Milk and Dairy Product Consumption: An Overview of Systematic Reviews and Meta-Analyses Shows There is No Increase of Risk of All-Cause Mortality

Milk and Dairy Product Consumption and Risk of Mortality: An Overview of Systematic Reviews and Meta-Analyses. Ivan Cavero-Redondo et al. Advances in Nutrition, Volume 10, Issue suppl_2, May 15 2019, Pages S97–S104, https://doi.org/10.1093/advances/nmy128

ABSTRACT: The effect of dairy product consumption on health has received substantial attention in the last decade. However, a number of prospective cohort studies have shown contradictory results, which causes uncertainty about the effects of dairy products on health. We conducted an overview of existing systematic reviews and meta-analyses to examine the association between dairy product consumption and all-cause mortality risk. A literature search was conducted in MEDLINE (via PubMed), EMBASE, the Cochrane Central Database of Systematic Reviews, and the Web of Science databases from their inception to April, 2018. We evaluated the risk of bias of each study included using the AMSTAR 2 tool. The risk ratios (RRs) for each meta-analysis were displayed in a forest plot for dose-response and for high compared with low dairy consumption. The initial search retrieved 2154 articles; a total of 8 meta-analyses were finally included after applying the inclusion and exclusion criteria. The number of included studies in each meta-analysis ranged from 6 to 26 cohort studies, which reported data from 6–28 populations. The sample sizes varied across studies from 24,466 participants reporting 5092 mortality cases to 938,817 participants reporting 126,759 mortality cases. After assessing the risk of bias, 25% of the studies were categorized as acceptable, 25% as good, and 50% as very good. The RRs reported by the meta-analyses ranged from 0.96 to 1.01 per 200 g/d of dairy product consumption (including total, high-fat, low-fat, and fermented dairy products), from 0.99 to 1.01 per 200–244 g/d of milk consumption, and from 0.99 to 1.03 per 10–50 g/d of cheese consumption. The RR per 50 g/d of yogurt consumption was 0.97 (95% CI: 0.85, 1.11). In conclusion, dairy product consumption is not associated with risk of all-cause mortality. This study was registered in PROSPERO as CRD42018091856.

Keywords: milk, cheese, yogurt, butter, meta-analysis, review, mortality



Check also Dietary Protein Sources and All-Cause and Cause-Specific Mortality: The Golestan Cohort Study in Iran. Maryam S. Farvid et al. American Journal of Preventive Medicine, Volume 52, Issue 2, February 2017, Pages 237-248. https://doi.org/10.1016/j.amepre.2016.10.041

Introduction: Dietary protein comes from foods with greatly different compositions that may not relate equally with mortality risk. Few cohort studies from non-Western countries have examined the association between various dietary protein sources and cause-specific mortality. Therefore, the associations between dietary protein sources and all-cause, cardiovascular disease, and cancer mortality were evaluated in the Golestan Cohort Study in Iran.

Methods: Among 42,403 men and women who completed a dietary questionnaire at baseline, 3,291 deaths were documented during 11 years of follow up (2004–2015). Cox proportional hazards models estimated age-adjusted and multivariate-adjusted hazard ratios (HRs) and 95% CIs for all-cause and disease-specific mortality in relation to dietary protein sources. Data were analyzed from 2015 to 2016.

Results: Comparing the highest versus the lowest quartile, egg consumption was associated with lower all-cause mortality risk (HR=0.88, 95% CI=0.79, 0.97, ptrend=0.03). In multivariate analysis, the highest versus the lowest quartile of fish consumption was associated with reduced risk of total cancer (HR=0.79, 95% CI=0.64, 0.98, ptrend=0.03) and gastrointestinal cancer (HR=0.75, 95% CI=0.56, 1.00, ptrend=0.02) mortality. The highest versus the lowest quintile of legume consumption was associated with reduced total cancer (HR=0.72, 95% CI=0.58, 0.89, ptrend=0.004), gastrointestinal cancer (HR=0.76, 95% CI=0.58, 1.01, ptrend=0.05), and other cancer (HR=0.66, 95% CI=0.47, 0.93, ptrend=0.04) mortality. Significant associations between total red meat and poultry intake and all-cause, cardiovascular disease, or cancer mortality rate were not observed among all participants.

Conclusions: These findings support an association of higher fish and legume consumption with lower cancer mortality, and higher egg consumption with lower all-cause mortality.