SAN FRANCISCO – in a review of almost 200,000 participants presented at the annual scientific sessions at the American Diabetes Association.
M. Alexander Otto/MDedge News
Dr. Jean-Philippe Drouin-Chartier
Increasing yogurt consumption was also independently associated with a moderately lower risk of type 2 diabetes, and increasing cheese consumption with a moderately higher risk.
It might have been that yogurt and low-fat milk were simply indicators of healthier living and that cheese consumption – in the study, most commonly on pizza or as processed slices on cheeseburgers – indicated a less healthy way of life, but “we tried our best to control for confounders,” said study lead Jean-Philippe Drouin-Chartier, PhD, of the Harvard School of Public Health, Boston.
And it is possible, he said, that lactic acid bacteria in yogurt could have some effect on the gut microbiome that protects against type 2 disease.
Total dairy consumption has not changed much over the past few decades, but people are drinking less milk and eating more cheese and yogurt. Dr. Drouin-Chartier and colleagues wondered how that affected the risk of type 2 diabetes.
The investigators correlated changes in dairy consumption during 4-year intervals with the incidence of type 2 diabetes in subsequent 4-year intervals using three large, prospective cohort studies that all started about 30 years ago: the Health Professionals Follow-Up Study, Nurses’ Health Study I, and Nurses’ Health Study II.
There were almost 200,000 participants in the pooled analysis, with 2.9 million person-years of follow-up and 12,007 new cases of type 2 diabetes. Participants completed food-frequency questionnaires every 4 years. About 82% of the participants were women. At baseline, they reported consuming about one to four servings of dairy a day.
After adjustment for race, body mass index, calorie intake, family history, physical activity, and other factors associated with type 2 diabetes, the investigators found that increasing yogurt intake by one 4-ounce serving a day while decreasing cheese intake by one 1-ounce serving a day was associated with a 16% (95% confidence interval, 10%-22%) reduction in subsequent risk of type 2 disease. There was an 11% (95% CI, 7%-15%) reduction in risk when a cheese serving was subbed out for a daily 8-ounce serving of reduced-fat milk.
An extra 2 ounces of yogurt a day was associated with a 13% (95% CI, 6%-19%) lower risk of type 2 diabetes, compared with stable consumption, while an extra half ounce of cheese was associated with an 8% (95% CI, 2%-16%) increase in risk.
Overall, substitution of low-fat products (such as 0%-2% milk and low-fat cheese, yogurt, or sherbet) for high-fat products (such as whole milk, ice cream, and high-fat cheese) was associated with a 4% decrease in risk (hazard ratio, 0.96; 95% CI, 0.93-0.99).
However, substitution of reduced-fat milk for whole milk or low-fat cheese for high-fat cheese did not influence the risk, possibly because there is actually not much difference in fat content, Dr. Drouin-Chartier said.
The National Institutes of Health funded the study. Dr. Drouin-Chartier has served as a speaker and consultant for Dairy Farmers of Canada, one other author has advised the group, another has advised the U.S. Department of Agriculture, and the remaining authors had no disclosures.
SOURCE: Drouin-Chartier J et al. ADA 2019, Abstract 159-OR.