There is no evidence to support the practice of parents providing alcohol to their teenagers to protect them from alcohol-related risks during early adolescence, according to a prospective cohort study in Australia published in The Lancet Public Health journal.
The six year study of 1927 teenagers aged 12 to 18 and their parents found that there were no benefits or protective effects associated with giving teenagers alcohol when compared to teenagers who were not given alcohol. Instead, parental provision of alcohol was associated with increased likelihood of teenagers accessing alcohol through other sources, compared to teenagers not given any alcohol.
Alcohol consumption is the leading risk factor for death and disability in 15-24 year olds globally. Drinking during adolescence is of concern as this is when alcohol use disorders (ie, dependence on or abuse of alcohol) are most likely to develop.
“In many countries, parents are a key provider of alcohol to their children before they are of legal age to purchase alcohol. This practice by parents is intended to protect teenagers from the harms of heavy drinking by introducing them to alcohol carefully, however the evidence behind this has been limited,” says lead author Professor Richard Mattick, University of New South Wales, Australia. “Our study is the first to analyse parental supply of alcohol and its effects in detail in the long term, and finds that it is, in fact, associated with risks when compared to teenagers not given alcohol. This reinforces the fact that alcohol consumption leads to harm, no matter how it is supplied. We advise that parents should avoid supplying alcohol to their teenagers if they wish to reduce their risk of alcohol-related harms.” 
The study recruited teenagers and their parents between 2010 and 2011 from secondary schools in Perth, Sydney and Hobart (Australia). The teenagers and their parents completed separate questionnaires every year from 2010 to 2016 including information about how teenagers accessed alcohol (from parents, other non-parental sources, or both), binge drinking levels (defined as drinking more than four drinks on a single occasion in the past year), experience of alcohol-related harm, and alcohol abuse symptoms . In the final two years, teenagers were also asked about symptoms of alcohol dependence and alcohol use disorder that could predict alcohol misuse problems in the future.
At the start of the study, the average age of the teenagers was 12.9 years old and by the end of the study the average age was 17.8 years old. The proportion of teenagers who accessed alcohol from their parents increased as the teenagers aged, from 15% (291/1910) at the start of the study to 57% (916/1618) at the end of the study , while the proportion with no access to alcohol reduced from 81% (1556/1910) teenagers to 21% (341/1618).
At the end of the study, 81% (632/784) of teenagers who accessed alcohol through their parents and others reported binge drinking, compared with 62% (224/361) of those who accessed it via other people only, and 25% (33/132) of teens who were given alcohol by their parents only. Similar trends were seen for alcohol-related harm, and for symptoms of possible future alcohol abuse, dependence and alcohol use disorders. The group of teenagers supplied with alcohol from both their parents and other sources were at the greatest risk of the five adverse outcomes, potentially as a result of their increased exposure.
Importantly, teenagers supplied with alcohol by only their parents one year were twice as likely to access alcohol from other sources the next year. As a result, the authors suggest that having alcohol supplied by parents does not mitigate risk of it being supplied by other people, and that parental provision of alcohol did not appear to help teenagers deal with alcohol responsibly.
“While governments focus on prevention through school-based education and enforcement of legislation on legal age for buying and drinking alcohol, parents go largely unnoticed. Parents, policy makers, and clinicians need to be made aware that parental provision of alcohol is associated with risk, not with protection, to reduce the extent of parental supply in high-income countries, and in low-middle-income countries that are increasingly embracing the consumption of alcohol.” Says Professor Mattick. 
The authors note some limitations, including that teenagers from low socioeconomic status backgrounds – for whom alcohol-related issues are more common – were underrepresented in the study. In addition, the binge drinking measure (defined as drinking more than four drinks on a single occasion in the past year) was conservative, which may affect the associations identified.
The results may not apply to other countries, in particular where there is lower alcohol consumption than Australia, and the research does not account for the amount of alcohol supplied by parents, or the context in which it is given.
Writing in a linked Comment, Professor Stuart Kinner, Murdoch Children’s Research Institute, Australia, says: “An important strength of the study is the careful adjustment for potential confounders. Nevertheless, it is difficult to exclude the possibility that some parents provided alcohol to their children in response to other, unmeasured risk factors, such as alcohol expectancies… Further research is required to better understand why some parents choose to supply their children with alcohol… The findings by Mattick and colleagues strongly suggest that parental supply of alcohol to adolescents does not protect against future alcohol-related harm, and might in fact increase risk. However, before drawing firm conclusions, it will be important to replicate this finding in larger samples that permit more granular characterisation of both exposures and outcomes, and in samples with at least proportionate representation of socioeconomically disadvantaged families. In view of the substantial role of alcohol in the burden of disease for adolescents, evidence-based prevention of alcohol-related harm across the social gradient is crucial."