Table 2 Characteristics of studies on food and beverage taxation in high-income countries
Study, year & location | Study type, study period & intervention period | Nature of tax or subsidy | Outcome measure | Study population | Sample size | Outcome data source | Major findings | Other impacts | Peer reviewed | Study quality |
|---|---|---|---|---|---|---|---|---|---|---|
Bahl [48] 2003 Ireland | Natural experiment | Excise tax on soft drinks decreased from IR£ 0.37/gal in 1980–1990 to IR£ 0.29/gal in 1990–1992 | Soft drink consumption data | Total population | Not specified | Soft Drink Association of Ireland | Soft drink consumption increase was 6.8 % between 1990 and 1992 | Revenue loss approximately IR£ 2 million/year | Yes | Moderate |
1975–1996 | ||||||||||
21 years | ||||||||||
Oaks [49] 2005 State of Marine, USA | Interrupted time series with a control group | State tax of 5.5 % on soft drinks and selected snacks | BMI | Adults in Maine | Not specified | Behavioural Risk Factor Surveillance system (BRFSS) | No association between obesity and state tax | None recorded | No | Strong |
1991–2001 | ||||||||||
8 years | ||||||||||
Kim [43] 2006 USA | Cross sectional study | State level taxes on soft drinks or snacks | State level obesity prevalence | Total population | Not specified | BRFSS | No association between soft drink taxes and the obesity. | None recorded | Yes | Moderate |
1991–1998 | States that repealed soft drink tax were 13 times more likely to have a high relative increase in obesity prevalence (defined as 75th percentile in the relative increase OR = 13.3; 95 % CI =0.7 – 272.0, p = 0.09) compared to states with a tax. | |||||||||
8 years | ||||||||||
Fletcher [42] 2010 USA | Cross sectional study | Mean soft drink tax rate among states with a tax between 4.1–5.1 %. | Soft drink and other beverage consumption, BMI, obesity, overweight | Children and adolescents in the USA | n = 22,132 | National Health Examination and Nutrition Survey (NHANES) | 1 % point increase in the soft drink tax rate resulted in a reduction in the daily consumption of soft drinks by 18 g (p < 0.05). | Whole milk as a substitute for soft drinks; a 1 % point increase in the soft drink tax rate increased whole milk consumption by 11.1 g per day (p < 0.001) | Yes | Weak |
1989–1994 1999–2006 | Reduction in consumption of soda is completely offset by increase in consumption of other high-calorie drinks. | |||||||||
15 years | No association between soft drink taxes and BMI, obesity, overweight (p > 0.05). | |||||||||
Powel [35] USA 2009 | Longitudinal study | State-level carbonated soda sales tax range 0–8 % | BMI | 8th, 10th and 12th grade students (13 – 19 years of age). | n = 153,673 | Monitoring the Future Survey | No association between taxes and obesity among adolescents at state level. | None recorded | Yes | Moderate |
1997–2006 | Small weakly statistically significant (p < 0.1) negative association was found between vending machine soda tax rates and BMI (−0.006) among teens at risk for overweight (p = 0.09). | |||||||||
10 years | ||||||||||
Fletcher [36] 2010 USA | Cross sectional study | State - level soft drink taxes. Range of mean total tax 3.3 – 5.0 % | BMI | Age ≥18 years in the USA | n = 2,709,422 | BRFSS | 1 % point increase in state soft drink tax rate leads to a decrease in BMI of 0.003 points (p < 0.01) and a decrease in obesity and overweight of 0.01 % (p < 0.1) and 0.02 % (p < 0.01) percentage points respectively. | None recorded | Yes | Moderate |
1990 – 2006 | The impact of state soft drink taxes is larger for females, middle-aged and older individuals, individuals with greater education, and varies according to race and ethnic categories. | |||||||||
16 years | ||||||||||
Fletcher [47] 2010 USA | Cross sectional comparison study | Mean soft drink tax rate among states with a tax 4.7 % | Soft drink consumption, BMI | Children and adolescents in the USA | n = 20,968 | NHANES | Soft drink tax was not effective at reducing soft drink consumption or BMI. | None recorded | Yes | Moderate |
1988–1994 1999–2006 | ||||||||||
15 years | ||||||||||
Nicholson [50] 2010 USA | Cross sectional comparison study | State level fast food restaurant and soda taxes | BMI | Adults 20–64 years of age | n = 1,948,833 | BRFSS | High tax rate (≥8 %) in fast food restaurants significantly reduce mean BMI (−0.55) among females (p < 0.05). | None recorded | No | Moderate |
1997–2008 | Soda tax did not significantly change BMI for all individuals. | |||||||||
12 years | ||||||||||
Sturm [46] 2010 USA | Cross sectional study 2004 1 year | State level carbonated soda sales tax is 4.2 % | Soda consumption, BMI | Children in 5th grade students | n = 7300 | Early Childhood Longitudinal study - Kindergarten cohort 2004 | Soft drink taxes did not significantly affect overall levels of soda consumption or obesity rates. | None recorded | Yes | Moderate |
Higher soda taxes were associated with significantly lower (p < 0.05) BMI gain (−0.033) for the heavier children. Higher soda taxes were associated with significantly lower (p < 0.05) consumption (− 0.165 soda drinks per week) at school for the heavier children. |