Moderate alcohol benefits vary by race and sex, finds huge US survey
24 April 2015
Compared with no alcohol consumption, sensible levels of drinking have correlated with better heart health. However, a new analysis has revealed that a cardioprotective link from moderate drinking is not the same for people of African ancestry as it is for white ethnicity, and nor across the sexes.
The lowest death risk for black men, including from heart disease, was linked to no alcohol – but it was linked to moderate drinking for white men.
The findings are drawn from the national health interview survey, run by the US Centers for Disease Control and Prevention (CDC), and the analysis of data from 152,180 adults has been published in the American Journal of Public Health.
Data were available for numerous ethnicities and this analysis looked at drinking habits and health outcomes specifically across participants describing themselves as either white or black. Results were also compared between the two sexes.
The relationship of overall death rates from any cause with levels of alcohol consumption varied by both groupings. The researchers, from the Harvard T.H. Chan School of Public Health in Boston, MA, found the following correlations.
For males, the lowest risk of mortality was:
For white men, linked to having 1-2 drinks on 3-7 days a week
For black men, found in those who never drank.
Moderate drinking was protective for females similarly – for white, but not for black women:
The lowest risk of mortality was among white women consuming one drink on 3-7 days a week
But among black women, the lowest death rates were among those having one drink on 2 or fewer days a week.
The study’s lead author says the findings could change public health policy. Chandra Jackson, PhD, epidemiologist and research associate in clinical and translational research at Harvard, says:
“Current dietary guidelines recommend moderate consumption for adult Americans who consume alcoholic beverages. Our study suggests that additional refinements based on race/ethnicity may be necessary.”
Why does alcohol effect differ by race?
The authors discuss the potential explanations for their main finding of racial difference in effects of alcohol consumption, including lifestyle and social factors, and biological and genetic mechanisms.
The researchers call for future research against a list of factors that may vary across different groups of people to explain direct and indirect links to the healthiness and otherwise of alcohol consumption in terms of death risk. They offer these examples for further analysis:
Lifestyle related to diet, physical activity, sleep and “youthful experimentation versus coping with hardships”
Socioeconomic status and other markers of “social integration”
Differences in physical, chemical and social exposures to alcohol, in both occupational and residential environments
Genetic and gender differences.
The epidemiological analysis was of data from 126,369 white people and 25,811 black. The CDC survey data were collected from 1997 to 2002, and follow-up continued to monitor death rates through 2006.
The survey respondents reported the amount and frequency of their intake and answered sociodemographic questions about education, employment and income. The researchers also looked at lack of “social integration” into society, such as living in poverty or being unemployed.
Participants also reported other health-related behaviors, including whether they smoked, and gave information on any medical conditions.
Moderate alcohol consumption was broadly defined as 1-2 drinks a day for men and 1 a day for women, with the paper citing what this might comprise:
“The standard-size drink is typically a 12 fl oz bottle or can of beer, 8-9 fl oz of malt liquor, a 5 fl oz of wine, and a 1.5 fl oz shot of 80-proof spirits.”
All the people surveyed had first been asked: “In your entire life, have you had at least 12 drinks of any type of alcoholic beverage?” Never-drinkers were thus identified, and the rest were categorized further according to their drinking levels in the past year, and the researchers were able to test associations against detailed data on drinking habits.
The conclusion reached for the study’s analysis against death rates is given by this summary:
“Among white men and women, moderate alcohol consumption on most days of the week was associated with lowest mortality risk, but black men and women with similar drinking patterns did not have the same risk reduction compared with those who abstained or drank infrequently.”
On the potential differences in terms of drinking as a social activity, the authors say: “It would be particularly interesting to investigate racial/ethnic differences in reasons for consuming alcohol.”
Touching on potential biological differences, meanwhile, they discuss confusing results: “The rapid metabolism of alcohol among blacks resulting from potential genetic differences could reduce cardiovascular benefits, yet we found a suggestion of benefit for light consumption among black women, but not among black men.”
They call for more research on potential environmental and physiological differences by gender within people of African ethnicity, citing the following potential examples between black men and women:
Occupational and other social conditions
Gastric absorption of alcohol.
Further findings are sure to come on the question of whether alcohol consumption itself, or other factors linked to it, really is beneficial to health. The authors end their paper by stating:
“The divergent findings between white and black men and women in this and other US cohorts raise the unresolved question of whether the apparent cardioprotective effect of alcohol is real, differs for people of African ancestry, or is confounded by the varying lifestyle characteristics of drinkers versus nondrinkers.”