IN THE first such study on impact of pollution on neurological disorders in the country, doctors at AIIMS have examined at least 800 patients, who suffered a brain stroke, to find out if there is any “statistically significant” correlation between the disorder and the capital’s rising pollution levels. The research has been going on for two years, and AIIMS officials said it will take at least three more years to ascertain the correlation between stroke — the second most common medical emergency that leads to disability — and rise in pollution levels.
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“We have examined at least 800 patients. We cannot objectively state the findings of the research with such a small number. To ascertain the correlation between stroke and pollution, we need to have more subjects. In the next three years, the number of subjects would be more…,” said Dr Professor Kameshwar Prasad, head of the Department of Neurology at AIIMS.
The research gained significance after a recent AIIMS study revealed that the average age for onset of stroke in the capital is 55 years, much lower than the 70 years worldwide. Even more alarming is the fact that 15 per cent of stroke cases in the capital are witnessed in people under 40, and 25 per cent in people under 45. While the research had concluded hypertension, diabetes and alcohol consumption as triggers for stroke, which happens when poor blood flow to the brain results in cell deaths, the present study is examining if rise in pollution can trigger it too.
Connecting the dots
According to principal investigators conducting the research, the investigation will be done in four phases. In the first phase — the “hazardous period” — investigators are examining pollution levels in the area where a patient resides, the week he suffered a stroke. The pollutants under examination are PM 10, PM 2.5, ozone and Nox levels.
In the last three phases — termed “control period”— investigators are examining pollution levels during the week before the onset of stroke; the pollution levels two weeks after the onset of stroke; and three weeks after the onset of stroke. According to investigators, if the same patient who suffered stroke when pollution levels were high remained normal when pollution levels were low, then the condition is termed “discordant”.
It would then be proved that there is a statistically significant correlation between the onset of stroke and rise in pollution levels. “However, if it is found that pollution levels were high even during the time he remained normal, then the impact of pollutants are not statistically significant on the onset of stroke. This is the basis of the investigation,” Dr Rao said.
This is the first ever research in India that is studying the effects of pollutants on neurological disorders.