Researchers at University of California San Diego in the US found a link between higher blood pressure and pesticide exposures in children -- especially heightened pesticide spraying period around the Mother's Day flower harvest, a holiday with one of the highest sales of flowers.

According to the researchers, Ecuador is among the largest commercial flower growers in the world, with significant rose exports to North America, Europe and Asia. Commercial rose production relies on the use of insecticides, fungicides and other pest controls, but little is known about their human health effects.

The study, published in the journal Environmental Research, involved boys and girls living near flower crops in Ecuador.

"These findings are noteworthy in that this is the first study to describe that pesticide spray seasons not only can increase the exposure to pesticides of children living near agriculture but can increase their blood pressures and overall risk for hypertension," said Jose R Suarez, an assistant professor at UC San Diego.

The team assessed 313 boys and girls, ages four to nine, residing in floricultural communities in Ecuador.

The children were examined up to 100 days after the Mother's Day harvest.

"We observed that children examined sooner after the Mother's Day harvest had higher pesticide exposures and higher systolic and diastolic blood pressures compared to children examined later," said Suarez.

"In addition, children who were examined within 81 days after the harvest were three times more likely to have hypertension than children examined between 91 and 100 days," he said.

Research regarding the effects of pesticides on the cardiovascular system is limited, but Suarez said there is some evidence that insecticides, such as organophosphates, can increase blood pressure. Organophosphates and several other classes of insecticides and fungicides are commonly used to treat flowers for pests before export.

In a previous study, researchers had reported that children examined sooner after the harvest displayed lower performances in tasks of attention, self-control, visuospatial processing and sensorimotor than children examined later.

"These new findings build upon a growing number of studies describing that pesticide spray seasons may be affecting the development of children living near agricultural spray sites," said Suarez. "They highlight the importance of reducing the exposures to pesticides of children and families living near agriculture," he added.