Cohort studyindependent cross-checkabstract checked★ key study I-DRY-108 in-depth review

Men eating more dairy had more prostate cancer in a large Adventist cohort

Dairy foods, calcium intakes, and risk of incident prostate cancer in Adventist Health Study-2.

Overview

Orlich MJ et al.. Am J Clin Nutr 2022 · PMID 35672028 · DOI 10.1093/ajcn/nqac093

About 27% higher risk at 430 g/day v 20 g/day; also for advanced cancer.

Does the study support the specific claim? Yes · Methodological quality: moderate

Study explained simply

What did the researchers want to find out?: Check dairy and prostate cancer where many eat no dairy.
How was the study done?: Prospective cohort.
How many people, animals or samples were studied?: 28,737 men.
What was actually found?: Higher dairy, higher risk; non-dairy calcium no link.
How large was the observed effect?: HR 1.27 (1.12-1.43).
What do the results mean in everyday life?: Very high dairy may modestly raise prostate cancer risk.
What are the study's limitations?: Observational; screening differences possible.
What does it say about Elawady's specific claim?: Supports the claim as an association.
Do the results apply to Germany and Europe?: Applicable.
What can explicitly not be concluded from this study?: Cannot prove dairy causes prostate cancer or distinguish milk from cheese.

Authors: Orlich MJ et al.
Journal: Am J Clin Nutr
Year: 2022
Identifier: PMID 35672028 DOI 10.1093/ajcn/nqac093
Verification: verified – PubMed efetch 2026-10-26
Retracted: no
Corrections: none
Extent checked: abstract only
Conflicts of interest and funding: NCI grant (record); COI not stated in abstract.

Are dairy foods and calcium associated with incident prostate cancer in a cohort with many low/no-dairy consumers?

Study design: Cohort study – Prospective cohort with calibration substudy (repeated 24-h recalls) and regression calibration
Population: Seventh-day Adventist men, USA and Canada (6389 Black men)
Country: USA/Canada
Period: mean 7.8 y follow-up
Sample size: 28,737 men; 1254 cases (190 advanced)
Inclusion and exclusion criteria: AHS-2 male participants

Exposure / intervention: Dairy foods (g/d), dairy and non-dairy calcium
Comparator: 10th percentile (20.2 g/d) or zero intake
Endpoints: Incident prostate cancer, advanced and non-advanced
Statistical methods: Multivariable proportional hazards; regression calibration

Results: 90th (430 g/d) v 10th percentile (20.2 g/d): HR 1.27 (1.12-1.43); advanced 1.38 (1.02-1.88); non-advanced 1.27 (1.11-1.45); Black participants 1.24 (0.98-1.58); excluding vegans 1.22 (1.03-1.43); calibrated HR 1.75 (1.32-2.32); 90th percentile v zero 1.62 (1.26-2.05). Non-dairy calcium not associated: 1.16 (0.94-1.44). Associations non-linear, steepest at low doses.
Absolute risks: Not reported; crude cohort incidence 5.6 per 1000 person-years; applying HR 1.27 gives roughly 15 extra cases per 1000 men over 10 years (approximation, stats/C-DRY-04_prostate.py).
Authors' conclusion: Men with higher intake of dairy foods, but not non-dairy calcium, had a higher risk of prostate cancer.

Moderate relative association; non-linear; calibrated estimate larger. CIs log-symmetric.

The strongest recent cohort supporting a dairy-prostate cancer association, including advanced cancer.

MR (I-DRY-109) did not find a causal effect overall; WCRF rates the evidence as limited (I-DRY-102).

North American; biologically transferable.

Strengthens the association; causality still unproven.

Multidimensional assessment
Multidimensional assessment
Authenticity of the source	verified
Methodological quality	moderate
Risk of bias	some concerns
Precision of results	moderate
Directness	direct
Reproducibility	partly replicated
Consistency with the overall evidence	mixed
Regional transferability	moderate
Adequacy of the interpretation (by the archive)	not applicable

Which dairy component; causality.