Diabetes Risk May Be Lowest Drinking 3 to 4 Days Per Week

Miriam E Tucker

July 28, 2017

Drinking alcohol 3 to 4 days per week confers a lower risk of developing diabetes vs never drinkers, new research suggests.

The findings, from a 5-year follow-up of more than 70,000 participants in the Danish Health Examination Survey (DANHES) 2007–2008, were published online July 27 in Diabetologia by Charlotte Holst, of the University of Southern Denmark, Copenhagen, and colleagues.

In terms of quantity, they found the lowest risk of diabetes at 14 drinks per week for men and nine drinks per week for women, with hazard ratios 0.57 and 0.42, respectively, compared with nondrinkers.

Principal investigator Janne S Tolstrup, PhD, urged caution about the clinical implications from these findings.

"In this study, we have a narrow focus on diabetes only. But since alcohol is related to more than 50 different diseases and conditions, reflecting that alcohol affects virtually every organ system of the body, any recommendations about how to drink and how much to drink should not be inferred from this study or any study investigating associations between alcohol and a single outcome such as diabetes," she told Medscape Medical News.

For instance, she noted, the study doesn't take into account the possible link that has been shown between even low alcohol levels and breast cancer. "Our results are interesting because they tell us something about the specific effects of alcohol when it comes to diabetes."

U-Shaped Curve

Among 70,551 DANHES participants surveyed about their frequency and amount of alcohol consumption, 859 men and 887 women developed diabetes (type was not reported) during a median follow-up of 4.9 years (incidence rates 619 and 436 per 100,000 person-years, respectively, P < .0001 for sex difference).

Those who drank alcohol reported a median of eight and four drinks per week in men and women, respectively. Examined all the way up to 40 drinks per week for men and 28 drinks per week for women, the risk for diabetes didn't exceed that of abstainers.

After adjustment for confounders and for average weekly alcohol amount, only consumption of alcohol for 3 to 4 days per week was significant, with hazard ratio 0.73 for men and 0.68 for women compared with abstaining.

There was no clear association between binge drinking and diabetes risk, but that may be due to low numbers, the authors note.

By alcohol type, drinking one to six drinks of beer or wine per week was significantly associated with a lower risk of diabetes in men (HR 0.79), and men who drank seven or more glasses of wine per week had about a 30% lower risk of diabetes compared with abstainers. There was no significant association between frequency of drinking spirits and diabetes in men.

In women, drinking seven or more drinks of spirits per week was associated with a higher diabetes risk (HR 1.83) compared with those drinking less than one per week. But women who drank one or more glasses of wine per week had a lower risk for diabetes than the non–wine drinkers.

Red wine contains polyphenols, which have been shown to lower blood glucose levels and potentially could also lower the risk for type 2 diabetes, the authors note.

Sensitivity analyses excluding people who had dramatically altered their drinking habits within the past 5 years or those under age 40 years didn't change the results.

Dr Tolstrup told Medscape Medical News that while these data don't shed light on the mechanisms, alcohol has been suggested to increase insulin sensitivity and lower fasting insulin resistance, which might play an important role in the progression of diabetes. But "due to limited knowledge about mechanisms between alcohol and glycemic control, the mechanism explaining our results is not clear. That is something future studies should definitely look into."

The collection of data to DANHES was funded by the Ministry of the Interior and Health and the Tryg Foundation. The authors have no further relevant financial relationships.  

Diabetologia. Published online July 27, 2017. Article

For more diabetes and endocrinology news, follow us on Twitter and on Facebook.