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Biomedical subjects

P R Burch

Publications and source records attributed to P R Burch.

At least 19 recordsLinked to original sources
PubMed1988

Period and cohort trends for mortality and cigarette consumption in England and Wales, 1946 to 1980, with emphasis on sex ratios.

In an earlier paper (Burch P. R. J. J Chron Dis 1981; 34: 87-103) changes in sex- and age-specific mortality from all causes of death in England and Wales were studied in relation to changes in sex- and age-specific cigarette consumption. The absence of a consistent correlation between the two variables, and the general characteristics of the data, suggested that studies of sex ratios might provide a better test of the hypothesis that the association between smoking and mortality has a causal basis. In this paper temporal changes in the sex ratio of cumulative cigarette consumption by cohort, and of smoking rates by age, are considered in relation to changes in the sex ratio of mortality. Again, no consistent correlations emerge and it is evident that factors other than smoking have played a dominant part in determining recent changes in the sex ratio of mortality in all age groups from 35-39 to 80-84 years. Among these "other factors" are birth cohort effects that can be attributed, in part, to birth cohort changes in the sex ratio of mortality from bronchitis and emphysema. The present results, together with other evidence (vide supra; and Burch P. R. J. J Chron Dis 1984; 37: 148-156), show that great care needs to be exercised when attempts are made to deduce causation from epidemiologic surveys.

Adult↗
PubMed1986

Period and cohort trends in mortality from cancers of the uterus in England and Wales. A new theory of changing gene frequencies.

Analysis of the age distribution of cancers of the uterus reveals three clearly distinctive types: early- and late-onset cancers of the cervix and one form of cancer of the corpus. England and Wales mortality data are available for the three types combined from 1911; cancers of the cervix and corpus have been listed separately from 1951. In the highest age groups, 60-64 yr and above, death rates fell fairly steadily from 1921-25 to 1981-82 whereas cigarette smoking - an alleged cause of cervical cancer - rose over much of that period. In the younger age groups, 55-59 yr and below, the more complicated temporal trends include two marked cohort dips. The first dip affected cohorts born around 1911; this was followed by a rise up to the 1921 central cohort, then a steep fall to the 1936 central cohort and, finally, a further rise up to the 1946 cohort (at least). The period trends are probably caused by a decline in the impact of one or more precipitators of cervical cancer, such as the papilloma virus. Cohort shifts are attributed to autoaggressive attacks on parental germ cells, the zygote, or early-stage embryo that induce gene change to affect the frequency of women genetically predisposed to early-onset cervical cancer. Attacks are also triggered by one or more precipitating agents with a temporal, and possibly a seasonal, dependence. Implications of this hypothesis of cohort shifts are discussed.

Adult↗
PubMed1985

Client characteristics associated with behavior change for treated and untreated aggressive boys.

This study examined the relationship between subject characteristics of aggressive boys and their behavioral changes during a school year. Seventy-six boys in the fourth, fifth, and sixth grades were identified by their teachers as the most disruptive and aggressive in their classes. These boys were assigned to untreated control, anger-coping, anger-coping plus goal-setting treatment, and minimal treatment goal-setting cells. The anger-coping treatment was based on cognitive behavioral procedures. In both anger-coping cells, greater reductions in rates of disruptive/aggressive off-task classroom behavior was predicted by having higher rates of these behaviors initially, and greater reductions in parents' ratings of aggression was predicted by having poor social problem-solving skills initially. Additional predictors of reductions in parents' ratings of aggression in one, but not both, anger-coping cells included having higher rates of somatic symptoms and poorer social acceptance by peers. In contrast to the other cells, those boys in the no-treatment group who demonstrated the greatest spontaneous improvement on these change measures were the ones who initially were the best problem-solvers and who had higher levels of self-esteem. This cognitive-behavioral treatment appeared to have most impact with those boys who were the most in need of intervention.

Aggression↗
PubMed1985

Natural and radiation-induced cataracts in man and mouse, and natural macular degeneration in man: proposed mechanisms.

A unified theory of growth and age-dependent disorders is applied to the interpretation of epidemiological data for natural and radiation-induced cataracts and natural macular degeneration in man. Using the same unified theory, mechanisms are also proposed to explain the experimental evidence for natural and radiation-induced lenticular opacities in the lens of the mouse. Epidemiological and experimental data are strikingly consistent with the hypothesis that natural cataract formation is an autoaggressive process but the details of pathogenesis differ greatly between the two species. Radiation dose-response relations reflect these contrasts. Lenticular opacities in the nuclear-bomb survivors at Hiroshima and Nagasaki were probably induced by a 'single-track' mechanism. Radiation-induced generalised opacification in the lens of the mouse results from a 'multi-track' process. The pathogenesis of natural macular degeneration in man happens to have close parallels with that of natural opacification in the mouse. We discuss some implications of these inferences for the phenomenon of radiation-induced lethal disorders in man.

Age Factors↗