CI 0.64-0.96), fiber (RR = 0.89, 95% CI 0.81-0.98), flavonoids (RR = 0.83, 95% CI 0.78-0.89) and green tea (RR = 0.61, 95% CI 0.49-0.76) intake could significantly reduce ovarian cancer risk. Total fat (RR = 1.10, 95% CI 1.02-1.18), saturated fat (RR = 1.11, 95% CI 1.01-1.22), saturated fatty acid (RR = 1.19, 95% CI 1.04-1.36), cholesterol (RR = 1.13, 95% CI 1.04-1.22) and retinol (RR = 1.14, 95% CI 1.00-1.30) intake could significantly increase ovarian cancer risk. In addition, acrylamide, nitrate, water disinfectants and polychlorinated biphenyls were significantly associated with an increased risk of ovarian cancer.

CONCLUSION

These results could support recommendations to green leafy vegetables, allium vegetables, fiber, flavonoids and green tea intake for ovarian cancer prevention.

Effects of dairy products, calcium and vitamin D on ovarian cancer risk: a meta-analysis of twenty-nine epidemiological studies

Findings for the roles of dairy products, Ca and vitamin D on ovarian cancer risk remain controversial. We aimed to assess these associations by using an updated meta-analysis. Five electronic databases (e.g. PubMed and Embase) were searched from inception to 24 December 2019. Pooled relative risks (RR) with 95 % CI were calculated. A total of twenty-nine case–control or cohort studies were included. For comparisons of the highest v. lowest intakes, higher whole milk intake was associated with increased ovarian cancer risk (RR 1·35; 95 % CI 1·15, 1·59), whereas decreased risks were observed for higher intakes of low-fat milk (RR 0·84; 95 % CI 0·73, 0·96), dietary Ca (RR 0·71; 95 % CI 0·60, 0·84) and dietary vitamin D (RR 0·80; 95 % CI 0·67, 0·95). Additionally, for every 100 g/d increment, increased ovarian cancer risks were found for total dairy products (RR 1·03; 95 % CI 1·01, 1·04) and for whole milk (RR 1·07; 95 % CI 1·03, 1·11); however, decreased risks were found for 100 g/d increased intakes of low-fat milk (RR 0·95; 95 % CI 0·91, 0·99), cheese (RR 0·87; 95 % CI 0·76, 0·98), dietary Ca (RR 0·96; 95 % CI 0·95, 0·98), total Ca (RR 0·98; 95 % CI 0·97, 0·99), dietary vitamin D (RR 0·92; 95 % CI 0·87, 0·97) and increased levels of circulating vitamin D (RR 0·84; 95 % CI 0·72, 0·97). These results show that whole milk intake might contribute to a higher ovarian cancer risk, whereas low-fat milk, dietary Ca and dietary vitamin D might reduce the risk.

Associations of dairy intake with risk of mortality in women and men: three prospective cohort studies

OBJECTIVE

To examine the association of consumption of dairy foods with risk of total and cause specific mortality in women and men.

DESIGN

Three prospective cohort studies with repeated measures of diet and lifestyle factors.

SETTING

Nurses' Health Study, Nurses' Health Study II, and the Health Professionals Follow-up Study, in the United States.

PARTICIPANTS

168 153 women and 49 602 men without cardiovascular disease or cancer at baseline.

MAIN OUTCOME MEASURE

Death confirmed by state vital records, the national death index, or reported by families and the postal system. During up to 32 years of follow-up, 51 438 deaths were documented, including 12 143 cardiovascular deaths and 15 120 cancer deaths. Multivariable analysis further adjusted for family history of cardiovascular disease and cancer, physical activity, overall dietary pattern (alternate healthy eating index 2010), total energy intake, smoking status, alcohol consumption, menopausal status (women only), and postmenopausal hormone use (women only).

RESULTS

Compared to the lowest category of total dairy consumption (average 0.8 servings/day), the multivariate pooled hazard ratio for total mortality was 0.98 (95% confidence interval 0.96 to 1.01) for the second category of dairy consumption (average 1.5 servings/day), 1.00 (0.97 to 1.03) for the third (average 2.0 servings/day), 1.02 (0.99 to 1.05) for the fourth (average 2.8 servings/day), and 1.07 (1.04 to 1.10) for highest category (average 4.2 servings/day; P for trend <0.001). For the highest compared to the lowest category of total dairy consumption, the hazard ratio was 1.02 (0.95 to 1.08) for cardiovascular mortality and 1.05 (0.99 to 1.11) for cancer mortality. For subtypes of dairy products, whole milk intake was significantly associated with higher risks of total mortality (hazard ratio per 0.5 additional serving/day 1.11, 1.09 to 1.14), cardiovascular mortality (1.09, 1.03 to 1.15), and cancer mortality (1.11, 1.06 to 1.17). In food substitution analyses, consumption of nuts, legumes, or whole grains instead of dairy foods was associated with a lower mortality, whereas consumption of red and processed meat instead of dairy foods was associated with higher mortality.

CONCLUSION

These data from large cohorts do not support an inverse association between high amount of total dairy consumption and risk of mortality. The health effects of dairy could depend on the comparison foods used to replace dairy. Slightly higher cancer mortality was non-significantly associated with dairy consumption, but warrants further investigation.

Dairy foods and health: an umbrella review of observational studies

Evidence on consumption of dairy foods and human health is contradictory. This study aimed to summarize the level of evidence of dairy consumption on various health outcomes. A systematic search for meta-analyses was performed: study design, dose-response relationship, heterogeneity and agreement of results over time, and identification of potential confounding factors were considered to assess the level of evidence. Convincing and probable evidence of decreased risk of colorectal cancer, hypertension and cardiovascular disease, elevated blood pressure and fatal stroke, respectively, was found for total dairy consumption; possible decreased risk of breast cancer, metabolic syndrome, stroke and type-2 diabetes, and increased risk of prostate cancer and Parkinson's disease was also found. Similar, yet not entirely consistent evidence for individual dairy products was reported. Among potential confounding factors, geographical localisation and fat content of dairy have been detected. In conclusions, dairy may be part of a healthy diet; however, additional studies exploring confounding factors are needed to ascertain the potential detrimental effects.

Dairy product consumption and development of cancer: an overview of reviews

OBJECTIVES

To provide a comprehensive systematic overview of current evidence from pooled analyses/meta-analyses and systematic reviews (PMASRs) pertaining to dairy consumption and incident cancer and/or all-cause or cancer-specific mortality.

DESIGN

Overview of reviews.

SETTING

Community setting.

PARTICIPANTS

The unit of analysis is PMASRs. A total of 42 PMASRs was included in this overview of reviews.

INTERVENTIONS/EXPOSURES

Any dairy product consumption (eg, milk, yogurt, etc).

PRIMARY AND SECONDARY OUTCOMES MEASURES

Primary outcome measure is development of any type of cancer. Secondary outcome measures are all-cause mortality and cancer-specific mortality.

RESULTS

From 9693 citations identified, we included 42 PMASRs (52 study reports) published between 1991 and 2017. Thirty-one (74%) of these was pooled analyses/meta analyses, and only 11 (26%) were systematic reviews and meta-analyses. There was a wide variability in the type of study designs included within the other PMASRs, thus contributing to variable and, in instances, divergent estimates of cancer risk for several cancer subtypes. For example, only one systematic review and meta-analysis exclusively included prospective study designs. Most PMASRs were of low to moderate quality based on the Assessing the Methodological Quality of Systematic Reviews (AMSTAR) scores. The median AMSTAR score was 5 (IQR 2-7). Our overview identified conflicting evidence from PMASRs on association between dairy consumption and incident cancers or mortality. Heterogeneity in summary estimates reflected the inclusion of variable study designs and overall low methodological quality of individual PMASRs.

CONCLUSIONS

The association between dairy consumption and cancer risk has been explored in PMASRs with a variety of study designs and of low to moderate quality. To fully characterise valid associations between dairy consumption and risk of cancer and/or mortality rigorously conducted, PMASRs including only high-quality prospective study designs are required.

TRIAL REGISTRATION NUMBER

CRD42017078463.

Lactose Intolerance, Dairy Avoidance, and Treatment Options

Lactose intolerance refers to symptoms related to the consumption of lactose-containing dairy foods, which are the most common source for this disaccharide. While four causes are described, the most common is the genetically-determined adult onset lactose maldigestion due to loss of intestinal lactase governed by control of the gene by a 14,000 kb promoter region on chromosome 2. Gastrointestinal symptoms from lactose have expanded to include systemic effects and have also been confounded by other food intolerances or functional gastrointestinal disorders. Partly because lactose maldigestion is often interpreted as lactose intolerance (symptoms), focus of therapy for these symptoms starts with lactose restriction. However, withholding of dairy foods completely is not appropriate due to a more favorable impact on health. Industrial efforts to substitute with plant-based products is not completely successful at this time. This narrative article reviews the complexities of the perception of lactose intolerance, its epidemiology, and pathogenesis. Treatments are discussed, including the inappropriateness of dairy avoidance. In conjunction, effects of dairy products on 19 common diseases are reviewed. Different methods of treatment, lactose-reduced products, plant-based dairy substitutes, adaptation, prebiotics, exogenous lactase, probiotics, and some other dietary interventions are further discussed.

Calcium Intake and the Risk of Ovarian Cancer: A Meta-Analysis

Several epidemiological studies have evaluated the association between calcium intake and the risk of ovarian cancer. However, the results of these studies remain controversial. Thus, we performed a meta-analysis to explore the association between calcium intake and the risk of ovarian cancer. Pubmed, Embase and Web of Science were searched for eligible publications up to April 2017. Pooled relative risks (RRs) with 95% confidence intervals (CIs) were calculated using the random-effects model. Small-study effect was estimated using Egger's test and the funnel plot. Among 15 epidemiological studies involving 493,415 participants and 7453 cases eligible for this meta-analysis, 13 studies were about dietary calcium intake, 4 studies about dairy calcium intake and 7 studies about dietary plus supplemental calcium intake. When comparing the highest with the lowest intake, the pooled RRs of ovarian cancer were 0.80 (95% CI 0.72-0.89) for dietary calcium, 0.80 (95% CI 0.66-0.98) for dairy calcium and 0.90 (95% CI 0.65-1.24) for dietary plus supplemental calcium, respectively. Dietary calcium was significantly associated with a reduced risk of ovarian cancer among cohort studies (RR = 0.86, 95% CI 0.74-0.99) and among case-control studies (RR = 0.75, 95% CI 0.64-0.89). In subgroup analysis by ovarian cancer subtypes, we found a statistically significant association between the dietary calcium (RR = 0.78, 95% CI 0.69-0.88) and the risk of epithelial ovarian cancer (EOC). This meta-analysis indicated that increased calcium intake might be inversely associated with the risk of ovarian cancer; this still needs to be confirmed by larger prospective cohort studies.

Dairy, calcium, vitamin D and ovarian cancer risk in African-American women

BACKGROUND

No previous study has evaluated the associations of dairy products, lactose, calcium and vitamin D with the risk of ovarian cancer in African-American women, who are known to have high mortality from the disease, as well as to be at risk for calcium and vitamin D deficiency.

METHODS

We evaluated these associations among 490 ovarian cancer cases and 656 age- and site-matched controls of African-American descent recruited into the African American Cancer Epidemiology Study, a population-based case-control study in 11 geographical areas in the US. Multivariable logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

An increased ovarian cancer risk was observed for whole milk consumption and lactose intake (highest quartile vs lowest: OR=1.97, 95% CI: 1.25-3.10;P-trend: 0.008). Calcium intake was associated with a decreased risk of ovarian cancer (OR=0.51, 95 CI%: 0.30-0.86; P-trend: 0.009), but vitamin D intake was not. Longer sun exposure in summer months was found to predict a lower risk (OR=0.71, 95% CI: 0.51-0.99; P-trend: 0.049).

CONCLUSIONS

Our findings suggest that a high-calcium, low-lactose diet, and sun exposure in summer months may reduce the risk of ovarian cancer in African-American women.

Dairy Product, Calcium Intake and Lung Cancer Risk: A Systematic Review with Meta-Analysis

The effects of dairy products on human health have been studied for years. However, the relationship between dairy products as well as calcium intake and the risk of lung cancer is still inconclusive. A total of 32 studies regarding this association were identified from the PubMed and Web of Science databases through April 1, 2015, including 12 cohort studies and 20 case-control studies. After pooling the results of individual studies, the summary RRs (relative risks) of lung cancer for the highest versus lowest intake were 1.05 (95%CI: 0.84–1.31) and 1.08 (95%CI: 0.80–1.46) for total dairy products and milk, respectively. The results on the consumption of cheese, yogurt and low-fat milk were also negative, and the RRs for total and dietary calcium intakes were 0.99 (95%CI: 0.70–1.38) and 0.85 (95%CI: 0.63–1.13), respectively. After stratifying by potential confounders, the results remained consistent in most subgroup analyses. Our study indicates that intake of dairy products or calcium was not statistically associated with the risk of lung cancer. This negative finding provides a conclusive answer to the disease association issue based on current evidence, and suggests that further efforts should be made to find other nutritional risk factors for lung cancer.

Goodness of fit tools for dose-response meta-analysis of binary outcomes

Goodness of fit evaluation should be a natural step in assessing and reporting dose-response meta-analyses from aggregated data of binary outcomes. However, little attention has been given to this topic in the epidemiological literature, and goodness of fit is rarely, if ever, assessed in practice. We briefly review the two-stage and one-stage methods used to carry out dose-response meta-analyses. We then illustrate and discuss three tools specifically aimed at testing, quantifying, and graphically evaluating the goodness of fit of dose-response meta-analyses. These tools are the deviance, the coefficient of determination, and the decorrelated residuals-versus-exposure plot. Data from two published meta-analyses are used to show how these three tools can improve the practice of quantitative synthesis of aggregated dose-response data. In fact, evaluating the degree of agreement between model predictions and empirical data can help the identification of dose-response patterns, the investigation of sources of heterogeneity, and the assessment of whether the pooled dose-response relation adequately summarizes the published results. © 2015 The Authors. Research Synthesis Methods published by John Wiley & Sons, Ltd.

Adaptation to Lactose in Lactase Non Persistent People: Effects on Intolerance and the Relationship between Dairy Food Consumption and Evalution of Diseases

Dairy foods contain complex nutrients which interact with the host. Yet, evolution of lactase persistence has divided the human species into those that can or cannot digest lactose in adulthood. Such a ubiquitous trait has differential effects on humanity. The literature is reviewed to explore how the divide affects lactose handling by lactase non persistent persons. There are two basic differences in digesters. Firstly, maldigesters consume less dairy foods, and secondly, excess lactose is digested by colonic microflora. Lactose intolerance in maldigesters may occur with random lactose ingestion. However, lactose intolerance without maldigestion tends to detract from gaining a clear understanding of the mechanisms of symptoms formation and leads to confusion with regards to dairy food consumption. The main consequence of intolerance is withholding dairy foods. However, regular dairy food consumption by lactase non persistent people could lead to colonic adaptation by the microbiome. This process may mimic a prebiotic effect and allows lactase non persistent people to consume more dairy foods enhancing a favorable microbiome. This process then could lead to alterations in outcome of diseases in response to dairy foods in lactose maldigesters. The evidence that lactose is a selective human prebiotic is reviewed and current links between dairy foods and some diseases are discussed within this context. Colonic adaptation has not been adequately studied, especially with modern microbiological techniques.

Adult lactose digestion status and effects on disease

BACKGROUND

Adult assimilation of lactose divides humans into dominant lactase-persistent and recessive nonpersistent phenotypes.

OBJECTIVES

To review three medical parameters of lactose digestion, namely: the changing concept of lactose intolerance; the possible impact on diseases of microbial adaptation in lactase-nonpersistent populations; and the possibility that the evolution of lactase has influenced some disease pattern distributions.

METHODS

A PubMed, Google Scholar and manual review of articles were used to provide a narrative review of the topic.

RESULTS

The concept of lactose intolerance is changing and merging with food intolerances. Microbial adaptation to regular lactose consumption in lactase-nonpersistent individuals is supported by limited evidence. There is evidence suggestive of a relationship among geographical distributions of latitude, sunhine exposure and lactase proportional distributions worldwide.

DISCUSSION

The definition of lactose intolerance has shifted away from association with lactose maldigestion. Lactose sensitivity is described equally in lactose digesters and maldigesters. The important medical consequence of withholding dairy foods could have a detrimental impact on several diseases; in addition, microbial adaptation in lactase-nonpersistent populations may alter risk for some diseases. There is suggestive evidence that the emergence of lactase persistence, together with human migrations before and after the emergence of lactase persistence, have impacted modern-day diseases.

CONCLUSIONS

Lactose maldigestion and lactose intolerance are not synonymous. Withholding dairy foods is a poor method to treat lactose intolerance. Further epidemiological work could shed light on the possible effects of microbial adaptation in lactose maldigesters. The evolutionary impact of lactase may be still ongoing.

Dose-response relationship between serum 2,3,7,8-tetrachlorodibenzo-p-dioxin and diabetes mellitus: a meta-analysis

We systematically evaluated studies published through May 2014 in which investigators assessed the dose-response relationship between serum levels of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and the occurrence of diabetes mellitus (DM), and we investigated the extent and sources of interstudy heterogeneity. The dose-response relationship between serum TCDD and DM across studies was examined using 2 dependent variables: an exposure level-specific proportion of persons with DM and a corresponding natural log-transformed ratio measure of the association between TCDD and DM. Regression slopes for each dependent variable were obtained for each study and included in a random-effects meta-analysis. Sensitivity analyses were used to assess the influence of inclusion and exclusion decisions, and sources of heterogeneity were explored using meta-regression models and a series of subanalyses. None of the summary estimates in the main models or in the sensitivity analyses indicated a statistically significant association. We found a pronounced dichotomy: a positive dose-response in cross-sectional studies of populations with low-level TCDD exposures (serum concentrations <10 pg/g lipid) and heterogeneous, but on balance null, results for prospective studies of persons with high prediagnosis TCDD body burdens. Considering the discrepancy of results for low current versus high past TCDD levels, the available data do not indicate that increasing TCDD exposure is associated with an increased risk of DM.

Consumption of low-fat dairy products and energy and protein intake in cancer patients at risk of malnutrition

Current nutritional guidelines encourage the reduction of fat intake from animal sources like dairy products. The aim was to determine whether the consumption of low-fat dairy is related to poorer dietary intake and nutritional status in cancer patients at risk of malnutrition. This cross-sectional included patients with solid or hematological malignancies at risk of malnutrition. Nutritional status was studied using Subjective Global Assessment, anthropometry, and grip strength. Dietary intake was evaluated with a 24-h recall and dairy consumption with a structured questionnaire. Seventy-four patients were recruited; 71.6% males of 64.8 yr, most with gastrointestinal malignancies. Only 37.8% consumed whole milk, and 61.4% consumed whole yogurt. Reasons for consumption of low-fat dairies were healthy diet (58.0%), hypercholesterolemia (20.0%), and digestive intolerance (10.0%). There were similar rates of malnutrition according the type of dairy (whole 60.9% vs. low-fat 66.7%, P = 0.640). Low-fat dairies were related to a reduction in energy (whole 1980.1 kcal vs. low-fat 1480.9, P = 0.007) and protein intake (whole 86.0 g vs. low-fat 63.0 g, P = 0.030).

Dairy product consumption and gastric cancer risk: A meta-analysis

AIM: To investigate whether dairy product consumption is a risk factor for gastric cancer.

METHODS: We searched the PubMed and Web of Science databases for English-language studies on dairy product consumption and gastric cancer risk that were published between October 1980 and September 2013. One author independently extracted data and assessed study quality. Based on the heterogeneity results, we used either the fixed effects model or the random effects model to compute the summary relative risks and 95% confidence intervals (CIs). We also analyzed subgroups according to the study design, geographic region, sex, and whether there were adjustments for confounders (smoking and drinking) with respect to the sources of heterogeneity.

RESULTS: We found 39 studies that were potentially eligible for inclusion in this meta-analysis, including 10 cohort studies and 29 case-control studies. The summary relative risk for gastric cancer, comparing the highest and lowest dairy product consumption categories, was 1.06 (95%CI: 0.95-1.18). Specific analyses for milk, butter, and margarine yielded similar results, but the results for cheese and yogurt were different. There was significant heterogeneity for all studies (Q = 112.61; P = 0.000; I² = 67.1%). No publication bias was observed (Egger’s test: P = 0.135; Begg’s test: P = 0.365). There was a nonsignificant association between dairy product consumption and gastric cancer risk in the subgroup analysis for the study design, sex, geographic region, and whether there were adjustments for confounders (smoking and drinking).

CONCLUSION: In our meta-analysis, dairy product consumption was associated with a nonsignificantly increased risk of gastric cancer. However, this result should be verified using large, well-designed prospective studies.

Milk drinking and mortality: findings from the Japan collaborative cohort study

Background

Findings regarding the association between milk consumption and all-cause mortality reported by studies carried out in Western populations have been inconsistent. However, no studies have been conducted in Japan on this issue. The present study aimed to investigate the association of milk drinking with all-cause, cardiovascular, and cancer mortality in Japan.

Methods

The data were obtained from the Japan Collaborative Cohort (JACC) study. A total of 94 980 Japanese adults aged 40–79 years who had no history of cancer, stroke, or chronic cardiovascular diseases were followed between 1988 and 2009. Multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) of mortalities were assessed using a Cox proportional hazard regression model and taking the lowest milk consumption group as the reference.

Results

During a median of 19 years of follow-up, there were 21 775 deaths (28.8% and 35.3% from cardiovascular diseases and cancer, respectively). Drinking milk 1–2 times a month was associated with lower all-cause mortality in men compared to those who never drank milk (multivariable-adjusted HR 0.92; 95% CI, 0.85–0.99). In women, those who drank 3–4 times a week also had a lower mortality risk compared with those who never drank milk (HR 0.91; 95% CI 0.85–0.98). Inverse associations between drinking milk and mortality from cardiovascular diseases and cancer were found only in men.

Conclusions

Drinking milk at least 1–2 times a month was associated with lower all-cause mortality in men compared to never drinking milk. An inverse association was also found between drinking milk and mortality from both cardiovascular diseases and cancer. However, lower all-cause mortality in women was found only in those who drank milk 3–4 times/week.

Lactose intolerance and risk of lung, breast and ovarian cancers: aetiological clues from a population-based study in Sweden

Background:

Individuals with lactose intolerance are recommended to avoid milk or dairy products, which may affect the development of cancer.

Methods:

We identified individuals with lactose intolerance from several Swedish Registers linked to the Swedish Cancer Registry to calculate standardised incidence ratios (SIRs) for cancers in the breast, lung, and ovary.

Results:

A total of 22 788 individuals with lactose intolerance were identified, and their risks of lung (SIR=0.55), breast (SIR=0.79), and ovarian (SIR=0.61) cancers were significantly decreased. Cancer incidences in the siblings and parents of individuals with lactose intolerance were similar to those in the general population.

Conclusions:

In this large cohort study, people with lactose intolerance, characterised by low consumption of milk and other dairy products, had decreased risks of lung, breast, and ovarian cancers, but the decreased risks were not found in their family members, suggesting that the protective effects against these cancers may be related to their specific dietary pattern.

Milk, yogurt, and lactose intake and ovarian cancer risk: a meta-analysis

Inconclusive information for the role of dairy food intake in relation to ovarian cancer risk may associate with adverse effects of lactose, which has been hypothesized to increase gonadotropin levels in animal models and ecological studies. Up to now, several studies have indicated the association between dairy food intake and risk of ovarian cancer, but no identified founding was reported. We performed this meta-analysis to derive a more precise estimation of the association between dairy food intake and ovarian cancer risk. Using the data from 19 available publications, we examined dairy food including low-fat/skim milk, whole milk, yogurt and lactose in relation to risk of ovarian cancer by meta-analysis. Pooled odds ratio (OR) with 95% confidence interval (CI) were used to assess the association. We observed a slightly increased risk of ovarian cancer with high intake of whole milk, but has no statistical significance (OR = 1.228, 95% CI = 1.031-1.464, P = 0.022). The results of other milk models did not provide evidence of positive association with ovarian cancer risk. This meta-analysis suggests that low-fat/skim milk, whole milk, yogurt and lactose intake has no associated with increased risk of ovarian cancer. Further studies with larger participants worldwide are needed to validate the association between dairy food intake and ovarian cancer.

Dairy food and nutrient intake in different life periods in relation to risk of ovarian cancer

PURPOSE

High lactose intake has been suggested to increase epithelial ovarian cancer (EOC) risk. We evaluated the association between lactose consumed during specific life periods (high school, premenopause, and postmenopause) and later risk of EOC.

METHODS

We assessed the association of dairy food and nutrient intake with risk of EOC during 28 years of follow-up including 764 cases in the Nurses' Health Study (NHS) and NHSII. Cox proportional hazards regression was used to model the hazard ratios (HRs) and 95% confidence intervals (CIs) for EOC across categories of dairy food or nutrient intake. We examined dietary intake in adulthood overall, as well as during premenopausal/postmenopausal years and high school.

RESULTS

In analyses of the highest versus lowest cumulative average intake in adulthood, we observed a non-significant inverse association with skim milk intake (HR 0.76, 95% CI 0.54-1.06, p(trend) = 0.05), a non-significant inverse association with lactose intake (HR 0.87, 95% CI 0.69-1.11, p(trend) = 0.22) and no association with consumption of whole milk, dairy calcium, or dairy fat. Similar risk estimates were observed for dairy food/nutrient intake during high school, premenopause or postmenopause. Lactose intake in adulthood was inversely associated with risk of endometrioid EOC (HR 0.32, 95% CI 0.16-0.65, p(trend) < 0.001).

CONCLUSIONS

These findings do not support the hypothesis that higher lactose intake increases EOC risk. The inverse association with endometrioid tumors deserves further study.

Milk, dairy products, and their functional effects in humans: a narrative review of recent evidence

Milk is a widely consumed beverage that is essential to the diet of several millions of people worldwide because it provides important macro- and micronutrients. Milk is recognized as being useful during childhood and adolescence because of its composition; however, its relatively high saturated fat proportion raises issues of potential detrimental effects, namely on the cardiovascular system. This review evaluates the most recent literature on dairy and human health, framed within epidemiologic, experimental, and biochemical evidence. As an example, the effects of milk (notably skimmed milk) on body weight appear to be well documented, and the conclusions of the vast majority of published studies indicate that dairy consumption does not increase cardiovascular risk or the incidence of some cancers. Even though the available evidence is not conclusive, some studies suggest that milk and its derivatives might actually be beneficial to some population segments. Although future studies will help elucidate the role of milk and dairy products in human health, their use within a balanced diet should be considered in the absence of clear contraindications.

Correlation of cancer incidence with diet, smoking and socio- economic position across 22 districts of Tehran in 2008

BACKGROUND

Variation in cancer incidence in geographical locations is due to different lifestyles and risk factors. Diet and socio-economic position (SEP) have been identified as important for the etiology of cancer but patterns are changing and inconsistent. The aim of this study was to investigate correlations of the incidence of common cancers with food groups, total energy, smoking, and SEP.

MATERIALS AND METHODS

In an ecological study, disaggregated cancer data through the National Cancer Registry in Iran (2008) and dietary intake, smoking habits and SEP obtained through a population based survey within the Urban Health Equity Assessment (Urban-HEART) project were correlated across 22 districts of Tehran.

RESULTS

Consumption of fruit, meat and dairy products adjusted for energy were positively correlated with bladder, colorectal, prostate and breast and total cancers in men and women, while these cancers were adversely correlated with bread and fat intake. Also prostate, breast, colorectal, bladder and ovarian cancers had a positive correlation with SEP; there was no correlation between SEP and skin cancer in both genders and stomach cancer in men.

CONCLUSIONS

The incidence of cancer was higher in some regions of Tehran which appeared to be mainly determined by SEP rather than dietary intake. Further individual data are required to investigate reasons of cancer clustering.

Dietary intake and ovarian cancer risk: a systematic review

Ovarian cancer is a leading cause of gynecological cancer death. There is a need to identify modifiable dietary risk factors for this disease. To evaluate the role of diet in ovarian cancer risk, we performed a PRISMA-directed systematic review that included prospective cohort studies with >200 cases (n = 24). Higher risk for ovarian cancer was shown for total, animal, and dairy fat (five of nine studies), as well as total nitrate and possibly total vitamin C. No associations were demonstrated for red meat, fiber, vitamin A, vitamin E, β-carotene, or folate. Vegetables were associated with lower risk in one of three studies; fruit showed no association, although risk estimates were all greater than 1.0. Isoflavones and flavonoids were associated with modestly lower risk in two studies and tea intake was associated with lower risk in one of two studies. This review suggests that no specific dietary factors are consistently associated with ovarian cancer risk. Data by tumor subtypes are limited, but suggest that differential associations by tumor subtype may exist and should be evaluated. Studies of ample sample size, varied exposure, which can better control for dietary measurement error, are needed to fully define dietary recommendations for ovarian cancer prevention.

High- and low-fat dairy intake, recurrence, and mortality after breast cancer diagnosis

BACKGROUND

Dietary fat in dairy is a source of estrogenic hormones and may be related to worse breast cancer survival. We evaluated associations between high- and low-fat dairy intake, recurrence, and mortality after breast cancer diagnosis.

METHODS

We included 1893 women from the Life After Cancer Epidemiology study diagnosed with early-stage invasive breast cancer from 1997 to 2000, who completed the Fred Hutchinson Cancer Research Center Food Frequency Questionnaire after diagnosis. A total of 349 women had a recurrence and 372 died during a median follow-up of 11.8 years, with 189 deaths from breast cancer. We used delayed entry Cox proportional hazards regression to evaluate associations between categories of the cumulative average of dairy fat at baseline and at follow-up 5 to 6 years later and subsequent outcomes. Tests of statistical significance were two-sided.

RESULTS

In multivariable-adjusted analyses, overall dairy intake was unrelated to breast cancer-specific outcomes, although it was positively related to overall mortality. Low-fat dairy intake was unrelated to recurrence or survival. However, high-fat dairy intake was positively associated with outcomes. Compared with the reference (0 to <0.5 servings/day), those consuming larger amounts of high-fat dairy had higher breast cancer mortality (0.5 to <1.0 servings/day: hazard ratio [HR] = 1.20, 95% confidence interval [CI] = 0.82 to 1.77; and ≥1.0 servings/day: HR = 1.49, 95% CI = 1.00 to 2.24, P trend = .05), higher all-cause mortality (P trend < .001), and higher non-breast cancer mortality (P trend = .007); the relationship with breast cancer recurrence was positive but not statistically significant. The higher risk appeared consistent across different types of high-fat dairy products.

CONCLUSIONS

Intake of high-fat dairy, but not low-fat dairy, was related to a higher risk of mortality after breast cancer diagnosis.

Bladder cancer: a simple model becomes complex

Bladder cancer is one of the most frequent malignancies in developed countries and it is also characterized by a high number of recurrences. Despite this, several authors in the past reported that only two altered molecular pathways may genetically explain all cases of bladder cancer: one involving the FGFR3 gene, and the other involving the TP53 gene. Mutations in any of these two genes are usually predictive of the malignancy final outcome. This cancer may also be further classified as low-grade tumors, which is always papillary and in most cases superficial, and high-grade tumors, not necessarily papillary and often invasive. This simple way of considering this pathology has strongly changed in the last few years, with the development of genome-wide studies on expression profiling and the discovery of small non-coding RNA affecting gene expression. An easy search in the OMIM (On-line Mendelian Inheritance in Man) database using "bladder cancer" as a query reveals that genes in some way connected to this pathology are approximately 150, and some authors report that altered gene expression (up- or down-regulation) in this disease may involve up to 500 coding sequences for low-grade tumors and up to 2300 for high-grade tumors. In many clinical cases, mutations inside the coding sequences of the above mentioned two genes were not found, but their expression changed; this indicates that also epigenetic modifications may play an important role in its development. Indeed, several reports were published about genome-wide methylation in these neoplastic tissues, and an increasing number of small non-coding RNA are either up- or down-regulated in bladder cancer, indicating that impaired gene expression may also pass through these metabolic pathways. Taken together, these data reveal that bladder cancer is far to be considered a simple model of malignancy. In the present review, we summarize recent progress in the genome-wide analysis of bladder cancer, and analyse non-genetic, genetic and epigenetic factors causing extensive gene mis-regulation in malignant cells.

Dairy foods and nutrients in relation to risk of ovarian cancer and major histological subtypes

Inconsistent results for the role of dairy food intake in relation to ovarian cancer risk may reflect the potential adverse effects of lactose, which has been hypothesized to increase gonadotropin levels, and the beneficial antiproliferative effects of calcium and vitamin D. Using data from the New England case-control study (1,909 cases and 1,989 controls), we examined dairy foods and nutrients in relation to risk of ovarian cancer overall, histological subtypes and rapidly fatal versus less aggressive disease. We used logistic regression and polytomous logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs). In models that were simultaneously adjusted for total (dietary plus supplements) calcium, total vitamin D and lactose, we observed a decreased overall risk of ovarian cancer with high intake of total calcium [Quartile 4 (Q4, >1,319 mg/day) vs. Quartile 1 (Q1, <655 mg/day), OR = 0.62, 95% CI = 0.49-0.79]; the inverse association was strongest for serous borderline and mucinous tumors. High intake of total vitamin D was not associated overall with ovarian cancer risk, but was inversely associated with risk of serous borderline (Q4, >559 IU/day vs. Q1, <164 IU/day, OR = 0.51, 95% CI = 0.34-0.76) and endometrioid tumors (Q4 vs. Q1, OR = 0.55, 95% CI = 0.39-0.80). We found no evidence that lactose intake influenced ovarian cancer risk or that risk varied by tumor aggressiveness in the analyses of intake of dairy foods and nutrients. The overall inverse association with high intake of calcium and the inverse associations of calcium and vitamin D with specific histological subtypes warrant further investigation.

Use of dairy products, lactose, and calcium and risk of ovarian cancer - results from a Danish case-control study

BACKGROUND

A number of epidemiological studies have examined the association between use of dairy products and risk of ovarian cancer, but results are conflicting. Using data from a large Danish population-based case-control study we here further examined the association between dairy consumption, lactose, and calcium and risk of overall ovarian cancer and histological types of ovarian cancer.

MATERIAL AND METHODS

In the period 1995-1999 we included 554 women with epithelial ovarian cancer and 1554 randomly selected age-matched controls (35-79 years). All women participated in a detailed personal interview that included questions about dairy consumption. Data were analysed using multiple logistic regression models.

RESULTS

Total dairy intake was associated with ovarian cancer risk (OR = 1.11; 95% CI: 1.07-1.15 per 100 ml/day). The association was strongest for milk [OR = 1.14; 95% CI: 1.03-1.27 per glass (200 ml)/day], soured milk products [OR = 1.49; 95% CI: 1.22-1.81 per portion (250 ml)/day] and yoghurt [OR = 1.65; 95% CI: 1.22-2.23 per portion (250 ml)/day]. In contrast, intake of cheese was associated with a decreased risk [OR = 0.70; 95% CI: 0.55-0.89 for > 1 portion (100 ml)/day compared with no intake]. Intake of lactose, but not calcium, was also associated with an increased ovarian cancer risk (OR = 1.24; 95% CI: 1.10-1.40 per 10 g of lactose/day). Similar risk patterns were observed for the different histological types of ovarian cancer, indicating virtually identical aetiologies with regard to dairy intake, lactose, and calcium.

CONCLUSIONS

Our results indicate that intake of dairy products is associated with a modest increased risk of ovarian cancer. In addition, ovarian cancer development was associated with lactose intake.

Diet and prevention of oral cancer: strategies for clinical practice

BACKGROUND

Oral health care professionals can play an important role in preventing oral cancer by performing oral mucosal examinations to detect pre-cancerous changes and by educating patients about oral cancer prevention strategies, including dietary approaches.

CONCLUSIONS

Current evidence supports a diet high in fruits, vegetables and plant-based foods for prevention of oral cancer. Dietary supplements-including vitamins and minerals-have not been shown to be effective as substitutes for a diet high in fruits and vegetables.

CLINICAL IMPLICATIONS

In addition to discussing tobacco and alcohol use with patients (and, if relevant, betel nut and gutka consumption), as well as the risk of sexual transmission of human papillo-mavirus, clinicians should provide dietary advice for the prevention of oral cancer as part of routine patient education practices.

Milk consumption and bladder cancer risk: a meta-analysis of published epidemiological studies

Studies investigating the association of milk consumption with bladder cancer risk have reported inconsistent findings. We conducted a meta-analysis of published cohort and case-control studies to pool the risk estimates of the association between milk intake and bladder cancer. We quantified associations with bladder cancer using meta-analysis of odds ratio (OR) associated with the highest vs. the lowest category of milk intake using fixed- or random-effect models depending on the heterogeneity of effects among studies. Nineteen cohort and case-control studies were eligible for inclusion. High milk intake was significantly associated with decreased risk of bladder cancer (OR, 0.84; 95% CI, 0.71-0.97) when comparing the highest with the lowest category of milk intake. The inverse association was stronger in Asia (OR, 0.60; 95% CI, 0.40-0.81) than North America (OR, 0.89; 95% CI, 0.76-1.03), and no association was observed in Europe (OR, 1.05; 95% CI, 0.85-1.26). This relationship also varied significantly by specific dairy products. Our results suggest that milk may be related to the reduction of bladder cancer risk. Further studies need to clarify the biological mechanisms.

Determinants of geographic patterns of diseases: interaction of lactose/lactase status and sunshine exposure

Geographic patterns of diseases depend on multilayered causes. However, the division of the world's population into two phenotypes regarding lactose digestion and sunshine exposure to fixed areas of the globe are two relatively slow changing variables. It is hypothesized that it is a vectorial interaction between these two variables that provide a backbone to risk modification of many diseases. Lactase non persistence status tends to follow sunshine exposure particularly in Europe but Lactase persistence status is also been shown to be related to pastoral life styles in spotty regions of Africa, Middle East and China. Current emphasis of research favours the modifying role of vitamin D and sunshine. Nevertheless it was demonstrated that national digester/nondigester status has mathematical relationships to geographic distribution of some diseases. These relationships are also similar to that described for the effects of latitude through sunshine and vitamin D. This observation raises a question as to how each one affects disease outcome. In this paper lactose/lactase interactions are first reviewed for eight exemplary diseases. Based on population findings and corroborative meta-analyses gleaned from the literature 6 types of interactions may be classified. Then in a preliminary fashion lactose digester and maldigester status are related to relative annual sunshine exposure. Further the relative national annual sunshine exposure is evaluated to outcomes of the same exemplary diseases. The patterns related to sunshine reflect that obtained with national lactase status proportions and also corroborate a literature review. However, correlations are weak to moderate and only ovarian cancer reached conventional statistical significance. Because these comparisons are based on modest number of national data firm conclusions cannot be made. However, it is argued that evolutionary pressures exerted by regional sunshine exposure may have had influence on a number of relevant genetic polymorphisms in parallel with lactase status. Furthermore influences of ancestral herding and dairy food consumption also may have exerted independent influences on either lactose phenotype. As such both discussed variables are postulated to exert parallel as well as independent effects on modifying geographic disease patterns. These could partly explain both north to south and west to east directional changes.

Effects of cow's milk on reproduction in ICR male mice

OBJECTIVE

To study the effects of Cow's milk on the reproduction in male mice.

METHODS

Twenty-four male mice were divided randomly into two groups: milk group (M) and control group (C). Each mouse was given 10 mL milk per day from 4 to 16 weeks in the group M. At the age of 17 weeks, all the mice were sacrificed.

RESULTS

Serum testosterone was decreased in the group M (P=0.037). No significant difference was found in weight of testes, seminal vesicle or adrenal gland of mice between the groups C and M. However, the weight of seminal vesicle decreased when expressed in g/100 g body weight in the group M. Epididymal sperm concentration, motility, morphology, and sperm head number were not affected by milk.

CONCLUSION

Cow's milk has adverse effects on the reproductive system in ICR male mice. Further studies are needed to clarify the specific effects of milk on reproductive health.

Dairy food, calcium, and risk of cancer in the NIH-AARP Diet and Health Study

BACKGROUND

Dairy food and calcium intakes have been hypothesized to play roles that differ among individual cancer sites, but the evidence has been limited and inconsistent. Moreover, their effect on cancer in total is unclear.

METHODS

Dairy food and calcium intakes in relation to total cancer as well as cancer at individual sites were examined in the National Institutes of Health (NIH)-AARP (formerly known as the American Association of Retired Persons) Diet and Health Study. Intakes of dairy food and calcium from foods and supplements were assessed with a food frequency questionnaire. Incident cancer cases were identified through linkage with state cancer registries. A Cox proportional hazard model was used to estimate relative risks and 2-sided 95% confidence intervals (CIs).

RESULTS

During an average of 7 years of follow-up, we identified 36 965 and 16 605 cancer cases in men and women, respectively. Calcium intake was not related to total cancer in men but was nonlinearly associated with total cancer in women: the risk decreased up to approximately 1300 mg/d, above which no further risk reduction was observed. In both men and women, dairy food and calcium intakes were inversely associated with cancers of the digestive system (multivariate relative risk for the highest quintile of total calcium vs the lowest, 0.84; 95% CI, 0.77-0.92 in men, and 0.77; 95% CI, 0.69-0.91 in women). Decreased risk was particularly pronounced with colorectal cancer. Supplemental calcium intake was also inversely associated with colorectal cancer risk.

CONCLUSION

Our study suggests that calcium intake is associated with a lower risk of total cancer and cancers of the digestive system, especially colorectal cancer.