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. METHODS: A cross-sectional survey was conducted during 10 summers between 2001/02 and 2011/12 to investigate how often adolescents engaged in various sun-protection behaviours, including outdoor protective measures (wearing a hat, wearing protective clothing, using sunscreen, wearing sunglasses, seeking shade) and avoidance of UV radiation by staying inside. RESULTS: Hat use significantly decreased between 2001/02 and 2011/12, whereas use of sunscreen and wearing covering clothes were unchanged in most survey years relative to 2001/02. Use of sunglasses peaked in 2006/07 and 2007/08, but returned to first survey year levels in 2011/12, while staying inside was more frequently reported from 2006/07 onwards. CONCLUSIONS: New approaches are needed to minimise reactance responses in adolescents while fostering favourable attitudes to sun protection. Implications and opportunities for interventions to promote better sun-protection practices among adolescents are provided.

Assessing the potential to combine attitude tracking and health campaign evaluation surveys.

Issue addressed: Online surveys are becoming increasingly popular in health research because of the low cost and fast completion time. A large proportion of online survey costs are allocated to setup and administration expenses, which suggests that conducting fewer, longer surveys would be a cost-effective approach. The current study assessed whether the incorporation of a health campaign evaluation survey within a longitudinal attitudes and behaviours tracking survey produced different outcomes compared with the separate administration of the evaluation survey.Methods: Data were collected via an online panel, with 688 respondents completing the combined survey and 657 respondents completing the evaluation-only survey. Regression analyses were conducted to examine whether survey type was related to the campaign evaluation results.Results: Those who completed the combined survey perceived the campaign advertisement to be more personally relevant than those completing the evaluation-only survey. There were no differences in results relating to campaign awareness and reported behavioural change as a result of campaign exposure.Conclusions: There were minimal differences between results obtained from combining an attitude/behaviour tracking survey with a campaign evaluation survey. Any priming or order effects were limited to respondents' cognitive responses to the advertisement.So what?: The results suggest that health practitioners with limited resources available for tracking and evaluation research may be able to maximise outcomes by administering fewer, longer surveys.

The perinatal androgen to estrogen ratio and autistic-like traits in the general population: a longitudinal pregnancy cohort study.

BACKGROUND: Prenatal androgen exposure has been hypothesized to be linked to autism spectrum disorder (ASD). While previous studies have found a link between testosterone levels in amniotic fluid and autistic-like traits, a similar relationship has not been found for testosterone in umbilical cord blood. However, it may be the net biological activity of multiple androgens and estrogens that influences postnatal effects of prenatal sex steroids. Accordingly, composite levels of androgens (A) and estrogens (E) were investigated, along with their ratio, in relation to autistic-like traits in young adulthood. METHODS: Sex steroid data in umbilical cord blood were available from 860 individuals at delivery. Samples were analyzed for androgens (testosterone, androstenedione, and dehydroepiandrosterone) and estrogens (estrone, estradiol, estriol, and estetrol). Levels of bioavailable testosterone, estradiol, and estrone were measured and used to calculate A and E composites and the A to E ratio. Participants were approached in early adulthood to complete the autism-spectrum quotient (AQ) as a self-report measure of autistic-like traits, with 183 males (M = 20.10 years, SD = 0.65 years) and 189 females (M =19.92 years, SD = 0.68 years) providing data. RESULTS: Males exhibited significantly higher androgen composites and A to E composite ratios than females. Males also scored significantly higher on the details/patterns subscale of the AQ. Subsequent categorical and continuous analyses, which accounted for covariates, revealed no substantial relationships between the A/E composites or the A to E ratio and the AQ total or subscale scores. CONCLUSIONS: The current study found no link between the A/E composites or the A to E ratio in cord blood and autistic-like traits in the population as measured by the AQ. These outcomes do not exclude the possibility that these sex steroid variables may predict other neurodevelopmental traits in early development.

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.

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.