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David C Whiteman

Publications and source records attributed to David C Whiteman.

35 records · Page 2Linked to original sources
PubMed2006

Temporal changes in the endoscopic frequency of new cases of Barrett's esophagus in an Australian health region.

OBJECTIVES: The number of patients diagnosed with Barrett's esophagus (BE) has increased in recent decades, although data from populations outside Europe and North America are scarce. This increase has significant implications for health resource utilization and costs. We sought to determine changes in the endoscopic frequency of new cases of BE in an Australian population during the period 1990-2002. METHODS: We identified all persons newly diagnosed with BE in an Australian health region in 1990, 1998, and 2002. BE cases were categorized as short segment (SSBE) (<3 cm), long segment (>or=3 cm), or undefined length. We compared the total number of esophagogastroduodenoscopies (EGD) and the number of new cases of BE for the three time periods. RESULTS: Between 1990 and 2002, the endoscopic frequency of new cases of BE increased from 2.9 to 18.9 per 1,000 endoscopies (p<0.001). The greatest increase was for SSBE, increasing from no new cases in 1990 to 6.2 new cases per 1,000 EGD in 2002. In contrast there was a 17% decrease (2.3-1.9 new cases per 1,000 EGD) for long segment BE during the same period. There were 3,090 EGDs undertaken in 1990, 3,518 in 1998, and 2,593 in 2002, an increase of 14% over the first 8-yr interval (p<0.001), and a decline of 26% over the subsequent 4 yr (p<0.001). CONCLUSIONS: In an Australian population undergoing EGD, the endoscopic frequency and absolute number of new cases of BE, particularly SSBE disease, has increased significantly between 1990 and 2002. This increased frequency of patients diagnosed with BE has broad future economic and clinical implications.

Aged↗
PubMed2005

Nonsteroidal anti-inflammatory drugs and the risk of actinic keratoses and squamous cell cancers of the skin.

BACKGROUND: Although animal studies suggest that nonsteroidal anti-inflammatory drugs (NSAIDs), including aspirin, may protect against cutaneous squamous cell carcinoma (SCC) and actinic keratoses (AKs), possible effects on keratinocytic cancers in humans are unknown. OBJECTIVE: We sought to examine the relationship between ingestion of NSAIDs and the risk of SCC and AKs in humans. METHODS: We conducted a case-control study nested within a community-based cohort of 1621 people in southern Queensland, Australia. Eighty-six persons with SCC were compared with 187 age- and sex-matched control subjects randomly selected from within the cohort. NSAID use was captured through face-to-face interviews with study participants, supplemented by color photographs of product packaging. We defined regular use of NSAIDs as consumption of at least two tablets per week (low frequency) or at least 8 tablets per week (high frequency) for at least 1 year. AKs were counted on the face, ears, right hand, and right forearm by a single physician. RESULTS: Patients with SCC were significantly less likely than control subjects to have used any NSAIDs 8 or more times per week for more than 1 year (multivariate odds ratio [OR] 0.07, 95% confidence interval [CI] 0.01-0.71) and to have used full-dose NSAIDs 2 or more times per week for more than 5 years (OR, 0.20; 95% CI, 0.04-0. 96). Among participants without SCC, current regular users of NSAIDs (> or =2 times per week) had significantly lower counts of AKs than nonusers (rate ratio [RR], 0.52; 95% CI, 0.30-0.91). LIMITATIONS: Estimates of NSAID use were based on self-reported data. Statistical power to detect associations was limited by the number of cases with SCC. CONCLUSION: Regular users of NSAIDs appear to have lower risks of SCC and lower counts of AKs than nonusers.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2005

An analysis of risk factors for cutaneous melanoma by anatomical site (Australia).

OBJECTIVE: Emerging evidence suggests that melanomas arising on the head and neck that are not lentigo maligna melanomas have different associations with phenotypic and environmental risk factors than those on the trunk and other sites. We sought to test this hypothesis in a population-based study in Queensland, Australia. METHODS: Risk factor data were collected from 2360 participants with incident cutaneous melanoma diagnosed 1982--1990, including 167 participants with lentigo maligna melanoma. For each risk factor, polytomous logistic regression analysis, using the trunk as a reference category, was used to estimate the odds ratio and 95% confidence interval for cutaneous melanomas by anatomical site. RESULTS: Participants with melanomas of the head and neck were significantly older than those with melanomas of the trunk (males 52.7 versus 49.7 years; females 47.8 versus 40.5 years). Compared with patients with truncal melanomas, those of the head and neck were less likely to have many nevi (OR 0.41, 95% CI 0.13--1.31), although this did not reach statistical significance. Among females, melanomas of the lower limb were negatively associated with a past history of non-melanoma skin cancer (OR 0.41, 95% CI 0.23-0.74). CONCLUSIONS: We have observed heterogeneity for melanoma risk by anatomical site, lending weight to the hypothesis that cutaneous melanomas may develop through multiple causal pathways.

Adult↗
PubMed2005

Melanocytic nevi in very young children: the role of phenotype, sun exposure, and sun protection.

BACKGROUND: Melanocytic nevi are strongly associated with cutaneous melanoma, yet little is known about factors influencing nevus development in the first years of life. OBJECTIVE: We sought to identify phenotypic and environmental factors associated with nevus counts in very young children. METHODS: In a cluster prevalence survey, full body nevus counts and phenotypic assessments were conducted on 193 children aged 1 to 3 years. Information on each child's sun exposure and sun protection practices was obtained through parental questionnaire. RESULTS: High total nevus counts were associated with heavy facial freckling, time spent outdoors on weekends in summer, and Caucasian ethnicity. Low nevus counts were associated with dark skin color, ability to tan, and frequent application of sunscreen. Frequent wearing of hats was specifically associated with low nevus counts on the face, but not at other sites. CONCLUSIONS: Nevi are common at a very young age among children in Queensland, Australia, and are associated with sun exposure and freckling. Diligent sun protection practices appear to reduce nevus burden, even after accounting for the effects of phenotype and sun exposure factors. Primary prevention strategies aimed at reducing sun exposure in very early life may be effective in reducing nevus prevalence and melanoma risk.

Australia↗
PubMed2005

Reproducibility of a short semi-quantitative food group questionnaire and its performance in estimating nutrient intake compared with a 7-day diet diary in the Million Women Study.

OBJECTIVES: To assess the short- and long-term reproducibility of a short food group questionnaire, and to compare its performance for estimating nutrient intakes in comparison with a 7-day diet diary. DESIGN: Participants for the reproducibility study completed the food group questionnaire at two time points, up to 2 years apart. Participants for the performance study completed both the food group questionnaire and a 7-day diet diary a few months apart. Reproducibility was assessed by kappa statistics and percentage change between the two questionnaires; performance was assessed by kappa statistics, rank correlations and percentages of participants classified into the same and opposite thirds of intake. SETTING: A random sample of participants in the Million Women Study, a population-based prospective study in the UK. SUBJECTS: In total, 12 221 women aged 50-64 years. RESULTS: In the reproducibility study, 75% of the food group items showed at least moderate agreement for all four time-point comparisons. Items showing fair agreement or worse tended to be those where few respondents reported eating them more than once a week, those consumed in small amounts and those relating to types of fat consumed. Compared with the diet diary, the food group questionnaire showed consistently reasonable performance for the nutrients carbohydrate, saturated fat, cholesterol, total sugars, alcohol, fibre, calcium, riboflavin, folate and vitamin C. CONCLUSIONS: The short food group questionnaire used in this study has been shown to be reproducible over time and to perform reasonably well for the assessment of a number of dietary nutrients.

Cross-Sectional Studies↗
PubMed2005

Childhood and adult cancer in twins: evidence from the Utah genealogy.

OBJECTIVE: Evidence suggests that the in utero environment may contribute to subsequent development of cancers in childhood and adulthood. Raised levels of estrogen during pregnancy may be the primary in utero etiologic factor. Mothers of twins have higher estrogen levels during pregnancy than mothers of singletons, therefore, assessment of cancer risk in twins may be informative. METHOD: We conducted a retrospective cohort study of cancer among twin and singleton newborns selected from the Utah Population Database, matched on birth year and sex. Cancer diagnoses were determined by linkage with the Utah state cancer register. Relative rates of all cancers in childhood and in adulthood in twins compared with singletons, and for specific cancers including testicular, breast and melanoma, were calculated using Poisson regression. RESULTS: Twin (35,271) and singleton (74,199) births were identified, among whom there were 336 and 691 cancer diagnoses, respectively. The relative risk (RR) of childhood cancer in twins compared with singletons was 0.82 [95% confidence interval (CI) 0.55-1.24] and of adult cancer was 1.06 (0.92-1.22). We found nonsignificant increases in risk among adult twins for cancers of the breast, prostate, testis, lymphatic system, thyroid, and large bowel. The largest departures from unity were for testicular cancer (RR 1.47; 95% CI, 0.73-2.95) and melanoma (RR 0.67; 95% CI, 0.42-1.06). CONCLUSIONS: These results are consistent with the body of evidence suggesting that twins have a reduced risk of cancer in childhood. Although there is no overall differential in adult cancer risk, these data support the hypothesis that the in utero environment may play an important role in specific cancers.

Adolescent↗
PubMed2005

Interactions among smoking, obesity, and symptoms of acid reflux in Barrett's esophagus.

BACKGROUND: Barrett's esophagus, a metaplastic precursor to esophageal adenocarcinoma, is becoming increasingly prevalent in many populations. Clinical studies suggest acid reflux causes Barrett's esophagus; however, no population-based estimates of risk have been reported, and the role of other health factors in modifying risk is unclear. METHODS: We conducted a population-based case-control study in Brisbane, Australia. Cases were 167 patients with histologically confirmed Barrett's esophagus diagnosed between February and December 2003. Age-matched and sex-matched controls (n = 261) were randomly selected from a population register. Data on exposure to self-reported symptoms of acid reflux, smoking, obesity, and other factors were collected through self-completed questionnaires followed by telephone interview. Risks of Barrett's esophagus and Barrett's esophagus with dysplasia associated with these exposures were estimated by the odds ratio (OR) and 95% confidence interval (95% CI), both crude and adjusted for other factors. RESULTS: Self-reported weekly episodes of acid reflux were associated with greatly increased risks of Barrett's esophagus (adjusted OR, 29.7; 95% CI, 12.2-72.6) and Barrett's esophagus with dysplasia (OR, 59.7; 95% CI, 18.5-193). Smoking was also associated with risk of Barrett's esophagus. We found evidence of interactions between symptoms of acid reflux and smoking and obesity. Obese people with self-reported symptoms of acid reflux had markedly higher risks of Barrett's esophagus (OR, 34.4; 95% CI, 6.3-188) than people with reflux alone (OR, 9.3; 95% CI, 1.4-62.2) or obesity alone (OR, 0.7; 95% CI, 0.2-2.4). Similarly, those reporting both acid reflux symptoms and smoking were at substantially higher risks of Barrett's esophagus (OR, 51.4; 95% CI, 14.1-188) than those reporting acid reflux or smoking alone. CONCLUSIONS: Although history of symptoms of acid reflux is the principle factor associated with Barrett's esophagus, risks are substantially increased by obesity and smoking.

Aged↗
PubMed2004

Twinning and the incidence of breast and gynecological cancers (United States).

Increasing epidemiological and experimental evidence indicates that the carcinogenic pathway in the breast and female reproductive organs is driven, at least in part, by factors associated with reproduction. We conducted a retrospective cohort study, comparing the risk of ovarian, breast, endometrial, and cervical cancers among women who had records of at least one twin pregnancy, compared with women who had given birth to only single children. Subjects were selected from the Utah Population Database, which consists of multiple linked datasets including genealogy, births and deaths and cancer registries. We used Poisson regression to calculate relative risks, adjusted for the number of pregnancies and the age of the mother at the birth of first and last children, with singleton mothers as the reference group in each case. The risks of breast and ovarian cancers did not differ between mothers of twins and mothers of single children. The risk of endometrial cancer was slightly lower in mothers of twins than in mothers of singleton children (RR = 0.90, 95% CI 0.67-1.21). Conversely the risk of cervical cancer was higher among twin mothers (RR = 1.78, 95% CI 0.88-3.52). This latter finding supports previous data suggesting that reproductive hormones act as cofactors in the etiology of cervical cancer.

Adolescent↗
PubMed2003

Prevalence and anatomical distribution of naevi in young Queensland children.

Sunlight is the principal environmental cause of melanoma and has also been implicated in the pathogenesis of melanocytic naevi. Epidemiological evidence indicates that childhood is a period during which melanocytes are susceptible to the effects of sunlight, yet little is known about the development of naevi in infancy. We conducted a survey of child-care centres to document the prevalence and anatomical distribution of melanocytic naevi among 193 young children aged 1-3 years in Brisbane, Australia (latitude 27 degrees S). Naevi were counted on all skin surfaces except for the scalp, buttocks and genitalia. Overall, almost 90% of children in the study sample had at least 1 naevus of any size, and more than 30% of children had 10 or more naevi. Total naevus counts ranged from 0 to 45 and were strongly determined by age. When taken together, naevus densities were highest on exposed body sites such as the face and limbs; however the density of large naevi (> or = 5 mm) was significantly higher on the trunk than on the face, neck and ears. These data support the concept that melanocytic neoplasia commences early in life and that naevus evolution is influenced by the anatomical site of the target cell.

Child, Preschool↗
PubMed2003

Melanocytic nevi, solar keratoses, and divergent pathways to cutaneous melanoma.

BACKGROUND: Some melanomas form on sun-exposed body sites, whereas others do not. We previously proposed that melanomas at different body sites arise through different pathways that have different associations with melanocytic nevi and solar keratoses. We tested this hypothesis in a case-case comparative study of melanoma patients in Queensland, Australia. METHODS: We randomly selected patients from among three prespecified groups reported to the population-based Queensland Cancer Registry: those with superficial spreading or nodular melanomas of the trunk (n = 154, the reference group), those with such melanomas of the head and neck (n = 77, the main comparison group), and those with lentigo maligna melanoma (LMM) (n = 75, the chronic sun-exposed group). Each participant completed a questionnaire, and a research nurse counted melanocytic nevi and solar keratoses. We calculated exposure odds ratios (ORs) and 95% confidence intervals (CIs) to quantify the association between factors of interest and each melanoma group. RESULTS: Patients with head and neck melanomas, compared with patients with melanomas of the trunk, were statistically significantly less likely to have more than 60 nevi (OR = 0.34, 95% CI = 0.15 to 0.79) but were statistically significantly more likely to have more than 20 solar keratoses (OR = 3.61, 95% CI = 1.42 to 9.17) and also tended to have a past history of excised solar skin lesions (OR = 1.87, 95% CI = 0.89 to 3.92). Patients with LMM were also less likely than patients with truncal melanomas to have more than 60 nevi (OR = 0.32, 95% CI = 0.14 to 0.75) and tended toward more solar keratoses (OR = 2.14, 95% CI = 0.88 to 5.16). CONCLUSIONS: Prevalences of nevi and solar keratoses differ markedly between patients with head and neck melanomas or LMM and patients with melanomas of the trunk. Cutaneous melanomas may arise through two pathways, one associated with melanocyte proliferation and the other with chronic exposure to sunlight.

Cell Division↗
PubMed2003

A rapid method for determining recent sunscreen use in field studies.

The role of sunscreens in preventing skin cancer and melanoma is the focus of ongoing research. Currently, there is no objective measure which can be used in field studies to determine whether a person has applied sunscreen to their skin, and researchers must use indirect assessments such as questionnaires. We sought to develop a rapid, non-invasive method for identifying sunscreen on the skin for use in epidemiological studies. Our basic method is to swab the skin, elute any residues which have been adsorbed onto the swab by rinsing in ethanol, and submit the eluted washings for spectrophotometric analysis. In a controlled study, we applied 0.1 ml of sunscreen to a 50 cm(2) grid on both forearms of 21 volunteers. Each forearm was allocated one of 10 different sunscreen brands. The skin was swabbed after intervals of 20 min, 1 h, 2 h and 4 h. In a field study conducted among 12 children aged 2-4 years attending a child care centre, sunscreen was applied to the faces of half the children. Swabs were then taken from the face and back of all children without knowledge of sunscreen status. In the controlled study, sunscreen was clearly detectable up to 2 h after application for all brands containing organic sunscreen, and marginally detectable at 4 h. In the field study, this method correctly identified all children with and without sunscreen. We conclude that spectrophotometric analysis of skin swabs can reliably detect the presence of sunscreen on the skin for up to 2 h after application.

Adult↗
PubMed2003

Induction of metallothionein in human skin by routine exposure to sunlight: evidence for a systemic response and enhanced induction at certain body sites.

Expression of metallothionein, an antioxidant induced by a variety of stimuli including ultraviolet light, was quantitated by immunohistochemistry in the skin of males aged over 50 who had known short- and long-term exposures to sunlight. Skin punch biopsies were taken from two sites in each subject: the hand in all subjects and a range of other sites matched to patients with a previously excised primary melanoma. Metallothionein expression (strongest in the basal layers of the epidermis and primarily nuclear) was associated with both short- and long-term exposure to sunlight. A plateau of staining intensity was reached after 3 h sun exposure, within the previous 3 d before biopsy. Expression was also elevated in the nonexposed skin sites of subjects who had recent sun exposure, indicating a systemic response to exposure of remote sites. Using the skin of the hand to normalize responses to chronic exposure between individuals, the systemically modulated response to sunlight was significantly greater on the unexposed back than on other sites. The possibility of ultraviolet-induced cytokines selectively modifying the response of skin on a site-specific basis was investigated. The circulating leukocytes, but not lymphocytes, of two individuals exposed to 1 minimal erythema dose whole-body solar-simulated ultraviolet showed increased interleukin-6 mRNA 4 h after exposure. Interleukin-6 was not directly induced in these cell populations 4 h after ultraviolet A or ultraviolet B irradiation ex vivo. Leukocytes may therefore contribute to and amplify the systemic effects of ultraviolet-induced interleukin-6 and metallothionein expression.

Gene Expression Regulation↗
PubMed2003

Timing of pregnancy and the risk of epithelial ovarian cancer.

Recent animal studies suggest that progestagen-induced apoptosis of transformed ovarian surface epithelial cells may underlie the observed protective effect of pregnancy on the risk of ovarian cancer. Assuming that increasing numbers of cells are transformed with advancing age, we postulated that the benefits of pregnancy would be greater for older than younger women and tested this hypothesis in a population-based case-control study. We conducted interviews with 620 parous women, ages 18-79 years, with histologically confirmed incident ovarian cancer and 723 parous controls of the same age. Detailed information was collected on reproductive history, as well as hormonal exposures, smoking, medical history, and other factors. We estimated the relative risk of ovarian cancer associated with births at different ages through multiple logistic regression models. After adjusting for parity, older age at first and last births, and shorter time since last birth were all associated with significantly reduced risks of ovarian cancer. Age at first birth and time since last birth were not associated with ovarian cancer when adjusted for each other, whereas age at last birth remained strongly protective [odds ratio (OR), 0.57; 95% confidence interval (CI), 0.36-0.90] among women >35 years versus women less than 25 years. The effect was independent of total parity (per year of age among women with one birth: OR, 0.93; 95%CI, 0.87-1.01; among women with four or more births: OR, 0.96; 95%CI, 0.90-1.02). Our finding that ovarian cancer risk is reduced by pregnancy at older ages is further evidence that pregnancy confers a benefit beyond anovulation and is consistent with the theory that ovarian surface epithelial cell apoptosis induced by pregnancy hormones may be the underlying protective mechanism.

Adolescent↗
PubMed2002

Nuclear PTEN expression and clinicopathologic features in a population-based series of primary cutaneous melanoma.

Germline mutations of the PTEN tumor-suppressor gene, on 10q23, cause Cowden syndrome, an inherited hamartoma syndrome with a high risk of breast, thyroid and endometrial carcinomas and, some suggest, melanoma. To date, most studies which strongly implicate PTEN in the etiology of sporadic melanomas have depended on cell lines, short-term tumor cultures and noncultured metastatic melanomas. The only study which reports PTEN protein expression in melanoma focuses on cytoplasmic expression, mainly in metastatic samples. To determine how PTEN contributes to the etiology or the progression of primary cutaneous melanoma, we examined cytoplasmic and nuclear PTEN expression against clinical and pathologic features in a population-based sample of 150 individuals with incident primary cutaneous melanoma. Among 92 evaluable samples, 30 had no or decreased cytoplasmic PTEN protein expression and the remaining 62 had normal PTEN expression. In contrast, 84 tumors had no or decreased nuclear expression and 8 had normal nuclear PTEN expression. None of the clinical features studied, such as Clark's level and Breslow thickness or sun exposure, were associated with cytoplasmic PTEN expressional levels. An association with loss of nuclear PTEN expression was indicated for anatomical site (p = 0.06) and mitotic index (p = 0.02). There was also an association for melanomas to either not express nuclear PTEN or to express p53 alone, rather than both simultaneously (p = 0.02). In contrast with metastatic melanoma, where we have shown previously that almost two-thirds of tumors have some PTEN inactivation, only one-third of primary melanomas had PTEN silencing. This suggests that PTEN inactivation is a late event likely related to melanoma progression rather than initiation. Taken together with our previous observations in thyroid and islet cell tumors, our data suggest that nuclear-cytoplasmic partitioning of PTEN might also play a role in melanoma progression.

Aged↗
PubMedDate not supplied

Repeatability of self-reported information for population-based studies of cancer.

PURPOSE: To measure the repeatability of a cancer risk factor questionnaire in a population-based case-control study. METHODS: Questionnaires were completed on two occasions by patients with cancer of the ovary (n=25) or esophagus (n=23) and by 37 controls without cancer. We assessed general cancer risk factors including height and weight (for calculating body mass index (BMI)), smoking and anti-inflammatory (NSAID) use. Risk factors specific for ovarian and esophageal cancers were also assessed. Agreement was measured by the correlation coefficient and weighted kappa statistic (kw) for continuous and categorical variables respectively. RESULTS: We observed very high levels of agreement for BMI (kw=0.84) and smoking history, including ages at initiation and quitting (Pearson correlation = 0.87 and 0.86 respectively). There was moderate to substantial agreement for use of anti-inflammatory drugs (aspirin kw =0.52, other NSAIDS kw =0.72). Agreement for lifetime prevalence of medical conditions varied from almost perfect (e.g. history of benign breast disease (k =0.86)) to moderate (e.g. heartburn (k =0.57)). Item repeatability was not materially altered by case-control status, age or sex of respondents or interval between completions. CONCLUSIONS: Self-reported cancer risk factor information demonstrates moderate to almost perfect levels of agreement, suggesting these items are suitable for risk estimation and epidemiologic inference.

Adult↗