ORCID Profile
0000-0003-0002-7724
Current Organisation
UNSW Sydney
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Publisher: Elsevier BV
Date: 05-2019
Publisher: Oxford University Press (OUP)
Date: 14-05-2008
DOI: 10.1093/IJE/DYN071
Publisher: Springer Science and Business Media LLC
Date: 05-11-2014
DOI: 10.1007/S00345-013-1201-5
Abstract: We aim to determine the relationship between season, personal solar UV exposure, serum 25(OH)D and 1,25(OH)2D and serum prostate-specific antigen (PSA) levels. Questionnaire data and blood s les were collected at baseline from participants of the Concord Health and Ageing in Men Project (n = 1,705), aged 70 and above. They were grouped as men 'free of prostate disease' for those with no record of having prostate cancer, benign prostatic hyperplasia, or prostatitis and with serum PSA levels below 20 ng/mL, and 'with prostate disease' for those with a record of either of these diseases or with serum PSA levels 20 ng/mL or above. Personal solar UV exposure (sUV) was estimated from recalled hours of outdoor exposure and weighted against ambient solar UV radiation. Sera were analysed to determine levels of PSA, 25(OH)D and 1,25(OH)2D, and analysed using multiple regression, adjusting for age, BMI and region of birth. The association between sUV and serum PSA levels was conditional upon season (p interaction = 0.04). There was no direct association between serum PSA and 25(OH)D in both groups of men. There was a positive association between serum PSA and 1,25(OH)2D in men with prostate disease (mean = 110.6 pmol/L p heterogeneity = 0.03), but there was no such association in men free of prostate disease (mean = 109.3 pmol/L p heterogeneity = 0.8). The association between PSA and sUV may only be evident at low solar UV irradiance, and this effect may be independent of serum vitamin D levels.
Publisher: Wiley
Date: 17-10-2016
DOI: 10.1002/CAM4.929
Publisher: Oxford University Press (OUP)
Date: 29-10-2005
Abstract: Polymorphisms in six genes involved in nucleotide excision repair of DNA were examined in a large population-based case-control study of melanoma. Genotyping was conducted for 2485 patients with a single primary melanoma (controls) and 1238 patients with second or higher order primary melanomas (cases). Patients were ascertained from nine geographic regions in Australia, Canada, Italy and the United States. Positive associations were observed for XPD 312 Asn/Asn versus Asp/Asp [odds ratio (OR) = 1.5, 95% confidence interval (CI) 1.2-1.9] and XPD 751 Gln/Gln versus Lys/Lys (OR = 1.4, 95% CI 1.1-1.7) genotypes and melanoma. The combined XPD Asn (A) 312 + Gln (C) 751 haplotype was significantly more frequent in cases (32%) compared with controls (29%) (P = 0.003) and risk of melanoma increased significantly with one and two copies of the haplotype (ORs 1.2, 95% CI 1.0-1.4, and 1.6, 95% CI 1.2-2.0, trend P = 0.002). No significant associations were observed for HR23B codon 249, XPG codon 1104, XPC codon 939, XPF codon 415, XPF nt 2063, ERCC6 codon 1213 or ERCC6 codon 1230. ORs for XPD and XPC genotypes were stronger for melanoma diagnosed at an early age, but tests for interaction were not statistically significant. The results provide further evidence for a role of XPD in the etiology of melanoma.
Publisher: Wiley
Date: 10-2015
DOI: 10.1002/PDS.3848
Publisher: AMPCo
Date: 20-06-2019
DOI: 10.5694/MJA2.50244
Abstract: To estimate the prevalence of polypharmacy among Australians aged 70 years or more, 2006-2017. Analysis of a random 10% s le of Pharmaceutical Benefits Scheme (PBS) data for people aged 70 or more who were dispensed PBS-listed medicines between 1 January 2006 and 31 December 2017. Prevalence of continuous polypharmacy (five or more unique medicines dispensed during both 1 April - 30 June and 1 October - 31 December in a calendar year) among older Australians, and the estimated number of people affected in 2017 changes in prevalence of continuous polypharmacy among older concessional beneficiaries, 2006-2017. In 2017, 36.1% of older Australians were affected by continuous polypharmacy, or an estimated 935 240 people. Rates of polypharmacy were higher among women than men (36.6% v 35.4%) and were highest among those aged 80-84 years (43.9%) or 85-89 years (46.0%). The prevalence of polypharmacy among PBS concessional beneficiaries aged 70 or more increased by 9% during 2006-2017 (from 33.2% to 36.2%), but the number of people affected increased by 52% (from 543 950 to 828 950). The prevalence of polypharmacy among older Australians is relatively high, affecting almost one million older people, and the number is increasing as the population ages. Our estimates are probably low, as we could not take over-the-counter or complementary medicines or private prescriptions into account. Polypharmacy can be appropriate, but there is substantial evidence for its potential harm and the importance of rationalising unnecessary medicines, particularly in older people.
Publisher: Elsevier BV
Date: 10-2017
DOI: 10.1016/J.EURONEURO.2017.07.001
Abstract: The objective of this study was to assess international trends in antipsychotic use, using a standardised methodology. A repeated cross-sectional design was applied to data extracts from the years 2005 to 2014 from 16 countries worldwide. During the study period, the overall prevalence of antipsychotic use increased in 10 of the 16 studied countries. In 2014, the overall prevalence of antipsychotic use was highest in Taiwan (78.2/1000 persons), and lowest in Colombia (3.2/1000). In children and adolescents (0-19 years), antipsychotic use ranged from 0.5/1000 (Lithuania) to 30.8/1000 (Taiwan). In adults (20-64 years), the range was 2.8/1000 (Colombia) to 78.9/1000 (publicly insured US population), and in older adults (65+ years), antipsychotic use ranged from 19.0/1000 (Colombia) to 149.0/1000 (Taiwan). Atypical antipsychotic use increased in all populations (range of atypical/typical ratio: 0.7 (Taiwan) to 6.1 (New Zealand, Australia)). Quetiapine, risperidone, and olanzapine were most frequently prescribed. Prevalence and patterns of antipsychotic use varied markedly between countries. In the majority of populations, antipsychotic utilisation and especially the use of atypical antipsychotics increased over time. The high rates of antipsychotic prescriptions in older adults and in youths in some countries merit further investigation and systematic pharmacoepidemiologic monitoring.
Publisher: Wiley
Date: 16-02-2022
DOI: 10.1111/PPE.12870
Abstract: Medicine prescribing for children is impacted by a lack of paediatric‐specific dosing, efficacy and safety data for many medicines. To estimate the prevalence of medicine use among children and the rate of ‘off‐label’ prescribing according to age at dispensing. We used population‐wide primarily outpatient dispensing claims data for 15% of Australian children (0–17 years), 2013–2017 ( n = 840,190). We estimated prescribed medicine use and ‘off‐label’ medicine use according to the child's age ( year, 1–5 years, 6–11 years, 12–17 years) defined as medicines without age‐appropriate dose recommendations in regulator‐approved product information. Within off‐label medicines, we also identified medicines with and without age‐specific dose recommendations in a national prescribing guide, the Australian Medicines Handbook Children's Dosing Companion (AMH CDC). The overall dispensing rate was 2.0 dispensings per child per year. The medicines with the highest average yearly prevalence were systemic antibiotics (435.3 per 1000 children), greatest in children 1–5 years (546.9 per 1000). Other common medicine classes were systemic corticosteroids (92.7 per 1000), respiratory medicines (91.2 per 1000), acid‐suppressing medicines in children year (47.2 per 1000), antidepressants in children 12–17 years (40.3 per 1000) and psychostimulants in children 6–11 years (27.0 per 1000). We identified 12.2% of dispensings as off‐label based on age, but 66.3% of these had age‐specific dosing recommendations in the AMH CDC. Among children year, off‐label dispensings were commonly acid‐suppressing medicines (35.5%) and topical hydrocortisone (33.1%) in children 6–11 years, off‐label prescribing of clonidine (16.0%) and risperidone (13.1%) was common. Off‐label dispensings were more likely to be prescribed by a specialist (21.7%) than on‐label dispensings (7.5%). Prescribed medicine use is common in children, with off‐label dispensings for medicines without paediatric‐specific dosing guidelines concentrated in classes such as acid‐suppressing medicines and psychotropics. Our findings highlight a need for better evidence to support best‐practice prescribing.
Publisher: Oxford University Press (OUP)
Date: 23-03-2006
DOI: 10.1093/IJE/DYL044
Abstract: The population-based case-control study is not suited to the evaluation of rare genetic (or environmental) factors. The use of a novel case-control design in which cases have second primaries and controls are cancer survivors has been proposed for this purpose. We report results from an international study of melanoma that involved population-based ascertainment of incident cases of second or subsequent primary melanoma as the 'case' group and incident cases of first primary melanoma as the 'control' group. We evaluate the validity of the study design by comparing the results obtained for phenotypic factors that have been shown consistently to be associated with melanoma in previous conventional studies with the results from a conventional case-control study conducted in Connecticut and from literature reviews. All but one of the known risk factors for melanoma were shown to be significantly associated with melanoma in our study, though the in idual odds ratios appear to be somewhat attenuated relative to the magnitudes typically observed in the literature. Patients with a second or subsequent primary cancer of a single type represent a potentially valuable and under-utilized resource for the study of cancer aetiology.
Publisher: Oxford University Press (OUP)
Date: 19-10-2005
DOI: 10.1093/JNCI/DJI312
Abstract: Germline mutations in the CDKN2A gene have been linked to melanoma incidence in many families with multiple cases of the disease. Previous studies of multiple-case families have indicated that the lifetime risk (i.e., penetrance) of melanoma in CDKN2A mutation carriers is very high, ranging from 58% in Europe to 91% in Australia by age 80 years. In this study, we examined lifetime melanoma risk among CDKN2A mutation carriers using carriers who were identified in a population-based study of melanoma. Probands for the study were incident case patients with either first or subsequent melanoma who were identified in nine geographic regions in Australia, Canada, the United States, and Italy. A total of 3626 probands (53% participation rate) with adequate DNA for analysis were recruited and genotyped for CDKN2A mutations. From the 3550 probands whose DNA could be lified by polymerase chain reaction of CDKN2A exons 1alpha, 2, and 3 and surrounding regions, 65 mutation carriers were identified. Melanoma histories in first-degree relatives of these probands were used to calculate the lifetime risk in CDKN2A mutation carriers using the kin-cohort method. The risk of melanoma in CDKN2A mutation carriers was approximately 14% (95% CI = 8% to 22%) by age 50 years, 24% (95% CI = 15% to 34%) by age 70 years, and 28% (95% CI = 18% to 40%) by age 80 years. Eighteen probands had three or more first-degree relatives with melanoma, but only one was a carrier of a CDKN2A mutation. CDKN2A mutation carriers in the general population have a much lower risk of melanoma than that suggested by estimates obtained from multiple-case families. The preponderance of familial clustering of melanoma occurs in families without identifiable mutations in CDKN2A.
Publisher: Mary Ann Liebert Inc
Date: 02-2020
Publisher: Wiley
Date: 20-02-2019
DOI: 10.1002/PDS.4755
Abstract: Countries worldwide are developing a variety of strategies to combat the opioid epidemic, such as restricting access to high-strength opioid formulations. We aimed to examine the dispensing patterns of strong opioids by dose units (DUs), age, and sex. We used Australian population-level dispensing data from January 2003 to December 2015 and categorised strong opioids by DU: very low, low, moderate, and high, corresponding to total daily doses of less than or equal to 25, 26 to 50, 51 to 100, and greater than 100 morphine milligramme equivalents, respectively. We measured trends in strong opioid use as dispensings/1000 population/year and stratified dispensing in 2015 by patient age and sex. From 2003 to 2015, strong opioid dispensing of very low, low, moderate, and high DU increased 6.7-, 6.2-, 2.2-, and 1.8-fold, respectively. The increase in very low and low DU dispensing was driven primarily by oxycodone (5, 10, and 15 mg tablets and capsules) and buprenorphine transdermal patches. In 2015, the number of dispensings/1000 population for very low, low, moderate, and high DU were 180.3, 77.0, 52.7, and 34.8, respectively. Females aged greater than or equal to 85 years had the highest opioid use, ranging from 157.1 dispensings/1000 population for high DU to 2104.5 dispensings/1000 population for very low DU. In contrast, the high DU dispensings in males aged 25 to 64 years exceeded their female counterparts by approximately 1.3-fold. Relative to moderate and high DU strong opioids, dispensing of very low and low DU strong opioids increased dramatically during the study period in Australia. Future studies investigating opioids use and harms in elderly females and males between 25 to 64 years are warranted.
Publisher: Springer Science and Business Media LLC
Date: 02-11-2015
Publisher: Wiley
Date: 27-12-2017
DOI: 10.1002/PDS.4369
Abstract: Population-based observational studies have documented global increases in opioid analgesic use. Many studies have used a single population-adjusted metric (number of dispensings, defined daily doses [DDDs], or oral morphine equivalents [OMEs]). We combine these volume-based metrics with a measure of the number of persons dispensed opioids to gain insights into Australian trends in prescribed opioid use. We obtained records of prescribed opioid dispensings (2006-2015) subsidised under Australia's Pharmaceutical Benefits Scheme. We used dispensing claims to quantify annual changes in use according to 3 volume-based metrics: DDD/1000 pop/day, OME/1000 pop/day, and dispensings/1000 pop. We estimated the number of persons dispensed at least one opioid in a given year (persons)/1000 pop using data from a 10% random s le of Pharmaceutical Benefits Scheme-eligible Australians. Total opioid use increased according to all metrics, especially OME/1000 pop/day (51% increase) and dispensings/1000 pop (44%). Weaker opioid use remained stable or declined strong opioid use increased. The rate of persons accessing weaker opioids only decreased 31%, and there was a 238% increase in persons dispensed only strong opioids. Strong opioid use also increased according to dispensings/1000 pop (140%), OME/1000 pop/day (80%), and DDD/1000 pop/day (71% increase). Our results suggest that the increases in total opioid use between 2006 and 2015 were predominantly driven by a growing number of people treated with strong opioids at lower medicine strengths/doses. This method can be used with or without person-level data to provide insights into factors driving changes in medicine use over time.
Publisher: Springer Science and Business Media LLC
Date: 13-06-2018
Publisher: Springer Science and Business Media LLC
Date: 23-06-2010
DOI: 10.1007/S00198-010-1332-0
Abstract: The association between socioeconomic status (SES) and bone health, specifically in men, is unclear. Based upon data from the large prospective Concord Health in Ageing Men Project (CHAMP) Study of community-dwelling men aged 70 years or over, we found that specific sub-characteristics of SES, namely, marital status, living circumstances, and acculturation, reflected bone health in older Australian men. Previous studies reported conflicting results regarding the relationship between SES and bone health, specifically in men. The main objective of this study was to investigate associations of SES with bone health in community-dwelling men aged 70 years or over who participated in the baseline phase of the CHAMP Study in Sydney, Australia. The Australian Socioeconomic Index 2006 (AUSEI06) based on the Australian and New Zealand Standard Classification of Occupations was used to determine SES in 1,705 men. Bone mineral density and bone mineral content (BMC) were determined by dual-energy X-ray absorptiometry. Bone-related biochemical and hormonal parameters, including markers of bone turnover, parathyroid hormone, and vitamin D, were measured in all men. General linear models adjusted for age, weight, height, and bone area revealed no significant differences across crude AUSEI06 score quintiles for BMC at any skeletal site or for any of the bone-related biochemical measures. However, multivariate regression models revealed that in Australian-born men, marital status was a predictor of higher lumbar BMC (β = 0.07, p = 0.002), higher total body BMC (β = 0.05, p = 0.03), and lower urinary NTX-I levels (β=-0.08, p = 0.03), while living alone was associated with lower BMC at the lumbar spine (β=-0.05, p = 0.04) and higher urinary NTX-I levels (β=0.07, p = 0.04). Marital status was also a predictor of higher total body BMC (β = 0.14, p = 0.003) in immigrants from Eastern and South Eastern Europe. However, in immigrants from Southern Europe, living alone and acculturation were predictors of higher femoral neck BMC (β = 0.11, p = 0.03) and lumbar spine BMC (β = 0.10, p = 0.008), respectively. Although crude occupation-based SES scores were not significantly associated with bone health in older Australian men, specific sub-characteristics of SES, namely, marital status, living circumstances, and acculturation, were predictors of bone health in both Australia-born men and European immigrants.
Publisher: American Association for Cancer Research (AACR)
Date: 11-2010
DOI: 10.1158/1055-9965.EPI-10-0686
Abstract: Background: Solar elastosis adjacent to melanomas in histologic sections is regarded as an indicator of sun exposure, although the associations of UV exposure and phenotype with solar elastosis are yet to be fully explored. Methods: The study included 2,589 incident primary melanoma patients with assessment of histologic solar elastosis in the population-based Genes, Environment, and Melanoma study. Ambient erythemal UV (UVE) at places of residence and sun exposure hours, including body site–specific exposure, were collected. We examined the association of cumulative site-specific and non–site-specific sun exposure hours and ambient UVE with solar elastosis in multivariable models adjusted for age, sex, center, pigmentary characteristics, nevi, and, where relevant, body site. Results: Solar elastosis was associated most strongly with site-specific UVE [odds ratio (OR) for top exposure quartile, 5.20 95% confidence interval (95% CI), 3.40-7.96 P for trend & .001] and also with site-specific sun exposure (OR for top quartile, 5.12 95% CI, 3.35-7.83 P for trend & .001). Older age (OR at & years, 7.69 95% CI, 5.14-11.52 P for trend & 0.001) and having more than 10 back nevi (OR, 0.77 95% CI, 0.61-0.97 P = 0.03) were independently associated with solar elastosis. Conclusion: Solar elastosis had a strong association with higher site-specific UVE dose, older age, and fewer nevi. Impact: Solar elastosis could be a useful biomarker of lifetime site-specific UV. Future research is needed to explore whether age represents more than simple accumulation of sun exposure and to determine why people with more nevi may be less prone to solar elastosis. Cancer Epidemiol Biomarkers Prev 19(11) 2932–41. ©2010 AACR.
Publisher: Public Library of Science (PLoS)
Date: 06-12-2018
Publisher: Wiley
Date: 07-07-2019
DOI: 10.1111/BCP.13976
No related grants have been discovered for Melisa Litchfield.