Association analysis of self-reported outcomes with a validated subset.

In health-science research, outcomes ascertained through surveys and interviews are subject to potential bias with respect to the true outcome status, which is only ascertainable with clinical and laboratory assessment. This measurement error may lead to biased inference when evaluating associations between exposures and outcomes of interest. Here, we consider a cohort study in which the outcome of interest is ascertained via questionnaire, subject to imperfect ascertainment, but where a subset of participants also have a clinically assessed, validated outcome available. This presents a methodological opportunity to address potential bias. Specifically, we constructed the likelihood in two parts, one using the validated subset and the other using a subset without validation. This work expands on that proposed by Pepe and enables inference with standard statistical software. Weighted generalized linear model estimates for our method and maximum likelihood estimates (MLE) for Pepe's method were computed, and the statistical inference was based on the standard large-sample likelihood theory. We compare the finite sample performance of two approaches through Monte Carlo simulations. This methodological work was motivated by a large cohort study of long-term childhood cancer survivors, allowing us to provide a relevant application example where we examined the association between clinical factors and chronic health conditions.

Effect of gold nanoparticles on the efficiency of poly(3-hexylthiophene): phenyl-C61-butyric-acid-methylester solar cells.

Different surface densities of gold nanoparticles (AuNPs) were deposited on (3-aminopropyl)-trimethoxysilane (APTMS)-modified indium tin oxide (ITO) electrode. The electrodes were then used in poly(3-hexylthiophene): phenyl-C61-butyric-acid-methylester (P3HT:PCBM) solar cells. Enhanced photo-conversion efficiency was observed from solar cells containing adsorbed AuNPs with surface density equals to 10 +/- 3 NPs/microm2. For higher surface densities (215 +/- 10 NPs/microm2), the presence of the plasmonic material significantly reduced the efficiency of the solar cell. Impedance spectroscopy (IS) indicates changes of the electrical characteristics, evident by a drastic reduction of the impedance relative to the reference cells, from electrodes modified with high densities of AuNPs.

Statistical Analysis of Self-Reported Health Conditions in Cohort Studies: Handling of Missing Onset Age.

OBJECTIVE: This paper discusses methodological challenges in epidemiological association analysis of a time-to-event outcome and hypothesized risk factors, where age/time at the onset of the outcome may be missing in some cases, a condition commonly encountered when the outcome is self-reported. STUDY DESIGN AND SETTING: A cohort study with long-term follow-up for outcome ascer- tainment such as the Childhood Cancer Survivor Study (CCSS), a large cohort study of 5-year survivors of childhood cancer diagnosed in 1970-1999 in which occurrences and age at onset of various chronic health conditions (CHCs) are self-reported in surveys. Simple methods for handling missing onset age and their potential bias in the exposure-outcome association infer- ence are discussed. The interval-censored method is discussed as a remedy for handling this problem. The finite sample performance of these approaches is compared through Monte Carlo simulations. Examples from the CCSS include four CHCs (diabetes, myocardial infarction, osteoporosis/osteopenia, and growth hormone deficiency). RESULTS: The interval-censored method is usable in practice using the standard statisti- cal software. The simulation study showed that the regression coefficient estimates from the 'Interval censored' method consistently displayed reduced bias and, in most cases, smaller stan- dard deviations, resulting in smaller mean square errors, compared to those from the simple approaches, regardless of the proportion of subjects with an event of interest, the proportion of missing onset age, and the sample size. CONCLUSION: The interval-censored method is a statistically valid and practical approach to the association analysis of self-reported time-to-event data when onset age may be missing. While the simpler approaches that force such data into complete data may enable the standard analytic methods to be applicable, there is considerable loss in both accuracy and precision relative to the interval-censored method.

Hypogonadism and neurocognitive outcomes among childhood cancer survivors.

OBJECTIVE: Childhood cancer survivors are at risk for hypogonadism. The impact of hypogonadism on neurocognitive impairment and emotional distress in the non-cancer population has been shown; however, the relationship among the childhood cancer survivor population is unknown. We aimed to evaluate the contribution of hypogonadism to neurocognitive impairment and emotional distress among survivors. DESIGN: Cross-sectional study using retrospective cohort. METHODS: In total, 3628 survivors who completed standard neurocognitive tests (six domains: processing speed, memory, executive function, attention, academics, and global cognition) and self-reported emotional distress were included in our study. Participants were stratified by sex and gonadal status. Outcomes were compared between hypogonadal and eugonadal groups by multivariable analysis, adjusting for established predictors, and mediation analyses to determine the direct/indirect effects of hypogonadism on outcomes. RESULTS: The hypogonadal group exhibited a higher prevalence of neurocognitive impairment across domains, but no difference in emotional distress. Hypogonadal females exhibited higher relative risk (1.7, 95% CI, 1.2-2.5) for impaired visual processing speed, compared to eugonadal females after adjusting for cancer-related variables. In mediation models, hypogonadism had a significant direct (P < .01) and indirect (from P < .01) impact on impairment in visual processing speed among females. Males demonstrated direct (P = .03) and indirect (P = .04) impact of hypogonadism on motor processing speed. CONCLUSION: Processing speed may be the most vulnerable neurocognitive domain associated with hypogonadism in survivors, while other domains were mainly impacted by cancer-related variables. Our findings support the need for further evaluation of the impact of sex hormone replacement therapy on neurocognitive function.

Lifestyle and Subsequent Malignant Neoplasms in Childhood Cancer Survivors: A Report from the St. Jude Lifetime Cohort Study.

INTRODUCTION: This study aimed to assess longitudinal associations between lifestyle and subsequent malignant neoplasms (SMNs) in young adult childhood cancer survivors. METHODS: Members of the St. Jude Lifetime Cohort (SJLIFE) aged ≥18 years and surviving ≥5 years after childhood cancer diagnosis were queried and evaluated for physical activity, cardiorespiratory fitness (CRF), muscle strength, body mass index (BMI), smoking, risky drinking, and a combined lifestyle score. Time to first SMN, excluding nonmalignant neoplasms and nonmelanoma skin cancer, was the outcome of longitudinal analysis. RESULTS: Survivors (n = 4072, 47% female, 29% smokers, 37% risky drinkers, 34% obese, and 48% physically inactive) had a mean (SD) time between baseline evaluation and follow-up of 7.0 (3.3) years, an age of 8.7 (5.7) years at diagnosis, and an age of 30 (8.4) years at baseline lifestyle assessment. Neither individual lifestyle factors nor a healthy lifestyle score (RR 0.8, 0.4-1.3, p = 0.36) were associated with the risk of developing an SMN. CONCLUSIONS: We did not identify any association between lifestyle factors and the risk of SMN in young adult childhood cancer survivors.

Examining attention-deficit/hyperactivity disorder and related behavioral disorders by fertility treatment exposure in a prospective cohort.

PURPOSE: To evaluate whether underlying infertility and mode of conception are associated with childhood behavioral disorders. METHODS: Oversampling on fertility treatment exposure using vital records, the Upstate KIDS Study followed 2057 children (of 1754 mothers) from birth to 11 years. Type of fertility treatment and time to pregnancy (TTP) were self-reported. Mothers completed annual questionnaires reporting symptomology, diagnoses, and medications at 7-11 years of age. The information identified children with probable attention-deficit/hyperactivity disorder, anxiety or depression, and conduct or oppositional defiant disorders. We estimated adjusted relative risks (aRR) for disorders by underlying infertility (TTP > 12 months) or treatment exposure groups compared to children born to parents with TTP ≤ 12 months. RESULTS: Children conceived with fertility treatment (34%) did not have an increased risk of attention-deficit/hyperactivity disorder (aRR): 1.21; 95% CI: 0.88, 1.65), or conduct or oppositional defiant disorders (aRR: 1.31; 0.91, 1.86), but did have an increased risk of anxiety or depression (aRR: 1.63; 1.18, 2.24), which remained elevated even after adjusting for parental mood disorders (aRR: 1.40; 0.99, 1.96). Underlying infertility without the use of treatment was also associated with a risk of anxiety or depression (aRR: 1.82; 95% CI: 0.96, 3.43). CONCLUSIONS: Underlying infertility or its treatment was not associated with risk of attention-deficit/hyperactivity disorder. Observations of increased anxiety or depression require replication.

A systematic review of program circumstances in training social skills to adolescents with high-functioning autism.

Despite many programs for educating social skills to adolescents with autism, insufficient attention has been paid to examine the optimal conditions and strategies that are important for improvement and generalization of the learned skills. So after reviewing and searching for three PubMed, Scopus, and ProQuest databases, 20 studies were finally analyzed and shared conditions were extracted. The results showed that the most important condition is parental involvement. The rehearsal and practice of social skills, attention to developmental trajectories, strengths and weaknesses of the individual and use of quantitative and qualitative tools are the other circumstances. In conclusion, taking into account these conditions for improvement, generalization and durability of the skills can be helpful.