How Smoking Bans Prevented Heart Attacks In Singapore

An analysis by Duke-NUS researchers finds that Singapore’s 2013 extension of the smoking ban averted heart attacks.

Asian Scientist Magazine (Jan. 13, 2023) —Smoking is a major risk factor for cardiovascular diseases like hypertension and stroke. Even second-hand smoke elevates the risk of developing these diseases. Conversely, stopping smoking or being around smokers less reduces the risk of heart-related diseases, even bringing it down to the same level as that for non-smokers over time.

This is why many countries have smoking-free laws in place. It’s known that the impact of smoking on heart attack increases by dose. Therefore, smoking bans don’t just benefit non-smokers but also help smokers by reducing their exposure to smoke.

Singapore has one of the strictest smoking regulations that it has updated often. In 2013, the country extended the smoking ban to public spaces in residential areas, such as corridors or staircases. In 2016, the ban was extended to parks and reservoirs. In 2017, another law extended the restrictions to taxis, private buses, and educational institutions.

While these were well-intentioned moves, it wasn’t clear if each extension added to the public health benefits of smoke-free spaces. To fill this gap, researchers looked at the impact of anti-smoking laws in Singapore on the rates of heart attack among Singaporeans.

In a study published in the journal BMJ Global Health, researchers observed that the number of heart attacks dropped between 2010 and 2019. “Smoke-free legislation benefitted those aged 65 years and above and, in particular, males”, said Aik, an epidemiologist at Duke-NUS Medical School and the study’s corresponding author.

The authors analyzed monthly reports of heart attack cases from the Singapore Myocardial Infarction Registry. The team found that the 2013 legislation had a protective effect. Before the 2013 law, the rate of heart attacks rose by 0.9 cases per million people every month. After the 2013 law, heart attack rates continued to rise but at a more modest monthly increase of 0.6 cases per million people.

The team calculated that in the absence of the 2013 law, nearly 21,000 additional cases of heart attacks would have occurred, with 93% of those among people aged 65 and above. On the contrary, they did not find any protective outcome after the 2016 extension.

Following the 2017 extension, data showed a protective effect but it wasn’t statistically significant. However, the fact that the effect was consistent across age groups and male and female sexes suggested that there may have been some benefit of the ban.

Some of the decline in heart attacks may be explained by better diagnostic technology that identifies those at risk. Moreover, heart attacks are only one of the ways second-hand smoke kills. Further research is required to investigate if smoking bans have any impact on the prevalence of respiratory illnesses or other cardiovascular diseases like stroke.

For cities looking to implement or extend smoke-free bans, it is critical to carry out surveillance to identify which parts of the cities, and at what times of the day, have the highest concentration of smokers. Aik said that this would enable a risk-based approach by first focusing the bans on areas where non-smokers are most likely to be exposed to second-hand smoke.

Implementing smoke-free bans, or any public health intervention, involves significant public expenditure. Governments should not assume that each intervention will bring population health benefits. “It’s nice to be optimistic but it’s always important to evaluate the policy for the intended effect”, said Aik.

Source: Duke-NUS Medical School ; Image: EQRoy/Shutterstock

The paper can be found at: Association between the extension of smoke-free legislation and incident acute myocardial infarctions in Singapore from 2010 to 2019: an interrupted time-series analysis | BMJ Global Health

Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

 

Sachin Rawat is a freelance science writer & journalist based in Bangalore, India.

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