1,721,406 research outputs found
R. Bhopal, Concepts of epidemiology : an integrated introduction to the ideas, theories, principles and methods of epidemiology
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Compositional data analysis and diversity indicies: different approaches to define the role of nutrients in the study of diet-cancer relationship
No full textIn epidemiological studies the relationship between diet and risk of disease is usually investigated considering the absolute intake of nutrients/foods (often opportunely coded in categories of increasing consumption). The total intake of a nutrient is usually scattered among different food items and the modalities of intake could influence the impact on the risk. In order to evaluate the impact of nutrient dispersion on risk we suggest two different approaches: a) in the first each nutrient is described with a couple of variables rapresenting the estimated absolute intake (Z) and a diversity index (d) measuring the dispersion intake on different dietary sources; b) the second approach is based on standard techniques used in analysis of compositional data
Trends in mortality from cerebrovascular disease in Italy, 1955-78
No full textTrends in age-specific and age-standardized death certification rates from all cerebrovascular diseases and various diagnostic subcategories in Italy during the period 1955-78 have been analysed. In both sexes, a decrease in excess of 25% was evident in the overall age-standardized cerebrovascular disease mortality. However, rates were roughly stable in males up to age 50 and in females up to age 45, and slightly but consistently increasing in the younger age groups (under 40), mostly in females. The largest downward trends were for both sexes in the 55 to 74 age groups, and the declines were more marked in females, averaging 3% per year. Since death certification is most reliable in the younger age groups and it is difficult to imagine any modification of risk factors which should affect mortality in later middle age but not in younger age groups, there is no obvious and simple interpretation of this pattern of trends. A comparison with similar trends in ischemic heart disease and other causes of death suggests that the decline in overall cerebrovascular disease mortality might be partially or largely artefactual, though a between-sexes comparison indicates that at least part of the decrease registered in females may well be real. The extent of the decline, however, has been almost certainly more limited in Italy than in most other Western countries. Only in the younger age group (30-34) did rates show a larger increase in females, which might be related to increased prevalence of cigarette smoking, or the use of oral contraceptives
Diversity indices and analysis of diet-cancer relationship
No full textIn epidemiologiacl studies concerning chronic disease, more often it is common to evaluate the relatioship between dietary habits, expressed as absolute intake of different nutrient/foods, and risk of disease. Total intake of a nutrient is usually scatterd among many food items and the modalities with which a nutrient is assimilated in the diet may act as a modifier of its impact on the risk. It would be of interst to quantify the different patterns of nutrients intake. This could be done by characterizing each nutrient assimilated in the diet with a diversity index to measure its degree of dispersion
Metodologie e limiti nel rilevamento dei consumi alimentari. Studio della relazione dieta-cancro per l'individuazione dei gruppi a rischio
No full textTrends in childhood cancer mortality in Italy, 1955-78
No full textTrends in childhood cancer death rates in Italy from 1955 to 1978 were analyzed. All cancer age-standardized mortality below age 15 fell about 20%, with a clear downward trend since the early 1970's. Declines were evident for leukemias (-25%), Hodgkin's disease (-56%), non-Hodgkin's lymphomas (-27%), kidney cancer (-25%), retinoblastoma (-50%), and bone sarcomas (-31%), for a total number of about 200-250 fewer deaths per year in the late 1970's compared to the expected values using rates of the 1950's. The observed fall was apparently confined within the first age group considered (0-4 years), but the age-specific patterns of trend were partly influenced by simple postponement of some deaths to older age groups. Comparisons with similar data in other developed countries suggest that, although there has undoubtedly been some progress, there is still wide scope for further reduction in childhood cancer mortality in Italy, simply through more rational use of currently available diagnostic and therapeutic knowledge
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