What pregnant moms eat and where they live can cause high blood pressure in their children

Researchers analyzed over 200 environmental exposures during pregnancy and childhood, and found that some of them such as exposure to chemicals, low city walkability and duration of fish intake could have an impact on blood pressure in children


                            What pregnant moms eat and where they live can cause high blood pressure in their children

Exposure to certain chemicals as well as tobacco smoke, duration of fish intake, and a lack of walkable environment during pregnancy could lead to hypertension or high blood pressure in children.

According to a study which analyzed over 200 environmental exposures during pregnancy and childhood, the place where a mother lives and the temperature outside when she is pregnant along with other environmental factors can impact if her child is prehypertensive or hypertensive.

Mothers who live in a walkable environment, for example, with access to green spaces, shops, restaurants, and public transportation during pregnancy were associated with normal blood pressure in their children. Alternatively, mothers who did not live in an urban or highly walkable environment had higher blood pressure, says the study led by the Barcelona Institute for Global Health (ISGlobal).
 
The study is the first to simultaneously consider the possible effects of exposure to hundreds of environmental factors during early life on blood pressure in children. "Our results show that starting in the fetal stage, where we live, the food we eat, the air we breathe, and the chemical compounds that reach our bodies can affect blood pressure before adolescence,” says ISGlobal researcher Charline Warembourg, the lead author of the study.

Warembourg adds, "This is important because evidence shows that children with high blood pressure are more likely to be hypertensive as adults."

Hypertension is a serious medical condition that significantly increases the risks of heart, brain, kidney and other diseases. According to the World Health Organization (WHO), an estimated 1.13 billion people worldwide have hypertension, and it is a major cause of premature death. 

Results show that starting in the fetal stage, where we live, the food we eat, the air we breathe, and the chemical compounds that reach our bodies can affect blood pressure before adolescence, say researchers. (Getty Images)

The study was conducted as part of the Human Early-Life Exposome (HELIX) project, which compiles data from birth cohorts in six European countries — the UK, Spain, France, Greece, Norway, and Lithuania. The research included data from a total of 1,277 children and their mothers.

Exposures were assessed during pregnancy and when the children were between 6 and 11 years of age. The children underwent a clinical examination that included blood and urine sample collection and blood pressure measurements. At the time of the examination, 10% of the children could be classified as prehypertensive or hypertensive.

The research team examined 89 prenatal maternal exposures and 128 postnatal child exposures grouped in three categories: outdoor exposures (air pollution, meteorological conditions, green spaces, etc.), chemicals (pesticides, metals, plasticizers, etc.) and lifestyle factors (diet, physical activity, sleep patterns, etc.).

Of these, analysis shows that four broader environmental factors were determined to influence blood pressure status in children: Built environment (where the mother was living during pregnancy), outdoor temperature, fish intake and exposure to chemicals. The findings were published in the Journal of the American College of Cardiology.

"In this study, researchers presented a comprehensive analysis of the association of early-life environmental exposures with blood pressure in children. Due to the innovation shown by the researchers, this study provides a model that may greatly advance investigations of the influences of environmental exposures on human health," says Dr. Andrea A. Baccarelli, chair and Leon Hess professor of environmental health sciences at the Columbia University Mailman School of Public Health.

Exposures associated with higher blood pressure

Exposure to negative lifestyle factors in pregnancy, such as obesity, physical inactivity, poor diet, and tobacco consumption has long been established as heart disease risk factors for mothers. It is only in recent years that researchers have started to link these risk factors to prehypertensive status in children and their likelihood of developing hypertension, or high blood pressure, later in life.

For the current study, exposures were assessed through a mix of predictive modeling from home address and questionnaire and through the determination of biological samples from the mother and child.

According to the findings, exposure to bisphenol-A (BPA) concentrations — a chemical found in various consumer plastics — during pregnancy resulted in higher blood pressure in children, as did exposure to perfluorooctanoate (PFOA) concentrations — a compound found in cosmetics, household cleaners, clothing, and non-stick pots and pans. Children who had been exposed to copper during childhood also had higher blood pressure.

A summary of the exposures assessed and the associations found in relation to blood pressure in children. (Warembourg, C. et al. J Am Coll Cardiol.2019;74(10):1317-28 / Journal of the American College of Cardiology)

"Statistical analysis revealed an association between various exposures and higher blood pressure in children. The exposures associated with increases in blood pressure included exposure to tobacco smoke and bisphenol-A (a plasticizer) during pregnancy. Similarly, children with higher serum concentrations of copper and perfluorooctanoic acid had higher blood pressure," says the study.

Both low and high fish intake during pregnancy — less than twice a week and more than four times a week, respectively — were associated with an increase in blood pressure in children. While the omega-3 fatty acids found in fish are beneficial for overall cardiovascular health, fish contaminated by chemicals or metals could reduce any positive effects of omega-3 fatty acids, says the team. 

"Some of the associations found in children in this study, such as tobacco smoke and bisphenol-A, had already been observed in adults in previous studies. Other associations, such as fish intake during pregnancy, are more difficult to interpret," says Warembourg who adds, "Fish contains essential fatty acids that are necessary and beneficial, but we also know that it is a source of chemical compounds, which perhaps helps to explain why the moderate fish intake is associated with better blood-pressure results."

Researchers also identified exposures associated with lower blood pressure, such as higher outdoor temperatures during childhood and facility density in the neighborhood where the mother lived during pregnancy.

The analysis shows that exposure to a higher outdoor temperature during the time of the blood pressure assessment was associated with lower diastolic blood pressure in children.

The researchers hypothesized that lower blood pressure that resulted from living in an urban setting was due to the higher amount of physical activity during pregnancy. "Urban-design factors such as the number of shops, restaurants, parks and public-transport hubs determine how people use the city and get around, and they are important for health because they promote physical activity and social contact," says ISGlobal researcher Xavier Basagaña.

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