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G G Giles

Publications and source records attributed to G G Giles.

At least 19 recordsLinked to original sources
PubMed2006

Population-based estimates of breast cancer risks associated with ATM gene variants c.7271T>G and c.1066-6T>G (IVS10-6T>G) from the Breast Cancer Family Registry.

The ATM gene variants segregating in ataxia-telangiectasia families are associated with increased breast cancer risk, but the contribution of specific variants has been difficult to estimate. Previous small studies suggested two functional variants, c.7271T>G and c.1066-6T>G (IVS10-6T>G), are associated with increased risk. Using population-based blood samples we found that 7 out of 3,743 breast cancer cases (0.2%) and 0 out of 1,268 controls were heterozygous for the c.7271T>G allele (P=0.1). In cases, this allele was more prevalent in women with an affected mother (odds ratio [OR]=5.5, 95% confidence interval [CI]=1.2-25.5; P=0.04) and delayed child-bearing (OR=5.1; 95% CI=1.0-25.6; P=0.05). The estimated cumulative breast cancer risk to age 70 years (penetrance) was 52% (95% CI=28-80%; hazard ratio [HR]=8.6; 95% CI=3.9-18.9; P<0.0001). In contrast, 13 of 3,757 breast cancer cases (0.3%) and 10 of 1,268 controls (0.8%) were heterozygous for the c.1066-6T>G allele (OR=0.4; 95% CI=0.2-1.0; P=0.05), and the penetrance was not increased (P=0.5). These findings suggest that although the more common c.1066-6T>G variant is not associated with breast cancer, the rare ATM c.7271T>G variant is associated with a substantially elevated risk. Since c.7271T>G is only one of many rare ATM variants predicted to have deleterious consequences on protein function, an effective means of identifying and grouping these variants is essential to assess the contribution of ATM variants to individual risk and to the incidence of breast cancer in the population.

Adolescent↗
PubMed2006

Parity and decreased use of oral contraceptives as predictors of asthma in young women.

BACKGROUND: Asthma is more prevalent among males in childhood, but females report higher rates in adulthood. The reasons are unknown; although it has been hypothesized that hormonal factors may explain this sex-dependent risk of adult-onset asthma. OBJECTIVE: To determine whether a woman's reproductive history or use of oral contraceptives is associated with adult-onset asthma. METHODS: In 1991-1993, we surveyed 681 women aged 29-32 years randomly sampled from participants first surveyed at age 7 years by the 1968 Tasmanian Asthma Survey, a study of all children born in 1961 and attending school. Current asthma was defined as reporting asthma or wheezy breathing in the past 12 months. RESULTS: In women who did not have asthma or wheezy breathing by age 7 years, 13% had current asthma. The risk of current asthma in these who were parous increased with the number of births (odds ratio (OR) 1.50 per birth, 95% confidence interval (CI) 1.01-2.23 P=0.04) while women with one birth were at a lower risk than nulliparous women (OR 0.46 95% CI 0.2-1.06, P=0.07). Independent of parity, the risk decreased by 7% (95% CI 0-13%) per year of oral contraceptive pill use in all women. In women who did have asthma or wheezy breathing by age 7 years, neither reproductive history nor oral contraceptive pill use predicted current asthma. CONCLUSION: Our observation that parity and decreased oral contraceptive use predict asthma in women, is consistent with the hypothesis that the asthma that develops after childhood is in part a response to endogenous and exogenous female hormones. This may be due to alterations of cytokine responses by the pregnant state, triggering adult-onset asthma in women.

Adult↗
PubMed2006

Increasing underrepresentation of elderly patients with advanced colorectal or non-small-cell lung cancer in chemotherapy trials.

BACKGROUND: Elderly patients are underrepresented in chemotherapy trials for advanced colorectal cancer (CRC) and non-small-cell lung cancer (NSCLC). However, the change in underrepresentation over time has not been documented. AIMS: This study aimed to quantify (i) the change in the median age of patients enrolled in clinical trials for metastatic CRC and NSCLC between 1982-1991 and 1992-2001 compared with the general colorectal and lung cancer population, and (ii) the proportion of trials with an upper age limit for eligibility. METHODS: A retrospective review of data from the Victorian Cancer Registry and all large published randomized chemotherapy trials for advanced CRC and NSCLC between 1982 and 2001 was conducted. RESULTS: The median age of patients with CRC enrolled in clinical trials remained constant between the two decades (62.0 and 62.2 years), whereas the median age of the CRC population increased from 68.4 to 70.2 years, increasing the median age difference from 6.4 to 8.0 years. The median age of patients with lung cancer in clinical trials increased from 59.8 to 61.8 years, whereas the median age of the lung cancer population increased from 67.4 to 70.4 years, widening the age difference from 7.6 to 8.6 years. More trials set an upper age limit for eligibility in the first decade than in the second decade for both CRC (51 vs 29%, P = 0.04) and NSCLC (68 vs 41%, P = 0.03). CONCLUSION: International clinical trials for CRC and NSCLC are becoming increasingly unsuitable for application to Australian patients because of the increasing age discrepancy, despite fewer trials restricting eligibility by age.

Age Distribution↗
PubMed2006

Alcohol intake, consumption pattern and beverage type, and the risk of Type 2 diabetes.

AIMS: To examine associations between amount and frequency of alcohol consumption, and Type 2 diabetes. METHODS: A prospective study of 36 527 adults aged 40-69 at baseline. Incident cases of Type 2 diabetes were identified by questionnaire 4 years later. Sex-specific logistic regression models, adjusting for country of birth, dietary glycaemic index, energy intake and age, and in a second model body mass index (BMI) and waist-hip ratio (WHR), were used. RESULTS: Diabetes status was ascertained for 31 422 (86%) participants, and 362 cases identified. Former drinkers had higher risks than lifetime abstainers. Female drinkers had lower risk than lifetime abstainers (ORs < 10 g/day 0.54, 95% CI 0.36-0.82; 10-19.9 g/day 0.57, 0.34-0.94; > or = 20 g/day 0.46, 0.24-0.88, P trend = 0.005). There was no relationship after adjustment for body size. For men, a weak inverse association was observed after adjustment for body size (ORs relative to lifetime abstainers: < 10 g/day 1.56, 0.95-2.55; 10-19.9 g/day 1.21, 0.69-2.10; 20-29.9 g/day 0.80, 0.40-1.60; = 30 g/day 0.86, 0.50-1.58, P trend = 0.036). Wine was the only beverage for which an inverse association was observed. Compared with men who did not drink in the week before baseline, men who drank > or = 210 g over 1-3 days had an increased risk of diabetes (OR 5.21, 1.79-15.19), while the same amount over more days did not increase risk. CONCLUSIONS: Total alcohol intake was associated with reduced risk only in women. Alcohol from wine was associated with reduced risk of Type 2 diabetes. A high daily intake of alcohol, even on only 1-3 days a week, may increase the risk of diabetes in men.

Adult↗
PubMed2006

Validation of short term recall of mobile phone use for the Interphone study.

AIM: To validate short term recall of mobile phone use within Interphone, an international collaborative case control study of tumours of the brain, acoustic nerve, and salivary glands related to mobile telephone use. METHODS: Mobile phone use of 672 volunteers in 11 countries was recorded by operators or through the use of software modified phones, and compared to use recalled six months later using the Interphone study questionnaire. Agreement between recalled and actual phone use was analysed using both categorical and continuous measures of number and duration of phone calls. RESULTS: Correlations between recalled and actual phone use were moderate to high (ranging from 0.5 to 0.8 across countries) and of the same order for number and duration of calls. The kappa statistic demonstrated fair to moderate agreement for both number and duration of calls (weighted kappa ranging from 0.20 to 0.60 across countries). On average, subjects underestimated the number of calls per month (geometric mean ratio of recalled to actual = 0.92, 95% CI 0.85 to 0.99), whereas duration of calls was overestimated (geometric mean ratio = 1.42, 95% CI 1.29 to 1.56). The ratio of recalled to actual use increased with level of use, showing underestimation in light users and overestimation in heavy users. There was substantial heterogeneity in this ratio between countries. Inter-individual variation was also large, and increased with level of use. CONCLUSIONS: Volunteer subjects recalled their recent phone use with moderate systematic error and substantial random error. This large random error can be expected to reduce the power of the Interphone study to detect an increase in risk of brain, acoustic nerve, and parotid gland tumours with increasing mobile phone use, if one exists.

Case-Control Studies↗
PubMed2005

Physical activity, insulin-like growth factor 1, insulin-like growth factor binding protein 3, and survival from colorectal cancer.

BACKGROUND: Recent reports have shown that physical activity improves the outcome of patients with colorectal cancer as well as breast and prostate cancer. However, the mechanisms whereby physical activity reduces cancer mortality are not well established. METHODS: Incident cases of colorectal cancer were identified among participants of the Melbourne Collaborative Cohort Study, a prospective cohort study of 41,528 Australians recruited from 1990 to 1994. Information on tumour site and stage, treatments given, recurrences, and deaths were obtained from systematic review of the medical records. Baseline assessments of physical activity and body size were made, and cases with available plasma had pre-diagnosis insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 3 (IGFBP-3) levels measured. We assessed associations between these hormones and colorectal cancer specific deaths with respect to physical activity. RESULTS: A total of 526 cases of colorectal cancer were identified, of which 443 had IGF-1/IGFBP-3 levels measured. Median follow up among survivors was 5.6 years. For the physically active, increasing IGFBP-3 by 26.2 nmol/l was associated with a 48% reduction in colorectal cancer specific deaths (adjusted hazard ratio (HR) 0.52 (0.33-0.83); p = 0.006). No association was seen for IGF-1 (adjusted HR 0.90 (0.55-1.45); p = 0.65). For the physically inactive, neither IGF-1 nor IGFBP-3 was associated with disease specific survival. CONCLUSIONS: This study supports the hypothesis that the beneficial effects of physical activity in reducing colorectal cancer mortality may occur through interactions with the insulin-like growth factor axis and in particular IGFBP-3.

Adult↗
PubMed2005

Effect of physical activity and body size on survival after diagnosis with colorectal cancer.

BACKGROUND: Physical inactivity and obesity increase the risk of colorectal cancer but little is known about whether they influence prognosis after diagnosis. METHODS: Incident cases of colorectal cancer were identified among participants of the Melbourne Collaborative Cohort Study, a prospective cohort study of 41 528 Australians recruited from 1990 to 1994. Participants diagnosed with their first colorectal cancer between recruitment and 1 August 2002 were eligible. At the time of study entry, body measurements were taken and participants were interviewed about their physical activity. Information on tumour site and stage, treatments given, recurrences, and deaths were obtained from systematic review of the medical records. RESULTS: A total of 526 cases of colorectal cancer were identified. Median follow up among survivors was 5.5 years, and 208 deaths had occurred, including 181 from colorectal cancer. After adjusting for age, sex, and tumour stage, exercisers had an improved disease specific survival (hazard ratio 0.73 (95% confidence interval (CI) 0.54-1.00)). The benefit of exercise was largely confined to stage II-III tumours (hazard ratio 0.49 (95% CI 0.30-0.79)). Increasing per cent body fat resulted in an increase in disease specific deaths (hazard ratio 1.33 per 10 kg (95% CI 1.04-1.71)). Similarly, increasing waist circumference reduced disease specific survival (hazard ratio 1.20 per 10 cm (95% CI 1.05-1.37)). CONCLUSIONS: Increased central adiposity and a lack of regular physical activity prior to the diagnosis of colorectal cancer is associated with poorer overall and disease specific survival.

Adenocarcinoma↗
PubMed2005

A comparison of estradiol levels between women with a hysterectomy and ovarian conservation and women with an intact uterus.

OBJECTIVES: To compare the distribution of estradiol levels between women with a hysterectomy and ovarian conservation and women with an intact uterus. METHODS: A large cross-sectional study of women aged between 40 and 69 years, residing in Melbourne, Australia. Estradiol levels were available for 152 women with a hysterectomy and ovarian conservation and 1423 women with an intact uterus. All of the women were 'never-users' of hormone replacement therapy. RESULTS: For women under 55 years of age, we observed that those with a hysterectomy and ovarian conservation had slightly higher estradiol levels compared with those with an intact uterus after adjustment for age, body mass index, smoking status and alcohol intake (ratio of geometric means of estradiol levels = 1.24; 95% confidence interval = 1.00-1.53). For women who were 55 years or greater, the distribution of estradiol levels varied little by hysterectomy status. CONCLUSIONS: Our data do not suggest that women with hysterectomy and ovarian conservation have markedly different estradiol levels compared to women with an intact uterus.

Adult↗
PubMed2004

Cytomegalovirus, Epstein-Barr virus and risk of breast cancer before age 40 years: a case-control study.

We investigated whether there is an association between cytomegalovirus (CMV) and Epstein-Barr virus (EBV) IgG levels and risk of breast cancer before age 40 years. CMV and EBV IgG levels were measured in stored plasma from 208 women with breast cancer and 169 controls who participated in the Australian Breast Cancer Family Study (ABCFS), a population-based case-control study. CMV and EBV IgG values were measured in units of optical density (OD). Cases and controls did not differ in seropositivity for CMV (59 and 57% respectively; P=0.8) or EBV (97 and 96% respectively; P=0.7). In seropositive women, mean IgG values were higher in cases than controls for CMV (1.20 vs 0.98 OD, P=0.005) but not for EBV (2.65 vs 2.57 OD, P=0.5). The adjusted odds ratios per OD unit were 1.46 (95% CI 1.06-2.03) for CMV IgG and 1.11 (0.93-1.33) for EBV IgG. The higher mean CMV IgG levels found in women with breast cancer could be the result of a more recent infection with CMV, and may mean that late exposure to CMV is a risk factor for breast cancer.

Adult↗
PubMed2003

Biological markers that predict clinical recurrence in ductal carcinoma in situ of the breast.

The optimal management of ductal carcinoma in situ (DCIS) is controversial, due in part to our poor understanding of its natural history. We undertook to identify subgroups of DCIS based on the expression of biomarkers, which were related to the likelihood of clinical recurrence. Biomarker expression of a total of 95 DCIS lesions in a nested case-control study within a population-based cohort with up to 135 months follow-up data (median 101 months) was analysed using immunohistochemistry. ERBB2-positivity and bcl-2-, oestrogen receptor (ER)- and progesterone receptor (PR)-negativity were individually associated with the risk of clinical recurrence. The predictive value of these biomarkers was independent of cytonuclear grade. ERBB2, bcl-2, ER and PR expression were conserved in the recurrent lesions, including subsequent invasive cancers. p21-positive DCIS was also associated with clinical recurrence, independently of the associations with ERBB2/bcl-2/ER/PR expression. These data identify clinically and biologically relevant subcategories of DCIS lesions, an essential basis for improving management.

Adult↗
PubMed2003

Risk of prostate cancer associated with a family history in an era of rapid increase in prostate cancer diagnosis (Australia).

OBJECTIVE: We conducted a case-control study of prostate cancer and familial risk of the disease in Australia between 1994 and 1998, a period during which the incidence of prostate cancer increased dramatically with widespread use of prostate-specific antigen (PSA) testing. METHODS: 1475 cases and 1405 controls were asked about prostate cancer in their first-degree relatives. Odds ratios (OR) were calculated using logistic regression. RESULTS: Cases were more likely to report a family history of prostate cancer than controls (OR 3.0; 95% confidence interval (CI) 2.3-3.9) and cases reporting an affected relative were younger (58.8 versus 60.9 years, p < 0.0001). The OR for an affected first-degree relative increased with increasing number of affected relatives and decreased with increasing age of the case. The OR for more than one affected first-degree relative was 6.9 (95% CI 2.7-18). The OR for an affected brother was 3.9 (95% CI 2.5-6.1) and for an affected father was 2.9 (95% CI 2.1-3.9) but these were not significantly different (p = 0.2). When analyses were repeated including only diagnoses made in relatives prior to 1992, the risks were generally similar except that the OR for an affected brother decreased to 3.1 (95% CI 1.2-3.9). When only relatives' diagnoses made after 1991 were included results were again similar to those for all relatives, although the effect for brothers was greater and the attenuation with age at diagnosis dissipated. CONCLUSIONS: The recent introduction of PSA testing that has resulted in a greater prevalence of apparent prostate cancer, does not appear to have substantially altered familial risks of disease, although effects associated with brothers may be inflated.

Adenocarcinoma↗
PubMed2003

Sexual factors and prostate cancer.

OBJECTIVE: To assess whether prostate cancer might be related to hormone levels and, by inference, to differences in sexual activity. PATIENTS, SUBJECTS AND METHODS: In a case-control study of men with prostate cancer aged < 70 years at diagnosis and age-matched control subjects, information was collected on two aspects of sexual activity; the number of sexual partners and the frequency of total ejaculations during the third to fifth decades of life. RESULTS: There was no association of prostate cancer with the number of sexual partners or with the maximum number of ejaculations in 24 h. There was a negative trend (P < 0.01) for the association between risk and number of ejaculations in the third decade, independent of those in the fourth or fifth. Men who averaged five or more ejaculations weekly in their 20s had an odds ratio (95% confidence interval) of 0.66 (0.49-0.87) compared with those who ejaculated less often. CONCLUSIONS: The null association with the number of sexual partners argues against infection as a cause of prostate cancer in this population. Ejaculatory frequency, especially in early adult life, is negatively associated with the risk of prostate cancer, and thus the molecular biological consequences of suppressed or diminished ejaculation are worthy of further research.

Adult↗
PubMed2003

Evaluation of the organised mammographic screening programme in Australia.

An organised approach to mammographic screening in Australia commenced in 1992 as a free service for asymptomatic women in the target age range 50-69 years and accessible to all women aged >/=40 years. Screening is performed by two-view mammography, women aged 50-69 years being sent reminders every 2 years for repeat screens. National Accreditation Standards have been agreed and BreastScreen Australia has developed mechanisms to monitor and report performance including systems and standards for data collection. The national report includes participation rates, small cancer detection rates and programme sensitivities. These indicate that BreastScreen Australia is meeting its accreditation standards with respect to most measures. Routinely collected outcome data reflect an increasing trend in the proportion of women receiving breast conserving surgery; a decline in the proportion of women diagnosed with ductal carcinoma in situ undergoing axillary dissection and an increasing use of combination therapies with a corresponding decrease in the use of hormonal therapy alone. There have been increases in breast cancer incidence and falls in mortality with the largest changes in women aged 50-69 years. As the BreastScreen Australia database is routinely linked in future to population cancer registries, the mortality reduction due to mammographic screening may be estimated more precisely.

Age Distribution↗
PubMed2003

Androgenetic alopecia in men aged 40-69 years: prevalence and risk factors.

BACKGROUND: The epidemiology of androgenetic alopecia (AGA) is not fully understood. Although a strong genetic basis has long been identified, little is known of its non-genetic causes. OBJECTIVES: To estimate the prevalence of and to determine risk factors for AGA in men aged 40-69 years in Australia. METHODS: Men (n = 1390) were recruited at random from the electoral rolls to serve as controls in a population-based case-control study of prostate cancer. All were interviewed in person and direct observations of AGA were made. Men were grouped into the following categories; no AGA, frontal AGA, vertex AGA and full AGA (frontal and vertex AGA). Epidemiological data collected from these men were used for an analysis of risk factors for each AGA category using unconditional logistic regression with AGA category as the response variable adjusting for age, education and country of birth. RESULTS: The prevalence of vertex and full AGA increased with age from 31% (age 40-55 years) to 53% (age 65-69 years). Conversely, the proportion of men with only frontal AGA was very similar across all age groups (31-33%). No associations were found between pubertal growth spurt or acne, reports of adult body size at time of interview, urinary symptom score, marital status, or current smoking status or duration of smoking and the risk of any form of AGA. The consumption of alcohol was associated with a significant increase in risk of frontal and vertex AGA but not full AGA. Men with vertex AGA had fewer female sexual partners but average ejaculatory frequency did not differ between men in different AGA categories. Reported weight and lean body mass at reaching maturity at about 21 years of age were negatively associated with vertex balding (P for trend < 0.05) but not with frontal AGA or full AGA. CONCLUSIONS: Evidence for environmental influences on AGA remains very slight. Our study failed to confirm previously reported or hypothesized associations with smoking and benign prostatic hypertrophy. The associations that we found with alcohol consumption and with lean body mass at age 21 years would be worthy of further research if they were able to be replicated in other studies.

Adult↗
PubMed2002

Contacts with animals and humans as risk factors for adult brain tumours. An international case-control study.

While numerous studies have addressed the possible role of farming and related exposures as risk factors for brain tumours in adults, few of them have examined the potential effect of exposure to farm animals or pets. In an international multicentre case-control study, we investigated whether residence on a farm, contact with animals, or working in occupations with a high degree of potential contact with animals or humans were associated with brain tumours. Using a common questionnaire, 1177 cases of glioma, 330 with meningioma and 2478 controls from eight centres were interviewed about the exposures and, in particular, about their contacts with nine species of animals: dairy cattle, beef cattle, pigs, horses, sheep, goats, poultry, dogs and cats. Living or working on a farm was not a risk factor, for either glioma or meningioma. Except in some centres, there was no relationship between having contacts with farm animals or pets and the risk of brain tumour, for either type of tumour or either sex. In relation to seven industrial groups involving frequent human and/or animal contacts, no association was apparent for either glioma or meningioma. In relation to 25 occupational groups with potential frequent contact with humans and/or animals, for glioma there was a reduced risk for biological technicians (Odds Ratio (OR)/=0, P=0.01), and general farm workers (OR=0.66, 95% Confidence Interval (CI): 0.5-0.9). For meningioma, there was an increased risk for cooks (OR=2.0; CI: 1.2-3.4). With some exceptions, these results indicate no association between either the type of brain tumour and contacts with animals, or with occupations that include a high level of contact with animals or a high level of contact with humans.

Adult↗
PubMed2001

Eye color and cutaneous nevi predict risk of ocular melanoma in Australia.

Ethnicity, cutaneous nevi and eye color are generally accepted risk factors for melanoma of the eye, although case-control studies have produced conflicting results. We sought to determine the constitutional risk factors for melanomas of the choroid, ciliary body, iris and conjunctiva in Australia. A population-based case-control study was conducted, with case ascertainment from a prospective national incidence survey and randomly selected community controls. Two hundred and ninety cases aged 18-79 years and diagnosed between 1st January 1996 and 31st July 1998 were enrolled with 916 controls frequency matched by age, sex and State or Territory of residence. Risk of choroidal and ciliary body melanoma (n = 246) was increased in people with grey (OR 2.9, 95% CI 1.5-5.5), hazel (OR 2.2, 95% CI 1.4-3.7) and blue eyes (OR 1.7, 95% CI 1.0-2.7) compared with brown eyes. Risk was also increased in those with 4 or more nevi on their back, those unable to tan, and those who squinted when outdoors as a child. Risk was reduced in people born other than in Australia and New Zealand (OR 0.7, 95% CI 0.5-1.0). Non-brown eye color was a risk factor for iris melanoma (n = 25). No risk factors were identified for conjunctival melanoma (n = 19). Eye color is the strongest constitutional predictor of choroidal and ciliary body melanoma, and may indicate a protective effect of melanin density at these sites. An independent association with cutaneous nevi suggests a role for other genetic factors.

Adolescent↗