New York, Dec 4 (IANS): Taking a deep breath might be a bit harder for children exposed early in life to a widely used class of pesticides in agriculture, according to a new study.

The study, carried out by researchers at the University of California - Berkeley, has linked the levels of organophosphate pesticide metabolites in the urine of 279 children living in California's Salinas Valley with decreased lung function.

Each tenfold increase in concentrations of organophosphate metabolites was associated with a 159-millilitre decrease in lung function, or about eight percent less air, on average, when blowing out a candle.

"Researchers have described breathing problems in agricultural workers who are exposed to these pesticides, but these new findings are about children who live in an agricultural area where the organophosphates are being used," said study senior author Brenda Eskenazi, a professor of epidemiology and of maternal and child health.

The children were part of the Centre for the Health Assessment of Mothers and Children of Salinas (CHAMACOS), a longitudinal study in which the researchers follow children from the time they are in the womb up to adolescence.

The researchers collected urine samples five times throughout the children's lives, from age six months to five years, and measured the levels of organophosphate pesticide metabolites each time. When the children were seven years old, they were given a spirometry test to measure the amount of air they could exhale.

"The kids in our study with higher pesticide exposure had lower breathing capacity," said study lead author Rachel Raanan, who conducted the research while she was a postdoctoral scholar in Eskenazi's lab.

"If the reduced lung function persists into adulthood, it could leave our participants at greater risk of developing respiratory problems like COPD (chronic obstructive pulmonary disease)," Raanan added.

The study findings were published in the journal Thorax on Thursday.