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Biomedical subjects

D C Skegg

Publications and source records attributed to D C Skegg.

At least 19 recordsLinked to original sources
PubMed1992

Variation and covariates of the number of benign nevi in adolescents.

Melanocytic nevi of diameter greater than or equal to 2 mm were counted on most of the skin surface of 349 adolescents aged 14-15 years of European race or ethnicity in Dunedin, New Zealand. Total counts are described by means of a form of Poisson-error log-linear modeling suitable for data showing unexplained variation (NE Breslow, Appl Statist 1984;33:38-44). There were marked interpersonal variation in the number of nevi; only some was attributable to observed factors. The mean and median counts were 23.8 and 18 nevi, respectively. The estimated ratio of the number of nevi for females compared with males was 0.7 (95% confidence interval (CI) 0.6-0.8). Greater amounts of sunbathing were associated with greater numbers of nevi. Hair and eye color, socioeconomic status, and sunburn history did not show statistically significant effects. Time since menarche and shaving status also showed no effects. Lack of suntan was associated with lower counts. Freckling was positively correlated with higher counts; the severe freckling group had an estimated ratio of 1.9 (95% CI 1.3-2.8) compared with those with no or very few freckles. The results are consistent with the hypothesis that ultraviolet radiation exposure from recreational sun exposure positively influences the total burden of nevi in normal subjects. Comparison with other epidemiologic studies suggests that the typical ultraviolet radiation dose-nevus yield curve might be steeper in males than females. Unexplained variation of nevus count may reflect heterogeneity of constitutional factors not yet measured in epidemiologic studies.

Adolescent↗
PubMed1992

Projections of cervical cancer mortality and incidence in New Zealand: the possible impact of screening.

STUDY OBJECTIVE: The aim was to estimate the likely burden of cervical cancer in New Zealand over the next two decades, according to whether cervical screening services are made more effective. DESIGN: The study was based on national mortality and incidence data for the periods 1954-87 and 1954-86, respectively. An age-period-cohort model was used to estimate the contributions of age, time period, and birth cohort effects to the occurrence of cervical cancer. Using age specific estimates of the future female population of New Zealand, projections of cervical cancer mortality and incidence until the year 2008 were derived from the model. Projections were made assuming either that screening services will not be improved, or that an immediate improvement in the organisation of screening will lead to a decline in period effects for incidence of 15% per five year time period (with a slightly delayed effect on mortality). It was also assumed either that the risk in new birth cohorts will be similar to that in recent cohorts, or that their risk will be halved as a result of changes in sexual behaviour (due to education about AIDS or other factors). Combining these assumptions produced four sets of estimates, reflecting a range of possible scenarios. SETTING: Both the data used and the projections obtained related to the entire population of New Zealand women. MAIN RESULTS: For both mortality and incidence, projections were made of age specific rates, cumulative rates, and absolute numbers of deaths or new cases. With the first assumption about new birth cohorts, it was estimated that both mortality and incidence rates will increase if screening services are are not improved. In absolute terms, the present 100 deaths per year could increase to about 148 deaths per year, while there could be a much larger increase in incidence from 235 per year to about 440 per year). With improved screening, there could be a reduction in age specific mortality rates and a modest decline in the number of deaths, while a reduction in incidence rates would be accompanied by about the same number of new cases as at present. In comparison with improvements in screening, changes in the underlying risk in new birth cohorts would have much smaller effects on the occurrence of cervical cancer over the next two decades. CONCLUSIONS: Plausible improvements in cervical screening are likely to be accompanied by only small changes in the burden of cervical cancer over the next two decades. If screening services are not improved, however, there will be striking increases in both mortality and incidence.

Adult↗
PubMed1991

Alcohol consumption and risk of breast cancer.

In a national case-control study, 891 New Zealand women aged 25 to 54 with newly diagnosed breast cancer were compared with 1,864 control subjects selected at random from the electoral rolls. The relative risk of breast cancer for current drinkers of alcohol, compared with women who had never drunk alcohol, was 1.0 (95% confidence interval 0.64 to 1.7). For ex-drinkers the relative risk was 1.3 (95% confidence interval 0.74 to 2.5). Women drinking up to 14 drinks per week had no increase in risk, while the relative risk in those consuming more than 14 drinks per week was 1.8 (95% confidence interval 0.87 to 3.8). There was no evidence of effect modification by age at diagnosis, menopausal status, body mass index, or any of the other variables examined. While these results provide little support for the hypothesis that moderate alcohol consumption increases the risk of breast cancer, they are not inconsistent with the weak associations that have been found in many other studies. Possible explanations for such a relationship are considered.

Adult↗
PubMed1991

Occurrence of AIDS in New Zealand: the first seven years. MRC AIDS Epidemiology Group.

The 179 people in New Zealand with AIDS diagnosed up to the end of 1989 and notified by 30 June 1990 are reviewed. Retrospective data collection provided the first available information on date of diagnosis, ethnic affiliation, district of usual residence, and survival. Of the 179 people with AIDS, 173 were male. AIDS occurred most commonly between the ages of 30 and 50, but there were two children under 10. The standardised cumulative incidence rates (per 100,000) in the European, Maori, and Pacific Island populations were 5.3, 4.5, and 5.5, respectively. The majority affected (154) were men who had had sexual contact with men. Three of five intravenous drug users also reported such contact. Smaller numbers were presumed to have been infected through heterosexual contact (7), treatment of haemophilia (3), blood transfusions (2), or perinatally (1). In seven cases the mode of transmission was unknown. The proportion of people who had been living overseas when first diagnosed was initially high but declined, so that 134 were known to have been diagnosed in New Zealand. Of these, 107 lived in Auckland or Wellington. Survival analysis using the Kaplan-Meier method showed that the median time from diagnosis to death was 58 weeks.

Acquired Immunodeficiency Syndrome↗
PubMed1991

A feasibility study of organised cervical screening in southern New Zealand.

The 1985 electoral roll was used as a register to invite 1013 women to participate in a screening program. Appointment times and a choice of venues for having a smear were not provided. Overall, 26 per cent of the women sent invitations registered with the program. After adjustment for the prevalence of hysterectomy, the proportion who registered with the program was about 32 per cent. The low level of registration and difficulties experienced in tracing registrants and nonregistrants over time using the electoral roll resulted in the cessation of the program after 3 years. An assessment of the original invitation was made using a small case-control study, and associations between the screening history stated at interview and screening over the duration of the program were examined in nonregistrants.

Feasibility Studies↗
PubMed1990

Oral contraceptives and risk of breast cancer.

A national population-based case-control study was conducted in New Zealand to assess the effects of hormonal contraception on breast-cancer risk. A total of 891 women aged 25 to 54 with a first diagnosis of breast cancer, and 1864 control subjects, randomly selected from the electoral rolls, were interviewed. The relative risk of breast cancer for women who had ever used oral contraceptives was 1.0 (95% confidence interval 0.82-1.3). There was no increase in risk with duration of use, even among women who had continued to use oral contraceptives for 14 or more years (relative risk = 1.1, 95% confidence interval 0.78-1.7). The risk of breast cancer was not increased by use of oral contraceptives for long periods before the first pregnancy or by starting use at a young age. Parity, age at menarche, family history of breast cancer, or history of benign breast disease did not modify the effect of oral contraceptives on breast-cancer risk. Relative risk estimates were slightly, although not significantly, increased during the first few years after starting oral contraception and in women under 35 years of age at diagnosis.

Adolescent↗
PubMed1990

Multiple sclerosis in Australia and New Zealand: are the determinants genetic or environmental?

The prevalence of multiple sclerosis (MS) has been recently reported from nine regions of Australia and New Zealand. There is a marked variation of prevalence with latitude. MS is seven times more common in southern New Zealand than in tropical Queensland. On current evidence, it is suggested that in both countries this variation is predominantly due to environmental rather than genetic factors.

Australia↗
PubMed1989

Depot medroxyprogesterone (Depo-Provera) and risk of breast cancer.

OBJECTIVE: To determine whether use of the injectable contraceptive depot medroxyprogesterone acetate (Depo-Provera) affects the risk of breast cancer in women. DESIGN: A population based case-control study. SETTING: Nationwide community study. SUBJECTS: 891 Women aged 25-54 with newly diagnosed breast cancer were compared with 1864 women selected at random from the electoral rolls. INTERVENTION: Women were interviewed by telephone about past use of contraceptives and about possible risk factors for breast cancer. MAIN OUTCOME MEASURE: Relative risk of breast cancer in women who had used medroxyprogesterone. RESULTS: Medroxyprogesterone had been used by 110 patients and 252 controls. Overall, the relative risk of breast cancer associated with any duration of use was 1.0 (95% confidence interval 0.80 to 1.3). In women aged 25-34 the relative risk was 2.0 (1.0 to 3.8). The relative risk was highest in women aged 25-34 who had used the drug for six years or longer, although there were few women in this category. Women who had used it for two years or longer before age 25 had an increased risk of breast cancer (relative risk 4.6; 1.4 to 15.1). CONCLUSION: Despite the lack of an overall association these findings suggest that medroxyprogesterone may increase the risk of breast cancer in young women.

Adult↗
PubMed1988

Contraceptive practice in New Zealand.

A survey of contraceptive practice in New Zealand was carried out using a population-based sample of women, aged 25 to 54, selected as control subjects in a national case-control study. The results showed that sterilisation has become the most common means of family limitation. Overall, 45% of women aged 25 to 54 were in a union where one or the other partner had been sterilised. Vasectomy was the most common method of contraceptive sterilisation. The frequency of hysterectomy contributed to the high rates of sterilisation; 12% of women had had a hysterectomy. Over 80% of New Zealand women had used an oral contraceptive at some time, but only 11% were using the pill at the time of the survey. Comparison with earlier studies of contraceptive use in New Zealand show there has been a marked increase in the prevalence of contraceptive sterilisation, and a marked decrease in the use of oral contraceptives.

Acquired Immunodeficiency Syndrome↗
PubMed1988

The changing patterns of disease.

The pattern of disease in New Zealand is changing and will continue to do so. Some trends are predictable, while others (such as the epidemic of AIDS) may be unexpected. Analysis of past improvements in health suggests that medical research would be more productive if greater attention were paid to the external influences and personal behaviour which are the chief determinants of health. Apart from such general implications, analysis of the changing patterns of disease is vital as a stimulus and guide for medical research of all kinds. More effective monitoring of disease trends in New Zealand will require improvement in the quality and timeliness of routine health statistics, and training of adequate numbers of epidemiologists to analyse and interpret the data. Such developments are essential if medical research is to make a full contribution to the health of New Zealanders.

Epidemiology↗
PubMed1988

How often is multiple sclerosis mistaken for a psychiatric disorder?

In a defined population of 112,000, an attempt was made to discover every patient with multiple sclerosis. Using strict diagnostic criteria, 91 patients were identified. A search of psychiatric records for the same population revealed that 15 (16%) of these patients were referred to psychiatrists between the onset of their symptoms and the diagnosis of multiple sclerosis. Ten (11%) were seen with symptoms attributable to multiple sclerosis. These symptoms were recognized as neurological in only two cases, while the other eight patients received a variety of psychiatric diagnoses. Possible reasons for diagnostic error included the subjective nature of many early symptoms, histrionic behaviour, and psychiatric disturbance which drew attention away from physical symptoms. The results underline the caution needed when patients with physical symptoms are referred for psychiatric assessment.

Adult↗