Improving a Case-Control Study of Multiple Sclerosis Using Formative Research.

Formative research (i.e. focus groups and key informant interviews) was conducted to understand risk perceptions and identify barriers to participation in a case-control study of environmental exposures and genetic susceptibility as risk factors for multiple sclerosis (MS). Individuals with MS were recruited to participate in a focus group discussion and individual interviews. Participants were asked to review and comment on study materials and process including participation, interview, genetic testing, confidentiality, and questionnaire. A structured discussion guide was used with all participants to ensure uniformity and coverage of all predetermined topics. Participants reported an increased likelihood of participation if they were informed about the study by their neurologist and not a government agency. All participants expressed willingness to provide a blood sample for genotyping but disagreed about the setting for the blood draw (at home or in a lab). Participants were concerned that they would not receive their individual genotyping results. The study protocol and materials were revised based on comments from the focus group participants. Formative research is an under-utilized resource for researchers conducting epidemiologic studies. Even with limited resources, piloting study materials with individuals similar to the proposed study population can provide opportunities to make modifications to effectively meet the needs of participants and promote participation and retention.

The prevalence of multiple sclerosis in 3 US communities.

INTRODUCTION: We estimated the prevalence of multiple sclerosis (MS) in 3 large geographic areas in the southern, middle, and northern United States. METHODS: The primary data source was medical records from office visits to private neurologists' practices or to neurology departments in tertiary care facilities during a 3-year period. Additional data sources included patient advocacy groups, nursing homes, and general practitioners. RESULTS: Three-year US age-adjusted prevalence estimates for the study areas varied substantially. The prevalence was lowest (47.2 per 100,000 population) in the Texas study area (33 degrees 30' north latitude), intermediate (86.3 per 100,000 population) in the Missouri study area (39 degrees 07' north latitude), and highest (109.5 per 100,000 population) in the Ohio study area (41 degrees 24' north latitude). The geographic differences remained strong after age-adjustment to the world standard population. The inverse association between UV light exposure and MS prevalence estimates was consistent with this observed latitude gradient. In all 3 areas, MS prevalence was highest among women, people aged 40 to 59 years, and non-Hispanics. CONCLUSION: These results provide necessary prevalence estimates for community cluster investigations and establish baseline estimates for future studies to evaluate temporal trends in disease prevalence.

Maternal pesticide exposure and neural tube defects in Mexican Americans.

PURPOSE: The relation between maternal pesticide exposures and neural tube defects (NTDs) in offspring was evaluated in 184 Mexican American case-women and 225 comparison women. METHODS: In-person interviews solicited information about environmental and occupational exposures to pesticides during the periconceptional period. RESULTS: With adjustment for maternal education, smoking, and folate intake, women who reported using pesticides in their homes or yards were two times more likely (95% confidence interval [CI], 1.2-3.1) to have NTD-affected pregnancies than women without these reported exposures. Case-women were also more likely to report living within 0.25 mile of cultivated fields than control-women (odds ratio [OR] 3.6; 95% CI, 1.7-7.6). As sources of pesticide exposure opportunities increased, risk of NTDs also increased. The adjusted ORs and 95% CIs for one, two, and three or more exposure sources were 1.2 (0.69-1.9), 2.3 (1.3-4.1) and 2.8 (1.2-6.3) respectively, and this positive trend was stronger for risk of anencephaly than for spina bifida. CONCLUSIONS: Self-reported pesticide exposures were associated with NTD risk in this study population, especially use of pesticides within the home and a periconceptional residence within 0.25 mile of cultivated fields.

Updated prevalence estimates of multiple sclerosis in Texas, 1998 to 2003.

The Texas Department of State Health Services extended a prevalence study of multiple sclerosis (MS) in a 19-county area in North Texas to include 3 additional years of data and included a new geographic area with a predominantly Hispanic population (El Paso County). Patients in whom MS was diagnosed by a neurologist, who resided in the study areas, and who had an office visit between 1998 and 2003 were included in the study. The 6-year MS prevalence estimate for the North Texas counties was 71.5 per 100,000, and for El Paso County it was 49.4 per 100,000. In both areas, prevalence estimates were higher for females, age groups 40 to 49 and 50 to 59, and for non-Hispanic whites. These estimates provide valuable information about the epidemiology of MS in Texas and allow for a comparison with national estimates. The results also provide much needed prevalence data for the Hispanic population.

Investigation of a cluster of multiple sclerosis in two elementary school cohorts.

The authors investigated a cluster of multiple sclerosis (MS) among people who had attended two elementary schools in El Paso, Texas, from 1948 through 1970. The community was concerned about the possibility of childhood exposure to heavy metals from a large nearby smelter because historical environmental and biological sampling data demonstrated the potential for study cohort members to have been exposed to heavy metals during their pre-adolescent years. One cohort had no reported cases of MS. In the second cohort, 22 members self-reported a diagnosis of MS, and 16 of these cases were confirmed as MS by an independent board-certified neurologist. The crude MS prevalence estimate was 411 per 100,000 (95 percent confidence interval [CI] = 197-603), Prevalence estimates from four different populations were used for calculation of standardized morbidity ratios (SMRs). At the extremes, the study cohort represents a deficit of cases (SMR= 0.9; 95 percent CI = 0.51-1.44) or a four-fold excess (SMR = 4.0; 95 percent Cl = 2.29-6.5).

Prevalence of multiple sclerosis in 19 Texas counties, 1998-2000.

The study reported here determined the prevalence of multiple sclerosis (MS) between January 1, 1998, and December 31, 2000, for a 19-county study area surrounding Lubbock, Texas. The primary data source for case ascertainment was medical records from the offices of neurologists practicing in the study area. The study found that the overall prevalence for the 19-county study area was 42.8 per 100,000 population (95 percent CI = 36.8-49.5). The prevalence estimate for females was 68.6 per 100,000 (95 percent CI = 58.0-80.6), and for males it was 16.6 per 100,000 (95 percent CI = 11.6-23.1). The prevalence estimate for non-Hispanic whites was 56.0 per 100,000 (95 percent CI = 47.1-66.1); the next highest prevalence was among non-Hispanic blacks at 22.1 per 100,000 (95 percent Cl = 8.1-48.1), and Hispanics at 11.2 per 100,000 (95 percent CI = 6.4-18.2). This project generated the first Texas-specific population-based MS prevalence estimates, including prevalence estimates specific to Hispanics and blacks in Texas. The results underscore the need for additional epidemiologic information on the distribution of MS in other areas of Texas and the United States, as well as information on the underlying etiology of the disease.

Including residents in epidemiologic studies of adverse health effects in communities with hazardous exposures.

For individuals who live within the shadows of hazardous waste sites, there is a constant worry about what impact releases from these sites are having on their health and environment. Public health agencies at the local, state, and federal levels are routinely asked to investigate these concerns and determine what, if any, exposures are occurring or may have occurred in the past, and what the health risk to nearby residents may be. To ensure the credibility of research findings, full participation of affected communities is needed. Including communities in research activities can, however, be a difficult process. This paper discusses the concerns, needs, and expectations of U.S. communities in which environmental exposures are occurring, or in which exposures have occurred in the past. Three case studies are presented in which activities were undertaken to involve a community in the research process where environmental contaminants were of concern. The strengths and limitations of these activities are discussed, and recommendations for community involvement in future research are made.

Challenges in addressing community concerns regarding clusters of multiple sclerosis and potential environmental exposures.

Citizens living around hazardous waste sites in the USA have expressed concern to public health officials at the local, state and federal level about a perceived high prevalence of multiple sclerosis (MS) in their communities. Many believe the occurrence of the disease is directly linked to exposure to chemical agents from the nearby hazardous waste site. Although the public's concern regarding these clusters should be addressed, epidemiologists have long known that evaluating perceived clusters is rarely fruitful for identifying an etiologic agent. In order to adequately address concerns regarding clusters of MS, as well as examining the role of environmental exposures and genetic susceptibility in the causal mechanism of disease, several activities need to be conducted including characterizing the occurrence of disease, developing a standardized case definition and establishing partnerships to develop innovative research techniques. Only with collaboration across disciplines and lessons learned from past research will we be able to effectively guide research efforts directed at determining the etiology of this disease.