High dairy food intake ups risk of prostate cancer

Men who regularly consume dairy foods are more likely to develop prostate cancer than those with a lower level of consumption, a prospective cohort study has found.

“Associations were nonlinear, suggesting greatest increases in risk at relatively low doses,” according to the authors.

A total of 28,737 Seventh-day Adventist men in the US and Canada were included, of whom 6,389 were Black. Some 275 male participants provided repeated 24-h dietary recalls as a calibration substudy. A food frequency questionnaire was used to measure diet.

The authors identified incident cancers by matching with cancer registries. They also performed some analyses using multivariable proportional hazards regressions and regression calibration.

During an average follow-up of 7.8 years, a total of 1,254 incident prostate cancer cases were recorded, of which 190 were advanced. Men at the 90th percentile of dairy intake (430 g/d) showed a higher risk of prostate cancer (hazard ratio [HR], 1.27, 95 percent confidence interval [CI], 1.12‒1.43) than those at the 10th percentile (20.2 g/d).

When comparing the same g/d intakes, the authors noted similar findings for advanced prostate cancers (HR, 1.38, 95 percent CI, 1.02‒1.88), for nonadvanced cases (HR, 1.27, 95 percent CI, 1.11‒1.45), in Black participants (HR, 1.24, 95 percent CI, 0.98‒1.58), and when excluding vegan participants (HR, 1.22, 95 percent CI, 1.03‒1.43).

In calibrated dairy regressions involving all participants and all prostate cancer cases, adjusting for dietary measurement error, the HR was 1.75 (95 percent CI, 1.32‒2.32). Men in the 90th percentile intake, compared to those with zero intakes (uncalibrated), had an HR of 1.62 (95 percent CI, 1.26‒2.05).

Notably, higher intakes of nondairy calcium (905 mg/d) showed no significant effect on prostate cancer risk (HR, 1.16, 95 percent CI, 0.94‒1.44) compared with lower intakes (349 mg/d).

“Prostate cancer is the most common noncutaneous cancer in American males,” the authors said. “Causal links between dairy, or dietary calcium, and this cancer are considered suggestive but limited.”