Children from wealthier families in Bangladesh have higher lead levels in blood

Children from wealthier families in Bangladesh have higher levels of lead in their blood than children from low-income households. Researchers reached this conclusion after analysing data from a national survey of children under the age of five.

According to the survey data, 30.2 per cent of children from the poorest 20 per cent of households had elevated lead levels in their blood. The proportion rose to 51.9 per cent among children from the wealthiest 20 per cent of households.

High levels of lead in children’s blood are a cause for concern. Lead can damage the development of the brain and nervous system, potentially affecting intellectual ability, attention, learning and behaviour. Such damage does not always produce immediate symptoms. In many cases, a child may appear healthy while their development is impaired.

Leading pediatricians in Bangladesh say the number of children experiencing neurodevelopmental problems has increased in recent years.

According to the World Health Organization (WHO), no level of lead in children’s blood is known to be completely safe. Previous studies in Bangladesh have also found an association between lead levels in children’s blood and lower scores on tests of intellectual development.

The 14th International Lead Poisoning Prevention Week of Action, led by the WHO, is being observed from 18 to 24 October. This year’s theme is “From Detection to Prevention”.

The study on elevated blood lead levels among children from wealthier families is titled “Social patterning of elevated blood lead among children aged 12–59 months in Bangladesh: A national cross-sectional analysis of MICS 2025”.

Syed Toushik Hossain and Md Imam Hasan, researchers at the Institute of Health Economics at the University of Dhaka, conducted the study. The research paper was published on 14 October this year on medRxiv, an online platform for sharing medical and public health research.

The researchers analysed data from the 2025 Multiple Indicator Cluster Survey (MICS), conducted by the Bangladesh Bureau of Statistics (BBS).

With technical support from the United Nations Children’s Fund (UNICEF), the survey collected information on various issues, including the health, nutrition and education of children and women, living conditions and environmental risks.

For the first time, the MICS report examined blood levels of lead and several other heavy metals among children under the age of five at the national level.

The researchers did not conduct new blood tests. Instead, they used existing blood test results and household socio-economic data collected through the survey to carry out a new statistical analysis.

The survey covered 18,905 children aged 12–59 months. Blood lead test results were available for 10,622 of them. The main analysis, which considered several socio-economic characteristics simultaneously, included complete data for 9,717 children.

The researchers defined a blood lead level of 5 micrograms per decilitre or higher as elevated. They analysed the relationship between elevated blood lead levels in children and factors including household wealth, mothers’ educational attainment, place of residence, housing conditions and other characteristics.

The study found that 38.5 per cent of children aged 12–59 months in Bangladesh had lead levels of 5 micrograms per decilitre or higher in their blood. In other words, approximately 39 out of every 100 children in this age group had blood lead levels at or above the threshold used in the study.

However, the figures varied considerably according to household wealth. The researchers divided households into five wealth quintiles.

Among children from the poorest 20 per cent of households, 30.2 per cent had elevated blood lead levels. The proportion rose to 51.9 per cent among children from the wealthiest 20 per cent of households.

The gap between the two groups was 21.7 percentage points. This means children from the wealthiest households were substantially more likely to have elevated blood lead levels than those from the poorest households.

The researchers found that the proportion of children with elevated blood lead levels increased as household wealth rose. This association remained even after they accounted for household wealth, maternal education, housing conditions and other characteristics.

Syed Tausik Hossain, one of the researchers, told Prothom Alo that children from wealthier families might consume more packaged food. Their homes might also contain more furniture, painted walls and various household utensils, some of which could contain lead. Exposure to these products could therefore be a potential route through which lead enters children’s bodies.

However, the study did not examine these sources separately. It is therefore not possible to conclude directly that packaged food, furniture or wall paint causes higher blood lead levels among children from wealthier families.

Professor Mohammad Shahidullah, a pediatric specialist, also believes that children from wealthier families may have greater opportunities for exposure to lead.

Mohammad Shahidullah said children in these households often receive more imported toys and have various decorative items at home. Lead may also be present in feed given to poultry chickens. Many children from relatively affluent families eat more chicken, so lead could enter their bodies through such food as well.

After entering the body, lead can travel through the bloodstream to various organs, including the brain, liver, kidneys and bones. The greatest concern for children is that their brains and nervous systems are still developing.

Exposure to lead increases the risk of reduced intellectual ability, difficulty maintaining attention, learning problems and behavioural changes. Its effects may also extend to educational attainment in the long term. Lead exposure is also associated with anaemia, kidney damage and high blood pressure.

Professor Abid Hossain Mollah, a pediatric specialist, told Prothom Alo that external appearance and immediate symptoms alone cannot reveal whether lead has harmed a child’s body.

He added that exposure to high levels of lead can cause severe symptoms. However, even exposure to relatively low levels can impair a child’s development. Lead can disrupt brain development and damage the functioning of sensory nerves. It can also reduce hemoglobin levels in some cases.

Both Professor Abid Hossain Mollah and Professor Mohammad Shahidullah said they were seeing more children with neurological problems than in the past.

Researchers have previously investigated the presence of lead in children’s blood in Bangladesh and its potential effects on their development.

A study published in the journal Environmental Health in 2016 analysed data from 524 children in Sirajdikhan and Pabna. Researchers measured blood lead levels in children aged 20–40 months and assessed their intellectual and motor development.

The study found relatively higher blood lead levels among children in Sirajdikhan. In that area, higher blood lead levels were also associated with lower scores on tests of intellectual development.

However, the researchers presented these findings as an association between the two factors. The results do not establish lead exposure as the sole cause of developmental problems in every child.

Another study, published in the Journal of Neurodevelopmental Disorders in 2020, examined 734 children in Bangladesh. Researchers analysed lead levels in umbilical cord blood at birth and assessed the children’s intellectual development at the age of two to three years.

The study found an association between prenatal lead exposure and lower intellectual scores among children with stunting caused by malnutrition. However, the association was not consistent across all study sites. The researchers suggested that malnutrition or stunting might make children more vulnerable to the harmful effects of lead.

The prevalence of elevated blood lead levels among children also varies considerably across divisions. According to the preliminary findings of the 2025 MICS, 65.2 per cent of children aged 12–59 months in Dhaka had elevated lead levels in blood. The figures were 46.7 per cent in Sylhet and 42.1 per cent in Chattogram.

By contrast, the proportions were 29 per cent in Barishal, 30.6 per cent in Mymensingh, 17.8 per cent in Khulna, 15.9 per cent in Rajshahi and 19.6 per cent in Rangpur.

The researchers’ adjusted statistical analysis also identified differences between divisions. Using Barishal as the reference category, the analysis found a stronger association with elevated lead levels in blood among children in Dhaka and a weaker association among children in Rajshahi.