A study led by the Barcelona Institute for Global Health (ISGlobal), a centre supported by the “la Caixa” Foundation, has found that exposure to phthalates in the womb is associated with reduced lung function during childhood. The findings of the study, published in Environmental Pollution , support the European Union’s current restrictions on the use of these substances .
Phthalates are chemical compounds that are widely used as plasticisers, as well as in lacquers and varnishes. They are found in a wide variety of consumer products, ranging from toys to food packaging, clothing, detergents, cosmetics, solvents, etc. Over time, phthalates in these products leach into the surrounding environment — for example, into the air, dust and food — making them virtually ubiquitous. Moreover, human exposure to phthalates starts as early as in utero, given that these compounds are able to cross the placental barrier. Phthalates act as endocrine disruptors and have been associated with numerous developmental and reproductive health problems.
“Research has consistently found that gestational phthalate exposure is associated with increased risk of childhood asthma, but the evidence on its possible association with lung function is scarce and unclear,” explained ISGlobal researcher Magda Bosch de Basea, lead author of the study.
The study included 641 mother-child pairs from the INMA Project birth cohorts in Sabadell and Gipuzkoa. Gestational phthalate exposure was analysed using urine samples collected from the mothers during pregnancy. The children’s lung function was assessed by spirometry at various stages of development between the ages of four and eleven years.
As an indication of the ubiquity of these compounds, laboratory analyses detected all nine of the studied phthalate metabolites — i.e. substances into which phthalates are transformed once metabolised by the human body — in nearly 100% of the urine samples examined. At all stages of development, the studied metabolites were associated with decreases in two lung function parameters: forced vital capacity (FVC), which measures the maximum volume of air a person is able to exhale, and forced expiratory volume in 1 second (FEV1), which measures the maximum exhaled volume in the first second of exhalation. However, the researchers found that the associations between certain metabolites (e.g. MiBP and MBzP) and decreased lung function were generally statistically significant only at younger ages, but not in spirometries performed in later years. This pattern is consistent with the findings of studies in animal models suggesting that the possible effects of these compounds on lung function revert over time.
Moreover, using statistical methods that account for exposure to mixtures of compounds, the study identified MBzP as an important contributor to the observed effect on lung function. “This leads us to believe that this metabolite — MBzP — could be one of the main drivers of the observed association with reduced lung function during childhood,” commented Judith Garcia-Aymerich, head of the Non-Communicable Diseases and Environment Programme at ISGlobal and senior co-author of the study.
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