Lauren P. Hollier

Measurement of androgen and estrogen concentrations in cord blood: accuracy, biological interpretation, and applications to understanding human behavioral development

Accurately measuring hormone exposure during prenatal life presents a methodological challenge and there is currently no “gold standard” approach. Ideally, circulating fetal hormone levels would be measured at repeated time points during pregnancy. However, it is not currently possible to obtain fetal blood samples without significant risk to the fetus, and therefore surrogate markers of fetal hormone levels must be utilized. Umbilical cord blood can be readily obtained at birth and largely reflects fetal circulation in late gestation. This review examines the accuracy and biological interpretation of the measurement of androgens and estrogens in cord blood. The use of cord blood hormones to understand and investigate human development is then discussed.

The association between perinatal testosterone concentration and early vocabulary development: A prospective cohort study

Prenatal exposure to testosterone is known to affect fetal brain maturation and later neurocognitive function. However, research on the effects of prenatal testosterone exposure has been limited by indirect measures of testosterone and small unrepresentative samples. This study investigated whether bioavailable testosterone (BioT) concentrations in umbilical cord blood are associated with expressive vocabulary development, in a large birth cohort. Cord blood samples were taken immediately after delivery and expressive vocabulary was measured at two years of age using the language development survey (LDS). BioT concentration significantly predicted vocabulary size in males (n=197), such that higher concentrations were associated with lower LDS scores, indicating smaller vocabulary. This relationship between BioT concentrations and vocabulary at aged 2 years was not observed in girls (n=176). Higher circulating prenatal testosterone concentrations at birth may be associated with reduced vocabulary in early childhood among boys.

Adult digit ratio (2D:4D) is not related to umbilical cord androgen or estrogen concentrations, their ratios or net bioactivity

BACKGROUND Ratio of second digit length to fourth digit length (2D:4D) has been extensively used in human and experimental research as a marker of fetal sex steroid exposure. However, very few human studies have measured the direct relationship between fetal androgen or estrogen concentrations and digit ratio. AIMS We investigated the relationships between both androgen and estrogen concentrations in umbilical cord blood and digit ratio in young adulthood. In addition we calculated measures of total serum androgen and total estrogen bioactivity and investigated their relationship to digit ratio. STUDY DESIGN Prospective cohort study. SUBJECTS An unselected subset of the Western Australian Pregnancy Cohort (Raine) Study (159 female; 182 male). OUTCOME MEASURES Cord serum samples were collected immediately after delivery. Samples were assayed for androgen (testosterone, Δ4-androstenedione, dehydroepiandrosterone) and estrogen (estrone, estradiol, estriol, estetrol) concentrations using liquid-chromatography mass-spectrometry. Digit ratio measurements were taken from hand photocopies at age 19-22years. RESULTS For both males and females, there were no significant correlations between digit ratio and any androgen or estrogen concentrations considered individually, the testosterone to estradiol ratio, total androgen bioactivity measure or ratio of androgen to estrogen bioactivity (all p>.05). In males, but not females, total estrogen bioactivity was negatively correlated with left hand digit ratio (r=-.172, p=.02), but this relationship was no longer significant when adjusted for variables known to affect sex steroid concentrations in cord blood. CONCLUSIONS Our findings indicate that digit ratio is not related to fetal androgens or estrogens at late gestation.

Perinatal testosterone exposure and cerebral lateralisation in adult males: Evidence for the callosal hypothesis

Two competing theories address the influence of foetal testosterone on cerebral laterality: one proposing exposure to high foetal testosterone concentrations is related to atypical lateralisation (Geschwind-Galaburda hypothesis), the other that high foetal testosterone concentrations exaggerate typical lateralisation (callosal hypothesis). The current study examined the relationship between cord testosterone concentrations and cerebral laterality for language and spatial memory in adulthood. Male participants with high (>0.15nmol) and low (<0.10nmol) cord testosterone levels were invited to take part in the study (n=18 in each group). Cerebral laterality was measured using functional Transcranial Doppler ultrasonography, while participants completed word generation and visual short-term memory tasks. Typical left lateralisation of language was more common in the high-testosterone group than in the low-testosterone group, χ(2)=4.50, df=1, p=034. Spatial memory laterality was unrelated to cord testosterone level. Our findings indicate that foetal testosterone exposure is related to language laterality in a direction that supports the callosal hypothesis.

Comparing online and telephone survey results in the context of a skin cancer prevention campaign evaluation.

Background A large proportion of health promotion campaign evaluation research has historically been conducted via telephone surveys. However, there are concerns about the continued viability of this form of surveying in providing relevant and representative data. Online surveys are an increasingly popular alternative, and as such there is a need to assess the comparability between data collected using the two different methods to determine the implications for longitudinal comparisons. The present study compared these survey modes in the context of health promotion evaluation research. Methods Data were collected via computer-assisted telephone interviewing and an online panel. In total, 688 and 606 respondents aged between 14 and 45 years completed the online and telephone surveys, respectively. Results Online respondents demonstrated higher awareness of the advertisement, rated the advertisement as more personally relevant and had better behavioural outcomes compared with the telephone respondents. Conclusion The results indicate significant differences between the telephone and online surveys on most measures used to assess the effectiveness of a health promotion advertising campaign. Health promotion practitioners could consider the combination of both methods to overcome the deterioration in telephone survey response rates and the likely differences in respondent outcomes.

Trends in Australian adolescents’ sun‐protection behaviours: implications for health campaigns

Objective: Protecting the skin from ultraviolet (UV) radiation is critical during adolescence to reduce the risk of developing skin cancer later in life, but adolescents tend to be less likely to engage in sun‐protective behaviours than adults. The present study examined changes and trends (2001/02–2011/12) in sun‐protection behaviours among adolescents living in Western Australia – a region with high levels of UV radiation.