This dementia risk factor is modifiable: Lancet study in Karnataka flags household air pollution

Why is this study significant?

As dementia becomes a global burden and a significant challenge for India, the study helps in identifying household air pollution as a modifiable risk factor and prevent onset of such conditions. About 153 million individuals aged over 60 live in India. Altogether 19.1 per cent of the country’s population will comprise older people by 2050. The burden of dementia is, therefore, expected to increase exponentially, significantly challenging the current healthcare capacity.

With recent statistical data showing that 57% of rural households still use polluting cooking fuels, changing fuels could lower risk in the rural Indian population (which has been found to have a significantly higher prevalence of dementia than the urban Indian population).

What is household air pollution (HAP)?

This is a specific type of indoor air pollution, which primarily results from the use of polluting cooking technology — coal stoves, biomass stoves, earthen stoves and polluting fuels such as firewood, cow dung cake, coal, lignite or charcoal and kerosene. All of these produce gaseous toxins.

As of 2020, according to the WHO, 3.2 million premature deaths occurred worldwide from illnesses attributed to HAP. These include ischaemic heart disease, stroke and chronic pulmonary conditions. In India, as of 2019, 0.81 million deaths were attributed to HAP. The 2019–21 National Family Health Survey-5 reported that 41.4 per cent of households in India lacked access to clean cooking fuels. This disparity was more pronounced in rural areas, where 56.8 per cent of households used polluting cooking fuels, compared to 10.3 per cent in urban areas.

What were the study findings?

Participants were classified into three groups – those using only polluting cooking fuels, those using at least one polluting cooking fuel and those using clean cooking fuels. Then their cognitive functions were evaluated. The group that reported using only polluting cooking fuels had the worst cognitive functions, followed by the group using at least one polluting cooking fuel in comparison to those using clean cooking fuels.

The study also found that women participants, who are likely to be more exposed than men, could be more vulnerable to damage as evidenced by lower volumes of the hippocampus, a key brain region for learning and memory. This usually leads to dementia.