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

Abstract

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.

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.

Trial registration number CRD42017078463.