Moderate alcohol consumption over three-to-four days a week is associated with a markedly reduced risk of diabetes in both men and women, according to data from the Danish Health Examination Survey (DAHNES). Meanwhile, a separate University of California study over 29-years found that among people aged 85 and older, light alcohol consumption is not only associated with reduced mortality, but with greater chances of remaining cognitively healthy.
Previous studies have consistently suggested that light to moderate alcohol consumption – in terms of amount consumed – is associated with a lower risk of diabetes compared with abstention in men and women, whilst heavy consumption is associated with a risk greater than or equal to that of abstainers. However, previous studies examining the role of drinking patterns (number of days drinking per week rather than volume) in relation to diabetes risk have given inconsistent findings, and studies on the effects of particular types of beverage are likewise inconclusive.
The present study, by Professor Janne Tolstrup and colleagues from the National Institute of Public Health of the University of Southern Denmark, examined the effects of drinking frequency on diabetes risk, and also considered association with specific beverage types. In line with earlier studies, intake of wine was more beneficial compared with wine and spirits.
The study used data from the Danish Health Examination Survey (DAHNES) from 2007-2008, in which Danish citizens aged 18 and over completed a self-reporting questionnaire including items on lifestyle and health. Those who already had diagnosed diabetes were excluded, as were women who were pregnant or had recently given birth (likely to result in a change in drinking habits). The study comprised 70,551 DAHNES participants who had given details of alcohol consumption. Follow up information, continued until 2012 with a median follow up of 4.9 years, was gathered via linking to Danish nationwide registries.
Drinking patterns from the questionnaires were established as follows: abstainers – lifetime and current – distinguished to reduce the risk of bias in the results as a consequence of current abstinence being chosen because of health issues; and individuals drinking alcohol — at frequencies of less than 1 day per week; 1-2 days/ week; 3-4 days/ week and 5-7 days/ week. Frequency of binge drinking (of 5 or more beverages on one occasion) was reported as never; less than one day per week; and once or more per week.
Consumption of specific beverage types – wine, beer and spirits – was coded as less than one drink per week, 1-6 drinks per week and 7 or more drinks per week for women and 7-13 and 14 or more drinks per week for men. Beverage specific and overall average weekly alcohol amounts were calculated. Participants were also asked whether their alcohol consumption had increased, decreased or remained stable over the previous 5 years. Information on incident diabetes was obtained from the Danish National Diabetes Register.
The data was adjusted for various confounders: age, sex, level of education, body mass index, smoking status, diet (frequent or infrequent intake of fibre rich bread or grain, vegetables, salad, fruit and fish), leisure time activity, current or previous hypertension and family history of diabetes.
During follow up, 859 men and 887 women developed diabetes. In terms of weekly alcohol amount, the current findings mirrored those of previous studies – the lowest risk of developing diabetes being found in individuals consuming moderate amounts of alcohol. Men consuming 14 drinks per week were found to have a 43% lower risk of diabetes relative to no alcohol intake, and women consuming 9 drinks per week had a 58% lower risk compared with women who did not drink at all.
In terms of frequency, the data revealed that consumption of alcohol 3-4 days a week gave the lowest risk of diabetes – a 27% lower risk in men and a 32% lower risk in women – when compared to individuals drinking less than one day per week.
The study found no clear evidence of an association between binge drinking and diabetes risk, which the authors suggest may be due to low statistical power since few participants reported binge drinking.
Regarding beverage type, moderate to high intake of wine was associated with a lower risk of diabetes, in line with previous studies. The authors suggest that this might be due to a beneficial effect that polyphenols in wine have on management of blood sugar, giving red wine in particular a potential protective impact. Men and women who consumed 7 or more drinks of wine per week had a 25-30% lower risk of diabetes compared with those having less than 1 drink of wine per week.
Consuming between 1 and 6 beers per week gave a 21% lower risk of diabetes in men compared with men drinking less than 1 beer per week, while beer was not associated with diabetes risk in women. The authors found no statistically significant association between average weekly alcohol amount of spirits and diabetes in men. In women, however, having 7 or more drinks of spirits per week was associated with an 83% increased risk of diabetes when compared with women consuming less than 1 drink of spirits per week.
The authors conclude: “Our findings suggest that alcohol drinking frequency is associated with the risk of diabetes and that consumption of alcohol over 3-4 weekdays is associated with the lowest risks of diabetes, even after taking average weekly alcohol consumption into account.”
Aims/hypothesis: Alcohol consumption is inversely associated with diabetes, but little is known about the role of drinking patterns. We examined the association between alcohol drinking patterns and diabetes risk in men and women from the general Danish population.
Methods: This cohort study was based on data from the Danish Health Examination Survey 2007–2008. Of the 76,484 survey participants, 28,704 men and 41,847 women were eligible for this study. Participants were followed for a median of 4.9 years. Self-reported questionnaires were used to obtain information on alcohol drinking patterns, i.e. frequency of alcohol drinking, frequency of binge drinking, and consumption of wine, beer and spirits, from which we calculated beverage-specific and overall average weekly alcohol intake. Information on incident cases of diabetes was obtained from the Danish National Diabetes Register. Cox proportional hazards model was applied to estimate HRs and 95% CIs.
Results: During follow-up, 859 men and 887 women developed diabetes. The lowest risk of diabetes was observed at 14 drinks/week in men (HR 0.57 [95% CI 0.47, 0.70]) and at 9 drinks/week in women (HR 0.42 [95% CI 0.35, 0.51]), relative to no alcohol intake. Compared with current alcohol consumers consuming <1 day/week, consumption of alcohol on 3–4 days weekly was associated with significantly lower risk for diabetes in men (HR 0.73 [95% CI 0.59, 0.94]) and women (HR 0.68 [95% CI 0.53, 0.88]) after adjusting for confounders and average weekly alcohol amount.
Conclusions/interpretation: Our findings suggest that alcohol drinking frequency is associated with risk of diabetes and that consumption of alcohol over 3–4 days per week is associated with the lowest risk of diabetes, even after taking average weekly alcohol consumption into account.
Charlotte Holst, Ulrik Becker, Marit E Jørgensen, Morten Grønbæk, Janne S Tolstrup
Meanwhile, older adults who consume alcohol moderately on a regular basis are more likely to live to the age of 85 without dementia or other cognitive impairments than non-drinkers, according to a University of California – San Diego School of Medicine-led study.
Previous studies have found a correlation between moderate alcohol intake and longevity. “This study is unique because we considered men and women’s cognitive health at late age and found that alcohol consumption is not only associated with reduced mortality, but with greater chances of remaining cognitively healthy into older age,” said senior author Dr Linda McEvoy, an associate professor at UC San Diego School of Medicine.
In particular, the researchers found that among men and women 85 and older, individuals who consumed “moderate to heavy” amounts of alcohol five to seven days a week were twice as likely to be cognitively healthy than non-drinkers. Cognitive health was assessed every four years over the course of the 29-year study, using a standard dementia screening test known as the Mini Mental State Examination.
Drinking was categorised as moderate, heavy or excessive using gender and age-specific guidelines established by the National Institute on Alcohol Abuse and Alcoholism. By its definition, moderate drinking involves consuming up to one alcoholic beverage a day for adult women of any age and men aged 65 and older; and up to two drinks a day for adult men under age 65. Heavy drinking is defined as up to three alcoholic beverages per day for women of any adult age and men 65 and older; and four drinks a day for adult men under 65. Drinking more than these amounts is categorised as excessive.
“It is important to point out that there were very few individuals in our study who drank to excess, so our study does not show how excessive or binge-type drinking may affect longevity and cognitive health in aging,” McEvoy said. Long-term excessive alcohol intake is known to cause alcohol-related dementia.
The researchers said the study does not suggest drinking is responsible for increased longevity and cognitive health. Alcohol consumption, particularly of wine, is associated with higher incomes and education levels, which in turn are associated with lower rates of smoking, lower rates of mental illness and better access to health care.
The UC San Diego School of Medicine research team adjusted the statistical analyses to remove confounding variables, such as smoking or obesity, but noted the study is based only on statistical relationships between different demographic factors, behaviors and health outcomes. There remain on-going debates about whether and how alcohol impacts lifespan or potentially protects against cognitive impairments with age.
One of the study’s advantages, however, is that the data derive from a relatively homogenous population in a geographically well-defined area. All of the 1,344 older adults (728 women; 616 men) who participated in the study are from Rancho Bernardo, a white-collar, middle-to-upper-middle-class suburb in San Diego County. More than 99 percent of the study participants, tracked from 1984 to 2013, are Caucasian with at least some college education.
“This study shows that moderate drinking may be part of a healthy lifestyle to maintain cognitive fitness in aging,” said lead author Erin Richard, a graduate student in the Joint San Diego State University/UC San Diego doctoral programme in public health. “However, it is not a recommendation for everyone to drink. Some people have health problems that are made worse by alcohol, and others cannot limit their drinking to only a glass or two per day. For these people, drinking can have negative consequences.”
To better understand the association of alcohol intake with cognitively healthy longevity (CHL), we explored the association between amount and frequency of alcohol intake and CHL among 1,344 older community-dwelling adults. Alcohol intake was assessed by questionnaire in 1984–1987. Cognitive function was assessed in approximate four-year intervals between 1988 and 2009. Multinomial logistic regression, adjusting for multiple lifestyle and health factors, was used to examine the association between alcohol consumption and CHL (living to age 85 without cognitive impairment), survival to age 85 with cognitive impairment (MMSE score >1.5 standard deviations below expectation for age, sex, and education), or death before age 85. Most participants (88%) reported some current alcohol intake; 49% reported a moderate amount of alcohol intake, and 48% reported drinking near-daily. Relative to nondrinkers, moderate and heavy drinkers (up to 3 drinks/day for women and for men 65 years and older, up to 4 drinks/day for men under 65 years) had significantly higher adjusted odds of survival to age 85 without cognitive impairment (p’s < 0.05). Near-daily drinkers had 2-3 fold higher adjusted odds of CHL versus living to at least age 85 with cognitive impairment (odds ratio (OR) = 2.06; 95% confidence interval (CI): 1.21, 3.49) or death before 85 (OR = 3.24; 95% CI: 1.92, 5.46). Although excessive drinking has negative health consequences, these results suggest that regular, moderate drinking may play a role in cognitively healthy longevity.
Erin L Richard, Donna Kritz-Silverstein, Gail A Laughlin, Teresa T Fung, Elizabeth Barrett-Connor, Linda K McEvoy