A study of 23 EU countries found that larger price differences between high and low priced cigarettes are associated with higher infant mortality.

Scientists already know that high cigarette prices reduce smoking rates, and that levels of smoking affect infant mortality. However until now, there have been no studies to explore the link between cigarette price differentials and infant mortality.

Now, for the first time, researchers from Imperial College London have found an association between infant mortality rates and the differences in costs between higher and lower priced cigarettes. The authors say that eliminating budget cigarettes from the market may help to reduce infant deaths globally.

The paper, published in the journal JAMA Pediatrics, analysed nearly 54 million births across 23 EU countries from 2004 to 2014. The researchers obtained data on cigarette prices over this period and examined whether differences between average priced and budget cigarettes were linked to infant death rates.

Dr Filippos Filippidis, lead author of the study from Imperial's School of Public Health, said: "Thanks to tax and price control measures, cigarettes in EU countries are more expensive than ever before. However, the tobacco industry is good at finding loopholes to ensure that budget cigarettes stay available. In this study, we found that the availability of budget cigarettes is associated with more infant deaths."

During the ten years, overall infant mortality declined in all countries from 4.4 deaths per 1000 births in 2004 to 3.5 deaths per 1000 births in 2014. The cost of average priced cigarettes increased during this time in all countries studied. The difference between average priced and budget cigarettes varied from 12.8 per cent to 26.0 per cent on average over the study period.

According to the results, increases in the average price of cigarettes were associated with reductions in infant mortality. A one Euro increase per pack in the average cigarette price was associated with 0.23 fewer deaths per 1,000 live births in the same year, and an additional 0.16 fewer deaths per 1,000 live births in the following year.

However, a ten per cent increase in the price difference between budget and average priced cigarettes was associated with 0.07 more deaths per 1,000 live births the following year. This means that 3,195 infant deaths could potentially have been avoided if there had been no price difference between cigarette products over the study period.

Increasing the price of cigarettes reduces smoking in the general population and is particularly effective at encouraging young people and those on low incomes to stop smoking. The authors say the lower infant mortality link with price increases seen in this study is likely due to less exposure to second hand smoke among pregnant women and infants, especially in the home. It could also be due to fewer pregnant women smoking.

The authors say that although EU governments have made cigarettes more expensive by increasing taxes, tobacco companies have responded with differential pricing strategies, where tax increases are loaded onto premium brands. This causes a price gap between higher and lower priced cigarettes that gives smokers the option to switch to cheaper products, making tax increases less effective.

Professor Christopher Millett, senior author on the study from the School of Public Health, said: "Increasing taxation on tobacco is a highly effective strategy to protect child health. Our findings suggest that tobacco tax policy should be designed to not only increase the average price of cigarettes but also to eliminate the price difference between higher and lower priced cigarettes."

The article is titled,"Association of Cigarette Price Differentials With Infant Mortality in 23 European Union Countries."