New Zealand leads research on natural quit smoking remedy

New Zealand researchers have found that a low cost, plant-based product marketed for smoking cessation in parts of Europe for the last 40 years, is better than nicotine replacement therapy at helping smokers quit. 

Trial results show that the compound cytisine is more effective than nicotine replacement therapy (NRT) at helping smokers quit.

The trial is the first of its kind in the world and was carried out by the National Institute for Health Innovation at the University of Auckland.  The study results were published recently in the top-rated international medical journal, the New England Medical Journal.

Cytisine is a natural, plant-based compound that has been used in smoking cessation for more than 40 years in Eastern Europe and is commercially produced in Bulgaria and Poland.  The trial followed 1310 adult daily smokers who called the national Quitline in New Zealand.

 Smokers were randomly assigned to receive either cytisine for 25 days or eight weeks of NRT. Participants in both groups also received telephone-based Quitline behavioural support.

Results indicated that after using cytisine for 25 days, a smoker was more likely to have quit smoking at six months, compared to using NRT. Compared to NRT, cytisine users experienced a slight increase in side effects; the most common of which were nausea, vomiting and sleep disturbances.

 “Placebo-controlled trials showed that cytisine almost doubles the chances of still being smoke-free at six months,” says study senior author, Dr Natalie Walker, who is the Heart Foundation Douglas Senior Research Fellow (Prevention) at the University of Auckland’s National Institute for Health Innovation. “We wanted to see how effective cytisine was compared to NRT at helping smokers quit.”

 In New Zealand and many other Western countries NRT is the most common medication used to support people to quit smoking.

 Cytisine is an alkaloid which naturally occurs in the Golden Rain (Laburnum anagyroides) and other members of the Fabaceae plant family.

“To the brain cytisine looks a little like nicotine and so it works to alleviate any urges to smoke and reduces the severity of nicotine withdrawal symptoms.  Plus, if you do smoke whilst using cytisine it will be less satisfying - making quitting easier”, says Dr Walker.

Cytisine is a similar type of drug to varenicline (the most effective smoking cessation treatment available, marketed by Pfizer), but is substantially cheaper (cytisine: US$20-$30 for 25-days, NRT: US$112-$685 for 8-10 weeks, varenicline: US$474-501 for 12 weeks).

“There is a big opportunity for low and middle income countries to access a low priced quit remedy,” says Dr Walker. “It’s great for countries that cannot afford more expensive smoking cessation medicines.”

Cytisine is licensed for use as an ‘over the counter’ medication, on prescription or via the internet in a number of Central and Eastern European countries, but it is not yet available in New Zealand.  

“Internationally, very few researchers are undertaking research on the use of cytisine for smoking cessation,” says Associate Professor Chris Bullen, Director of the National Institute for Health Innovation.

“Researchers at the University of Auckland are leading the way.  For example, other researchers in the Department of Pharmacology and at the School of Pharmacy are looking at how cytisine is absorbed and metabolised by the body,” he says.

The trial is funded by the Health Research Council of New Zealand and is one of a number of studies the Institute have undertaken to find innovative options for smokers to stop smoking to achieve smoke-free New Zealand by 2025.  The last trial they completed was one involving e-cigarettes

The study, ‘Randomized comparison of cytisine versus nicotine for smoking cessation’, by Dr Natalie Walker (National Institute for Health Innovation, University of Auckland), Dr Colin Howe (NIHI), Dr Marewa Glover (Centre for Tobacco Control Research, UoA), Dr Hayden McRobbie (Queen Mary University London), Associate Professor Jo Barnes (School of Pharmacy, UoA), Dr Vili Nosa (UoA), Ms Varsha Parag (NIHI), Mr Bruce Bassett (Quit Group), Associate Professor Chris Bullen (Director, NIHI).

Source: Auckland University

Groundwater patches play important role in forest health, water quality

This is Kevin McGuire, associate director of the Virginia Water Resources Research Center. Credit: Virginia Tech

Even during summer dry spells, some isolated patches of soil in forested watersheds remain waterlogged.

These patches act as hot spots of microbial activity that remove nitrogen from groundwater and return it to the atmosphere, researchers from several institutions, including Virginia Tech, report in a leading scientific journal.

The discovery provides insight into the health of a forest. Nitrogen is an important nutrient for plant growth and productivity, but in streams, it can be a pollutant.

"The importance of these fragmented patches of saturated soil and their role in the fate of nitrogen in forested watersheds has been underappreciated until recently," said Kevin McGuire, an associate director of the Virginia Water Resources Research Center based in Virginia Tech's College of Natural Resources and Environment, co-author of the article to be published in the Proceedings of the National Academy of Sciences.

"We were able to determine the importance of denitrification in patches of shallow groundwater, which have largely been overlooked control points for nitrogen loss from temperate forested watersheds," McGuire said.

Most nitrogen is deposited by rain. Temperate forests receive much larger inputs of nitrogen from the atmosphere than they export to streams. Once nitrogen leaves the forest in streams, it can become a water pollutant.

"In some ecosystems, there have been long-term declines in stream water export of nitrogen when inputs have remained elevated," said co-author Christine Goodale, an associate professor of ecology and evolutionary biology at Cornell University.

"Understanding the fate of this nitrogen has been a challenge because denitrification -- a gaseous loss of nitrogen to the atmosphere -- is notoriously difficult to measure," said co-author Peter Groffman, an expert on denitrification at the Cary Institute of Ecosystem Studies.

Denitrification removes nitrogen from water and can therefore improve water quality in downstream lakes and estuaries.

However, nitrogen is also an important nutrient for plant growth in the forest so removals of nitrogen by natural processes can reduce the productivity of the forest.
The research, led by Sarah Wexler while she was a postdoctoral associate in hydrology and stable isotope geochemistry at Cornell University, took place in the Hubbard Brook Experimental Forest in the White Mountains of New Hampshire, where the atmosphere annually deposits five to seven pounds of nitrogen per acre.

The Hubbard Brook Experimental Forest is part of the National Science Foundation's Long Term Ecological Research Network.

McGuire, also an associate professor of hydrology in the Department of Forest Resources and Environmental Conservation, led another National Science Foundation-funded project at the site, which developed an organizing framework to describe and map variations of soil in the watershed that explain shallow groundwater occurrence and frequency.
Groundwater wells from this earlier study were used in the new research to monitor soils that may have had the right conditions to function as hot spots for denitrification.

At sites throughout the forest, the research team measured the presence of nitrate, a form of nitrogen that is highly mobile and reactive in the environment, determined whether the nitrate is a result of atmospheric deposition or microbial conversion, and discovered the nitrogen loss to the atmosphere.

"We were able to differentiate sources of nitrate and show that some of the nitrate was lost to the atmosphere by looking at nitrate at the atomic level, that is, at the isotopic composition of the nitrogen and oxygen in nitrate," said Wexler, who is now at the School of Environmental Sciences at the University of East Anglia in the United Kingdom. "The isotopic composition of nitrate provides a natural way to directly track the details of nitrogen cycling."

McGurie said, "Some work remains to be done, but the aim is to be able to develop a better sense of where and how nitrogen is processed in the environment and be in a position to predict how changes in climate, for example warmer and wetter conditions, affect nitrogen cycling and water quality in forested ecosystems."

Source: Virginia Tech