Lancet
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Vitamin D affects calcium metabolism and prevents proliferation of colon cells in vitro. In human beings the main circulating form of vitamin D is 25-hydroxyvitamin D; to regulate calcium homoeostasis, this form must be converted to 1alpha, 25-dihydroxyvitamin D by 1alpha-hydroxylation in the kidney with 25-hydroxyvitamin D-1alpha-hydroxylase. ⋯ We identified messenger RNA (mRNA) for 25-hydroxyvitamin D-1alpha-hydroxylase in normal colon tissue and in malignant and adjacent normal colon tissue. These findings support the notion that vitamin D might have a role in cell growth regulation and cancer protection, and might be the explanation for why the risk of dying from colorectal cancer is highest in areas with the least amount of sunlight.
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We describe here the methods used to produce the first estimates of healthy life expectancy (DALE) for 191 countries in 1999. These were based on estimates of the incidence, prevalence, and disability distributions for 109 disease and injury causes by age group, sex, and region of the world, and an analysis of 60 representative health surveys across the world. We used Sullivan's method to compute healthy life expectancy for men and women in each WHO member country. ⋯ Healthy life expectancy increases across countries at a faster rate than total life expectancy, suggesting that reductions in mortality are accompanied by reductions in disability. Although women live longer, they spend a greater amount of time with disability. As average levels of health expenditure per capita increase, healthy life expectancy increases at a greater rate than total life expectancy.
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Letter Comparative Study
World Health Report 2000: inequality index and socioeconomic inequalities in mortality.
Monitoring of inequality in health has become an increasingly important task of development agencies. We compared the inequality index as published in the World Health Report 2000 with available evidence on socioeconomic inequalities in mortality in 15 industrialised and 43 less-developed countries. We found that the World Health Report index does not correspond with international variations in the size of socioeconomic inequalities in mortality. These findings indicate that the index should not be interpreted as a reflection of socioeconomic inequalities in health, nor should the index be used to replace the indices developed to monitor socioeconomic inequalities in health.