Impact of low and no alcohol beers on purchases of alcohol: interrupted time series analysis of British household shopping data, 2015-2018

Abstract

Objective: To assess the impact of new low and no alcohol beers and reformulated beers in Great Britain on household purchases of grams of alcohol.

Design: Interrupted time series analysis.

Setting: Purchase data from Kantar Worldpanel's household shopping panel for 2015-2018.

Participants: 64 286 British households.

Interventions: Introduction of new no and low alcohol beers during 2017-2018 and reformulation of existing beers to contain less alcohol during 2018.

Main outcome measures: Average alcoholic strength of beer and number of grams of alcohol purchased by households.

Results: As assessed by British household purchase data, 46 new low and no alcohol beer products were introduced during 2015-2018, with a step-jump in volume purchased occurring at the beginning of March 2017 (event 1). During 2015-2018, 33 beer products were reformulated to contain less alcohol, with a step-jump in volume purchased occurring during mid-March 2018 (event 2). Interrupted time series analyses found a combined associated impact of both events with relative reductions of alcohol by volume of beer between 1.2% and 2.3%; purchases of grams of alcohol within beer between 7.1% and 10.2%; and purchases of grams of alcohol as a whole between 2.6% and 3.9%. The reductions were greater for reformulation than for the introduction of new low and no alcohol products. Reductions were independently higher for younger age groups of shoppers and for households that bought the most alcohol.

Conclusions: Even though the events were associated with significant beneficial changes, the volume of purchases of new low and no alcohol beer products (2.6% of the volume of all beers purchased during 2018) and of new reformulated beer products (6.9% of the volume of all beers purchased during 2018) was very small. This indicates that there are future opportunities to increase the volume of such products so as to reduce the harm done by alcohol.

Keywords: epidemiology; public health; substance misuse.

Figure 1

Volume (mL) of beer purchased per adult per household per week across all households from week 1 (first week of 2015) to week 208 (last week of 2018) for new no and low alcohol beer (green, mL right secondary axis; light green, single new product), reformulated beer since time of reformulation (orange, mL right secondary axis; light orange, single reformulated product) and all other beers (grey, left primary axis). Vertical lines, events, dividing periods.

Figure 2

Purchases of new and reformulated beer products (mL of beer) at each of the three periods by sociodemographic characteristics of households: age of the main shopper in years (A); number of grams of alcohol purchased overall per adult per household per week (B); class group (C); household income per adult per year (D); and area of Great Britain (E).

Figure 3

Plots of seasonally adjusted alcohol by volume (%), grams of alcohol purchased within beer and grams of alcohol purchased overall (dots), with predicted values (lines) from the Autoregressive Integrated Moving Average (ARIMA) model. Vertical lines: the two events (jump in purchased new low and no alcohol products, and jump in reformulated products).

Figure 4

Plots of fitted values from Autoregressive Integrated Moving Average (ARIMA) models reporting standardised coefficients that are SDs, resulting in coefficients that are relative and all on the same scale by sociodemographic characteristics of households: age of main shopper in years (A); number of grams of alcohol purchased overall per adult per household per week (B); class group (C); household income per adult per year (D); and area of Great Britain (E) (see online supplemental table 1 for coefficients). Black vertical lines: timing of events.