Snus withdrawal linked to weight gain and elevated blood pressure

Snus users who stopped using snus experienced higher blood pressure and gained weight. This has been shown by a research group at Linköping University, Sweden, in a study on 33 people, published in Harm Reduction Journal.

The use and marketing of nicotine snus, which does not contain tobacco, is increasing in the UK, the US, Sweden, and other countries. Nicotine is an addictive substance which, among other things, causes blood pressure and heart rate to rise immediately after intake. But it is unclear what happens in the body when snus users stop using snus.

Previous research in the field has consisted of observational studies comparing snus users and non-snus users, but from such studies it is not possible to draw conclusions about cause and effect. In the current study, researchers have studied differences that occur in connection with snus cessation.

"We show a clinically significant rise in blood pressure after snus cessation, and we think that if healthcare professionals encourage people to stop using snus, it would be best to also check their blood pressure after a while. The effect on blood pressure may vary from person to person. A person with blood pressure problems who stops using snus might need to have their blood pressure medicine adjusted after a few months," says Fredrik Nyström, professor at the Department of Health, Medicine and Caring Sciences at Linköping University and senior physician in internal medicine at the University Hospital in Linköping, who led the study.

According to Fredrik Nyström, the results from the study, which need to be further investigated in more studies, suggest that people who stop using snus and who have cardiovascular problems may need to be followed up by health care to monitor blood pressure readings and weight.

The study participants were aged18 to 70, had normal blood pressure and the majority (65%) were men. Most (65%) used tobacco snus, while 32% used nicotine snus (white snus) and 3% used both types of snus. Tobacco snus is banned in the EU, except in Sweden.

At the beginning of the study, the participants provided blood samples. The researchers measured blood sugar, blood lipids and insulin. The participants also responded to questionnaires about diet and exercise, and had their blood pressure and weight measured. This was repeated after four weeks, and at the end of the study after twelve weeks. Throughout the study, participants measured their blood pressure at home every day using semi-automatic equipment.

The research team has previously shown that nicotine snus raises blood pressure immediately after intake. They therefore expected blood pressure to drop in the 33 people who no longer used snus during the study. But they found something else.

What we saw was that blood pressure rose in those who had stopped using snus, on average 3.7 mm Hg. We find this surprising. We can't find anything that can really explain it. The participants gained an average of 1.8 kilos in weight, but this shouldn't cause that big a difference in blood pressure."

Fredrik Nyström, Professor, Department of Health, Medicine and Caring Sciences at Linköping University

Fredrik Nyström believes that a rise of 3.7 mm Hg in systolic blood pressure is quite high for a group like this, where people had normal blood pressure from the beginning. The increase in blood pressure is about the same as in one of the research group's previous studies on the effect of eating liquorice over a period of time. Too high blood pressure, also called hypertension, increases the risk of cardiovascular disease.

The study participants' blood pressure levelled out after a couple of weeks and then remained at the higher level for the next two months. One unanswered question is what would happen to blood pressure if people started using snus again. The researchers could not examine this in the study as too few participants relapsed into snus use.

"As, according to official figures, more than half of those who try to stop using snus relapse, the study was structured so that two groups would emerge: one that managed to not use snus throughout the study period and group that relapsed. The idea was that we would then be able to see what happens when you start using snus again after a break. But people managed to stop using snus to a much greater extent than we expected," says Fredrik Nyström.

It turned out that, out of the 37 people included in the study, 33 did not use snus during the entire12 weeks of the study. The study's findings are therefore based entirely on the group that stopped using snus and there was no relapse group to compare with.

The study was funded with support from the Primary Health Care Centers Research Fund, Region Östergötland, and the King Gustaf V and Queen Victoria Freemason Foundation. A couple of the researchers behind the study have received consultancy fees from several pharmaceutical companies in the hypertension and diabetes areas, and Fredrik Nyström has received consultancy fees from the Haypp Group and the Environment and Public Health Institute, a think tank. The fees received did not relate to the research project in question. The above organisations have not been involved in the study or influenced the structure or the design of the article.