Amyotrophic lateral sclerosis and Parkinsonism-dementia complex of Guam: Descriptive epidemiology, secular trends, and birth cohort effects on incidence, 1950--1989

This study describes the patterns of occurrence of amyotrophic lateral sclerosis (ALS) and parkinsonism-dementia complex (PDC) of Guam during 1950-1989. Both ALS and PDC occur with high frequency among the indigenous Chamorro population, first recognized in the early 1950's. Reports in the early 1980's indicated that both ALS and PDC were disappearing, due to a purported reduction in exposure to harmful environmental factors as a result of the dramatic changes in lifestyle that took place after World War II. However, this study provides compelling evidence that ALS and PDC have not disappeared on Guam and that rates for both are higher during 1980-1989 than previously reported.^ The patterns of occurrence for both ALS and PDC overlap in most respects: (1) incidence and mortality are decreasing; (2) median age at onset is increasing; (3) males are at increased risk for developing disease; (4) risk is higher for those residing in the south compared to the non-south; and (5) age-specific incidence is decreasing over time except in the oldest age groups.^ Age-specific incidence of ALS and PDC, separately and together, is generally higher for cohorts born before 1920 than for those born after 1920. A significant birth cohort effect on the incidence of PDC for the 1906-1915 birth cohort was found, but not for ALS and for ALS and PDC together. Whether or not a cohort effect, period effect, or both are associated with incidence of ALS and PDC cannot be determined from the data currently available and will require additional follow-up of individuals born after 1920.^ The epidemiological data amassed over this 40-year period provide evidence that supports an environmental exposure model for disease occurrence as opposed to a simple genetic or infectious disease model. Whether neurodegenerative disease in this population occurs as a consequence of a single exposure or is explained by a multifactorial model such as a genetic predisposition with some environmental interaction is yet to be determined. However, descriptive studies such as this can provide clues concerning timing and location of potential adverse exposures but cannot determine etiology, underscoring the urgent need for analytic studies of ALS and PDC to further investigate existing etiologic hypotheses and to test new hypotheses. ^

The construction of aging and health in older African American women

Persistence of racial and ethnic health disparities and governmental policies based on outdated ideas of aging call for inclusive approaches to the study of elder African Americans. The lived experiences of aging among urban, poor African American women, who comprise a vulnerable population, are not well known, as most studies focus on mainstream populations. Gerontological studies have tended to employ methods that collapse contextual information for ease of analysis, thus failing to capture nuanced information critically relevant to health of marginalized groups. Few researchers have been successful highlighting the importance of local knowledge, resilience, and resources for health by using participatory methods with older Black women. This study utilizes participatory principles to gather discursive data from nine older African American women, engaged in three generational cohorts: those born around World War II, women born after the great depression, and those born before the great depression. Videotaped and transcribed conversations of cohorts were analyzed in search of contextual factors that influence their experience of aging and health. As women responded to general themes that provoked their talk about their lives, they helped answer the study's questions: How do older African American women make sense of their aging experience? What are some of the important social and cultural influences that shape the construction of aging and health by these women? Are generational discourse groups an effective tool for exploring changes in the experiences of aging? A key finding demonstrated rich heterogeneity of experiences with strong generational influences on the construction of aging and health. The participants' moral orders comprised of traditional values of family, reinforced by personal experiences and the church, have guided their lives through oppression and stress but appear to be failing younger women who have greater exposure to new environmental pressures. Limited time and the size of the study were weaknesses although the women's interest in the study and their participation were gratifying. The participants served to highlight the importance of recognizing generational and other contextual factors in formation of ideas of aging and likelihood of additional challenges to the experience of old age among older, poorer, African Americans. ^

A literature review of the use of DDT to fight malaria

Background. First synthesized in 1874, dichlorodiphenyltrichloroethane (DDT) was not used until the second half of World War II after its insecticidal properties were discovered in 1939. For decades DDT has been used globally with the intent of eradicating malaria. This began in 1955 when the eighth World Health Assembly launched a global campaign selecting DDT as the chemical of choice for the eradication of malaria. The United States banned DDT use in 1972 partially due to the publication of “Silent Spring” by Rachel Carson in 1962 which suggested that DDT was harmful to the environment, wildlife and is a carcinogen. ^ Objectives. To critically review the literature on DDT, and evaluate its importance in malaria prevention and control. Methods: The design of this systematic literature review is a narrative summary and evaluation of the papers reviewed. The data came from searches using PubMed and MEDLINE which are free and publicly available databases. Inclusive criteria that were considered during the search are English language peer reviewed journal articles published in the last 20 years. The keywords were: “insecticidal and agricultural use of DDT”, “human impact of malaria”, “economic impact of malaria”, “benefits of DDT”, “effects of DDT”, “importance of malaria control”, and alternatives to DDT for malaria control. ^ Results. Malaria continues to be one of the most common infectious diseases and creates a tremendous global public health problem. WHO recommends DDT for malaria vector control because compared to other pesticides, it is the most persistent in indoor spraying. ^ Conclusion. Indoor spraying of DDT in malaria endemic areas may cause increased exposure of the chemical to humans; however I conclude that the overall benefits outweigh the risks because more lives are saved due to fewer infections with malaria.^