Dry January – What’s the Evidence?
The ‘Dry January’ campaign, set up by the charity Alcohol Concern, encourages people to abstain from alcohol for one month. The campaign has gained in popularity since its inauguration in 2013, with a reported two million people signed up in 2015. Alcohol Concern promote a variety of health benefits from participating, including weight loss, improved sleep quality and increased energy. However, despite mass media promotion and purported long-term drinking reductions, the evidence base is relatively sparse and the impact of the campaign has not been rigorously tested.
In December 2015, researchers from the University of Sussex published a study in the Journal of Health Psychology which analysed questionnaire data from 857 British adults (249 men, 608 women) who participated in Dry January in 2014. Data was collected pre-campaign, at the end of January, and 6 months later. The questionnaires collected data on alcohol consumption as well as drink refusal self-efficacy. Superficially the results look promising, with a mean of 71% of participants remaining abstinent for the time of the campaign. At 6 month follow-up approximately 60% reported a reduction in drinking days per week. Statistical analysis demonstrated that participants who were moderate drinkers and had higher self-efficacy were more likely to succeed. Overall, participating in the campaign was associated with reductions in alcohol use at six months, particularly for those who successfully completed the challenge.
However, these results must be taken with caution. The ‘pre- and post-‘ design adopted did not include a control group, and therefore causal inferences (i.e, that participating in Dry January is responsible for long-term drinking reduction) cannot be made, and caution should be adopted when concluding that participating in Dry January can have a positive impact on people’s long term drinking levels. Such statements are liable to be misinterpreted by the media and non-experts.
Conversely, there is indirect evidence of positive short term effects of taking a break from alcohol. For example, studies not conducted on Dry January participators show that short term alcohol abstinence improves insulin resistance and risk for non-alcoholic fatty liver disease. Furthermore, studies support a relationship between sleep disturbance and alcohol use. There is also evidence that alcohol consumption is associated with weight gain [1, 2], although there does seem to be individual variability depending on drinking level and genetic factors.
Data from the Office of National Statistics on alcohol consumption collected since 1980 show that drinking has been steadily falling since 2004, although this data ends in 2013 and so it is not possible to tell yet whether Dry January has contributed further to this general pattern. Other factors such as changing social norms or views on alcohol may have also contributed to these changes. On the other hand it is well documented that individuals consistently under-report how much they drink when asked to self-report. There are consistent differences between how much people report that they drink and sales of alcohol, as reported by HM Revenue and Customs, suggesting that people are drinking more than they are reporting.
To sum up, the evidence for benefits from Dry January is not clear, and robust and well-conducted studies have yet to be carried out. Although claims made in the media about the impact of Dry January are potentially misleading, as the recent guidance from the Chief Medical Officer highlights, there is no safe amount of alcohol to drink, and any attempts to cut-down must be applauded. The jury is still out on whether Dry January itself can have positive long-term effects on the UK’s drinking population.
1. Mozaffarian D, Hao T, Rimm EB, Willett WC, Hu FB. Changes in diet and lifestyle and long-term weight gain in women and men. N Engl J Med. 2011;364(25):2392-404
2. Wannamethee SG, Shaper AG. Alcohol, body weight, and weight gain in middle-aged men. The American journal of clinical nutrition. 2003;77(5):1312-7
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