Heavy metals in fuels, fertiliser and e-cigarettes increases heart disease risk 'even at low levels'

Heavy metal particles from industrial emissions, e-cigarettes and fertiliser-treated crops may increase the chances of heart attack and stroke, even at very low levels, according to new research.

Lead, copper, cadmium and arsenic are known to be poisonous or carcinogenic at high levels but may harm cardiovascular health in smaller doses, the study published in the British Medical Journal found.

While toxic metal pollution is a major concern in developing countries many are sufficiently common in the UK, Europe and the US to pose a risk at the population level, the study’s lead author Dr Rajiv Chowdhury from the University of Cambridge said.

His team reviewed 37 studies involving almost 350,000 participants, looking at metal exposure and coronary heart disease, stroke and composite cardiovascular disease.

While leaded fuel and paints have been phased out in many countries their residues remain and power plant and industrial waste products are adding more to the soil and waterways.

“[Lead] is in emissions due to metal industrial activities, other industrial uses of lead, leaded gasoline, and medical and household products can expose workers and nearby individuals to lead via inhalation and contamination of the surrounding environment,” Dr Chowdhury told The Independent.

“Additionally, corrosion of plumbing materials containing lead can introduce lead into drinking water.”

In Flint, Michigan thousands of residents have been exposed to poisonous lead levels in their water for years and this has been linked to foetal deaths as well as hair loss, rashes, and other risks.

Cadmium and arsenic are metals found in fertilisers and pesticides which can build up in crops, in particular rice, can also enter the body. Earlier in 2018 the European Union was considering a crackdown on cadmium fertilisers.

A total of 13,033 coronary heart disease, 4,205 stroke and 15,274 cardiovascular outcomes were reported across the studies.

The studies on lead, cadmium and copper exposure were all based on populations in the US or Europe and showed there was no safe amount and cardiovascular disease risk increased in step with metal exposure.

Arsenic exposure increased risk of cardiovascular disease by 30 per cent, while lead and cadmium also increase risk of stroke - by 62 per cent and 72 per cent respectively.

Mercury, another heavy metal, was not found to be associated with cardiovascular risk but this may be because it is primarily found in fish which could have other heart health benefits.

Despite the risks, a World Health Organisation report earlier in 2018 on factors contributing to increases in non-communicable disease, like heart disease and diabetes, did not mention heavy metals.

The authors of the BMJ study say this was a “major omission” as policies to minimise pollutants may be an alternative way to tackle these diseases while trying to change individual’s smoking, drinking and diet.

The findings are particularly important in developing nations like Bangladesh and India and where water filters and educational initiatives on washing rice and other staples could minimise exposure.

Independent researchers also writing in the BMJ said governments must do more to monitor and address major and emerging sources of heavy metal exposure.

“Emerging tobacco products such as electronic cigarettes also increase metal exposure,” Dr Maria Tellez-Plaza from the National Health Institute in Madrid, wrote. “The main source… seems to be the heating coil, from where metals leach into the inhaled aerosol.

“Since metals are associated with cardiovascular disease even at relatively low levels of exposure, population wide strategies to minimize exposure can further contribute to overall cardiovascular prevention efforts.”