Recent research highlights the significant cognitive and cardiovascular health risks associated with exposure to Di-2-ethylhexyl phthalate (DEHP), a chemical commonly used to make plastics more flexible.
Cognitive Impacts:DEHP exposure has been linked to a range of adverse effects on the nervous system and cognitive function. Studies indicate that DEHP can cross the placenta, blood-brain barrier, and enter breast milk, impacting neural development from fetal stages through adulthood.
- Developmental Effects: Maternal exposure to DEHP during gestation can impair fetal brain development, potentially leading to irreversible brain damage. It's associated with reduced learning capabilities, memory impairment, lower intelligence, and an increased risk of depression, anxiety, cognitive impairment, and autism spectrum disorders in offspring. Children are particularly vulnerable as critical brain development processes occur during childhood. DEHP exposure can delay these processes, leading to lasting negative impacts on cognitive function and mental health. Studies have found higher levels of DEHP metabolites in children's urine compared to their parents, possibly due to increased oxidative metabolism and behaviors like putting toys in their mouths.
- Neurological Damage: In animal studies, DEHP has been shown to impair brain growth and cause neurodegeneration. It can decrease neuronal growth, increase axonal degeneration, and alter levels of important brain lipids like sphingomyelin and phosphatidylcholine in the hippocampus. DEHP exposure is also associated with increased inflammatory factors and reduced testosterone levels, which play a crucial role in neural repair and cell survival. It can interfere with testosterone's role in nerve differentiation by reducing its concentration and the expression of androgen receptors in the brain.
- Behavioral and Mental Health: Exposure to DEHP has been linked to increased learning disabilities, attention deficit hyperactivity disorder (ADHD), anxiety-like behaviors, and reduced social interactions. Some studies suggest these adverse behavioral effects may persist across generations.
- Blood-Brain Barrier Disruption: Research indicates that DEHP can impair the blood-brain barrier, which is crucial for protecting the brain from toxins and pathogens. Subchronic exposure in animal models has been shown to increase BBB permeability and induce neuroinflammation.
- Sex-Specific Effects: Some research suggests that DEHP's neurotoxic effects may be more pronounced in males. For instance, hippocampal atrophy and anxiety-like behaviors were observed more in male rats exposed to DEHP. However, research on the sex-dependence of DEHP neurotoxicity is ongoing and sometimes yields inconsistent results.
Emerging evidence strongly links DEHP exposure to significant cardiovascular health problems.
- Increased Mortality: A recent global analysis estimated that DEHP exposure contributed to over 356,000 deaths from heart disease in 2018 alone, accounting for more than 13% of global heart disease mortality in individuals aged 55-64. Regions like the Middle East, South Asia, East Asia, and the Pacific bear a disproportionately high burden of these deaths. India, for example, had the highest number of DEHP-attributable heart disease deaths in this age group.
- Mechanism of Harm: DEHP is an endocrine-disrupting chemical. It is thought to contribute to cardiovascular disease by triggering chronic inflammation in the arteries, which can lead to heart attacks or strokes over time. DEHP and its primary metabolite, mono-(2-Ethylhexyl) phthalate (MEHP), have been shown to impair calcium signaling in cardiomyocytes (heart muscle cells), potentially leading to muscle contraction failure and impaired cardiac function. Endothelial dysfunction and increased vascular resistance have also been documented.
- Associated Conditions: Epidemiological studies suggest that increased exposure to DEHP and other phthalates is associated with a higher risk of hypertension (high blood pressure), tachycardia (rapid heart rate), and overall increased risk of cardiovascular diseases. Some studies have also linked DEHP exposure to an increased risk of myocardial infarction (heart attack) and arrhythmia (irregular heartbeat).
- Economic Burden: The health impacts of DEHP exposure, particularly cardiovascular mortality, also translate into significant economic losses, estimated to be in the billions of dollars annually due to healthcare expenses and lost productivity.
DEHP is found in a vast array of everyday products, including food packaging, medical devices (like IV tubing), toys, cosmetics, cleaning agents, and building materials. Humans are exposed through ingestion (e.g., from food contaminated through packaging), inhalation, and dermal contact. Due to its unstable bond with plastics, DEHP can leach into the environment and subsequently into the human body.
The widespread presence of DEHP and its potential to cause serious health issues, including neurodevelopmental problems, cognitive decline, and cardiovascular disease, underscores a significant public health concern. Further research is ongoing to fully understand the mechanisms of DEHP-induced toxicity and to identify safer alternatives. Regulatory actions to reduce DEHP exposure are also being considered and, in some cases, implemented in various regions.