Q&A: Weather Forecasts to Prevent Strokes and Asthma Attacks in Cuba

Patricia Grogg interviews LUIS LECHA, a researcher at the Centre for Environmental Studies and Services of Villa Clara

Doctors could prevent a crisis if they know ahead of time that the health of their patients will be affected by a change in the weather. Credit: Jorge Luis Baños/IPS

HAVANA, Jun 3 2013 (IPS) – A biometeorological forecast model developed in Cuba to sound the alert on weather conditions that exacerbate chronic diseases like asthma, hypertension and vascular disorders could also help predict the impacts of climate change on health.

Studies have found that significant changes in air oxygen density are related to an increase in visits to health centres by people with chronic ailments.

This service, available on the Internet, began to be used in the Provincial Centre for Hygiene and Epidemiology of the Health Directorate of the central province of Villa Clara.
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Luis Lecha, a researcher at the provincial Centre for Environmental Studies and Services, explains in this interview with IPS that the project to study the effects that weather could have on people’s health got under way in the 1990s.

Q: What does this forecast model, which makes it possible to set up an early warning system in the area of health, consist of?

A: The study was carried out in the period 1991-1995 in 17 hospitals, where for five years information was compiled on a daily basis about patient visits to the doctor for different ailments.

The data was compared with weather reports to study the relation between the climate and the increase in disease occurrence.

Atmospheric oxygen density turned out to be the indicator…that best reflects the influence of weather on the daily occurrence of the illnesses studied.

So the PronBiomet biometeorology model consists of a set of physical-mathematical algorithms programmed to run in computers and calculate ahead of time the day-to-day variations of air oxygen content in broad geographical regions.

Q: The changes in the air oxygen content beyond a certain threshold activate the human body’s response mechanisms and affect its health. Why does this occur?

A: We are all exposed to the actions of external factors, including environmental and meteorological ones.

Our capacity for adaptation, for self-regulation through homeostasis, enables us to adapt, to assimilate that change. As long as the organism can deal with the intensity and duration of the impact of that external factor, your state of health remains stable.

But if for some reason the intensity or duration of the impact exceeds the individual’s capacity for adaptation, the person can suffer from anything from a simple headache or sneeze to the worst consequences, like a heart attack, stroke, or even sudden death.

Q: What illnesses does this warning system cover?

A: So far the effects of weather have been studied for certain chronic diseases like bronchial asthma, hypertension, cardiovascular and cerebrovascular diseases, headaches and some kinds of acute respiratory infections.

Q: How effective have the forecasts proven to be?

A: Effectiveness was calculated using the data from health visits between 2007 and 2011 to the health services in the Playa municipality of Havana and in the Sagua la Grande municipality in Villa Clara.

Asthma is the illness that shows the clearest results, with 94 percent accuracy in the forecasts of the increase in the number of people seeking assistance on days with tropical weather effects, followed by hypertension, with 87 percent effectiveness.

Effectiveness in the case of cerebrovascular accidents and headaches reached 83 and 81 percent, respectively, while the forecasts were 75 percent correct in the case of heart disease – in other words, three out of four days.

Q: Is the system functioning in any health clinics?

A: In February 2012 the service began to be offered in the Provincial Centre for Hygiene and Epidemiology of the Health Directorate of the province of Villa Clara.

To introduce the system in practice, the authorities selected reference centres in Sagua la Grande, Santa Clara and Ranchuelo, where health institutions are applying new procedures to make the most of these forecasts and mitigate the consequences of tropical weather variations for the local population.

Q: What advantages or impacts have been achieved with this service?

A: If doctors know ahead of time that weather conditions could occur which could affect the health of some of their patients, preventive measures could be taken. These include the optimisation of the use and distribution of necessary medication and other scarce materials.

In addition, we know that more than 10 percent of the Cuban population is asthmatic and that mortality associated with acute crises of bronchial asthma is on the rise.

So, if thanks to the biometeorological forecast service just 20 percent of the asthma crises that could occur because of significant tropical weather effects were avoided or minimised, it would contribute to improving the health of more than 200,000 people.

Similar reasoning can be made for other diseases, which means the greatest impact of this service lies in its capacity to effectively and relatively rapidly contribute to reducing morbidity and mortality associated with some diseases that are frequent in the country, whose occurrence is closely linked to weather variability.

Q: What is needed for the system to be applied in the health system nationwide?

A: At this time we are in the process of extending the service to all of the municipalities of Villa Clara. But each illness entails a specific procedure.

This is a very broad, interdisciplinary field that we are starting to get involved in together with health professionals.

Q: What new scientific challenges are opening up now?

A: We now know the model works, that it is effective. Overall, we have achieved 85 percent effectiveness, and apart from applying these results in Cuba, today we are following this for the sake of the entire world.

The latest studies on climate tendencies in Cuba indicate that the average air temperature is on the rise.

So although the population is well-adapted to heat, we don’t know if we can also adapt to the rise in the conditions of stress that lie ahead of us in the future due to the variability not of weather but of the climate, especially because of the visible effects of climate change.

Perhaps for the most vulnerable or most weather-sensitive population to be able to withstand the hotter and more tropical summers of the future, strategic actions will have to begin to be adopted now.

We want to develop early warning systems to evaluate how heat waves will behave in the tropical context, thus contributing to prepare adaptation strategies to confront climate change in our Caribbean regional setting.