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Biomedical subjects

M McCredie

Publications and source records attributed to M McCredie.

At least 37 records · Page 2Linked to original sources
PubMed1998

Cancer epidemiology in migrant populations.

Migrant studies have taken advantage of the wide geographical variation in cancer risk. Cancer rates in migrants, obtained from routinely collected incidence or mortality statistics, are compared with those in the host country and in the country of origin; the rate of change with time since migration (or age at migration) and in subsequent generations is assessed; and the results are interpreted in the light of differences in socio-economic status and the degree of cultural assimilation. Rapid changes in cancer risk following migration imply that life-style or environmental factors are of overriding importance in aetiology. The susceptibility of fair-skinned races to ultraviolet (UV)-associated skin cancers is an example of racial differences based on inherited factors, but the long-term excess or deficit of other cancers in migrants has not yet been attributed definitively to genetic rather than persisting life-style factors. Are there racial differences in metabolism, DNA repair mechanisms or altered expression of oncogenes or tumour suppressor genes? Several genetic polymorphisms affecting the metabolism of known occupational carcinogens or hormonal factors do vary by race. While classical epidemiology has shown that the environment predominates in determining cancer incidence, molecular epidemiology has identified several examples of genetically determined differences between races.

Australia↗
PubMed1997

Family history and risk of breast cancer in New Zealand.

A national population-based case-control study was used to assess the influence on breast cancer risk of a family history of the disease and the possibility of an interaction with reproductive risk factors. A total of 891 women aged 25-54 years with a first diagnosis of breast cancer and 1,864 control subjects randomly selected from the electoral rolls were interviewed. Age-adjusted relative risks (RR) of breast cancer were similar for mothers (RR = 2.3) and sisters (RR = 2.7) but somewhat higher for first-degree (RR = 2.6) than for second-degree (RR = 1.7) relatives. Cases reporting a first- or second-degree relative with breast cancer were no more likely to be diagnosed at an early age than those with no family history. With regard to the age at diagnosis of the relative, the RR was higher if breast cancer had been diagnosed before the age of 45 years than later; this was true for first-degree as well as for second-degree relatives. In women with no family history, the falling RRs with increasing age at menarche reflected the usual pattern, but no such trend was apparent in those reporting a mother or sister with breast cancer. For age at first full-term pregnancy, parity, breast-feeding, menopausal status, infertility, history of benign breast disease and body mass index, no evidence was seen of effect modification by a family history of breast cancer. Mothers of cases had about twice the cumulative rate of breast cancer as mothers of controls, a similar difference being seen between sisters of cases and sisters of controls.

Adult↗
PubMed1997

Trends in colorectal cancer incidence and mortality in New South Wales, 1973-1992.

OBJECTIVE: To assess changes in incidence and mortality rates of colorectal cancer in different age groups in New South Wales (NSW) between 1973 and 1992. DESIGN: Descriptive analysis of data on incidence and mortality from the population-based NSW Central Cancer Registry and on colorectal cancer diagnostic tests from the Health Insurance Commission. MAIN OUTCOME MEASURES: Age-standardised incidence and mortality rates for colon and rectal cancer (defined by codes 153 and 154 in the International classification of diseases, 9th revision) by sex and age group (15-44, 45-59, 60-74 or > or = 75 years) and incidence by cancer spread at diagnosis; age-standardised rates for faecal occult blood tests, sigmoidoscopy and colonoscopy. RESULTS: From 1973 to 1992, colorectal cancer incidence increased significantly in NSW by an average of 2.0% per year in males (95% confidence interval [CI], 1.8 to 2.3) and 0.9% in females (95% CI, 0.7 to 1.1). Mortality rates remained nearly constant in males, but fell significantly in females by an average of -1.0% per year (95% CI, -1.3 to -0.7). In the youngest age group (15-44 years) both incidence and mortality rates fell significantly, while rates were stable or rose in older age groups, except for a significant fall in mortality in women aged > or = 75 years. Use of colonoscopy (an early detection method) increased, but a corresponding shift to detection of earlier-stage cancers was not seen. CONCLUSIONS: A reduction in risk factors and better treatment leading to longer survival may have contributed to the falls in incidence in younger people and in mortality in females.

Adolescent↗
PubMed1997

Second primary cancers after cancers of the colon and rectum in New South Wales, Australia, 1972-1991.

Data from the New South Wales Central Cancer Registry for the period 1972-1991 were examined to determine the risk of second primary cancers after an initial invasive cancer of the colon (ICD-9 153) or rectum (ICD-9 154). The expected numbers of cancers were obtained by assuming that subjects experienced the same cancer incidence as prevailed in the corresponding general population and by applying sex-, age-, and calendar-specific rates to the appropriate person-years at risk. The relative risk (RR) of a second primary cancer was taken to be the ratio of observed:expected numbers of second cancers. After colon cancer, there was an excess of cancers of the small intestine in both sexes (RRs of 4.5 and 4.4); prostate (RR = 1.4) and kidney (RR = 1.8) in men; and breast (RR = 1.3), body of uterus (RR = 1.9), ovary (RR = 2.8), and thyroid (RR = 2.7) in women. Lung cancer occurred less frequently in men than expected (RR = 0.7). After rectal cancer, men had increased risks of cancers of the colon (RR = 1.5) and prostate (RR = 1.3) and a reduced risk of pancreatic cancer (RR = 0.3). A reciprocal relationship of increased risk was seen between cancers of the proximal (but not the distal) colon and rectum. Shared luminal risk factors for proximal colon cancer and rectal cancer and three syndromes of hereditary predisposition to colon cancer seem to be the major contributors to second primary cancers in patients with an initial colon cancer. Sources of bias have been considered.

Age Factors↗
PubMed1996

International renal-cell-cancer study. VI. the role of medical and family history.

A number of medical conditions have been linked with renal-cell cancer, although the evidence is not consistent in every case. In a large international case-control study of renal-cell cancer, we examined, among other hypotheses, associations with a personal history of certain medical conditions and a family history of cancer of the kidney or thyroid. Relative risks (RR), adjusted for the effects of age, gender, body-mass index, tobacco smoking and study centre, were significantly increased by a history of kidney stones or thyroid or kidney disease. The RR were not altered by additional adjustment for hypertension, or when diagnoses were restricted to those made at least 5 or 10 years before 1987 (the usual "cut-off" date). The link with kidney injury is particularly likely to be affected by recall bias. Increased RR of borderline significance were found for kidney infection (RR, 1.2) and diabetes (RR, 1.4). Having one first-degree relative with kidney cancer was associated with a significantly increased risk of renal-cell cancer (RR, 1.6; 95% Cl, 1.1-2.4). Seven cases reported 2 first-degree relatives with kidney cancer. No controls had first-degree relatives with kidney cancer. None of our participants reported having von Hippel-Lindau disease. The data suggests that a few conditions of the kidney are strongly associated with renal-cell cancer and that heredity plays a role in a small proportion of cases.

Adult↗
PubMed1996

International renal cell cancer study. VII. Role of diet.

We investigated the role of diet in the etiology of renal cell cancer (RCC) in a multi-center, population-based case-control study conducted in Australia, Denmark, Sweden and the United States, using a shared protocol. A total of 1,185 incident histopathologically confirmed cases (698 men, 487 women) and 1,526 controls (915 men, 611 women) frequency-matched to cases by sex and age were included in the analyses. The association between RCC and diet was estimated by relative risks (RR) and 95% confidence intervals (CI) adjusted for age, sex, study center, body mass index and smoking. A statistically significant positive association was observed for total energy intake (RR = 1.7, 95% CI = 1.4-2.2 for the highest vs. lowest quartile, p value for trend < 0.00001), while the hypothesis that protein and fat are risk factors independent of energy was not supported. Fried meats were associated with increased RCC risk, while vegetables and fruits were protective, with the strongest effect observed for the highest quartile of consumption of orange/dark green vegetables but not vitamin C or beta carotene. Increased risk was associated with low intake (lowest decile) of vitamin E and magnesium. We observed an apparent protective effect of alcohol confined to women and probably due to chance. Our findings indicate an important role of nutrition in the development of RCC. The apparent positive association of energy intake with risk of RCC needs further investigation in a prospective cohort study to exclude the possible impact of differences in recall between cases and controls.

Adult↗
PubMed1996

Activated clotting time differential is a superior method of monitoring anticoagulation following coronary angioplasty.

The standard high-range activated clotting time (sHR ACT) is used to monitor anticoagulation postangioplasty (PTCA), but may be unreliable. We assessed the accuracy of a new method we termed the ACT differential (ACT Diff), obtained by measuring the difference between an sHR ACT and a heparinase ACT from the same sample. Heparinase removes heparin from its sample and provides a current heparin-free baseline. For phase 1 of the study, the sHR ACT, ACT Diff, and laboratory APTT were measured in 250 samples from 75 PTCA patients. In 125 samples with an APTT prolonged but within measurement range, linear regression against the APTT was performed. The correlation coefficient was 0.74 for the ACT Diff and 0.24 for the sHR ACT. An ACT Diff of 15-25 sec was found to equal an APTT of 2.5-3.5 x control. In 50 samples with a normal activated partial thromboplastin time (APT), there was good differentiation by the ACT Diff of results from those adequately heparinized, with a value of 0.9 +/- 4.4 sec. The sHR ACT was 114 +/- 15.5 sec, and could not reliably distinguish between anticoagulated and nonanticoagulated samples. In 75 samples obtained with a high APTT (above measurement range), the ACT Diff was > 30 sec in 95% of samples, and again this allowed differentiation from therapeutic samples. The equivalent sHR ACT was 148 sec, and could not reliably distinguish between anticoagulated and overanticoagulated samples as the ACT Diff could. In phase 2, to examine the clinical usefulness of the ACT Diff, 286 patients were managed post-PTCA by starting heparin when ACT Diff fell to < 50 sec, maintaining ACT Diff at 15-25 sec during heparin infusions, and following cessation of heparin, by removing sheaths when the ACT Diff was < 7 sec. These patients were compared to a control group of 250 patients. Major bleeding (5% vs. 0.5%, P < 0.005) and minor bleeding (30% vs. 13%, P < 0.001) were significantly reduced in the group managed using the ACT Diff. The reduction in bleeding was thought to be due to the rapid availability of reliable results. Abrupt closure was low in both groups (0% with ACT Diff vs. 0.8%). No other thrombotic events occurred. Following phases 1 and 2, the ACT Diff replaced the APTT in all PTCA patients at this institution. In the 18 mo from July 1993, 1,104 patients were managed this way. Incidence of major bleeding (0.2%), transfusion requirement (0.1%), false anneurysm (0.6%), and abrupt closure during heparin infusion (0.1%) remained low. In conclusion, the ACT Diff is more accurate than an sHR ACT, and its clinical use in PTCA patients is associated with a very low incidence of complications from anticoagulation. Its routine use should be considered by units unable to obtain rapid APTT results.

Adult↗
PubMed1996

Second primary cancers following cancers of the kidney and prostate in New South Wales (Australia), 1972-91.

Data from the New South Wales (NSW) (Australia) Central Cancer Registry for the period 1972-91 were examined to determine the risk of second primary cancers following an initial invasive cancer of the renal parenchyma (ICD-9 code 189.0), renal pelvis (code 189.1), or prostate (code 185). Eligible cases were restricted to those who had survived for at least two months after diagnosis of the first primary cancer. Expected numbers of cancers were obtained by assuming that subjects experienced the same cancer incidence as prevailed in the corresponding general population and applying gender-, age-, and calendar-specific rates to the appropriate person-years at risk. The relative risk (RR) of a second primary cancer was taken to be the ratio of observed to expected numbers of second cancers. Following prostatic cancer, there was an overall deficit of cancers at all sites combined (RR = 0.79, 95 percent confidence interval [CI] = 0.75-0.84), and no site had a significantly raised RR. Taking this into consideration, there appeared to be a reciprocal relationship of increased risk of prostatic cancer (RR = 1.7, CI = 1.2-2.3) following an initial cancer of the renal parenchyma and of renal parenchymal cancer (RR = 1.2, CI = 0.8-1.7) after cancer of the prostate. An increased risk of bladder cancer occurred following renal parenchymal (RR = 3.4, CI = 1.1-8.0, for women only) as well as after renal pelvic cancer (men: RR = 8.7, CI = 5.4-13; women: RR = 39, CI = 26-56). A tobacco-related pattern of excess risk was seen after renal pelvic cancer but not after cancer of the renal parenchyma. These data illustrate that an excess of second primary cancers may reflect shared etiologic factors or increased medical surveillance.

Aged↗
PubMed1996

Occurrence of melanomas on the upper and lower limbs in eastern Australia.

In view of the changing trends in the incidence of melanoma at different body sites and in particular on the limbs, the detailed distributions of over 10,000 invasive melanomas diagnosed on the upper and lower limbs in residents of mainland eastern Australia between 1987 and 1993 were examined. Cancer notifications and histopathology reports from the cancer registries of Queensland, New South Wales and Victoria were searched manually, and subsites when specified were recorded as shoulder, upper arm, forearm, elbow, wrist or hand, and thigh, leg, knee, ankle or foot. On the upper limbs relative tumour densities were highest on the shoulder, approximately equal on the upper arm and forearm and least on the hand in both men and women; on the lower limbs melanomas occurred more than twice as often on the leg than on the thigh or the foot, taking account of surface area. There was a clear inverse gradient of incidence of melanoma with latitude in the three eastern Australian states studied, but little difference between the states or between sexes in distribution of histological type: the majority specified being specified as superficial spreading melanomas. In contrast to predictions based on apparent frequency of sun exposure at subsites on the upper limbs, the relative concentration of melanomas on the shoulder suggests that wearing sleeveless garments outdoors in the sun should be avoided whenever possible. Also, the similar densities of leg and forearm melanomas seems inconsistent with the relative degree of exposure of each and further suggests that women's adoption of ankle-length skirts or trousers, in preference to knee-length skirts would be a worthwhile modern control measure.

Adolescent↗
PubMed1996

Differences in patterns of care of prostate cancer, New South Wales, 1991.

BACKGROUND: In this time of uncertainty about the benefits of earlier diagnosis for prostate cancer and the optimal choice of treatment in various clinical scenarios, we addressed the hypothesis that two groups in the population, namely country dwellers and migrants from non-English-speaking countries, were less likely to be offered new methods of diagnosis and treatment for prostate cancer. METHODS: Incident cases of prostate cancer in 1991 were identified through the population-based New South Wales Central Cancer Registry. For 73% of eligible cases information relating to diagnosis, staging and treatment was abstracted onto a checklist from clinical records in urologists' consulting rooms and in public hospitals. RESULTS: Transrectal ultrasound and prostatic biopsy were used for diagnosis significantly more often in urban than in rural cases while the reverse was true for transurethral resection of the prostate. Intravenous pyelography, ultrasound (other than transrectal) and bone scans were performed for staging more frequently in urban than rural cases. Rural cases were more likely to be treated with anti-androgens than urban cases and less likely to be given luteinizing-hormone releasing hormone (LH-RH) agonists. The pattern of use of various diagnostic and staging procedures for 1991 rural cases resembled that for urban men diagnosed with prostate cancer in 1986 rather than that for 1991 urban cases. CONCLUSIONS: At least in part, these urban-rural differences could be explained by the fact that some patients in the country would have been treated by general surgeons rather than urologists. The patterns of care for non-English-speaking migrants resembled those for the Australian-born and for English-speaking migrants.

Delivery of Health Care↗
PubMed1995

Changes in cancer incidence and mortality in New South Wales.

OBJECTIVE: To assess changes in cancer incidence and mortality in New South Wales (NSW) between 1973-1977 and 1988-1992. DESIGN: Descriptive analysis of statutory cancer notifications to the NSW Central Cancer Registry. OUTCOME MEASURES: Age-standardised incidence and mortality rates calculated with the "world" standard population. RESULTS: Overall cancer incidence rose markedly, from 251 to 318 per 100,000 in men and from 202 to 241 per 100,000 in women. The rise was greatest in the 60-and-over age group. Cancer mortality fell marginally in men (from 166 to 162 per 100,000) and did not change in women (100 per 100,000 in both periods). It fell in the under-60 age group, and remained stable or rose in older people. Prostate and breast cancers and melanoma of the skin accounted for about half the increase in incidence. Both incidence and mortality increased significantly (P < 0.01) for melanoma and non-Hodgkin's lymphomas in men and lung cancer in women, and fell substantially for stomach cancer in both sexes, lung cancer in men and cervical cancer in women. Despite increasing incidence, mortality, also fell for testicular cancer in men and rectal cancer in women and for leukaemias in children. CONCLUSIONS: The major factor causing the increased incidence of overall cancer was earlier detection. Altered exposure to risk factors could be identified for only a minority of the changes.

Adolescent↗
PubMed1995

International renal-cell cancer study. VIII. Role of diuretics, other anti-hypertensive medications and hypertension.

Risk of renal-cell cancer in relation to use of diuretics, other anti-hypertensive medications and hypertension was assessed in a multi-center, population-based, case-control study conducted in Australia, Denmark, Germany, Sweden and the United States, using a shared protocol and questionnaire. A total of 1,732 histologically confirmed cases and 2,309 controls, frequency-matched to cases by age and sex, were interviewed. The association between renal-cell cancer and the drugs was estimated by relative risks (RRs) and 95% confidence intervals (CIs). Risks were increased among users of diuretics and other anti-hypertensive medications. After adjustment for hypertension, risk for diuretics was reduced to unity, except among long-term (15+ years) users. Risk for use of non-diuretic anti-hypertensive drugs remained significantly elevated and increased further with duration of use. Overall risk was not enhanced when both classes of medications were used. Excess risk was not restricted to any specific type of diuretic or anti-hypertensive drug and no trend was observed with estimated lifetime consumption of any particular type of product. The RR for hypertension after adjustment for diuretics and other anti-hypertensive medications was 1.4 (95% CI = 1.2-1.7), although among non-users of any anti-hypertensive medications, there was little excess risk associated with a history of hypertension. Exclusion of drug use that first occurred within 5 years of cancer diagnosis or interview did not alter the associations. Our findings suggest small effects on renal-cell cancer risk associated with hypertension and use of diuretics and other anti-hypertensive medications. However, because of potential misclassifications of these highly correlated variables, it is difficult to distinguish the effect of treatment from its indication, hypertension.

Antihypertensive Agents↗
PubMed1995

Breast cancer in NSW women: a shift in tumour size.

OBJECTIVE: To determine whether there has been an increase in the proportion of small (< 1 cm in size) and localised breast cancers in women aged 50-69 (the group actively recruited to mammographic screening) compared with women aged 40-49. DESIGN: Cases of invasive breast cancer in women aged 40-69 notified to the NSW Central Cancer Registry in 1986, 1989 and 1992 were included. Tumour sizes were determined from histopathology reports. RESULTS: A higher percentage of breast cancers were under 1 cm in size in 1992 (10%) than in 1986 and 1989 (7%). The increase in the percentage of small breast cancers was statistically significant in women aged 50-69 (chi 2 for linear trend, 7.9; P = 0.005) but not in those aged 40-49 (chi 2 for linear trend, 2.5; P = 0.12). Slightly more than half the breast cancers (53%) in 1992 were localised to the breast, representing an increase from 49% in both 1986 and 1989. This increase was also statistically significant in women aged 50-69 (chi 2 for linear trend, 3.9; P = 0.05) but not in those aged 40-49 (chi 2 for linear trend, 1.4; P = 0.24). CONCLUSIONS: Breast cancers in 1986, 1989 and 1992 showed a moderately strong shift to smaller tumours and localised disease in women aged 50-69. As women of this age group were targeted by mammographic screening, the widespread availability of mammography may explain this shift.

Adult↗
PubMed1995

International renal-cell cancer study. IV. Occupation.

The relationship between renal-cell cancer (RCC) and occupation was investigated in an international multicenter population-based case-control study. Study centers in Australia, Denmark, Germany, Sweden and the United States interviewed 1732 incident RCC cases and 2309 controls. Significant associations were found with employment in the blast-furnace or the coke-oven industry [relative risk (RR), 1.7; 95% confidence interval (CI), 1.1-2.7], the iron and steel industry (RR, 1.6; 95% CI, 1.2-2.2) and exposure to asbestos (RR, 1.4; 95% CI, 1.1-1.8), cadmium (RR, 2.0; 95% CI, 1.0-3.9), dry-cleaning solvents (RR, 1.4; 95% CI, 1.1-1.7), gasoline (RR, 1.6; 95% CI, 1.2-2.0) and other petroleum products (RR, 1.6; 95% CI, 1.3-2.1). Asbestos, petroleum products and dry-cleaning solvents appear to merit further investigation, in view of the relationship between risk and duration of employment or exposure and after adjustment for confounding. There was a negative association between RCC and education, but it was not consistent across all centers. Overall, the results of our multicenter case-control study suggest that occupation may be more important in the etiology of RCC than indicated by earlier studies.

Aged↗
PubMed1995

International renal-cell cancer study. V. Reproductive factors, gynecologic operations and exogenous hormones.

The relationships between reproductive factors, exogenous hormones and renal-cell cancer were examined in an international, multicenter, population-based, case-control study undertaken in 1989-1991. Data from 5 centers situated in Australia, Denmark, Germany, Sweden and the United States included for analysis 608 women with renal-cell cancer and 766 female controls. A significant trend in risk (p = 0.002) was associated with number of births, with an 80% excess risk for 6 or more births [RR = 1.8, 95% confidence interval (CI) = 1.1 to 2.9] compared with one birth. A decreasing risk was seen for increasing age at first birth, although this was confounded by body-mass index and number of births. A suggestive reduction of risk was also seen for increasing age at menarche. Age at menopause was unrelated to risk of renal-cell cancer. An increased risk was observed for women having had both a hysterectomy and an oophorectomy. Use of oral contraceptives in non-smoking women reduced the risk of renal-cell cancer (RR = 0.5, 95% CI = 0.4 to 0.8); this reduction increased with longer duration of use. No association was observed for estrogen replacement therapy. Our results indicate that certain hormonal and reproductive variables may be related to risk of renal-cell cancer and deserve further investigation, both epidemiologically and experimentally.

Adult↗
PubMed1995

International renal-cell cancer study. II. Analgesics.

There has been concern about the role of analgesics in the development of renal-cell cancer, although a few studies have reported moderately elevated risks with regular or long-term use. In a large international case-control study of renal-cell cancer we examined, among other hypotheses, the effect of phenacetin-containing and of other types of analgesics: paracetamol (acetaminophen), salicylates (mainly aspirin) and pyrazolones (e.g., antipyrine or phenazone). Relative risks, adjusted for the effects of age, sex, body-mass index, tobacco smoking and study centre, were not significantly increased with intake of phenacetin, either when lifetime consumption was categorized at the level of > or = 0.1 kg or when subjects were subdivided further by amount. Nor were paracetamol, salicylates or pyrazolones linked with renal-cell cancer. No consistently increasing risks with consumption level was found. The lack of association was not altered by restricting analgesic use to that which occurred 5 or 10 years before the defined "cut-off" date or when analysis was restricted to exclusive users of a particular type of analgesic. Neither was the risk influenced by the rate of consumption or whether the consumption had occurred at a young age. Our study provides clear evidence that aspirin is unrelated to renal-cell cancer risk, and our findings do not support the hypothesis that analgesics containing phenacetin or paracetamol increase the risk, although the number of "regular" users and the amount of these types of analgesic consumed were too small to confidently rule out a minor carcinogenic effect of phenacetin and paracetamol.

Acetaminophen↗