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Environmental Factor

Environmental Factor

Your Online Source for NIEHS News

July 2024

Papers of the Month

How personal care products may affect health of Black young adult women

Young adult Black women who are more frequent users of a combination of personal care products (PCPs) are more likely to have higher socio-economic status (SES), and lifestyle and health behaviors with positive health implications, according to researchers from the Division of Translational Toxicology and the Division of Intramural Research.

Compared to White women, Black women in the United States are exposed to higher and more hazardous concentrations of endocrine-disrupting chemicals, which are found in PCPs. This may contribute to differential health outcomes in Black women, such as increased risk of breast cancer, cardiometabolic outcomes, adverse birth outcomes, and uterine fibroids. However, previous smaller studies lacked a comprehensive assessment of PCP use among a large cohort of Black women.

To address this gap, the researchers focused solely on Black women, grouped individuals together based on their complex patterns of PCP use, and examined differences in socio-demographic characteristics across these distinct groups. The participants for this study included 1,562 reproductive-aged Black women living in Detroit, Michigan. Researchers identified six distinct subgroups of PCP use which included: (1) lower overall PCP use, (2) lower overall PCP use except for higher use of nailcare products, (3) lower overall PCP use except for higher use of skin creams, (4) overall moderate PCP use, (5) higher use of makeup, hair care, and skin creams, and (6) higher overall PCP use. Participants with less frequent use of all PCPs, and those with only high use of nailcare products, were more likely to report lower SES, be current smokers, have a body mass index of more than 35 kg/m2, and have given birth to three or more children.

In comparison, participants with average and more frequent use of PCPs were more likely to report higher SES and ever use of oral contraceptives, be nonsmokers, and never have given birth to a child. According to the authors, this work demonstrates the importance of considering PCP exposures concurrently with other socio-demographic characteristics, lifestyle factors, and health behaviors when modeling health risks. (JW)

Citation: Taylor KW, Co CA, Gaston SA, Jackson CL, Harmon Q, Baird DD. 2024. Frequency of personal care product use among reproductive-aged Black individuals and associations with socio-demographic characteristics. J Expo Sci Environ Epidemiol [Online 29 May 2024].

Genital talc use may be associated with an increased risk of ovarian cancer

Using talcum powder as an intimate care product may be associated with an increased risk of developing ovarian cancer, according to NIEHS researchers and their collaborators.

Douching and the use of talc in the genital area are two common intimate care practices that may adversely affect reproductive health. Both may contain chemicals such as phthalates, parabens, and bisphenols, which have been reported to disrupt natural hormone levels. And talcum powder may additionally contain asbestos, a known carcinogen. Exposure to these chemicals could potentially increase the risk of developing hormone-related diseases such as breast, ovarian, or uterine cancer. Previous studies examining the relationship between genital talc use and ovarian cancer have been limited by potential reporting biases.

To overcome this limitation, the researchers incorporated a statistical method known as quantitative bias analysis to correct potential biases that might have affected the results reported in previous studies. Their study involved 50,884 women from the Sister Study, all of whom had a sister diagnosed with breast cancer. The findings showed a strong and consistent association between genital talc use and ovarian cancer, especially for frequent users and for use during the reproductive years. Douching was also associated with ovarian cancer. No significant associations were found between either intimate care product and breast or uterine cancer.

Together, these findings provide valuable insights into current discussions concerning the safety of intimate care products. According to the authors, further research is needed to identify specific chemicals in intimate care products that may affect cancer risk. [Read related article.] (SS)

Citation: O'Brien KM, Wentzensen N, Ogunsina K, Weinberg CR, D'Aloisio AA, Edwards JK, Sandler DP. 2024. Intimate care products and incidence of hormone-related cancers: a quantitative bias analysis. J Clin Oncol JCO2302037.

Measuring environmental phenols in infants

Some infants may be exposed to higher levels of parabens than older children, according to NIEHS researchers and their collaborators. Higher levels of exposure were observed in a diverse U.S. cohort of healthy infants compared to those reported in national biomonitoring data of children ages 3 to 11 years old.

Parabens and other phenols are potentially endocrine-disrupting chemicals that are used in personal care and consumer products. Data on infant exposures are limited despite heightened sensitivity to endocrine disruption during this developmental period.

The researchers examined the distributions and predictors of urinary phenol concentrations among healthy U.S. infants. They measured concentrations of seven phenols in urine samples collected from 199 infants who were aged 6-12 weeks and were enrolled from 2010-2013 in the Philadelphia region.

The results revealed widespread exposure to measured environmental phenols among this population, including much higher paraben concentrations compared to those reported for U.S. children. This finding supports the importance of expanding population-based biomonitoring programs to infants and toddlers. According to the authors, studies are needed to identify products and behaviors contributing to infant exposures to environmental phenols in the U.S., where there are few restrictions on use.

In addition, the results showed differences in most urinary phenol concentrations by race. These differences may inform the design of future studies of infant exposure sources and aid in developing targeted interventions to reduce the burden of chemical exposures in vulnerable populations. (JW)

Citation: Goldberg M, Adgent MA, Stevens DR, Chin HB, Ferguson KK, Calafat AM, Travlos G, Ford EG, Stallings VA, Rogan WJ, Umbach DM, Baird DD, Sandler DP. 2024. Environmental phenol exposures in 6- to 12-week-old infants: The Infant Feeding and Early Development (IFED) study. Environ Res 252(Pt 4):119075.

Quantifying mixture effects of environmental exposures

New findings may guide researchers on carefully choosing methods for environmental mixtures analysis to accommodate exposure measurements that lie below the limit of detection (LOD), according to NIEHS researchers and their collaborators.

Identifying the impact of environmental mixtures on human health is an important topic. However, there are challenges when exposure measurements lie below the LOD. Several statistical approaches have been used to accommodate values below LOD for a single exposure. But the impact of these approaches on downstream mixture analysis results when multiple correlated exposures are subject to LOD has not been thoroughly investigated.

To fill this knowledge gap, the researchers examined the performance of five popular LOD accommodation approaches for three mixture analysis methods. Extensive simulations favored the use of truncated multiple imputation (MI) and censored accelerated failure time (AFT) models to accommodate values below LOD for the stability of downstream mixtures analysis. By contrast, certain methods that are frequently used in environmental health studies due to their easy implementation, such as excluding incomplete measurements and substituting missing data with LOD divided by the square root of 2, can have quite unstable performance.

According to the authors, quantifying the impact of mixtures of environmental exposures is becoming increasingly important for identifying disease risk factors and developing targeted public health interventions. Their study provides insight into various LOD accommodation approaches in downstream mixture analyses, enhancing the quality and reliability of environmental health studies. (JW)

Citation: Lee M, Saha A, Sundaram R, Albert PS, Zhao S. 2024. Accommodating detection limits of multiple exposures in environmental mixture analyses: An overview of statistical approaches. Environ Health 23(1):48.

How inhibiting inflammation affects response to SARS-CoV-2 infection

The cytokine storm is primarily responsible for morbidity and mortality in mice infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), according to NIEHS researchers and their collaborators.

SARS-CoV-2 infection involves an initial viral infection phase followed by a host-response phase. The latter phase includes an eicosanoid and cytokine storm — an uncontrolled and excessive release of these cell signaling molecules — lung inflammation and respiratory failure. Although vaccination and early antiviral therapies are effective in preventing or limiting the initial viral phase, the latter phase is poorly understood with no highly effective treatment options.

To address this problem, the researchers used a mouse model of SARS-CoV-2 infection to investigate the effect of inhibiting soluble epoxide hydrolase (sEH) to increase levels of anti-inflammatory molecules. Within days, SARS-CoV-2 induced weight loss, clinical signs, an eicosanoid and cytokine storm, and severe lung inflammation with ~50% mortality. Treatment with the sEH inhibitor delayed weight loss but did not alter clinical signs, lung inflammation, or overall survival of infected mice. The sEH inhibitor significantly reversed the eicosanoid storm but had no effect on the cytokine storm.

Others have proposed inhibition of eicosanoid pathways to attenuate severity of SARS-CoV-2 infection. According to the authors, the suppression of the eicosanoid storm by the sEH inhibitor without corresponding changes in lung cytokines, lung inflammation, morbidity, or mortality suggests that the cytokine storm is primarily responsible for morbidity and mortality in this animal model. (JW)

Citation: Edin ML, Gruzdev A, Graves JP, Lih FB, Morisseau C, Ward JM, Hammock BD, Bosio CM, Zeldin DC. 2024. Effects of sEH inhibition on the eicosanoid and cytokine storms in SARS-CoV-2-infected mice. FASEB J 38(10):e23692.

(Janelle Weaver, Ph.D., is a contract writer for the NIEHS Office of Communications and Public Liaison. Shruti Somai, Ph.D., is a visiting fellow in the Genome Integrity and Structural Biology Laboratory.)

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