PERHLs of Wisdom: Environmental Reproductive Health Literacy and Phthalates

Short abstract

Most tools that measure environmental health literacy are broad in nature. Researchers have now developed a tool specific to phthalate awareness and behaviors as they relate to reproductive health.

Environmental health literacy as a discipline emerged in the 1970s,^1,2 but in the past decade the field has expanded beyond measuring a person’s environmental health knowledge and skills to assessing how social factors influence their decisions.^3,4 Most tools that measure environmental health literacy—such as the Short Assessment of Environmental Health Literacy⁴ or the Environmental Health Engagement Profile⁵—do so in a general fashion. Creating tools for specific populations and chemical classes, however, may prove useful for designing effective interventions that help people reduce their exposures.

In a recent paper in Environmental Health Perspectives,⁶ a research team presented the Phthalate Environmental Reproductive Health Literacy (PERHL) Scale, a tool they developed to help people who are pregnant or of reproductive age understand—and ultimately reduce—their exposure to phthalates. Similar to other endocrine-disrupting chemicals, phthalates are associated with impaired neurodevelopment,⁷ shortened anogenital distance in male infants,⁸ and reduced newborn penile size.^9,10 Higher scores on the PERHL Scale reflect greater environmental health literacy. The authors hope that improving environmental health literacy before and during pregnancy could help reduce exposures of both parent and child.

The new PERHL scale scores six factors to assess how well a person may understand reproductive health implications of phthalate exposures. Image: EHP.

To develop the PERHL Scale, the authors adapted an existing scale for endocrine disruptors¹¹ that assessed awareness, risk acceptance, perceived uncertainty, and protective behaviors. They first distributed a questionnaire to 117 participants in the Environmental Reproductive and Glucose Outcomes (ERGO) Study,^11,12 a cohort that started in 2016 to study reproductive health outcomes. Participants were over 18 years of age and between 15 weeks pregnant and 5 years postpartum.

Then they applied exploratory factor analysis, which is a strategy scientists use to identify the structure of data, identifying the variables, or factors, that give rise to patterns observed. With this approach, the team identified six factors that pertained to phthalate and reproductive environmental health literacy:

• Awareness of phthalate reproductive health impacts

• Uncertainty (e.g., due to lack of useful information)

• Protective behavior/risk control

• Regulatory interest (in this case, specific to regulation of phthalates)

• Awareness of phthalate exposure pathways

• General phthalate knowledge

They next assessed whether scoring higher for each factor was associated with avoiding phthalates in personal care products such as perfumes, deodorants, and soaps. The team also tested associations between these factor scores and sociodemographic characteristics (age, race and ethnicity, educational attainment) that have been linked to health disparities.^13,14

The researchers found that a 1-point higher score in the Protective behavior/risk control factor was associated with a 21% increase in odds that a participant would report avoiding phthalates in personal care products. “We expected there to be some level of association between the scale and avoiding products with phthalates, but I was surprised by how strong that association was,” says lead author Kathryn Tomsho, a postdoctoral fellow at the Harvard TH Chan School of Public Health.

The study found that, compared with White participants, the 33 non-White participants (no further racial or ethnic distinction was made due to small numbers) had notably lower PERHL Scale scores for three phthalate-related knowledge factors: a) Awareness of phthalate reproductive health impacts, b) Awareness of phthalate exposure pathways, and c) General phthalate knowledge. Because these factors relate to knowledge of phthalates and how people come into contact with them, the team “hypothesize[s] this may be due to a difference in access to phthalate-related environmental health information,” says Tomsho. “We know that non-White people are disproportionately exposed to phthalates.”¹⁵

Counterintuitively, participants with higher scores for Awareness of phthalate reproductive health impacts, Uncertainty, and Regulatory interest showed decreased odds of reporting avoidance of phthalates. The authors suggested the findings, particularly regarding the Awareness factor, might be due to competing factors at play in the participants’ decision making around health-protective behaviors.

With regard to this finding, Diana Rohlman, an associate professor of environmental health at Oregon State University who was not involved in the study, wonders whether a sense that something is a common exposure might lead to a decreased perception of risk. For example, she suggests that familiarity with the flu may be one reason people do not get flu shots.

“It is also important to note that exposures, prenatal or not, run the gamut between chosen [i.e., avoidable] exposures, and unavoidable exposures,” adds Rohlman. The authors do mention that the burden for prevention often falls on the individual, but their ability to avoid exposure may be limited, given the ubiquitous environmental presence of many chemicals.

“This is the first study that I am aware of to characterize the underlying factors contributing to specific environmental chemical exposures—in this case, phthalates—and reproductive environmental health literacy,” says Thad Schug, a health scientist administrator at the National Institute of Environmental Health Sciences who was not involved in the study. “Further development of this tool could potentially provide an opportunity to quickly identify individuals who may be at risk of specific environmental exposures, in a nonintrusive manner.”

Indeed, the authors hope that, after further development, the PERHL Scale and similar tools can be used not just by researchers but also by doctors. “We hope that down the road it could … be used by doctors to identify individuals who might be at risk of higher phthalate exposures, to help reduce their exposures, but that will require more testing of the scale’s performance in different contexts,” says Tomsho.

The authors acknowledge the limitations of their study, including the homogenous nature of the participants, the limited sample size, and other generalizable factors. Nearly 72% of the participants were non-Hispanic White, and 86% had a college degree or beyond. “It will be important to scale up the participant levels and heterogeneity of the study population in order to apply the findings to a larger population,” Schug says. The authors further note that they did not evaluate how scores might relate to phthalate levels in the body or adverse health outcomes.

In the meantime, Tomsho is looking forward to taking concrete action. “If we find our hypothesis that there are differences in access to phthalate-related information is true,” she says, “that is something we can change by making that information more accessible, available, and clear.”

Biography

Wendee Nicole is an award-winning science writer based in San Diego, California. Her work has appeared in Nature, Scientific American, and other publications.