Milk consumption and risk of mortality from all-cause, cardiovascular disease and cancer in older people

Background: Milk as a common diet is recommended by many guidelines, but the results on the association of milk consumption with the risk of cardiovascular disease (CVD) or cancer were contradictory. Moreover, evidence regarding milk consumption and mortality risk in Chinese is scarce.

Objective: We examined the associations of milk consumption with the risk of all-cause, CVD and cancer mortality in a low milk consumption population using data from the Guangzhou Biobank Cohort Study.

Design: 18,214 participants aged 50+ years without CVD history at baseline (2003-6) were included. Causes of death were identified through record linkage. Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

Results: Of the 18,214 participants, 12,670 (69.6%) did not consume milk, 2669 (14.7%) had moderate (1-3 portions/week; 1 portion = 250 ml) and 2875 (15.8%) had high (3+ portions/week) consumption. During an average follow-up of 11.5 (standard deviation = 2.3) years, 2697 deaths occurred, including 917 CVD and 1029 cancer deaths. Compared with no consumption, the adjusted HR (95% CIs) of all-cause, CVD, ischemic heart disease (IHD) and stroke mortality for moderate milk consumption was 0.92 (0.81-1.04), 0.72 (0.57-0.92), 0.57 (0.38-0.85) and 0.77 (0.63-0.94), respectively. High consumption was associated with a higher risk of total cancer and esophagus cancer mortality, with the adjusted HR (95% CIs) being 1.33 (1.12-1.57) and 3.20 (1.21-8.43) respectively. No significant association of high consumption with lung cancer, liver cancer, gastrointestinal cancer, or colorectal and anal cancer was found.

Conclusions: In our sample of Chinese with much lower milk consumption than those in the West, compared with no consumption, moderate milk consumption showed a lower risk of CVD mortality, but high milk consumption showed a higher risk of total cancer mortality. Further studies are warranted to verify the differential effects of milk on CVD and cancer.