American journal of epidemiology
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Comparative Study
The frequency of idiopathic Parkinson's disease by age, ethnic group, and sex in northern Manhattan, 1988-1993.
Sex and ethnic differences in the frequency of Parkinson's disease have become increasingly important, because putative genetic and environmental risk factors have been identified. The authors estimated the prevalence and incidence of Parkinson's disease in a culturally diverse community in New York City over a 4-year period (January 1, 1988-December 31, 1991) using a disease registry substantiated, for older individuals, by a subsequent survey of a random sample of Medicare recipients between January 1, 1992, and December 31, 1993. The prevalence rate was 107 per 100,000 persons, and over a 3-year period the average incidence rate was 13 per 100,000 person-years. ⋯ By ethnic group, the cumulative incidence was higher for blacks than for whites and Hispanics, but more deaths occurred among incident black cases. Discrepant prevalence and incidence rates of Parkinson's disease among blacks and women warrant further investigation. While selective mortality could partially account for this paradox, it is also possible that a delay in diagnosis due to limited access to appropriate health services among these individuals could have resulted in the observed discordant rates of disease.
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Vitamin A deficiency is a major public health problem among preschool-aged children in many developing countries. In Bangladesh, a national nutritional surveillance system was initiated in 1990 to monitor 1) the occurrence of vitamin A deficiency by history of night blindness and 2) the routine coverage of national twice-yearly prophylactic vitamin A capsule (VAC) distribution. This study comprised data collected from June 1990 to August 1994. ⋯ Night blindness was inversely related to the level of routinely attained coverage, and the degree of protection was associated with the time interval between the moment of VAC receipt and the moment of data collection. Although the prevalence of vitamin A deficiency in Bangladesh has been considerably lower in the 1990s than it was in the 1980s, it is still prevalent at all socioeconomic levels. Supplementation with high-dose VACs is an effective strategy for reducing night blindness, but the efficiency of the program will improve when coverage in the rural areas increases.
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The effects of marital status and change in marital status on mortality among middle-aged British men were examined in a prospective cohort study, the British Regional Heart Study. This is a nationally representative cohort of men selected at random from general medical practices in 24 towns in England, Wales, and Scotland. It comprises 7,735 men aged 40-59 recruited in 1978-1980 and followed up for 11.5 years. ⋯ It is unlikely that selection bias, chance, or artifact is responsible for the general relation between marital status and mortality. Variable and incomplete control for confounding by socioeconomic status and risk factors for common diseases may explain some of the inconsistencies observed between studies and between different categories of unmarried men (i.e., never-married, widowed, and divorced). It is possible that the social support offered by marriage exerts a protective effect for some men.