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Biomedical subjects

T W Anderson

Publications and source records attributed to T W Anderson.

At least 19 recordsLinked to original sources
PubMed1988

Genetic disorders in children and young adults: a population study.

The data base of an ongoing population-based registry with multiple sources of ascertainment was used to estimate the present population load from genetic disease in more than 1 million consecutive live births. It was found that, before approximately age 25 years, greater than or equal to 53/1,000 live-born individuals can be expected to have diseases with an important genetic component. This total was composed of single-gene disorders (3.6/1,000), consisting of autosomal dominant (1.4/1,000), autosomal recessive (1.7/1,000), and X-linked recessive disorders (0.5/1,000). Chromosomal anomalies accounted for 1.8/1,000, multifactorial disorders (including those present at birth and those of onset before age 25 years) accounted for 46.4/1,000, and cases of genetic etiology in which the precise mechanism was not identified accounted for 1.2/1,000. Previous studies have usually considered all congenital anomalies (ICD 740-759) as part of the genetic load, but only those judged to fit into one of the above categories were included in the present study. Data for congenital anomalies are therefore also presented separately, to facilitate comparison with earlier studies. If all congenital anomalies are considered as part of the genetic load, then greater than or equal to 79/1,000 live-born individuals have been identified as having one or other genetic disorder before approximately age 25 years. These new data represent a better estimate of the genetic load in the population than do previous studies.

Adult↗
PubMed1986

Optimal frequency of screening for cervical cancer: a Toronto case-control study.

A retrospective (case-control) study was conducted in Toronto, Canada, between 1973 and 1976 to evaluate the effectiveness of the Papanicolaou smear as a screening procedure for invasive carcinoma of the cervix. In the current study, data from cases of squamous cell cancer of the cervix and controls without hysterectomy were analysed to assess the optimal frequency of cervical screening. The time between the last normal smear and the date of diagnosis was divided into 12-month intervals. Relative protections were then calculated by comparing women who had had one or more normal smears with those who had never been screened. The results show a significant protective effect of screening in women who have had two or more normal smears, when the last was taken within two years of diagnosis. This trend, although not statistically significant, continued even when the last was taken four years before diagnosis, suggesting that screening intervals should not be greater than four years.

Adult↗
PubMed1983

A randomized placebo-controlled trial of ultraviolet light in the treatment of superficial pressure sores.

Ultraviolet (UV) light treatment of pressure sores enjoyed widespread popularity for many years, but recently its effectiveness has been increasingly questioned. Surprisingly, it appears that this form of treatment has never been tested by a randomized placebo-controlled trial. Eighteen patients residing in the Extended Care Unit of the Health Sciences Centre Hospital at the University of British Columbia and suffering from superficial pressure sores of recent onset were therefore randomly assigned to active and placebo treatment groups. Since treatment procedures appeared identical in both groups, both patients and hospital staff were blind as to individual allocation. Sixteen patients completed the study. Mean time to complete healing was 6.3 weeks in the UV treated group, significantly (P less than .02) less than the mean of 8.4 weeks in the placebo group. This difference persisted unchanged when each patient's age and the initial size of the sore were taken into account by an analysis of covariance. Thus, in spite of growing skepticism about its effectiveness, it appears that UV light may play a useful role in the treatment of pressure sores, and a systematic evaluation of different treatment protocols seems to be justified.

Aged↗
PubMed1979

Cold snaps, snowfall and sudden death from ischemic heart disease.

The short-term effect of low temperature on the incidence of ischemic heart disease over a 15-year period was examined. To reduce confounding by other seasonal factors the analysis was restricted to the winter months and was based on the change in the daily rate of sudden death at the time of cold snaps (arbitrarily defined as days on which the mean temperature was at least 4.4 degrees C lower than the day before) and around the time of heavy snowfalls. A statistically significant increase in the daily rate of sudden death at the time of cold snaps occurred only in men under 65 years of age, and even in this group the effect was of relatively small magnitude (+16%) compared with the large change in rate following heavy snowfalls (+88%). Among persons aged 65 years or over cold snaps had virtually no effect, and only the men in this group showed an increased daily rate of sudden death following a snowfall. These results suggest that much of the increased frequency of death from ischemic heart disease in winter, particularly among the elderly, must be due to factors other than short-term cold stress.

Adult↗
PubMed1979

Does screening by "Pap" smears help prevent cervical cancer? A case-control study.

The Papanicolaou (Pap)-smear history of 212 cases of invasive cervical cancer was compared with that of 1060 age-matched controls drawn from neighbours. In the 5 years before the year of diagnosis 32% of the cases had been screened by Pap smear, compared with 56% of the controls. This difference was statistically highly significant (p less than 0.0001) and indicated a relative risk of invasive cancer of 2.7 in women who had not been screened by Pap smear, compared with those who had. Differences in Pap-smear history between cases and controls persisted when the data were stratified by age, income, education, marital history, smoking habit, employment status, and access to medical care. These results support the belief that the Pap smear is an effective screening procedure for invasive cervical cancer.

Adenocarcinoma↗
PubMed1979

The sex differential in ischaemic heart disease: trends by social class 1931 to 1971.

The comparison of trends in ischaemic heart disease (IHD) mortality in different social classes is confounded by historical changes in diagnostic techniques and statistical classification, and possibly by different standards of diagnostic accuracy in the different social classes. The problems can be circumvented by taking advantage of the fact that in middle age (45 to 64) the IHD death rate is much higher in men than in women. This large sex differential is not present in any of the other causes of death with which IHD might easily be confused and it is therefore relatively unaffected by diagnostic errors and variation in classification. The changes that have occurred in the sex differential in Social Classes I and V in England and Wales between 1931 and 1971 confirm anecdotal clinical reports that the male vulnerability to IHD appeared first in Social Class I (professionsl). By 1971 Social Class V (unskilled) had caught up, and the men in these two social classes now experience an almost identical excess in cardiovascular death rate compared with their wives.

Coronary Disease↗
PubMed1978

Re-examination of some of the Framingham blood-pressure data.

Mathematical smoothing of data for the Framingham study leads to the conclusion that there is no threshold of normality for blood-pressure. A reasonable therapeutic goal might be "the lower the better". However, examination of the unsmoothed Framingham data indicates that while systolic pressures fit this no-threshold model reasonably well, changes in diastolic pressure below about 90 mm Hg have little or no prognostic significance. The poor fit of the diastolic points to the no-threshold model may also help to explain why at Framingham raised systolic pressure seemed to have a greater impact than raised diastolic pressure.

Blood Pressure↗