The health ravages of exposure to lead reassessed at more than 5 million deaths per year worldwide

2023-09-12 05:48:26
In an electronic waste dump in the suburbs of Accra (Ghana), February 23, 2023. JEAN-FRANCOIS FORT / HANS LUCAS

The health impacts of exposure to lead have until now been largely underestimated. According to a study published Tuesday September 12 in the scientific journal The Lancet Planetary Health, 5.5 million adults died worldwide in 2019 due to cardiovascular diseases caused by lead exposure. A cause which represents 30% of all deaths linked to cardiovascular pathologies and which mainly affects low or middle income countries (90%). An impressive figure, more than six times higher than the study’s baseline estimate of 850,000 deaths attributable to lead on the Global Burden of Disease for 2019, last year for which data on blood lead levels are widely available.

“These findings, that the global health burden of lead is comparable to that of air pollution, are compelling and consistent with the available literatureestimates epidemiologist Bruce Lanphear (Simon Fraser University, Canada), who did not participate in this work. However, as the authors point out, this is still an underestimate. For example, deaths from lead-induced chronic kidney disease were not included in the analysis. » The magnitude of the effect demonstrated overturns usual medical conceptions. “This work indicates that exposure to lead is one of the main risk factors for cardiovascular diseases, and this will surprise clinicians and scientists, who have focused more on the impact of lifestyles”adds M. Lanphear, co-author, in 2018, of the last large assessment of lead mortality in the United States.

Loss of intelligence quotient in young children

How can we explain such a reassessment? Unlike previous research, this new study, led by the World Bank, does not only take into account the effect of lead on blood pressure (hypertension). It includes other parameters such as atherosclerosis (thickening of the arteries leading to cardiac arrest and stroke) or reduction in heart rate variability, which induces long-term cardiovascular disorders.

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Another major consequence of lead exposure must be seriously reassessed upwards in the light of this publication: its impact on the development of children’s brains. Still based on data concerning the year 2019, it would have led to a loss of intelligence quotient (IQ) of around 765 million points among children under the age of 5 across the planet. This figure exceeds previous estimates by 80%.

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