Alcohol expenditure in grocery stores and their associations with tobacco and food expenditures

Alcohol consumption is a significant cause of disease, death and social harm in most countries [1]. Alcohol use tends to cluster with tobacco smoking and unhealthy diets [2, 3], exacerbating inequalities in health. It is difficult to measure alcohol consumption reliably. Traditional survey methods are prone to memory errors and underreporting bias [4]. Using automatically registered purchase data to track retail purchases provides a novel approach, which has already been proven feasible in dietary studies [5–9].

Studies using large retail purchase datasets to reflect alcohol consumption and its associations with other health behaviours related to the purchase of products for consumption, such as healthy and unhealthy foods, are scarce. Individual transactions in supermarkets have been analysed in Denmark [10], with the aim of comparing the diets of wine and beer purchasers. Tobacco purchases were not reported. Sales data from a French supermarket chain were used to analyse associations of alcohol and foods, aggregating the purchases over a period of 1 year [11]. In a sample of British households, alcohol purchases were studied using two-week diaries kept by the participants [12]. Two studies conducted in the United States used product codes from alcohol and food packages that were self-scanned by the participants [13, 14].

The aim of this study is to analyse alcohol purchase patterns from grocery stores of a major Finnish retail chain on the level of individual shopping occasions. In 2016 when the data were collected, alcoholic beverages (beer, cider and alcopops) containing ≤4.7% alcohol were sold in grocery stores in Finland. In this exceptionally large data set, we analysed which alcoholic beverages, and in what quantities, were included in typical shopping baskets and if the alcoholic content of the shopping baskets was associated with food and tobacco expenditures.

By far, the most common basket type was that with no alcoholic beverages (No-alco), followed by baskets with two beers (Two-Beers) or ciders (Two-Ciders) and then with beer for about 15€ (Beer-15) (Table 1). The basket type with cider for about 15€ (Cider-15) was purchased less often than the Beer-15 basket. The proportion of baskets with the largest expenditure on alcoholic beverages [beer for about 30€ (Beer-30) and upwards] was small. The results indicated that larger purchases of cider were typically accompanied by beer purchases as well.

Men were overrepresented among those who bought baskets dominated by beer, compared with those who did not buy alcoholic beverages. The difference was most pronounced in the largest basket, beer for almost 100€ (Beer-100). Women were slightly overrepresented among buyers of the smaller cider baskets, Two-Ciders and Cider-15, while male preponderance was seen in the basket of alcohol for almost 100€, half beer, half cider (Alco-100), when compared with customers who did not buy alcohol.

The mean age of customers who bought beer-dominated baskets was higher than the mean age of those who did not buy alcohol. The age group of 47–58 years was overrepresented in buying the baskets with alcohol. The youngest age group, younger than 35 years, was underrepresented in beer-dominated clusters, while customers 59 years or older were underrepresented in the cider-based clusters.

The amount of money spent on food increased along with the total price of alcohol in the basket (Fig. 1). The smallest alcohol baskets, Two-Beers and Two-Ciders, were similar to No-alco baskets, both in the total amount spent on food and in the food groups chosen. In contrast, the food content of shopping baskets with larger expenditure on alcoholic beverages differed from No-alco baskets. Several foods were systematically associated with alcohol expenditure. The higher the total price of alcohol in the basket, the more money was spent on sausages, soft drinks and waters, snacks, cheese, juices and nectars, juice drinks, sauces and mayonnaise, and cookies, rusks and bagels (examples given in Fig. 1). Baskets with alcohol also contained more foods such as meats, eggs, fish, fats, milks, bread, vegetables, ready-to-eat foods and sweet foods than No-alco baskets (Fig. 2). However, a clear linear relationship between the amount of money spent on alcohol and on food was not observed. Likewise, cigarettes were bought more with alcohol, but the money spent on cigarettes was at its highest in the Beer-50 basket, followed by the Beer-100 and Beer-30 baskets.

There were some differences in food choices according to the alcoholic beverage bought (Fig. 2). Soft drinks and waters, cheese, sweets, cookies, rusks and bagels, and milk and cream were included in larger quantities in the baskets with cider as the dominating alcoholic beverage. On the contrary, fresh pork and beef, pastries, and pickled cucumber and beetroot were bought in larger quantities in baskets with beer as the dominating alcoholic beverage.

In addition to absolute amounts of money, we compared the proportion of each food from the total food and tobacco expenditures between the alcohol-based clusters of shopping baskets (Fig. 2). The percentage of money spent on sausages and snacks increased systematically as the alcohol basket grew larger, and there were up to threefold differences in the proportion of these foods between the alcohol baskets. The proportion of soft drinks and waters peaked in the two largest alcohol baskets, Alco-100 and Beer-100.

The proportion of money spent on fruit and ready-to-eat foods tended to be smaller in the larger alcohol baskets, but the difference was not significant in all baskets. The proportion of canned herrings and roe, pig and bovine meat, and mild ciders and meads tended to increase with increasing alcohol expenditure, but again, the difference was not significant in all baskets. The proportions of ice cream, desserts and yoghurt tended to be smaller in the four largest alcohol baskets, although the differences were not significant in the Alco-100 and Beer-100 baskets or for yoghurt in the Beer-50 basket.

The proportion of cigarettes was at its highest in the mid-sized alcohol baskets, Beer-15, Cider-15 and Beer-30.

In this study, alcohol purchase patterns and the clustering of alcohol with unhealthy foods and tobacco were described in a large data set of Finnish loyalty card holders. The typical expenditure on alcoholic beverages bought from grocery stores at one time was small. In the large majority of cases, no alcoholic beverages were bought, and less than 1 of 20 customers bought more than two beers or ciders. Beer was the most purchased type of alcoholic beverage, and cider was not bought in larger numbers without buying beer as well. Expenditures on non-alcoholic options were negligible; they were not characteristic to any of the clusters. The expenditure on alcohol were associated with expenditures on tobacco and foods rich in saturated fat, salt and added sugar.

Alcohol consumption and smoking tobacco are known to cluster together [2, 16]. However, their co-occurrence on the level of individual shopping occasions has not been studied before. The shopping basket clusters with alcoholic beverages contained more cigarettes than baskets without alcohol. However, cigarette expenditures did not peak in the baskets with the largest expenditure on alcoholic beverages but were most pronounced in the mid-sized alcohol baskets. It may be that the largest alcohol baskets were bought to be shared with many people at a social event, and cigarettes are not shared alongside alcohol. In addition, it is possible that people in whom unhealthy behaviours may cluster buy alcohol in moderate numbers but at a higher frequency. Socially disadvantaged people may buy their alcohol in smaller quantities at a time. To identify groups with potential problems with alcohol consumption, we will analyse the frequency and temporal distribution of alcohol expenditures in our next study.

The finding that the expenditure on alcoholic beverages was positively associated with the expenditure on food does not suggest that those who buy large numbers of alcoholic beverages would have to trim their food budget to compensate for the alcohol expenditure. However, only mild alcoholic beverages are allowed for sale in supermarkets and grocery stores in Finland, so wines and spirits were not included in our data. Mild alcoholic beverages cover about half of the total alcohol consumption in Finland [17]. Correspondingly, a similar association of less alcohol and smaller food budget was observed in French supermarkets using purchase data over 1 year [11], and the authors speculated that this could be explained by a lower socio-economic status. Over a two-week period, the expenditures for alcohol and food purchases in British households were inversely associated [12]. Our findings could indicate that the larger alcohol baskets were bought for social occasions and were intended to be shared with others. In fact, many of the food groups bought alongside the larger alcohol baskets – for instance, sausages, meats, soft drinks, snacks, cookies, sweets and pastries – are typical party or barbecue foods. The Danish study found that those who bought wine and beer also bought more food items [10]. Purchasing two different types of alcohol could indicate a social drinking occasion with the need for more food.

The food most consistently associated with alcohol expenditure in this study were sausages, soft drinks and snacks, as both the absolute and proportional expenditures on them grew consistently with the expenditure on alcoholic beverages. All three food categories may be seen as unhealthy options. Sausages and snacks tend to contain plenty of energy and fat, whereas soft drinks are major sources of refined sugar [18]. The aim of the Danish supermarket study was to compare food purchases of wine versus beer buyers [10]. The results showed that wine buyers favoured healthier foods, such as fruit and vegetables, poultry, oils and low-fat cheese, than beer buyers, who bought more sugar, chips, pork, lamb, sausages and soft drinks. In the French study in which purchases were aggregated over 1 year, beer buyers made unhealthier food choices than those who bought wine or did not buy alcoholic beverages [11]. Our results add to the earlier research that showed that alcohol consumption tends to cluster with unhealthy dietary choices. In many of the previous studies, a simpler indicator variable, such as fruit and vegetable consumption, or a pre-defined index of healthiness has often been used [2, 13, 19].

The same foods were associated with both beer- and cider-dominated shopping baskets, but expenditure on cider tended to correlate with sweet foods more strongly than expenditure on beer did. Perhaps people who choose cider prefer sweet tastes, or possibly this has something to do with the unequal gender or age distribution of cider versus beer buyers. Diets of people with different alcohol preferences have been compared before, mainly to account for the observed health benefits associated with wine [19, 20], but to our knowledge, comparisons between food choices of beer and cider drinkers have not been published before. In a French study, cider was aggregated with beer [21]. In light of these novel results, cider does not seem to associate with healthier food choices than beer like wine does.

This study, using automatically registered purchase data, has its unique strengths and weaknesses compared with traditional survey methods in alcohol and food research. A major weakness is that we did not know whether the foods and beverages were consumed by the same individual who bought them or if they were for family members or friends. Correspondingly, we did not know what was purchased elsewhere or eaten outside the home [10, 11, 13]. Wine and spirits are available only in specialist shops in Finland; therefore, a significant share of alcoholic beverages is outside the scope of our analyses. In general, however, food purchase data were seen to reflect individual diets reasonably well. The first analyses from this study indicate a very high proportion of expenditure among loyalty card owners in S Group stores [15]. The estimated mean of total annual expenditure in our data was 2322€ per customer, while the average consumption of groceries and non-alcoholic drinks in Finnish households was 2916€ per consumption unit during the same time period (22). Another limitation was that purchase data were on product group level and were imprecise for certain purposes. For example, we could not differentiate between common bulk beer and more exclusive craft beer varieties. The unit of measurement of expenditure was euros, and the actual weight or volume of the purchases was unknown.

A major limitation in this study, shared with survey samples, is the potential selection bias according to sociodemographic factors and alcohol consumption patterns. We know that women were over-represented in the present study population, compared with the gender distribution among residents of the study area, whereas both young and old people were under-represented [15]. The present study design offers no means to assess whether individuals who consume more alcohol were less likely to participate. However, it should be noted that the study was not presented to the loyalty card holders specifically as an alcohol consumption study, but as a study on purchase patterns at large. Therefore, it may be unlikely that alcohol consumption patterns as such would be the main driver of the decision of not to participate. Also, the consent for data use does not require personal contact with e.g. an interviewed, which may lower the “shame bound” for some individuals to release the details.

The major strengths of this study were large sample size, objective measurement of consumption without over- or underreporting [5, 10] and unbiased by recall or reporting error, and a potentially more heterogeneous study population than in traditional surveys [15]. The assessment of the association of food and alcohol on single shopping occasions would not be possible in survey data either. Due to social undesirability, self-reported alcohol consumption is typically underestimated. In this study, the permission for data use was requested from the participants in retrospect; thus, they were unaware of their status as study subjects at the time of data collection. As the study period covered a whole calendar year, the results were not affected by potential seasonal variation [10].

In conclusion, clustering of unhealthy choices was seen on the level of individual shopping events, as alcohol expenditure coincided with expenditures on tobacco and foods with saturated fat, salt and added sugar. Numbers of alcoholic beverages bought from grocery stores at one time were small. When large amounts of alcoholic beverages were bought, the expenditure was not compensated by trimming the food budgetThe present study demonstrates the feasibility of analysing individual shopping occasions in large sales data to shed light on consumer choices connected with health behaviour. Automatically registered retail purchase data has its unique strengths and weaknesses compared with more traditional survey data, and as such it provides new points of view into population health behaviour, adding to knowledge based on other methods. The results can be used as an evidence base for targeting interventions and policies. For example, an electronic app providing automatic feedback to the customer based on the contents of individual shopping baskets seems feasible on the basis of the current results. Furthermore, large-scale, country-wide and timely expenditure data could serve as an alert system, should consumption patterns indicative of health risks emerge in certain premises, areas or subgroups.