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Biomedical subjects

C D Holman

Publications and source records attributed to C D Holman.

At least 91 records · Page 5Linked to original sources
PubMed1987

Occurrence and distribution of hepatitis B infection in the aboriginal population of Western Australia.

In 1986, the prevalences of hepatitis B surface antigen (HBsAg), and other serological markers of infection with hepatitis B virus in the Western Australian adult Aboriginal population, were estimated using a stratified random sample of 1,150 subjects. When the estimates were standardised to the age and sex distribution of the total population of aborigines aged 12 years or over, the prevalence of HBsAg was 7% (95% confidence interval 6-9%). The prevalence of any marker, that is HBsAg and/or hepatitis surface antibody (anti-HBs), was 49% (44-54%). The follow-up blood specimens obtained from three-fifths of the antigenemic subjects indicated that 96% (88-99%) were hepatitis B carriers. Male subjects had twice the prevalence of HBsAg (10%; 7-13%) when compared with females (4%; 3-6%). However, there was only a modest elevation of the prevalence of any marker in men (53%) compared with women (46%). There was evidence that the prevalence of HBsAg increased with age, but this was not the case with any marker. Geographically, there was substantial variation in hepatitis B infection rates. The Eastern Goldfields region had the highest prevalence (HBsAg 12%; any marker 66%), followed by the Kimberley, Pilbara and Central regions (HBsAg 7-9%; any marker 56-59%). The lowest rates were evident in Perth and the South West (HBsAg 3-5%; any marker 23-25%). The highest prevalence of markers in any discrete community was observed in the desert people of Warburton (HBsAg 22%; any marker 85%). These data indicate that, according to World Health Organisation criteria, the aboriginal population of Western Australia has an intermediate to high risk of infection with hepatitis B.

Adolescent↗
PubMed1987

Determinants of chronic bronchitis and lung dysfunction in Western Australian gold miners.

The relation of chronic bronchitis and respiratory dysfunction to age, tobacco smoking, and occupational exposure to surface and underground mining operations were examined in a cross sectional survey of 1363 men employed in the Kalgoorlie mining industry in 1985. Overall, the prevalence of chronic bronchitis was 14%. Eleven per cent of the workers had obstructive lung disorder (FEV1/FVC less than 0.70) and 9% had restrictive lung disorder (FVC less than 0.80 of predicted for height and age). There was little change in the prevalence of chronic bronchitis from that observed in a survey of the same industry in 1961-2. Only 1% of the workers in 1985 had radiographic signs of silicosis compared with 22% in 1961-2. Age, smoking, and underground mining experience all exerted strong effects on the development of chronic bronchitis with or without associated respiratory function abnormalities. After control of confounding by age and smoking, it was estimated that compared with a lifetime non-miner, the odds ratio (OR) of chronic bronchitis was 1.8 (95% confidence interval, 1.0-3.3) for one to nine years underground mining gold, 2.5 (1.2-5.2) for 10-19 years, and 5.1 (2.4-10.9) for 20 or more years. Underground mining of minerals other than gold was also associated with chronic bronchitis (OR = 5.1; 95% CI, 1.1-25.0) whereas exclusive surface mining had only a small empirical effect (OR = 1.3; 95% CI, 0.6-2.5). It is estimated that the proportion of cases of chronic bronchitis in working underground miners due to occupational factors is 50%. The results support the existence of an industrial cause of chronic bronchitis, although caution must be exercised in generalising the results to miners with progressive and sever respiratory impairment.

Adolescent↗
PubMed1987

Melanoma in Western Australia in 1980-81: incidence and characteristics of histological types.

All cutaneous malignant melanomas diagnosed in Western Australia in 1980-81 were reviewed and classified according to histological type (i.e., superficial spreading melanoma, Hutchinson's melanotic freckle melanoma (lentigo maligna melanoma), nodular melanoma and melanoma of unclassifiable type). The most common invasive melanoma was superficial spreading melanoma with an incidence rate of 14.3 per 100,000 person-years in females and 9.0 in males. It most commonly affected the trunk in males and the lower limbs in females and showed a peak incidence in middle life. Invasive Hutchinson's melanotic freckle melanoma was much less common than invasive superficial spreading melanoma (1.8 per 100,000 person-years in both sexes), occurred most commonly on the head and neck and increased progressively in incidence with age. Nodular melanomas were more frequent in men (4.5 per 100,000 person-years) than women (2.0). They were thicker than other types of invasive melanomas, showed more mitotic activity and had less evidence of regression. Their site distribution was similar to that of superficial spreading melanoma. In women the pattern of incidence with age was also similar to that of superficial spreading melanoma. In men it was more like that of Hutchinson's melanotic freckle melanoma. Melanomas of unclassifiable type did not have distinctive epidemiological features common to both sexes, although the trunk was the site most commonly affected in both men and women. With some exceptions the patterns of occurrence of in-situ lesions were similar to those of the corresponding invasive lesions. Benign melanocytic naevi were found less often in association with Hutchinson's melanotic freckle (melanoma) (6%) and nodular melanoma (9%) than with superficial spreading melanoma (22%) or melanoma of unclassifiable type (34%).

Adolescent↗
PubMed1987

Malignant melanoma of the skin.

Ultra-violet radiation (UVR) in sunlight is thought to be the main cause of malignant melanoma in lightly-pigmented populations. Individuals with fair skin, fair hair, blue eyes and/or a tendency to burn rather than tan when exposed to the sun are at particularly high risk of melanoma and should be given special attention in primary prevention programmes. Intermittent exposure to the sun, as in recreational exposure, may be a more potent cause of melanoma than more continuous exposure. Primary prevention offers the best prospects for a substantial reduction in mortality from malignant melanoma. However, there is little evidence available to judge the effectiveness of primary prevention of melanoma through reduction of exposure to the sun. Education for reducing exposure to the sun is common in high-risk populations but has never been evaluated adequately. Mortality from melanoma could also possibly be reduced by earlier diagnosis through education or screening of high-risk groups. Regular screening of patients with the familial dysplastic naevus syndrome should reduce their mortality from melanoma.

Humans↗
PubMed1986

Premature adult mortality and short-stay hospitalization in Western Australia attributable to the smoking of tobacco, 1979-1983.

The proportions of total deaths and premature adult mortality in 1979-1983, and of short-stay hospital admissions and bed-days in 1983, that were attributable to the smoking of tobacco were estimated in Western Australia by the use of aetiological fractions that had been derived from the published literature. Premature adult mortality was measured by the person-years of life that were lost from ages 15 to 69 years (PYLL 15-69). In men it was estimated that 25% of all deaths and 14% of PYLL 15-69 were attributable to smoking. In women the corresponding proportions were 15% of deaths and 8% of PYLL 15-69. The proportions of short-stay hospital bed-days that were attributable to smoking were estimated at 7% in men and 3% in women; for hospital admissions the estimates were 4% and 1% in men and women, respectively. In all, tobacco-related disease and injury accounted for around 1700 deaths and 7500 short-stay hospitalizations each year in a population of 1.4 million persons.

Adolescent↗
PubMed1986

Melanoma in Western Australia 1975-76 to 1980-81: trends in demographic and pathological characteristics.

Trends in incidence rates of cutaneous malignant melanoma in Western Australia from 1975-76 to 1980-1981 have been examined with reference to age, sex, body site, presence or absence of dermal invasion, tumour thickness, histological type, socioeconomic status and occupation. The incidence rates of all melanomas increased from 22.1 to 31.5 per 100,000 person-years in males and from 23.6 to 28.6 in females. In males, the relative annual increase in the incidence of invasive melanoma was 2.2%, and in females it was 5.6%. In-situ melanomas had larger relative increases in incidence (28% per annum in males and 10% in females) and the thickness of invasive lesions decreased between 1975-76 and 1980-81. The relative increase in incidence of invasive melanomas was greatest on the body sites with the highest rates initially--the trunk in males and the lower limbs in females. There was an increase in the proportion of invasive lesions classified as superficial spreading melanoma. The increase in incidence of in situ melanomas was largely restricted to the head and neck in older men of high socioeconomic status resident in Perth. This trend in in-situ melanoma was mainly due to an increase in the recorded incidence of Hutchinson's melanotic freckle. It may have been, in part, an artefact due to increased recognition of Hutchinson's melanotic freckle in this sub-group of the population.

Adolescent↗
PubMed1986

Relationship of cutaneous malignant melanoma to individual sunlight-exposure habits.

The relationships of different histologic types of cutaneous malignant melanoma to occupational and recreational sunlight exposure, habits of clothing, sunburn histories, and use of sunscreening agents were examined in a case-control study of 507 patients and 507 matched controls in Western Australia. Variations in relationships according to the primary site of melanoma were also examined. An increased incidence rate of superficial spreading melanoma was associated with low total outdoor exposure in early adulthood and frequent participation in boating and fishing. Superficial spreading melanoma of the trunk was also related to frequency of sunbathing at ages 15-24 years and of exposure of the trunk while working outdoors. In women the rate ratio for all types of melanoma occurring on the trunk was estimated at 13.0 (95% confidence interval, 2.0-83.9) in those who wore a bikini or bathed nude at ages 15-24 years compared with those wearing a conservative one-piece bathing suit. There was little evidence that sunbathing or wearing a bikini within 10 years of case diagnosis were risk factors for melanoma of the trunk. After control of confounding due to constitutional factors, only Hutchinson's melanotic freckle melanoma showed a relationship to severe sunburn. For nodular melanoma, sunburn appeared to be protective. Although many of the results supported the hypothesis that melanomas other than the Hutchinson's melanotic freckle type are related to occasional bursts of recreational sun exposure during a susceptible period in early adult life, little support for the hypothesis was obtained when recreational sun exposure was expressed as a proportion of total outdoor exposure, which had been considered a priori to be an index of intermittent sunlight exposure.

Adolescent↗
PubMed1986

Etiology of common acquired melanocytic nevi: constitutional variables, sun exposure, and diet.

Associations were sought between prevalence of nevi on the arms and other variables in controls from a case-control study of cutaneous malignant melanoma. The prevalence of nevi was higher in women than men, fell with age up to about 35 years of age, and was low in those born outside Australia. Among pigmentary characteristics, there was strong evidence only of an association with skin color of the upper inner arm. The highest prevalence of nevi was in those with skin of intermediate darkness. Peak prevalence of nevi was also seen in intermediate categories of variables indicating sun exposure, particularly mean annual hours of bright sunlight at places of residence when 10-24 years of age, total outdoor exposure time per week in the summer at 10-24 years of age, and usual summer suntan on the arms in the last 10 years. These dose-effect patterns may indicate conflicting effects of sun exposure on appearance and disappearance of nevi. The protective effect of birthplace outside Australia appeared to be due to the corresponding low mean annual hours of bright sunlight at places of residence when 10-24 years of age. The prevalence of nevi was comparatively lower in those who drank alcohol and in those who had average or high daily intakes of retinol. These associations were not explained by those of any of the other variables.

Adolescent↗
PubMed1985

Surgical treatment and survival from cutaneous malignant melanoma.

Varied methods of primary surgical treatment of 189 cases of cutaneous malignant melanoma studied in Western Australia had no statistically significant effect on prognosis. The results indicate that wide excision is not justified as the standard treatment of cutaneous malignant melanoma.

Adolescent↗
PubMed1985

Cutaneous malignant melanoma and fluorescent lighting.

A population-based case-control study of cutaneous malignant melanoma occurring during 1980-81 was conducted in Perth, Western Australia. Three hundred and thirty-seven cases and 349 matched controls were reinterviewed in 1983 with regard to their fluorescent light exposure. The incidence rate of all melanomas was not associated with rate of exposure or cumulative exposure to all fluorescent lights or just those without diffusers. Separate analyses by histogenetic type and, where possible, body site of melanoma showed, in most instances, no consistent association between incidence rate of melanoma and exposure to fluorescent lights without diffusers. Incidence of melanomas of unclassifiable histogenetic type, however, increased with increasing duration of exposure (P-value for trend .02). This association was weaker and the P-value higher (.11) when exposure was considered only in residential rooms and offices, where light fittings are closest to the subject. Adjustment for the effects of total and intermittent sun exposure on melanoma rates did not alter the above trends appreciably.

Adolescent↗
PubMed1984

Cytological abnormalities of the cervix. Fifteen years' follow-up of a gynaecological cancer survey.

In a gynaecological cancer survey of 1026 women aged 21 years and over in May 1967, 74 women were found to have cervical cytological changes (designated as mild atypia in 71), which were followed to April 1982. No case of cervical cancer was found (0.3 were expected on the basis of population rates). Six women had had hysterectomies (6.2 were expected on the basis of rates of hysterectomy in the region of the survey). Reports on cervical smears taken since January 1, 1980, were available for 46 (75%) of 61 women who were alive and had not had a hysterectomy. Of these, 11 showed mild atypia; the remainder were within normal limits.

Adult↗
PubMed1984

Cutaneous malignant melanoma in women: exogenous sex hormones and reproductive factors.

The roles of exogenous sex hormones and reproductive factors in the causation of malignant melanoma of the skin in women were examined in a case-control study of 276 patients and 276 matched controls in Western Australia. There was no consistent evidence of a relationship between the incidence rates of different histogenetic types of melanoma and age at menarche, duration of menstrual life, degree of obesity, number of pregnancies more than 20 weeks in duration or use of oral contraceptive preparations (OCP). Exposure to OCP was examined separately for different age periods and in different intervals of time before diagnosis; no consistent trend emerged. There was borderline evidence of an association of superficial spreading melanoma with duration of use of unopposed oestrogens. On the basis of seven studies of the relationship of melanoma to OCP published to date, we estimate that the total incidence rate of melanoma in OCP ever-users is unlikely to be increased by more than one third the rate in never-users.

Adolescent↗
PubMed1984

Analysis of interobserver variation on a programmable calculator.

A program for the analysis of interobserver variation using kappa statistics is described for the HP- 41C hand-held calculator. For an unlimited number of cases classified by as many as nine observers into a maximum of 10 categories of a normal scale, the program provides crude and adjusted measures of overall agreement, level of agreement on each category, and the extent of associations between categories. Use of the program is illustrated by an example.

Analysis of Variance↗
PubMed1984

The determinants of actinic skin damage: problems of confounding among environmental and constitutional variables.

Constitutional and environmental determinants of actinic skin damage, assessed by cutaneous microtopography, were evaluated in 1,216 subjects attending the 1981 Busselton Health Survey in Western Australia. Increasing age, male sex, the tendency to burn on exposure to sunlight and outdoor occupation were found to have independent predictive value for the presence of actinic skin damage. Crude positive and inverse associations of actinic skin damage with several other factors were shown to arise from confounding. Effect measures for outdoor leisure pursuits and sunscreen use were underestimated due to inverse associations of these factors with older age, and inverse associations of high-exposure outdoor activities with poor skin response to sunlight. Associations of constitutional traits typical of fair individuals and sunscreen use with the tendency to burn resulted in overestimation of effect measures. Empirical relationships of actinic skin damage with certain leisure activities and with use of sunscreens were also confounded by sex. The results indicate a need for greater attention to confounding in nonexperimental skin cancer research.

Adolescent↗