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Biomedical subjects

B K Armstrong

Publications and source records attributed to B K Armstrong.

At least 19 recordsLinked to original sources
PubMed1995

Risk of cutaneous melanoma associated with pigmentation characteristics and freckling: systematic overview of 10 case-control studies. The International Melanoma Analysis Group (IMAGE).

Using individual subject data from 10 case-control studies, comprising over 3000 cases and almost 4000 controls, we have estimated the relative risk of melanoma associated with aspects of complexion, namely, hair, eye and skin colour and freckling in adulthood, and have examined the relationships between these factors and naevus count in terms of melanoma risk. Compared with individuals with black or dark brown hair, the relative risks for developing melanoma in those with light brown, blonde and red hair were 1.49 (95% CI 1.31, 1.70), 1.84 (95% CI 1.54, 2.21) and 2.38 (95% CI 1.90, 2.97), respectively. Individuals with blue eyes had a risk 1.55 (95% CI 1.35, 1.78) times that for those with brown eyes, or 1.15 (95% CI 0.94, 1.40) after adjusting for hair colour and freckling in adulthood. The relative risks associated with hair and eye colour were independent of those for naevus count and skin colour. Light skin colour and high freckle density were also highly significant risk factors, independent of each other and of naevus count and hair and eye colour. The risks associated with these factors, while individually modest, are largely independent, and thus pigmentation characteristics and freckling tendency should be useful in identifying high risk groups to be targeted for prevention.

Case-Control Studies↗
PubMed1995

Risk of cutaneous melanoma associated with a family history of the disease. The International Melanoma Analysis Group (IMAGE).

In a combined analysis of 2952 melanoma patients and 3618 controls from 8 case-control studies in white populations the risk of cutaneous melanoma was 2.24-fold higher (95% CI, 1.76-2.86) in subjects who reported at least one affected first-degree relative than in subjects who did not. There was no evidence for heterogeneity in the relative risk between the studies, which were from a wide range of latitudes and hence degrees of sun exposure. The effect of family history on melanoma risk was independent of age, naevus count, hair and eye colour, and freckling. There was no evidence for a relationship between family history and primary site of melanoma but there was some suggestion that the familial patients were more likely to have superficial spreading melanoma or lentigo maligna melanoma than acral lentiginous melanoma or nodular melanoma.

Case-Control Studies↗
PubMed1995

A dose-response curve for sun exposure and basal cell carcinoma.

A population-based case-control study of sun exposure and basal cell carcinoma (BCC) was conducted in Western Australia in 1988. Its aim was to examine the relationship between risk of BCC and the amount and pattern of sun exposure. This report deals with amount of exposure. The odds ratios (ORs) for BCC on the head and neck and limbs decreased with increasing total exposure, whereas the opposite was observed for BCC on the less heavily exposed trunk, with the highest OR in those with the greatest exposure. In an analysis of all body sites together in which the total hours of exposure to the specific site was treated as a continuous variable, an initial rise in risk of BCC was seen with a peak OR of 1.4 at about 35,000 hr of exposure, followed by a fall. In contrast to these site-specific patterns, lifetime accumulated sun exposure of the whole body showed no appreciable association with BCC either in total or for working days only. Risk of BCC was positively associated with lifetime exposure on non-working days, however, with an OR for higher than baseline categories of around 1.7. There was a significant interaction between ability to tan and total and occupational sun exposure. Risk increased with increasing exposure in those who tanned well but not in those who tanned poorly. This pattern is consistent with other observations which indicate that beyond a certain level of sun exposure risk of BCC does not increase further.

Adult↗
PubMed1995

Does intermittent sun exposure cause basal cell carcinoma? a case-control study in Western Australia.

Our report deals with the relationship of pattern and timing of sun exposure to basal cell carcinoma (BCC) in a population-based case-control study conducted in Western Australia in 1988. The main measure of intermittent exposure was based on the amount of exposure on non-working days relative to that over the whole week. Outdoor recreational activities, holidays and sunburn were also considered to be markers of intermittent exposure. We observed a statistically significant increase in risk of BCC with increasing proportion of weekly sun exposure obtained at the weekend, especially in late teenage (OR = 3.9, 95% CI 1.9-7.8 for maximum intermittency of exposure), exposure of the site of skin cancer during holidays (OR = 1.9, 95% CI 1.1-3.1 for the highest exposure quarter) and sunburn to the site (ORs of 1.8 for 3-10 and 1.5 for 11+ sunburns in a lifetime). Risk of BCC increased substantially with increasing intermittency in poor tanners but not at all in good tanners. Our data suggest that a particular amount of sun exposure delivered in infrequent, probably intense increments will increase risk of BCC more than a similar dose delivered more continuously over the same total period of time.

Adult↗
PubMed1995

Skin cancer.

It is estimated that 92,000 new cases of melanoma and 2,750,000 cases of nonmelanocytic skin cancer occur worldwide each year. Incidence of these cancers varies more than 100-fold from low rates in Asian populations to very high rates in the white population of Australia. Incidence of melanoma has been increasing in white populations by some 3% to 7% per year over the past 30 years; recent very sharp increases in some populations are probably due to early and increasing detection of cancers that were already there. Incidence of nonmelanocytic skin cancers probably is also increasing. Sun exposure is the main cause of skin cancer, accounting for at least 65% of melanomas worldwide and a much higher proportion in white populations. Pattern as well as amount of sun exposure is important in determining the risk of melanoma and probably also of basal cell carcinoma, with an intermittent pattern being associated with the greatest risk. There is increasing evidence that nonsolar sources of ultraviolet radiation, in particular sunlamps and sunbeds, increase the risk of melanoma, and PUVA therapy and exposure to ionizing radiation are established causes of nonmelanocytic skin cancer.

Female↗
PubMed1995

Effects of low doses and low dose rates of external ionizing radiation: cancer mortality among nuclear industry workers in three countries.

Studies of the mortality among nuclear industry workforces have been carried out, and nationally combined analyses performed, in the U.S., the UK and Canada. This paper presents the results of internationally combined analyses of mortality data on 95,673 workers (85.4% men) monitored for external exposure to ionizing radiation and employed for 6 months or longer in the nuclear industry of one of the three countries. These analyses were undertaken to obtain a more precise direct assessment of the carcinogenic effects of protracted low-level exposure to external, predominantly gamma, radiation. The combination of the data from the various studies increases the power to study associations between radiation and specific cancers. The combined analyses covered a total of 2,124,526 person-years (PY) at risk and 15,825 deaths, 3,976 of which were due to cancer. There was no evidence of an association between radiation dose and mortality from all causes or from all cancers. Mortality from leukemia, excluding chronic lymphocytic leukemia (CLL)--the cause of death most strongly and consistently related to radiation dose in studies of atomic bomb survivors and other populations exposed at high dose rates--was significantly associated with cumulative external radiation dose (one-sided P value = 0.046; 119 deaths). Among the 31 other specific types of cancer studied, a significant association was observed only for multiple myeloma (one-sided P value = 0.037; 44 deaths), and this was attributable primarily to the associations reported previously between this disease and radiation dose in the Hanford (U.S.) and Sellafield (UK) cohorts. The excess relative risk (ERR) estimates for all cancers excluding leukemia, and leukemia excluding CLL, the two main groupings of causes of death for which risk estimates have been derived from studies of atomic bomb survivors, were -0.07 per Sv [90% confidence interval (CI): -0.4, 0.3] and 2.18 per Sv (90% CI: 0.1, 5.7), respectively. These values correspond to a relative risk of 0.99 for all cancers excluding leukemia and 1.22 for leukemia excluding CLL for a cumulative protracted dose of 100 mSv compared to 0 mSv. These estimates, which did not differ significantly across cohorts or between men and women, are the most comprehensive and precise direct estimates of cancer risk associated with low-dose protracted exposures obtained to date. Although they are lower than the linear estimates obtained from studies of atomic bomb survivors, they are compatible with a range of possibilities, from a reduction of risk at low doses, to risks twice those on which current radiation protection recommendations are based.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1994

Stratospheric ozone and health.

BACKGROUND: Stratospheric ozone is being depleted and ambient ultraviolet (UV) irradiance is probably increasing. While remedial steps have been taken through the Montreal protocols, at best it will take some 90 years for stratospheric ozone concentrations to return to the levels existing in the 1970s. METHODS: The evidence that these changes may have harmful effects on health has been reviewed. RESULTS: The direct harmful effects are skin cancer, ocular damage and, possibly, immune suppression with an increase in infectious disease. Indirect, harmful effects resulting from climate change, changes in atmospheric chemistry, and changes in food supply may also occur. Beneficial effects are also possible but have largely escaped attention. Quantification of these effects is either uncertain or impossible at present and the outcomes for health in 50 years time can only be guessed at. CONCLUSIONS: To understand better the health consequence of stratospheric ozone depletion, we need to know the quantitative relationship between ambient UV radiation and skin cancer, whether or not UV radiation really causes cataract and other ocular effects and what the quantitative relationships are, whether effects of UV radiation on immune function produce detectable health consequences, whether there are important beneficial effects of increasing UV radiation and, ultimately, what the balance of all these effects might be on health on a global scale.

Atmosphere↗
PubMed1994

Seven-year follow-up of a smoking-prevention program for children.

Smoking-prevention programs, run by both teachers, and teachers and peers, have been introduced into school curricula in many parts of the world. This paper describes a long-term follow-up of a randomised controlled trial of a smoking education program for children conducted in Western Australia. Seven years after the first survey of 2,366 Year 7 students in 1981, 68 per cent of initial participants were traced through public records; 53 per cent of these responded to a new survey concerning smoking. Previous follow-up after one and two years had shown that both teacher-led and peer-led programs continued to reduce the taking up of smoking by girls to about the same degree, whereas in boys, the teacher-led program appeared to be effective after one year but neither program was effective after two years. In nonsmoking girls, both the intervention programs maintained their effects at the seven-year follow-up, with an almost 50 per cent reduction in smoking prevalence in the intervention group. Nonsmoking girls appeared to respond to cigarette advertisements. Mothers seemed to influence nonsmokers of both sexes and brothers seemed to influence smokers of both sexes. The seven-year follow-up confirmed the results seen at two years for boys, that the effects of the education program had dissipated. However, this study suggests that the smoking-prevention program had a lasting effect on preventing girls from taking up smoking.

Adolescent↗
PubMed1994

Cutaneous melanoma.

Between the early 1960s and the late 1980s, the incidence of melanoma increased at a rate of 3-7% per year in populations of mainly European origin. Corresponding trends were observed in mortality. Higher rates of increase in incidence were observed in a few populations (eg 8.9% per year in Hawaii whites). With the exception of Japan and possibly Puerto Rico, incidence rates of melanoma have remained stable in the few populations of mainly non-European origin for which reliable incidence data were available. A comparison of age specific trends in incidence and mortality in populations of mainly European origin showed two general patterns: a continuous increase in incidence in all age groups but with moderation or cessation of the previous rising trend in mortality in younger people in more recent time periods (eg Canada, continental USA, Denmark and the UK) and recent moderation or cessation of both incidence and mortality trends in younger people (eg New Zealand and, possibly, Hawaii whites). The first of these two patterns appeared to be the most common. Studies of site specific trends in incidence in 13 populations indicate that the highest rates of increase have generally been for melanomas on the trunk and the lowest for those on the head and neck. There is weak evidence to suggest that the rate of increase on the lower limbs has been greater in women than in men. Studies of incidence trends in the 1980s by thickness of melanoma in seven populations show that relative and absolute incidence has increased most for the thinnest melanomas and least for the thickest lesions. Increasing detection, earlier diagnosis and a real rise may together explain the increase in incidence of melanoma. The increases in mortality suggest that incidence has really increased, and the recent moderation in mortality trends may be explained by improved survival from melanoma due, most likely, to increasingly early diagnosis. In some populations, it may also indicate that the incidence increases are coming to an end. The disproportionately increasing incidence of thin melanoma, the divergence between incidence and mortality trends and the recent sharp increases in incidence in some populations suggest that earlier diagnosis or greater detection of less aggressive melanomas may have contributed to the incidence trends. A progressive change from predominantly occupational to predominantly recreational patterns of sun exposure is the most likely cause of increasing real incidence of melanoma in populations of mainly European origin.

Adolescent↗
PubMed1992

The effects of surgical treatment on survival and local recurrence of cutaneous malignant melanoma.

All patients with a diagnosis of cutaneous malignant melanoma (CMM) in Western Australia from 1980 to 1981 were observed for up to 6 years to determine vital status and to detect the development of local recurrences of the primary lesion. Approximately 35% of all patients had their tumors excised with surgical margins of less than 1 cm. When compared with patients whose tumors were excised with margins of at least 2 cm, the fatality rate in those with narrow margins was slightly less (rate ratio, 0.60; 95% confidence interval [CI], 0.20% to 1.80% for margins of 5 to 9 mm; rate ratio, 0.69; 95% CI, 0.26% to 1.87% for margins of 1 to 4 mm); however, this difference could have been caused by chance alone. The risk of local recurrence within 5 years after diagnosis was 2% (95% CI, 1% to 4%). The risk was strongly related to age and tumor thickness, but did not appear to be influenced by the width of excision (greater than 1 cm versus less than 1 cm: rate ratio, 1.03; 95% CI, 0.25% to 4.34%). The apparent lack of effect could be caused by to chance alone because the number of local recurrences was small.

Adult↗
PubMed1992

The role of the cancer registry in cancer control.

It has been accepted generally that the cancer registry has more of a 'back room' than a 'front line' role in cancer control, its particular responsibilities lying in description of cancer patterns, care, and outcome, in monitoring these variables in relation to control activities, and in providing a research database--often, for others to utilize. While readily justifiable, this prevailing concept of the cancer registry's role may not be sustainable in times of economic restraint. A survey of members of the International Association of Cancer Registries showed that most registries fit the accepted mold. Some, however, extend beyond it, particularly in the direct conduct of epidemiologic research and in the implementation of control programs, particularly screening. Sixteen percent appeared only to be collecting incidence statistics and may be at risk of economic rationalization. It would be consonant with their basic role and skills, and promote more rational cancer control, if cancer registries were to take on an expanded role, including direct participation in epidemiologic research, evaluation of interventions against cancer at the population level, situation analysis and cancer control planning, and implementation of aspects of cancer control--particularly coordination of screening--and monitoring the performance of cancer control programs. This expanded role could become the responsibility of specialized cancer control units of which cancer registration would be the central function.

Cancer Care Facilities↗
PubMed1991

Survival among patients with clinical stage I cutaneous malignant melanoma diagnosed in Western Australia in 1975/1976 and 1980/1981.

Five-year survival rates were slightly higher for patients with cutaneous malignant melanoma (CMM) diagnosed in Western Australia in 1980/1981 (89% in men and 95% in women) than in those whose melanomas were diagnosed in 1975/1976 (88% in men and 91% in women). The improvement in survival was probably due to a decrease in median tumor thickness from 1.29 mm in 1975/1976 to 0.77 mm in 1980/1981 because tumor thickness was the most important histologic index of prognosis. Tumor cell type and cross-sectional profile were the only other histologic characteristics that independently influenced fatality rates. Prognosis was significantly worse in males than in females and in patients with tumors on the posterior head and neck. Ten-year survival rates of patients whose melanomas were diagnosed in 1975/1976 was 82% in men and 87% in women, indicating that these patients continued to experience some excess mortality up to 10 years after diagnosis. The comparatively small improvement in prognosis in the 5-year period between these two groups suggests that survival might be expected to continue to improve only gradually unless there is a sharp absolute decrease in the number of thick tumors diagnosed.

Adolescent↗
PubMed1991

Incidence of histologic types of uterine sarcoma in relation to menstrual and reproductive history.

To determine whether the occurrence of one or more histologic types of uterine sarcoma is related to events in a woman's reproductive life, a population-based case-control study was conducted. One-hundred sixty-seven women newly diagnosed with uterine sarcoma among residents of 6 geographic regions were compared to 208 women selected at random from the same populations with regard to histories of menstruation, pregnancy and childbearing, and breast feeding, as reported during a telephone interview. Compared to women whose menstrual periods began at age 13, women whose menses began earlier were at increased risk of leiomyosarcoma (OR = 2.0, 95% CI 0.9, 4.3); other histologic types were less strongly associated with early age at menarche. Women with leiomyosarcoma and endometrial stromal sarcoma, but not malignant mixed Müllerian tumors, tended to have ceased menstruating 2-3 years later than controls. None of the histologic types was clearly related to parity or to age at first live birth, but each was inversely related to age at last live birth. Associations were observed between leiomyosarcoma and histories of an induced abortion (OR = 4.2, 95% CI 1.2, 14.2) and of breast feeding after a live birth (OR = 0.5, 95% CI 0.3, 1.0); these relationships were not observed for other morphologic variants. These results suggest possible similarities and differences in menstrual and reproductive risk factors among histologic types of uterine sarcoma, and between these malignancies and the more common breast, endometrial and ovarian carcinomas.

Adult↗
PubMed1991

Pigmentary and cutaneous risk factors for non-melanocytic skin cancer--a case-control study.

The roles of ethnic origin, pigmentary traits, sun sensitivity and other cutaneous characteristics as risk factors for basal-cell carcinoma (BCC) and squamous-cell carcinoma (SCC) were examined in a case-control study of prevalent and incident cases of histopathologically confirmed skin cancers. Two hundred and twenty six confirmed cases of BCC, 45 of SCC and 1,015 controls with no lesions were identified in a population-based survey of skin cancer in 1987 in Geraldton, Western Australia. The risk of both cancers was higher in native-born Australians than in migrants. The risk of BCC decreased with increasing age at arrival in Australia. Southern European ancestry was strongly protective against BCC (for any southern European grandparents) and SCC (no case of SCC had any grandparents of southern European origin). Inability to tan was the strongest pigmentary risk factor for both BCC and SCC. Among factors that incorporated a measure of sun exposure as well as sun sensitivity, freckling on the arm in childhood was important for both cancers, the number of moles on the back was important for BCC, and forearm skin colour and having a permanent colour difference between the neck and adjacent protected areas were important for SCC. Among measures of sun damage to the skin, solar elastosis of the neck was a strong risk factor for both BCC and SCC, loss of fine texture of the skin of the back of the hands (as measured by cutaneous microtopography) was important for BCC and telangiectasia of the face for SCC. When all important variables for each cancer were examined together in a single model with age, sex, migrant status or age at arrival in Australia, and ethnicity, in ability to tan, solar elastosis of the neck, and the number of moles on the back were independently significant risk factors for BCC and solar elastosis of the neck and having a permanent colour difference between the neck and adjacent protected areas were independently significant risk factors for SCC. The effects of age at arrival or migrant status and ethnic origin remained important in the models incorporating these factors. A history of ever having acne and a history of warts were protective for BCC and a history of acne was protective for SCC.

Adult↗
PubMed1991

Smoking, exposure to crocidolite, and the incidence of lung cancer and asbestosis.

In 1979 all former workers from the Wittenoom asbestos industry who could be traced to an address were sent a questionnaire to determine smoking history. Occupational exposure to crocidolite was known from employment records. Of 2928 questionnaires sent, satisfactory replies were received from 2400 men and 149 women. Eighty per cent of these had smoked at some time and 50% were still smoking. Since that time 40 cases of lung cancer and 66 cases of compensatable asbestosis have occurred in this cohort. The incidence of both lung cancer and asbestosis was greatest in those subjects with the highest levels of exposure to crocidolite and in ex-smokers. Statistical modelling of the joint effects of these exposures on the incidence of each disease indicated that crocidolite exposure multiplied the rates of lung cancer due to smoking and that smoking has no measurable effect on the rates of asbestosis. There was also some evidence that the incidence rate of lung cancer is falling with time.

Asbestos↗