Search

Observational studies suggest that people with a high serum 25-hydroxyvitamin D (25(OH)D) concentration may have reduced risk of chronic diseases such as osteoporosis, multiple sclerosis, type 1 diabetes, cardiovascular disease, and some cancers. The AusD Study (A Quantitative Assessment of Solar UV Exposure for Vitamin D Synthesis in Australian Adults) was conducted to clarify the relationships between ultraviolet (UV) radiation exposure, dietary intake of vitamin D, and serum 25(OH)D concentration among Australian adults residing in Townsville (19.3°S), Brisbane (27.5°S), Canberra (35.3°S), and Hobart (42.8°S). Participants aged 18–75 years were recruited from the Australian Electoral Roll between 2009 and 2010. Measurements were made of height, weight, waist:hip ratio, skin, hair, and eye color, blood pressure, and grip strength. Participants completed a questionnaire on sun exposure and vitamin D intake, together with 10 days of personal UV dosimetry and an associated sun-exposure and physical-activity diary that was temporally linked to a blood test for measurement of 25(OH)D concentration. Ambient solar UV radiation was also monitored at all study sites. We collected comprehensive, high-quality data from 1,002 participants (459 males, 543 females) assessed simultaneously across a range of latitudes and through all seasons. Here we describe the scientific and methodological issues considered in designing the AusD Study. [ABSTRACT FROM PUBLISHER]

Objective: This study examines the prognostic significance of human papillomavirus (HPV) in patients with locally advanced oropharyngeal squamous cell carcinoma (SCC) treated primarily with surgery or definitive radiotherapy.Methods: One hundred and ninety-eight patients with Stage 3/4 SCC were followed up for recurrence in any form or death from any cause for between 1 and 235 months after diagnosis. HPV status was determined using HPV E6-targeted multiplex real-time PCR/p16 immunohistochemistry. Determinants of recurrence and mortality hazards were modelled using Cox's regression with censoring at follow-up dates.Results: Forty-two per cent of cancers were HPV-positive (87% type 16). HPV predicted loco-regional control, event-free survival and overall survival in multivariable analysis. Within the surgery with adjuvant radiotherapy (n=110), definitive radiotherapy-alone (n=24) and definitive radiotherapy with chemotherapy (n=47) groups, patients with HPV-positive cancers were one-third or less as likely to have loco-regional recurrence, an event or to die of any cause as those with HPV-negative cancers after adjusting for age, gender, tumour grade, AJCC stage and primary site. The 14 patients treated with surgery alone were considered too few for multivariable analysis.Conclusion: HPV status predicts better outcome in oropharyngeal cancer treated with surgery plus adjuvant radiotherapy as well as with definitive radiation therapy±chemotherapy. [ABSTRACT FROM AUTHOR]

Data regarding the effects of oral contraceptive use on women's risk of melanoma have been difficult to resolve. We undertook a pooled analysis of all case-control studies of melanoma in women completed as of July 1994 for which electronic data were available on oral contraceptive use along with other melanoma risk factors such as hair colour, sun sensitivity, family history of melanoma and sun exposure. Using the original data from each investigation (a total of 2391 cases and 3199 controls), we combined the study-specific odds ratios and standard errors to obtain a pooled estimate that incorporates inter-study heterogeneity. Overall, we observed no excess risk associated with oral contraceptive use for 1 year or longer compared to never use or use for less than 1 year (pooled odds ratio (pOR)=0.86; 95% CI=0.74-1.01), and there was no evidence of heterogeneity between studies. We found no relation between melanoma incidence and duration of oral contraceptive use, age began, year of use, years since first use or last use, or specifically current oral contraceptive use. In aggregate, our findings do not suggest a major role of oral contraceptive use on women's risk of melanoma. [ABSTRACT FROM AUTHOR]

Objectives: To investigate how closely the variables of exposures to magnetic fields based on the last job held in an electrical utility in Québec, Canada, compared with those based on the workers' entire employment history with the company.Methods: In large cohort studies, the last job held is often used to assign exposure to the study subjects. Exposure was assigned in this way for a mortality study of a cohort of electrical utility workers in Québec. For the present study, a sample of the cohort was used to compare the exposure estimates obtained from the last job with those obtained from full work histories.Results: The correlations between indices based on the last job and on all jobs varied between 0.75 and 0.78. The mean was slightly lower when only the last job was used. The last job was particularly good in identifying the most highly exposed people (for the exposure cut off point of 90th percentile for the last job and for all jobs, sensitivity = 0.69, specificity = 0.97, kappa = 0.66). The results suggest that although not all workers starting in highly exposed jobs stayed in them, it seemed that the workers who ended their working life in highly exposed jobs had stayed in these jobs throughout their working life.Conclusion: The results indicated some (but not catastrophic) loss of information when estimates of exposure were based on the last job only. [ABSTRACT FROM AUTHOR]

Objectives: This case cohort study examines whether there is an association between exposure to electric and magnetic fields and suicide in a population of 21,744 male electrical utility workers from the Canadian Province of Québec.Methods: 49 deaths from suicide were identified between 1970 and 1988 and a subcohort was selected comprising a 1% random sample from this cohort as a basis for risk estimation. Cumulative and current exposures to electric fields, magnetic fields, and pulsed electromagnetic fields (as recorded by the POSITRON meter) were estimated for the subcohort and cases through a job exposure matrix. Two versions of each of these six indices were calculated, one based on the arithmetic mean (AM), and one on the geometric mean (GM) of field strengths.Results: For cumulative exposure, rate ratios (RR) for all three fields showed mostly small non-significant increases in the medium and high exposure groups. The most increased risk was found in the medium exposure group for the GM of the electric field (RR = 2.76, 95% CI 1.15-6.62). The results did not differ after adjustment for socioeconomic state, alcohol use, marital state, and mental disorders. There was a little evidence for an association of risk with exposure immediately before the suicide.Conclusion: Some evidence for an association between suicide and cumulative exposure to the GM of the electric fields was found. This specific index was not initially identified as the most relevant index, but rather emerged afterwards as showing the most positive association with suicide among the 10 indices studied. Thus the evidence from this study for a causal association between exposure to electric fields and suicide is weak. Small sample size (deaths from suicide) and inability to control for all potential confounding factors were the main limitations of this study. [ABSTRACT FROM AUTHOR]

Background: A strong association has been found between skin cancer and exposure to UV radiation. The p53 tumor suppressor gene (also known as TP53), which is frequently mutated in human cancers, is believed to be an early target in UV radiation-associated skin carcinogenesis. We have previously developed a sensitive, polymerase chain reaction-based method capable of detecting and quantifying a UV radiation-specific mutation in the p53 gene (codons 247 and 248: AAC CGG --> AAT TGG) in normal skin. We have used this method to examine whether UV radiation-specific mutation frequency is associated with risk of basal cell carcinoma (BCC) and with sun exposure.Methods: This case-control study in Australia involved 53 case subjects with BCC and 75 control subjects. DNA was isolated from normal skin (mirror-image anatomic site to the cancer site for case subjects and a randomly selected site for control subjects) and assayed for p53 mutation. Relationships between p53 mutation frequency and risk of BCC, sun sensitivity, or sun exposure were estimated by use of odds ratios (ORs) and 95% confidence intervals (95% CIs).Results: Case subjects were more likely to have a p53 mutation than control subjects (OR = 3.1; 95% CI = 1.3-7.1). In addition, the odds of BCC increased monotonically with increasing frequency of p53 mutation. No statistically significant associations could be demonstrated between p53 mutation frequency and age, sex, sensitivity to the sun, pigmentary characteristics, total lifetime sun exposure, or sun exposure to the biopsy site.Conclusions: Our results indicate that tandem CC --> TT mutations involving codons 247 and 248 of the p53 gene are associated with an increased risk of BCC but cannot be used as an accurate measure of total UV-radiation exposure. [ABSTRACT FROM AUTHOR]

Objectives: To investigate the impact of a health adviser in genitourinary medicine as a training and support resource on the management of Chlamydia trachomatis in a large inner city health centre.Methods: A large, inner city health centre was selected at random for the intervention, with another selected as control. The health adviser offered support and training in the management of C trachomatis to clinical staff in the intervention health centre for 6 months. Data on testing activity were collected over the period of the intervention and during the equivalent period in the previous year. Data on partner notification activities were collected from case notes.Results: The research intervention was effective in increasing C trachomatis testing activity. However, the majority of tests were offered to women over 20 years of age and no increase in the proportion of positive results was observed.Conclusions: The intervention was effective in increasing C trachomatis testing activity, but did not improve the overall detection rate. Health centre staff accommodated opportunistic testing for C trachomatis into existing healthcare practices, as opposed to introducing new screening systems designed to reach the target population. [ABSTRACT FROM AUTHOR]