Objective: To test the hypothesis that milk drinking increases the risk of ischaemic heart disease (IHD) and ischaemic stroke in a prospective study.
Design: In the Caerphilly Cohort Study dietary data, including milk consumption, were collected by a semiquantitative food frequency questionnaire in 1979-1983. The cohort has been followed for 20-24 y and incident IHD and stroke events identified.
Subjects: A representative population sample in South Wales, of 2512 men, aged 45-59 y at recruitment.
Main outcome measures: In total, 493 men had an IHD event and 185 an ischaemic stroke during follow-up.
Results: After adjustment, the hazard ratio in men with a milk consumption of one pint (0.57 l) or more per day, relative to men who stated that they consumed no milk, is 0.71 (0.40-1.26) for IHD and 0.66 (0.24-1.81) for ischaemic stroke. At baseline, 606 men had had clinical or ECG evidence of vascular disease, and in these the vascular risk was even lower (0.37; 0.15-0.90). The hazard ratio for IHD and ischaemic stroke combined is 0.64 (0.39-1.06) in all men and 0.37 (0.15-0.90) in those who had had a prior vascular event.
Conclusion: The data provide no convincing evidence that milk consumption is associated with an increase in vascular disease risk. Evidence from an overview of all published cohort studies on this topic should be informative.
Sponsorship: : The Medical Research Council, the University of Wales College of Medicine and Bristol University. Current support is from the Food Standards Agency.