Maternal major depression during early pregnancy is associated with impaired child executive functioning at 4.5 years of age.

BACKGROUND: Maternal depression is a serious condition that affects up to 1 in 7 pregnancies. Despite evidence linking maternal depression to pregnancy complications and adverse fetal outcomes, there remain large gaps in its identification and treatment. More work is needed to define the specific timing and severity of depression that most urgently requires intervention, where feasible, to protect maternal health and the developing fetus. OBJECTIVE: This study aimed to examine whether the timing and severity of maternal depression and/or anxiety during pregnancy affect child executive functioning at age 4.5 years. Executive functioning in the preschool years is a strong predictor of both school readiness and long-term quality of life. STUDY DESIGN: This longitudinal observational pregnancy cohort study included a sample of 323 mother-child dyads taking part in the Ontario Birth Study, an open pregnancy cohort in Toronto, Ontario, Canada. Maternal symptoms of depression and anxiety were assessed at 12 to 16 and 28 to 32 weeks of gestation and at the time of child testing at age 4.5 years using the 4-item Patient Health Questionnaire. Child executive functioning was measured during a home visit using standardized computerized administration of the Flanker test (a measure of attention) and the Dimensional Change Card Sort (a measure of cognitive flexibility). Stepwise linear regressions, controlling for possible confounding variables, were used to assess the predictive value of continuous measures of maternal depression and/or anxiety symptoms at each assessment time on the Flanker test and Dimensional Change Card Sort. Posthoc general linear models were used to assess whether maternal depression severity categories (no symptom, mild symptoms, or probable major depressive disorder) were helpful in identifying children at risk. RESULTS: Across all children, after controlling for potential confounds, greater maternal depressive symptoms at weeks 12 to 16 weeks of gestation predicted worse performance on both the Flanker test (ΔR2=0.058; P<.001) and the Dimensional Change Card Sort (ΔR2=0.017; P=.018). Posthoc general linear modeling further demonstrated that the children of mothers meeting the screening criteria for major depression in early pregnancy scored 11.3% lower on the Flanker test and 9.8% lower on the Dimensional Change Card Sort than the children of mothers without maternal depressive symptoms in early pregnancy. Mild depressive symptoms had no significant effect on executive function scores. There was no significant effect of anxiety symptoms or maternal antidepressant use in early pregnancy or pandemic conditions or maternal symptoms in later pregnancy or at the time of child testing on either the Flanker or Dimensional Change Card Sort results. CONCLUSION: This study demonstrated that fetal exposure to maternal major depression, but not milder forms of depression, at 12 to 16 weeks of gestation is associated with impaired executive functioning in the preschool years. Child executive functioning is crucial for school readiness and predicts long-term quality of life. This emphasizes an urgent need to improve the recognition and treatment of maternal major depression, particularly in early pregnancy, to limit its negative effects on the patient and on child cognitive development.

Maternal acetaminophen use and cognitive development at 4 years: the Ontario Birth Study.

BACKGROUND: Studies have suggested a link between prenatal maternal acetaminophen use and adverse developmental outcomes in children. However, there exists a knowledge gap regarding overall cognitive development and use of acetaminophen, especially concerning the timing of use in pregnancy. This study aimed to characterize the relationship between maternal acetaminophen use and cognitive development at 4 years. METHODS: This analysis included data collected throughout pregnancy and delivery from women in the Ontario Birth Study prospective cohort from 2013 to 2019 and from the NIH Toolbox Early Childhood Cognition battery administered to 4-year-old children between 2018 and 2021 (n = 436). The exposure was maternal acetaminophen use and the primary outcome was a cognition composite score. The relationship between exposure and outcome was determined using Poisson regression with a robust error variance. RESULTS: We did not observe any association between maternal acetaminophen intake any time before or during pregnancy and low cognition composite score of offspring. The IRR of suboptimal overall cognition was 1.38 (0.78-2.45), 1.22 (0.67-2.22), 0.80 (0.44-1.47), and 1.56 (0.74-3.29) for maternal use of acetaminophen before, in early, late, or overall pregnancy, respectively. CONCLUSION: Current data do not provide evidence to support a relationship of maternal acetaminophen use during pregnancy with adverse cognitive effects at 4 years. IMPACT: Acetaminophen use during pregnancy may influence the risk of child neurocognitive disorders, but there is conflicting evidence of its relationship to sub-clinical measures of cognitive development such as executive function. The study design allowed us to examine the role of timing of acetaminophen use in its relationship with cognitive development, based on a validated and standardized tablet-administered instrument for children, instead of a teacher or parent report. We did not observe a clear relationship between maternal acetaminophen use at different timepoints during pregnancy and child cognitive development.

It's the Thoughts That Count: How Psychological Distance and Affect Heuristic Influence Support for Aid Response Measures During the COVID-19 Pandemic.

Guided by construal level-theory, this research seeks to understand the effect of perceived psychological distance on emotions and risk perception associated with the COVID-19 pandemic in its early stage. Survey data were collected from a nationally representative U.S. adult sample (N = 1009) in April 2020. Results reveal that social distance was negatively related to emotions and risk perception. However, hypothetical distance was not significantly related to these variables. Emotions and risk perception also mediated the relationship between social distance and support for aid response measures; theoretically, we demonstrate that people evaluate risks contingent on their emotions when making decisions. This research contributes to extant literature on psychological distance and its utility in communication messaging design during public health crises.

Maternal prenatal psychological distress and vitamin intake with children's neurocognitive development.

BACKGROUND: Maternal prenatal psychological distress (PPD) is increasingly linked to sub-optimal child neurodevelopment. Daily intake of prenatal vitamin during pre-conception and early pregnancy may ameliorate the effects of PPD on cognition in the offspring. METHODS: PPD was assessed in early (12-16 weeks) and late (28-32 weeks) gestation in the Ontario Birth Study. Prenatal vitamin supplement intake information was collected in early gestation. Child cognition at 4 years was assessed using the NIH Toolbox. Poisson regression was used to investigate associations between PPD and/or prenatal vitamin intake and child cognition. RESULTS: Four hundred and eighteen mother-child dyads were assessed. Moderate-severe PPD experienced during early gestation was associated with reduced cognition (adjusted incidence rate ratio (IRRadj) = 3.71, 95% confidence interval (CI): 1.57-8.77, P = 0.003). Daily intake of prenatal vitamins was not associated with cognition (IRRadj = 1.34, 95% CI: 0.73-2.46, P = 0.34). Upon stratification, the experience of mild-severe PPD with daily intake of prenatal vitamins was associated with higher incident rates of suboptimal cognition compared to children of women with daily prenatal vitamin intake without any episode of PPD (IRRadj = 2.88, 95% CI: 1.1-7.4). CONCLUSIONS: Moderate-severe PPD in early pregnancy is associated with poor cognition in children and daily intake of prenatal vitamin did not ameliorate this association. IMPACT: Our findings expand on existing literature by highlighting that exposure to prenatal psychological distress (PPD), in moderate-to-severe form, in the early stages of pregnancy, can have detrimental effects on the offspring's cognitive development at 4 years. Overall, prenatal vitamin intake did not ameliorate the effects of PPD. Early screening and treatment of prenatal maternal mental illness is crucial.

Misinformation, Anticipated Regret, and Vaccine-Related Behaviors.

A national survey (N = 1025) conducted in August 2021 reveals that Americans' belief in misinformation about COVID-19 was negatively associated with vaccine acceptance. Importantly, the more participants believe in misinformation, the less anticipated regret they experience for not getting vaccinated. Reduced anticipated regret is associated with lower levels of vaccination intention and vaccine acceptance. To counteract the negative impact of misinformation, this study reveals the potential of an under-researched emotion in overcoming vaccine hesitancy.

Comparative Risk: Dread and Unknown Characteristics of the COVID-19 Pandemic Versus COVID-19 Vaccines.

This research characterizes risk perceptions of the COVID-19 pandemic and the COVID-19 vaccines based on the dread and unknown dimensions of the psychometric paradigm. We examine if mental risk comparisons of these two risk objects influence risk mitigation behaviors (vaccination intention; vaccine acceptance; preventive behaviors) and emotional responses among unvaccinated and vaccinated Americans. A survey (N = 1532) was conducted based on a nationally representative sample of U.S. adults in May 2021. Results reveal considerable impact of risk comparison, especially along the dread dimension, on the outcomes of interest. In essence, this research reveals critical insights regarding vaccine hesitancy and risk communication about vaccination.

Predicting the U.S. Public's Prosocial Responses during the COVID-19 Pandemic.

This research examines three distinct processes that influence Americans' prosocial responses during the COVID-19 pandemic. Employing a nationally representative sample, participants read either a mock-up news article on COVID-19 with a clear responsibility attribution (n = 496) or one without (n = 513) in a survey embedded experiment. Participants exposed to the responsibility attribution condition engaged in less systematic processing; systematic processing and all emotions mediated the relationship between responsibility attribution and support for government response measures. For donation intention, only systematic processing and the two socially oriented emotions were significant mediators. In essence, responsibility attribution in media coverage can exert powerful influence on public perception in an ongoing crisis.

Fast and Frugal: Information Processing Related to The Coronavirus Pandemic.

This research focuses on three factors that influence how individuals cognitively process information related to the coronavirus outbreak. Guided by dual-process theories of information processing, we establish how the two different information processing modes (system 1: heuristic processing; system 2: systematic processing) are influenced by individuals' responsibility attribution, discrete negative emotions, and risk perception. In an experiment, participants were exposed to a news article that either blames China (n = 445) or does not blame China (n = 498) for the pandemic. Results reveal that exposure to the responsibility attribution frame led individuals to engage in more heuristic processing, but it did not influence systematic processing. Discrete negative emotions and risk perception mediated the relationship between responsibility attribution and information processing. The indirect relationships suggest a more intricate process underlying heuristic processing and systematic processing. In particular, information processing styles seem to be determined by social judgment surrounding the coronavirus pandemic.

Predictors of 25-Hydroxyvitamin D Concentration Measured at Multiple Time Points in a Multiethnic Population.

The evidence for a relationship between serum vitamin D levels and nonskeletal health outcomes is inconsistent. The validity of single or predicted measurements of 25-hydroxyvitamin D (25(OH)D) concentration is unknown, as levels of this biomarker are highly seasonally variable. We compared models of 25(OH)D measured at baseline, at multiple time points throughout the year, and averaged over the year among 309 persons in Toronto, Ontario, Canada (43°N latitude) during 2009-2013. Information and blood samples were collected every 2 months. Baseline and average 25(OH)D concentrations were correlated (r = 0.88). Major factors associated with 25(OH)D level were similar across models and included race/ethnicity (concentrations in non-European groups were lower than those in Europeans), vitamin D supplement use of ≥1,000 IU/day (18.9 nmol/L (95% confidence interval (CI): 16.1, 21.8) vs. no supplement use in a full data set with all factors), and the presence of the group-specific component/vitamin D binding protein gene (GC/DBP) rs4588 functional polymorphism (AA vs. CC: -16.7 nmol/L (95% CI: -26.2, -7.1); CA vs. CC: -10.7 nmol/L (95% CI: -14.9, -6.5)). Most factors had similar associations in Europeans and non-Europeans. Genetic factors may play a greater role in average 25(OH)D concentrations. Prediction models for 25(OH)D are challenging and population-specific, but use of genetic factors along with a few common population-relevant, quantifiable nongenetic factors with strong associations may be the most feasible approach to vitamin D assessment over time.

Protein-Based Rechargeable and Replaceable Antimicrobial and Antifouling Coatings on Hydrophobic Food-Contact Surfaces.

The growing concerns regarding foodborne illnesses related to fresh produce accentuate the necessity for innovative material solutions, particularly on surfaces that come into close contact with foods. This study introduces a sustainable, efficient, and removable antimicrobial and antifouling coating ideally suited for hydrophobic food-contact surfaces such as low-density polyethylene (LDPE). Developed through a crosslinking reaction involving tannic acid, gelatin, and soy protein hydrolysate, these coatings exhibit proper stability in aqueous washing solutions and effectively combat bacterial contamination and prevent biofilm formation. The unique surface architecture promotes the formation of halamine structures, enhancing antimicrobial efficacy with a rapid contact killing effect and reducing microbial contamination by up to 5 log10 cfu·cm-2 against both Escherichia coli (Gram-negative) and Listeria innocua (Gram-positive). Notably, the coatings are designed for at least five recharging cycles under mild conditions (pH6, 20 ppm free active chlorine) and can be easily removed with hot water or steam to refresh the depositions. This removal process not only conveniently aligns with existing sanitation protocols in the fresh produce industry but also facilitates the complete eradication of potential developed biofilms, outperforming uncoated LDPE coupons. Overall, these coatings represent sustainable, cost-effective, and practical advancements in food safety and are promising candidates for widespread adoption in food processing environments.

Measuring susceptibility to use tobacco in an increasingly complex consumer marketplace: How many questions do we really need?

OBJECTIVE: Predicting which young people are likely to use tobacco in the future is critical for prevention and intervention. Although measures for assessing susceptibility to using tobacco have fulfilled this goal for decades, there is almost no standard for the number of items that should be administered, or which items should be administered for which products. This study explored whether brief but psychometrically sound versions of commonly used susceptibility measures can adequately capture the construct relative to longer measures. METHOD: A sample of young people (N = 451; Mage = 16.5 years; 64% females; 65% White) completed 33 susceptibility items, which are designed to assess susceptibility to use different types of tobacco products (cigarette, smokeless tobacco, vaping products, and little cigars/cigarillos) of various flavors (tobacco, menthol, and sweet). RESULTS: Analysis of these 33 items indicated that asking about the likelihood of using each tobacco product class when a best friend offers it (four items in all) captures 98.5% of information that is captured using the longer set of items; asking the best friend question for each product by each flavor category (11 items in all) captures 99.7% of the information. CONCLUSIONS: Depending on research needs, tobacco use susceptibility can be measured with little loss of information by administering a limited set of items assessing the likelihood that a young person will use a tobacco product if a friend offers it for any product-flavor combination. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Doing more with less: A proposal to advance cigarette packaging regulations in the United States.

Cigarette packages are potent marketing tools. Following guidance from the WHO Framework Convention on Tobacco Control, many countries have sought to diminish this marketing power by mandating that (1) large graphic health warnings be affixed to the packages (i.e., text warnings combined with graphic images of the health consequences of smoking) and (2) all packages be fully "plain" in their design (i.e., all packages use the same drab/bland color and font type; no brand logos, other colors, or designs are permitted). Yet, the United States lags other countries in implementing regulations designed to blunt the marketing power of cigarette packages. This is not because of a lack of effort on the part of the Food and Drug Administration, the main governmental body charged with regulating tobacco products in the United States. Rather, it is because the regulatory options that that have been advanced in the country (e.g., graphic health warnings) have not been found - yet - to be legally feasible by its courts. This commentary works through some of the conceptual, practical, and legal issues regarding packaging regulations in the United States. It considers the political and bureaucratic risks involved with issuing new regulations. The overall intent is to prompt our field to think creatively about what is realistic in this regulatory space and to offer a novel perspective that may help move the United States tobacco control community forward in its efforts to reduce the promotional power of cigarette packages.

Does Reducing the Size of the Tobacco Power Wall Affect Young People's Risk of Future Use of Tobacco Products? An Experimental Investigation.

OBJECTIVE: A ban on tobacco power walls (in-store package displays) is unlikely in the United States because of concerns that such bans violate commercial free speech rights. This experiment evaluated the effectiveness of a more measured strategy for mitigating the influence of the power wall on young people's susceptibility to tobacco use: limiting its size. METHOD: The experiment took place in the RAND StoreLab, a life-sized replica of a convenience store. Participants (N = 275) ages 11-20 years were randomly assigned to shop in a variant of the StoreLab that had either a large (status quo), medium, or small power wall situated behind the checkout counter. Before and after shopping, participants completed measures of risk of future use of unflavored and flavored cigarettes and vaping products. RESULTS: Study condition was unrelated to future risk of smoking unflavored cigarettes, using menthol vaping products, and using sweet-flavored vaping products. Study condition was related to future risk of smoking menthol cigarettes and using unflavored vaping products; compared with exposure to a large power wall, exposure to a small power wall increased the odds of a participant's being at risk for future smoking of menthol cigarettes (odds ratio [OR] = 3.29, 95% CI [1.10, 9.83]) and the odds of a participant's being at risk for using unflavored vaping products (OR = 4.09, 95% CI [1.41, 11.85]). CONCLUSIONS: These findings call into question the viability of reducing the size of the power wall as a singular strategy for dampening its effect on young people's susceptibility to tobacco use.

Cognitive and Emotional Well-Being of Preschool Children Before and During the COVID-19 Pandemic.

Importance: The association between COVID-19 social disruption and young children's development is largely unknown. Objective: To examine associations of pandemic exposure with neurocognitive and socioemotional development at 24 and 54 months of age. Design, Setting, and Participants: This cross-sectional study evaluated associations between pandemic exposure vs nonexposure and developmental outcomes with covariate adjustment using data from the Ontario Birth Study collected between February 2018 and June 2022. Eligible participants were children aged 24 and 54 months. Data were analyzed from June to November 2022. Exposure: COVID-19 pandemic exposure defined as assessment after March 11, 2020. Main Outcome and Measures: Neurodevelopmental assessment using the ASQ-3 (Ages and Stages Questionnaire, Third Edition) and MCHAT-R (Modified Checklist for Autism in Toddlers, Revised) at 24 months of age, and neurocognitive and socioemotional assessment using the National Institutes of Health Toolbox at 54 months of age. Results: A total of 718 children at age 24 months (mean [SD] age, 25.6 [1.7] months; 342 female [47.6%]; 461 White [64.2%]) and 703 at age 54 months (mean [SD] age, 55.4 [2.6] months; 331 female [47.1%]; 487 White [69.3%]) were included. At 24 months of age, 460 participants (232 female [50.4%]) were assessed during the pandemic (March 17, 2020, to May 17, 2022) and 258 (110 female [42.6%]) were assessed prepandemic (April 17, 2018, to March 10, 2020). At 54 months of age, 286 participants (129 female [45.1%]) were assessed from March 14, 2020, to June 6, 2022, and 417 (202 female [48.4%]) were assessed from February 8, 2018, to March 10, 2020. At 24 months of age, pandemic-exposed children had reduced risk of problem-solving difficulties using cutoff scores (odds ratio [OR], 0.33; 95% CI, 0.18-0.62; P = .005) and higher problem-solving (B, 3.93; 95% CI, 2.48 to 5.38; P < .001) compared with nonexposed children. In contrast, pandemic-exposed children had greater risk for personal-social difficulties using cutoff scores (OR, 1.67; 95% CI, 1.09-2.56; P = .02) and continuous scores (B, -1.70; 95% CI, -3.21 to -0.20; P = .02) compared with nonexposed children. At 54 months of age, pandemic-exposed children had higher receptive vocabulary (B, 3.16; 95% CI, 0.13 to 6.19; P = .04), visual memory (B, 5.95; 95% CI, 1.11 to 10.79; P = .02), and overall cognitive performance (B, 3.89; 95% CI, 0.73 to 7.04; P = .02) compared with nonexposed children, with no differences in socioemotional development. Conclusions and Relevance: This cross-sectional study found both positive and negative associations between pandemic exposure and preschool children's cognitive and emotional well-being within a relatively socioeconomically advantaged sample.

Antimicrobial activity and cellular toxicity of nanoparticle-polymyxin B conjugates.

We investigate the antimicrobial activity and cytotoxicity to mammalian cells of conjugates of the peptide antibiotic polymyxin B (PMB) to Au nanoparticles and CdTe quantum dots. Au nanoparticles fully covered with PMB are identical in antimicrobial activity to the free drug alone, whereas partially-conjugated Au particles show decreased effectiveness in proportion to the concentration of Au. CdTe-PMB conjugates are more toxic to Escherichia coli than PMB alone, resulting in a flattening of the steep PMB dose-response curve. The effect is most pronounced at low concentrations of PMB, with a greater effect on the concentration required to reduce growth by half (IC50) than on the concentration needed to inhibit all growth (minimum inhibitory concentration, MIC). The Gram positive organism Staphylococcus aureus is resistant to both PMB and CdTe, showing minimal increased sensitivity when the two are conjugated. Measurement of reactive oxygen species (ROS) generation shows a significant reduction in photo-generated hydroxyl and superoxide radicals with CdTe-PMB as compared with bare CdTe. There is a corresponding reduction in toxicity of QD-PMB versus bare CdTe to mammalian cells, with nearly 100% survival in fibroblasts exposed to bactericidal concentrations of QD-PMB. The situation in bacteria is more complex: photoexcitation of the CdTe particles plays a small role in IC50 but has a significant effect on the MIC, suggesting that at least two different mechanisms are responsible for the antimicrobial action seen. These results show that it is possible to create antimicrobial agents using concentrations of CdTe quantum dots that do not harm mammalian cells.

A cross-sectional study of different patterns of oral contraceptive use among premenopausal women and circulating IGF-1: implications for disease risk.

BACKGROUND: Insulin-like growth factor-1 (IGF-1) is important in normal growth, development, and homeostasis. Current use of oral contraceptives (OC) decreases IGF-1 concentrations; however, the effect of past use, age/timing of use, and type of OC used on IGF-1 levels is unknown. OC are the most commonly used form of birth control worldwide. Both IGF-1 and OC use have been linked to premenopausal breast and colorectal cancers, osteoporosis and cardiovascular disease (CVD). Understanding the effects of different patterns of OC use on IGF-1 levels may offer insight into its influence on disease risk in young women. METHODS: In a cross-sectional study of 328 premenopausal women ages 18 to 21 and 31 to 40 we examined the relationship between different patterns of OC use and circulating IGF-1 using adjusted linear regression analysis. Information on OC use was obtained through an interviewer administered questionnaire. Plasma IGF-1 was assessed with enzyme linked immunosorbent assay (ELISA). RESULTS: Among women aged 18 to 21, ever OC use was significantly associated with decreased IGF-1 levels compared to never use (ß = -57.2 ng/ml, 95% confidence interval (CI): -88.7, -25.8). Among women aged 31 to 40, past users who first used OC at 25 years of age or older (ß = 43.8 ng/ml, 95% CI: 8.8, 78.8), in the last 15 years (ß = 35.1 ng/ml, 95% CI: 9.3, 61.0) or after 1995 (ß = 46.6 ng/ml, 95% CI: 13.4, 79.8) had significantly higher IGF-1 levels compared to never users. CONCLUSION: This is the first study to highlight the long term effects of OC use after cessation on IGF-1 levels among premenopausal women, which previously were thought to be transitory. Future studies of past use and IGF-1 levels are required and must consider age/timing of use and type/generation of OC used. Additional studies are needed to confirm the potential mediation of IGF-1 levels in the links between OC use and health outcomes.

Vitamin D association with estradiol and progesterone in young women.

OBJECTIVE: Vitamin D may reduce breast cancer risk through an effect on steroid hormones in cycling women.We conducted a study to determine whether there is an association between circulating 25-hydroxyvitamin D (25(OH)D) and estradiol and progesterone in young women. METHODS: Volunteer women aged 18-22 and not using hormonal contraceptives were recruited during summer and winter. They provided demographic and lifestyle information and a blood sample. Women recruited in winter gave a second sample after taking vitamin D supplement for 4 weeks. There were 101 women sampled during the luteal phase (1-14 days prior to the start of the next menstrual period). Generalized estimating equation linear regression models were used to examine the relationship between 25(OH)D and estradiol and progesterone. RESULTS: Per increase of 10 nmol/l of 25(OH)D, progesterone multiplicatively decreased by a factor of 10% (95% CI 5-14%, p < 0.001) and estradiol decreased by a factor of 3% (95% CI 0-6%, p = 0.04) after adjustment for age, body mass index, ethnicity, season, alcohol use, smoking, and physical activity. CONCLUSIONS: Higher levels of vitamin D may reduce progesterone and estradiol, providing a potential mechanism for reduction in breast cancer risk from increased vitamin D exposure in young women.

Optical spectroscopy of the breast in premenopausal women reveals tissue variation with changes in age and parity.

PURPOSE: Variations during breast tissue development can influence later breast cancer risk. In particular, prolonged nulliparity increases risk. The authors used optical spectroscopy to compare breast tissue in 115 nulliparous women aged 31-40 (group 2) to 140 nulliparous women aged 18-21 (group 1), and also to 36 parous women aged 31-40 (group 3), and to evaluate the relationship between IGF-1 and optical breast tissue properties. IGF-1 has been linked in particular to premenopausal breast cancer. METHODS: The authors measured the transmission spectra from 625 to 1050 nm wavelengths in each breast and determined regions of interindividual variation using principal components analysis. Spectral differences represent variation in lipid, water, oxyhemoglobin, deoxyhemoglobin, and collagen content. Group differences and the relationship with IGF-1 were estimated by linear regression after adjustment for multiple factors including height, weight, ethnicity, hormonal contraceptive use, and days since last menstrual period. RESULTS: Principal component 3 scores were more negative in the older nulliparous women compared to either younger nulliparous women or to parous women of the same age (beta = -0.16, p = 0.008 for group 2 vs group 1 and beta = 0.51, p = 0.03 for group 3 vs group 2). These differences appear to indicate increased deoxyhemoglobin relative to oxyhemoglobin content in the tissue of the older, nulliparous premenopausal women compared to the other groups, which may be an indicator of proportionally increased proliferative tissue. Principal component 4 also differed between older and younger nulliparous women (beta = 0.08, p = 0.02 for group 2 vs. group 1) and was negatively associated with IGF-1 in younger women (beta = -0.0004, p = 0.03) and positively associated with IGF-1 in older women (beta = 0.001, p = 0.004). CONCLUSIONS: Optical spectroscopy may be useful to identify breast tissue at increased risk of cancer development and track changes over time, particularly in young women where exposure to radiation is of particular concern. Additional work is needed to confirm the observed breast tissue differences and to determine the specific tissue chromophore changes with age and parity.